1 /* i2c-core.c - a device driver for the iic-bus interface */
2 /* ------------------------------------------------------------------------- */
3 /* Copyright (C) 1995-99 Simon G. Vogl
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details. */
14 /* ------------------------------------------------------------------------- */
16 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
17 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
18 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
19 Jean Delvare <jdelvare@suse.de>
20 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
21 Michael Lawnick <michael.lawnick.ext@nsn.com>
22 OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
23 (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
24 (c) 2013 Wolfram Sang <wsa@the-dreams.de>
25 I2C ACPI code Copyright (C) 2014 Intel Corp
26 Author: Lan Tianyu <tianyu.lan@intel.com>
27 I2C slave support (c) 2014 by Wolfram Sang <wsa@sang-engineering.com>
30 #define pr_fmt(fmt) "i2c-core: " fmt
32 #include <dt-bindings/i2c/i2c.h>
33 #include <asm/uaccess.h>
34 #include <linux/acpi.h>
35 #include <linux/clk/clk-conf.h>
36 #include <linux/completion.h>
37 #include <linux/delay.h>
38 #include <linux/err.h>
39 #include <linux/errno.h>
40 #include <linux/gpio.h>
41 #include <linux/hardirq.h>
42 #include <linux/i2c.h>
43 #include <linux/idr.h>
44 #include <linux/init.h>
45 #include <linux/irqflags.h>
46 #include <linux/jump_label.h>
47 #include <linux/kernel.h>
48 #include <linux/module.h>
49 #include <linux/mutex.h>
50 #include <linux/of_device.h>
52 #include <linux/of_irq.h>
53 #include <linux/pm_domain.h>
54 #include <linux/pm_runtime.h>
55 #include <linux/pm_wakeirq.h>
56 #include <linux/property.h>
57 #include <linux/rwsem.h>
58 #include <linux/slab.h>
62 #define CREATE_TRACE_POINTS
63 #include <trace/events/i2c.h>
65 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
66 #define I2C_ADDR_OFFSET_SLAVE 0x1000
68 /* core_lock protects i2c_adapter_idr, and guarantees
69 that device detection, deletion of detected devices, and attach_adapter
70 calls are serialized */
71 static DEFINE_MUTEX(core_lock);
72 static DEFINE_IDR(i2c_adapter_idr);
74 static struct device_type i2c_client_type;
75 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
77 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
78 static bool is_registered;
80 void i2c_transfer_trace_reg(void)
82 static_key_slow_inc(&i2c_trace_msg);
85 void i2c_transfer_trace_unreg(void)
87 static_key_slow_dec(&i2c_trace_msg);
90 #if defined(CONFIG_ACPI)
91 struct i2c_acpi_handler_data {
92 struct acpi_connection_info info;
93 struct i2c_adapter *adapter;
106 struct i2c_acpi_lookup {
107 struct i2c_board_info *info;
108 acpi_handle adapter_handle;
109 acpi_handle device_handle;
110 acpi_handle search_handle;
115 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
117 struct i2c_acpi_lookup *lookup = data;
118 struct i2c_board_info *info = lookup->info;
119 struct acpi_resource_i2c_serialbus *sb;
122 if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
125 sb = &ares->data.i2c_serial_bus;
126 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
129 status = acpi_get_handle(lookup->device_handle,
130 sb->resource_source.string_ptr,
131 &lookup->adapter_handle);
132 if (!ACPI_SUCCESS(status))
135 info->addr = sb->slave_address;
136 lookup->speed = sb->connection_speed;
137 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
138 info->flags |= I2C_CLIENT_TEN;
143 static int i2c_acpi_do_lookup(struct acpi_device *adev,
144 struct i2c_acpi_lookup *lookup)
146 struct i2c_board_info *info = lookup->info;
147 struct list_head resource_list;
150 if (acpi_bus_get_status(adev) || !adev->status.present ||
151 acpi_device_enumerated(adev))
154 memset(info, 0, sizeof(*info));
155 lookup->device_handle = acpi_device_handle(adev);
157 /* Look up for I2cSerialBus resource */
158 INIT_LIST_HEAD(&resource_list);
159 ret = acpi_dev_get_resources(adev, &resource_list,
160 i2c_acpi_fill_info, lookup);
161 acpi_dev_free_resource_list(&resource_list);
163 if (ret < 0 || !info->addr)
169 static int i2c_acpi_get_info(struct acpi_device *adev,
170 struct i2c_board_info *info,
171 struct i2c_adapter *adapter,
172 acpi_handle *adapter_handle)
174 struct list_head resource_list;
175 struct resource_entry *entry;
176 struct i2c_acpi_lookup lookup;
179 memset(&lookup, 0, sizeof(lookup));
182 ret = i2c_acpi_do_lookup(adev, &lookup);
187 /* The adapter must match the one in I2cSerialBus() connector */
188 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
191 struct acpi_device *adapter_adev;
193 /* The adapter must be present */
194 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
196 if (acpi_bus_get_status(adapter_adev) ||
197 !adapter_adev->status.present)
201 info->fwnode = acpi_fwnode_handle(adev);
203 *adapter_handle = lookup.adapter_handle;
205 /* Then fill IRQ number if any */
206 INIT_LIST_HEAD(&resource_list);
207 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
211 resource_list_for_each_entry(entry, &resource_list) {
212 if (resource_type(entry->res) == IORESOURCE_IRQ) {
213 info->irq = entry->res->start;
218 acpi_dev_free_resource_list(&resource_list);
220 strlcpy(info->type, dev_name(&adev->dev), sizeof(info->type));
225 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
226 struct acpi_device *adev,
227 struct i2c_board_info *info)
229 adev->power.flags.ignore_parent = true;
230 acpi_device_set_enumerated(adev);
232 if (!i2c_new_device(adapter, info)) {
233 adev->power.flags.ignore_parent = false;
234 dev_err(&adapter->dev,
235 "failed to add I2C device %s from ACPI\n",
236 dev_name(&adev->dev));
240 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
241 void *data, void **return_value)
243 struct i2c_adapter *adapter = data;
244 struct acpi_device *adev;
245 struct i2c_board_info info;
247 if (acpi_bus_get_device(handle, &adev))
250 if (i2c_acpi_get_info(adev, &info, adapter, NULL))
253 i2c_acpi_register_device(adapter, adev, &info);
258 #define I2C_ACPI_MAX_SCAN_DEPTH 32
261 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
262 * @adap: pointer to adapter
264 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
265 * namespace. When a device is found it will be added to the Linux device
266 * model and bound to the corresponding ACPI handle.
268 static void i2c_acpi_register_devices(struct i2c_adapter *adap)
272 if (!has_acpi_companion(&adap->dev))
275 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
276 I2C_ACPI_MAX_SCAN_DEPTH,
277 i2c_acpi_add_device, NULL,
279 if (ACPI_FAILURE(status))
280 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
283 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
284 void *data, void **return_value)
286 struct i2c_acpi_lookup *lookup = data;
287 struct acpi_device *adev;
289 if (acpi_bus_get_device(handle, &adev))
292 if (i2c_acpi_do_lookup(adev, lookup))
295 if (lookup->search_handle != lookup->adapter_handle)
298 if (lookup->speed <= lookup->min_speed)
299 lookup->min_speed = lookup->speed;
305 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
306 * @dev: The device owning the bus
308 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
309 * devices connected to this bus and use the speed of slowest device.
311 * Returns the speed in Hz or zero
313 u32 i2c_acpi_find_bus_speed(struct device *dev)
315 struct i2c_acpi_lookup lookup;
316 struct i2c_board_info dummy;
319 if (!has_acpi_companion(dev))
322 memset(&lookup, 0, sizeof(lookup));
323 lookup.search_handle = ACPI_HANDLE(dev);
324 lookup.min_speed = UINT_MAX;
325 lookup.info = &dummy;
327 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
328 I2C_ACPI_MAX_SCAN_DEPTH,
329 i2c_acpi_lookup_speed, NULL,
332 if (ACPI_FAILURE(status)) {
333 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
337 return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
339 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
341 static int i2c_acpi_match_adapter(struct device *dev, void *data)
343 struct i2c_adapter *adapter = i2c_verify_adapter(dev);
348 return ACPI_HANDLE(dev) == (acpi_handle)data;
351 static int i2c_acpi_match_device(struct device *dev, void *data)
353 return ACPI_COMPANION(dev) == data;
356 static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
360 dev = bus_find_device(&i2c_bus_type, NULL, handle,
361 i2c_acpi_match_adapter);
362 return dev ? i2c_verify_adapter(dev) : NULL;
365 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
369 dev = bus_find_device(&i2c_bus_type, NULL, adev, i2c_acpi_match_device);
370 return dev ? i2c_verify_client(dev) : NULL;
373 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
376 struct acpi_device *adev = arg;
377 struct i2c_board_info info;
378 acpi_handle adapter_handle;
379 struct i2c_adapter *adapter;
380 struct i2c_client *client;
383 case ACPI_RECONFIG_DEVICE_ADD:
384 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
387 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
391 i2c_acpi_register_device(adapter, adev, &info);
393 case ACPI_RECONFIG_DEVICE_REMOVE:
394 if (!acpi_device_enumerated(adev))
397 client = i2c_acpi_find_client_by_adev(adev);
401 i2c_unregister_device(client);
402 put_device(&client->dev);
409 static struct notifier_block i2c_acpi_notifier = {
410 .notifier_call = i2c_acpi_notify,
412 #else /* CONFIG_ACPI */
413 static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
414 extern struct notifier_block i2c_acpi_notifier;
415 #endif /* CONFIG_ACPI */
417 #ifdef CONFIG_ACPI_I2C_OPREGION
418 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
419 u8 cmd, u8 *data, u8 data_len)
422 struct i2c_msg msgs[2];
426 buffer = kzalloc(data_len, GFP_KERNEL);
430 msgs[0].addr = client->addr;
431 msgs[0].flags = client->flags;
435 msgs[1].addr = client->addr;
436 msgs[1].flags = client->flags | I2C_M_RD;
437 msgs[1].len = data_len;
438 msgs[1].buf = buffer;
440 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
442 dev_err(&client->adapter->dev, "i2c read failed\n");
444 memcpy(data, buffer, data_len);
450 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
451 u8 cmd, u8 *data, u8 data_len)
454 struct i2c_msg msgs[1];
458 buffer = kzalloc(data_len + 1, GFP_KERNEL);
463 memcpy(buffer + 1, data, data_len);
465 msgs[0].addr = client->addr;
466 msgs[0].flags = client->flags;
467 msgs[0].len = data_len + 1;
468 msgs[0].buf = buffer;
470 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
472 dev_err(&client->adapter->dev, "i2c write failed\n");
479 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
480 u32 bits, u64 *value64,
481 void *handler_context, void *region_context)
483 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
484 struct i2c_acpi_handler_data *data = handler_context;
485 struct acpi_connection_info *info = &data->info;
486 struct acpi_resource_i2c_serialbus *sb;
487 struct i2c_adapter *adapter = data->adapter;
488 struct i2c_client *client;
489 struct acpi_resource *ares;
490 u32 accessor_type = function >> 16;
491 u8 action = function & ACPI_IO_MASK;
495 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
496 if (ACPI_FAILURE(ret))
499 client = kzalloc(sizeof(*client), GFP_KERNEL);
505 if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
506 ret = AE_BAD_PARAMETER;
510 sb = &ares->data.i2c_serial_bus;
511 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
512 ret = AE_BAD_PARAMETER;
516 client->adapter = adapter;
517 client->addr = sb->slave_address;
519 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
520 client->flags |= I2C_CLIENT_TEN;
522 switch (accessor_type) {
523 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
524 if (action == ACPI_READ) {
525 status = i2c_smbus_read_byte(client);
531 status = i2c_smbus_write_byte(client, gsb->bdata);
535 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
536 if (action == ACPI_READ) {
537 status = i2c_smbus_read_byte_data(client, command);
543 status = i2c_smbus_write_byte_data(client, command,
548 case ACPI_GSB_ACCESS_ATTRIB_WORD:
549 if (action == ACPI_READ) {
550 status = i2c_smbus_read_word_data(client, command);
556 status = i2c_smbus_write_word_data(client, command,
561 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
562 if (action == ACPI_READ) {
563 status = i2c_smbus_read_block_data(client, command,
570 status = i2c_smbus_write_block_data(client, command,
571 gsb->len, gsb->data);
575 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
576 if (action == ACPI_READ) {
577 status = acpi_gsb_i2c_read_bytes(client, command,
578 gsb->data, info->access_length);
582 status = acpi_gsb_i2c_write_bytes(client, command,
583 gsb->data, info->access_length);
588 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
589 accessor_type, client->addr);
590 ret = AE_BAD_PARAMETER;
594 gsb->status = status;
603 static int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
606 struct i2c_acpi_handler_data *data;
609 if (!adapter->dev.parent)
612 handle = ACPI_HANDLE(adapter->dev.parent);
617 data = kzalloc(sizeof(struct i2c_acpi_handler_data),
622 data->adapter = adapter;
623 status = acpi_bus_attach_private_data(handle, (void *)data);
624 if (ACPI_FAILURE(status)) {
629 status = acpi_install_address_space_handler(handle,
630 ACPI_ADR_SPACE_GSBUS,
631 &i2c_acpi_space_handler,
634 if (ACPI_FAILURE(status)) {
635 dev_err(&adapter->dev, "Error installing i2c space handler\n");
636 acpi_bus_detach_private_data(handle);
641 acpi_walk_dep_device_list(handle);
645 static void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
648 struct i2c_acpi_handler_data *data;
651 if (!adapter->dev.parent)
654 handle = ACPI_HANDLE(adapter->dev.parent);
659 acpi_remove_address_space_handler(handle,
660 ACPI_ADR_SPACE_GSBUS,
661 &i2c_acpi_space_handler);
663 status = acpi_bus_get_private_data(handle, (void **)&data);
664 if (ACPI_SUCCESS(status))
667 acpi_bus_detach_private_data(handle);
669 #else /* CONFIG_ACPI_I2C_OPREGION */
670 static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
673 static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
675 #endif /* CONFIG_ACPI_I2C_OPREGION */
677 /* ------------------------------------------------------------------------- */
679 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
680 const struct i2c_client *client)
682 while (id->name[0]) {
683 if (strcmp(client->name, id->name) == 0)
690 static int i2c_device_match(struct device *dev, struct device_driver *drv)
692 struct i2c_client *client = i2c_verify_client(dev);
693 struct i2c_driver *driver;
698 /* Attempt an OF style match */
699 if (of_driver_match_device(dev, drv))
702 /* Then ACPI style match */
703 if (acpi_driver_match_device(dev, drv))
706 driver = to_i2c_driver(drv);
707 /* match on an id table if there is one */
708 if (driver->id_table)
709 return i2c_match_id(driver->id_table, client) != NULL;
714 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
716 struct i2c_client *client = to_i2c_client(dev);
719 rc = acpi_device_uevent_modalias(dev, env);
723 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
726 /* i2c bus recovery routines */
727 static int get_scl_gpio_value(struct i2c_adapter *adap)
729 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
732 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
734 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
737 static int get_sda_gpio_value(struct i2c_adapter *adap)
739 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
742 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
744 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
745 struct device *dev = &adap->dev;
748 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
749 GPIOF_OUT_INIT_HIGH, "i2c-scl");
751 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
756 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
757 /* work without SDA polling */
758 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
767 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
769 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
772 gpio_free(bri->sda_gpio);
774 gpio_free(bri->scl_gpio);
778 * We are generating clock pulses. ndelay() determines durating of clk pulses.
779 * We will generate clock with rate 100 KHz and so duration of both clock levels
780 * is: delay in ns = (10^6 / 100) / 2
782 #define RECOVERY_NDELAY 5000
783 #define RECOVERY_CLK_CNT 9
785 static int i2c_generic_recovery(struct i2c_adapter *adap)
787 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
788 int i = 0, val = 1, ret = 0;
790 if (bri->prepare_recovery)
791 bri->prepare_recovery(adap);
793 bri->set_scl(adap, val);
794 ndelay(RECOVERY_NDELAY);
797 * By this time SCL is high, as we need to give 9 falling-rising edges
799 while (i++ < RECOVERY_CLK_CNT * 2) {
801 /* Break if SDA is high */
802 if (bri->get_sda && bri->get_sda(adap))
804 /* SCL shouldn't be low here */
805 if (!bri->get_scl(adap)) {
807 "SCL is stuck low, exit recovery\n");
814 bri->set_scl(adap, val);
815 ndelay(RECOVERY_NDELAY);
818 if (bri->unprepare_recovery)
819 bri->unprepare_recovery(adap);
824 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
826 return i2c_generic_recovery(adap);
828 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
830 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
834 ret = i2c_get_gpios_for_recovery(adap);
838 ret = i2c_generic_recovery(adap);
839 i2c_put_gpios_for_recovery(adap);
843 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
845 int i2c_recover_bus(struct i2c_adapter *adap)
847 if (!adap->bus_recovery_info)
850 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
851 return adap->bus_recovery_info->recover_bus(adap);
853 EXPORT_SYMBOL_GPL(i2c_recover_bus);
855 static void i2c_init_recovery(struct i2c_adapter *adap)
857 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
863 if (!bri->recover_bus) {
864 err_str = "no recover_bus() found";
868 /* Generic GPIO recovery */
869 if (bri->recover_bus == i2c_generic_gpio_recovery) {
870 if (!gpio_is_valid(bri->scl_gpio)) {
871 err_str = "invalid SCL gpio";
875 if (gpio_is_valid(bri->sda_gpio))
876 bri->get_sda = get_sda_gpio_value;
880 bri->get_scl = get_scl_gpio_value;
881 bri->set_scl = set_scl_gpio_value;
882 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
883 /* Generic SCL recovery */
884 if (!bri->set_scl || !bri->get_scl) {
885 err_str = "no {get|set}_scl() found";
892 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
893 adap->bus_recovery_info = NULL;
896 static int i2c_device_probe(struct device *dev)
898 struct i2c_client *client = i2c_verify_client(dev);
899 struct i2c_driver *driver;
909 irq = of_irq_get_byname(dev->of_node, "irq");
910 if (irq == -EINVAL || irq == -ENODATA)
911 irq = of_irq_get(dev->of_node, 0);
912 } else if (ACPI_COMPANION(dev)) {
913 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
915 if (irq == -EPROBE_DEFER)
923 driver = to_i2c_driver(dev->driver);
924 if (!driver->probe || !driver->id_table)
927 if (client->flags & I2C_CLIENT_WAKE) {
928 int wakeirq = -ENOENT;
931 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
932 if (wakeirq == -EPROBE_DEFER)
936 device_init_wakeup(&client->dev, true);
938 if (wakeirq > 0 && wakeirq != client->irq)
939 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
940 else if (client->irq > 0)
941 status = dev_pm_set_wake_irq(dev, client->irq);
946 dev_warn(&client->dev, "failed to set up wakeup irq\n");
949 dev_dbg(dev, "probe\n");
951 status = of_clk_set_defaults(dev->of_node, false);
953 goto err_clear_wakeup_irq;
955 status = dev_pm_domain_attach(&client->dev, true);
956 if (status == -EPROBE_DEFER)
957 goto err_clear_wakeup_irq;
959 status = driver->probe(client, i2c_match_id(driver->id_table, client));
961 goto err_detach_pm_domain;
965 err_detach_pm_domain:
966 dev_pm_domain_detach(&client->dev, true);
967 err_clear_wakeup_irq:
968 dev_pm_clear_wake_irq(&client->dev);
969 device_init_wakeup(&client->dev, false);
973 static int i2c_device_remove(struct device *dev)
975 struct i2c_client *client = i2c_verify_client(dev);
976 struct i2c_driver *driver;
979 if (!client || !dev->driver)
982 driver = to_i2c_driver(dev->driver);
983 if (driver->remove) {
984 dev_dbg(dev, "remove\n");
985 status = driver->remove(client);
988 dev_pm_domain_detach(&client->dev, true);
990 dev_pm_clear_wake_irq(&client->dev);
991 device_init_wakeup(&client->dev, false);
996 static void i2c_device_shutdown(struct device *dev)
998 struct i2c_client *client = i2c_verify_client(dev);
999 struct i2c_driver *driver;
1001 if (!client || !dev->driver)
1003 driver = to_i2c_driver(dev->driver);
1004 if (driver->shutdown)
1005 driver->shutdown(client);
1008 static void i2c_client_dev_release(struct device *dev)
1010 kfree(to_i2c_client(dev));
1014 show_name(struct device *dev, struct device_attribute *attr, char *buf)
1016 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
1017 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
1019 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
1022 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
1024 struct i2c_client *client = to_i2c_client(dev);
1027 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
1031 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
1033 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
1035 static struct attribute *i2c_dev_attrs[] = {
1036 &dev_attr_name.attr,
1037 /* modalias helps coldplug: modprobe $(cat .../modalias) */
1038 &dev_attr_modalias.attr,
1041 ATTRIBUTE_GROUPS(i2c_dev);
1043 struct bus_type i2c_bus_type = {
1045 .match = i2c_device_match,
1046 .probe = i2c_device_probe,
1047 .remove = i2c_device_remove,
1048 .shutdown = i2c_device_shutdown,
1050 EXPORT_SYMBOL_GPL(i2c_bus_type);
1052 static struct device_type i2c_client_type = {
1053 .groups = i2c_dev_groups,
1054 .uevent = i2c_device_uevent,
1055 .release = i2c_client_dev_release,
1060 * i2c_verify_client - return parameter as i2c_client, or NULL
1061 * @dev: device, probably from some driver model iterator
1063 * When traversing the driver model tree, perhaps using driver model
1064 * iterators like @device_for_each_child(), you can't assume very much
1065 * about the nodes you find. Use this function to avoid oopses caused
1066 * by wrongly treating some non-I2C device as an i2c_client.
1068 struct i2c_client *i2c_verify_client(struct device *dev)
1070 return (dev->type == &i2c_client_type)
1071 ? to_i2c_client(dev)
1074 EXPORT_SYMBOL(i2c_verify_client);
1077 /* Return a unique address which takes the flags of the client into account */
1078 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
1080 unsigned short addr = client->addr;
1082 /* For some client flags, add an arbitrary offset to avoid collisions */
1083 if (client->flags & I2C_CLIENT_TEN)
1084 addr |= I2C_ADDR_OFFSET_TEN_BIT;
1086 if (client->flags & I2C_CLIENT_SLAVE)
1087 addr |= I2C_ADDR_OFFSET_SLAVE;
1092 /* This is a permissive address validity check, I2C address map constraints
1093 * are purposely not enforced, except for the general call address. */
1094 static int i2c_check_addr_validity(unsigned addr, unsigned short flags)
1096 if (flags & I2C_CLIENT_TEN) {
1097 /* 10-bit address, all values are valid */
1101 /* 7-bit address, reject the general call address */
1102 if (addr == 0x00 || addr > 0x7f)
1108 /* And this is a strict address validity check, used when probing. If a
1109 * device uses a reserved address, then it shouldn't be probed. 7-bit
1110 * addressing is assumed, 10-bit address devices are rare and should be
1111 * explicitly enumerated. */
1112 static int i2c_check_7bit_addr_validity_strict(unsigned short addr)
1115 * Reserved addresses per I2C specification:
1116 * 0x00 General call address / START byte
1118 * 0x02 Reserved for different bus format
1119 * 0x03 Reserved for future purposes
1120 * 0x04-0x07 Hs-mode master code
1121 * 0x78-0x7b 10-bit slave addressing
1122 * 0x7c-0x7f Reserved for future purposes
1124 if (addr < 0x08 || addr > 0x77)
1129 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
1131 struct i2c_client *client = i2c_verify_client(dev);
1132 int addr = *(int *)addrp;
1134 if (client && i2c_encode_flags_to_addr(client) == addr)
1139 /* walk up mux tree */
1140 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
1142 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
1145 result = device_for_each_child(&adapter->dev, &addr,
1146 __i2c_check_addr_busy);
1148 if (!result && parent)
1149 result = i2c_check_mux_parents(parent, addr);
1154 /* recurse down mux tree */
1155 static int i2c_check_mux_children(struct device *dev, void *addrp)
1159 if (dev->type == &i2c_adapter_type)
1160 result = device_for_each_child(dev, addrp,
1161 i2c_check_mux_children);
1163 result = __i2c_check_addr_busy(dev, addrp);
1168 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
1170 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
1174 result = i2c_check_mux_parents(parent, addr);
1177 result = device_for_each_child(&adapter->dev, &addr,
1178 i2c_check_mux_children);
1184 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
1185 * @adapter: Target I2C bus segment
1186 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
1187 * locks only this branch in the adapter tree
1189 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
1192 rt_mutex_lock(&adapter->bus_lock);
1196 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
1197 * @adapter: Target I2C bus segment
1198 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
1199 * trylocks only this branch in the adapter tree
1201 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
1204 return rt_mutex_trylock(&adapter->bus_lock);
1208 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
1209 * @adapter: Target I2C bus segment
1210 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
1211 * unlocks only this branch in the adapter tree
1213 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
1216 rt_mutex_unlock(&adapter->bus_lock);
1219 static void i2c_dev_set_name(struct i2c_adapter *adap,
1220 struct i2c_client *client)
1222 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
1225 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
1229 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
1230 i2c_encode_flags_to_addr(client));
1234 * i2c_new_device - instantiate an i2c device
1235 * @adap: the adapter managing the device
1236 * @info: describes one I2C device; bus_num is ignored
1237 * Context: can sleep
1239 * Create an i2c device. Binding is handled through driver model
1240 * probe()/remove() methods. A driver may be bound to this device when we
1241 * return from this function, or any later moment (e.g. maybe hotplugging will
1242 * load the driver module). This call is not appropriate for use by mainboard
1243 * initialization logic, which usually runs during an arch_initcall() long
1244 * before any i2c_adapter could exist.
1246 * This returns the new i2c client, which may be saved for later use with
1247 * i2c_unregister_device(); or NULL to indicate an error.
1250 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
1252 struct i2c_client *client;
1255 client = kzalloc(sizeof *client, GFP_KERNEL);
1259 client->adapter = adap;
1261 client->dev.platform_data = info->platform_data;
1264 client->dev.archdata = *info->archdata;
1266 client->flags = info->flags;
1267 client->addr = info->addr;
1268 client->irq = info->irq;
1270 strlcpy(client->name, info->type, sizeof(client->name));
1272 status = i2c_check_addr_validity(client->addr, client->flags);
1274 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
1275 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
1276 goto out_err_silent;
1279 /* Check for address business */
1280 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
1284 client->dev.parent = &client->adapter->dev;
1285 client->dev.bus = &i2c_bus_type;
1286 client->dev.type = &i2c_client_type;
1287 client->dev.of_node = info->of_node;
1288 client->dev.fwnode = info->fwnode;
1290 i2c_dev_set_name(adap, client);
1291 status = device_register(&client->dev);
1295 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
1296 client->name, dev_name(&client->dev));
1302 "Failed to register i2c client %s at 0x%02x (%d)\n",
1303 client->name, client->addr, status);
1308 EXPORT_SYMBOL_GPL(i2c_new_device);
1312 * i2c_unregister_device - reverse effect of i2c_new_device()
1313 * @client: value returned from i2c_new_device()
1314 * Context: can sleep
1316 void i2c_unregister_device(struct i2c_client *client)
1318 if (client->dev.of_node)
1319 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1320 if (ACPI_COMPANION(&client->dev))
1321 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1322 device_unregister(&client->dev);
1324 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1327 static const struct i2c_device_id dummy_id[] = {
1332 static int dummy_probe(struct i2c_client *client,
1333 const struct i2c_device_id *id)
1338 static int dummy_remove(struct i2c_client *client)
1343 static struct i2c_driver dummy_driver = {
1344 .driver.name = "dummy",
1345 .probe = dummy_probe,
1346 .remove = dummy_remove,
1347 .id_table = dummy_id,
1351 * i2c_new_dummy - return a new i2c device bound to a dummy driver
1352 * @adapter: the adapter managing the device
1353 * @address: seven bit address to be used
1354 * Context: can sleep
1356 * This returns an I2C client bound to the "dummy" driver, intended for use
1357 * with devices that consume multiple addresses. Examples of such chips
1358 * include various EEPROMS (like 24c04 and 24c08 models).
1360 * These dummy devices have two main uses. First, most I2C and SMBus calls
1361 * except i2c_transfer() need a client handle; the dummy will be that handle.
1362 * And second, this prevents the specified address from being bound to a
1365 * This returns the new i2c client, which should be saved for later use with
1366 * i2c_unregister_device(); or NULL to indicate an error.
1368 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
1370 struct i2c_board_info info = {
1371 I2C_BOARD_INFO("dummy", address),
1374 return i2c_new_device(adapter, &info);
1376 EXPORT_SYMBOL_GPL(i2c_new_dummy);
1379 * i2c_new_secondary_device - Helper to get the instantiated secondary address
1380 * and create the associated device
1381 * @client: Handle to the primary client
1382 * @name: Handle to specify which secondary address to get
1383 * @default_addr: Used as a fallback if no secondary address was specified
1384 * Context: can sleep
1386 * I2C clients can be composed of multiple I2C slaves bound together in a single
1387 * component. The I2C client driver then binds to the master I2C slave and needs
1388 * to create I2C dummy clients to communicate with all the other slaves.
1390 * This function creates and returns an I2C dummy client whose I2C address is
1391 * retrieved from the platform firmware based on the given slave name. If no
1392 * address is specified by the firmware default_addr is used.
1394 * On DT-based platforms the address is retrieved from the "reg" property entry
1395 * cell whose "reg-names" value matches the slave name.
1397 * This returns the new i2c client, which should be saved for later use with
1398 * i2c_unregister_device(); or NULL to indicate an error.
1400 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
1404 struct device_node *np = client->dev.of_node;
1405 u32 addr = default_addr;
1409 i = of_property_match_string(np, "reg-names", name);
1411 of_property_read_u32_index(np, "reg", i, &addr);
1414 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1415 return i2c_new_dummy(client->adapter, addr);
1417 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
1419 /* ------------------------------------------------------------------------- */
1421 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1423 static void i2c_adapter_dev_release(struct device *dev)
1425 struct i2c_adapter *adap = to_i2c_adapter(dev);
1426 complete(&adap->dev_released);
1430 * This function is only needed for mutex_lock_nested, so it is never
1431 * called unless locking correctness checking is enabled. Thus we
1432 * make it inline to avoid a compiler warning. That's what gcc ends up
1435 static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1437 unsigned int depth = 0;
1439 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1446 * Let users instantiate I2C devices through sysfs. This can be used when
1447 * platform initialization code doesn't contain the proper data for
1448 * whatever reason. Also useful for drivers that do device detection and
1449 * detection fails, either because the device uses an unexpected address,
1450 * or this is a compatible device with different ID register values.
1452 * Parameter checking may look overzealous, but we really don't want
1453 * the user to provide incorrect parameters.
1456 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
1457 const char *buf, size_t count)
1459 struct i2c_adapter *adap = to_i2c_adapter(dev);
1460 struct i2c_board_info info;
1461 struct i2c_client *client;
1465 memset(&info, 0, sizeof(struct i2c_board_info));
1467 blank = strchr(buf, ' ');
1469 dev_err(dev, "%s: Missing parameters\n", "new_device");
1472 if (blank - buf > I2C_NAME_SIZE - 1) {
1473 dev_err(dev, "%s: Invalid device name\n", "new_device");
1476 memcpy(info.type, buf, blank - buf);
1478 /* Parse remaining parameters, reject extra parameters */
1479 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1481 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1484 if (res > 1 && end != '\n') {
1485 dev_err(dev, "%s: Extra parameters\n", "new_device");
1489 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1490 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1491 info.flags |= I2C_CLIENT_TEN;
1494 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1495 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1496 info.flags |= I2C_CLIENT_SLAVE;
1499 client = i2c_new_device(adap, &info);
1503 /* Keep track of the added device */
1504 mutex_lock(&adap->userspace_clients_lock);
1505 list_add_tail(&client->detected, &adap->userspace_clients);
1506 mutex_unlock(&adap->userspace_clients_lock);
1507 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1508 info.type, info.addr);
1512 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1515 * And of course let the users delete the devices they instantiated, if
1516 * they got it wrong. This interface can only be used to delete devices
1517 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1518 * don't delete devices to which some kernel code still has references.
1520 * Parameter checking may look overzealous, but we really don't want
1521 * the user to delete the wrong device.
1524 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1525 const char *buf, size_t count)
1527 struct i2c_adapter *adap = to_i2c_adapter(dev);
1528 struct i2c_client *client, *next;
1529 unsigned short addr;
1533 /* Parse parameters, reject extra parameters */
1534 res = sscanf(buf, "%hi%c", &addr, &end);
1536 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1539 if (res > 1 && end != '\n') {
1540 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1544 /* Make sure the device was added through sysfs */
1546 mutex_lock_nested(&adap->userspace_clients_lock,
1547 i2c_adapter_depth(adap));
1548 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1550 if (i2c_encode_flags_to_addr(client) == addr) {
1551 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1552 "delete_device", client->name, client->addr);
1554 list_del(&client->detected);
1555 i2c_unregister_device(client);
1560 mutex_unlock(&adap->userspace_clients_lock);
1563 dev_err(dev, "%s: Can't find device in list\n",
1567 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1568 i2c_sysfs_delete_device);
1570 static struct attribute *i2c_adapter_attrs[] = {
1571 &dev_attr_name.attr,
1572 &dev_attr_new_device.attr,
1573 &dev_attr_delete_device.attr,
1576 ATTRIBUTE_GROUPS(i2c_adapter);
1578 struct device_type i2c_adapter_type = {
1579 .groups = i2c_adapter_groups,
1580 .release = i2c_adapter_dev_release,
1582 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1585 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1586 * @dev: device, probably from some driver model iterator
1588 * When traversing the driver model tree, perhaps using driver model
1589 * iterators like @device_for_each_child(), you can't assume very much
1590 * about the nodes you find. Use this function to avoid oopses caused
1591 * by wrongly treating some non-I2C device as an i2c_adapter.
1593 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1595 return (dev->type == &i2c_adapter_type)
1596 ? to_i2c_adapter(dev)
1599 EXPORT_SYMBOL(i2c_verify_adapter);
1601 #ifdef CONFIG_I2C_COMPAT
1602 static struct class_compat *i2c_adapter_compat_class;
1605 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1607 struct i2c_devinfo *devinfo;
1609 down_read(&__i2c_board_lock);
1610 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1611 if (devinfo->busnum == adapter->nr
1612 && !i2c_new_device(adapter,
1613 &devinfo->board_info))
1614 dev_err(&adapter->dev,
1615 "Can't create device at 0x%02x\n",
1616 devinfo->board_info.addr);
1618 up_read(&__i2c_board_lock);
1621 /* OF support code */
1623 #if IS_ENABLED(CONFIG_OF)
1624 static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
1625 struct device_node *node)
1627 struct i2c_client *result;
1628 struct i2c_board_info info = {};
1629 struct dev_archdata dev_ad = {};
1630 const __be32 *addr_be;
1634 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1636 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
1637 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
1639 return ERR_PTR(-EINVAL);
1642 addr_be = of_get_property(node, "reg", &len);
1643 if (!addr_be || (len < sizeof(*addr_be))) {
1644 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
1646 return ERR_PTR(-EINVAL);
1649 addr = be32_to_cpup(addr_be);
1650 if (addr & I2C_TEN_BIT_ADDRESS) {
1651 addr &= ~I2C_TEN_BIT_ADDRESS;
1652 info.flags |= I2C_CLIENT_TEN;
1655 if (addr & I2C_OWN_SLAVE_ADDRESS) {
1656 addr &= ~I2C_OWN_SLAVE_ADDRESS;
1657 info.flags |= I2C_CLIENT_SLAVE;
1660 if (i2c_check_addr_validity(addr, info.flags)) {
1661 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1662 info.addr, node->full_name);
1663 return ERR_PTR(-EINVAL);
1667 info.of_node = of_node_get(node);
1668 info.archdata = &dev_ad;
1670 if (of_get_property(node, "wakeup-source", NULL))
1671 info.flags |= I2C_CLIENT_WAKE;
1673 result = i2c_new_device(adap, &info);
1674 if (result == NULL) {
1675 dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
1678 return ERR_PTR(-EINVAL);
1683 static void of_i2c_register_devices(struct i2c_adapter *adap)
1685 struct device_node *node;
1687 /* Only register child devices if the adapter has a node pointer set */
1688 if (!adap->dev.of_node)
1691 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
1693 for_each_available_child_of_node(adap->dev.of_node, node) {
1694 if (of_node_test_and_set_flag(node, OF_POPULATED))
1696 of_i2c_register_device(adap, node);
1700 static int of_dev_node_match(struct device *dev, void *data)
1702 return dev->of_node == data;
1705 /* must call put_device() when done with returned i2c_client device */
1706 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1709 struct i2c_client *client;
1711 dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1715 client = i2c_verify_client(dev);
1721 EXPORT_SYMBOL(of_find_i2c_device_by_node);
1723 /* must call put_device() when done with returned i2c_adapter device */
1724 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1727 struct i2c_adapter *adapter;
1729 dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1733 adapter = i2c_verify_adapter(dev);
1739 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1741 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
1742 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
1744 struct i2c_adapter *adapter;
1746 adapter = of_find_i2c_adapter_by_node(node);
1750 if (!try_module_get(adapter->owner)) {
1751 put_device(&adapter->dev);
1757 EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
1759 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
1760 #endif /* CONFIG_OF */
1762 static int i2c_do_add_adapter(struct i2c_driver *driver,
1763 struct i2c_adapter *adap)
1765 /* Detect supported devices on that bus, and instantiate them */
1766 i2c_detect(adap, driver);
1768 /* Let legacy drivers scan this bus for matching devices */
1769 if (driver->attach_adapter) {
1770 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1771 driver->driver.name);
1772 dev_warn(&adap->dev,
1773 "Please use another way to instantiate your i2c_client\n");
1774 /* We ignore the return code; if it fails, too bad */
1775 driver->attach_adapter(adap);
1780 static int __process_new_adapter(struct device_driver *d, void *data)
1782 return i2c_do_add_adapter(to_i2c_driver(d), data);
1785 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1786 .lock_bus = i2c_adapter_lock_bus,
1787 .trylock_bus = i2c_adapter_trylock_bus,
1788 .unlock_bus = i2c_adapter_unlock_bus,
1791 static int i2c_register_adapter(struct i2c_adapter *adap)
1795 /* Can't register until after driver model init */
1796 if (WARN_ON(!is_registered)) {
1802 if (WARN(!adap->name[0], "i2c adapter has no name"))
1806 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1810 if (!adap->lock_ops)
1811 adap->lock_ops = &i2c_adapter_lock_ops;
1813 rt_mutex_init(&adap->bus_lock);
1814 rt_mutex_init(&adap->mux_lock);
1815 mutex_init(&adap->userspace_clients_lock);
1816 INIT_LIST_HEAD(&adap->userspace_clients);
1818 /* Set default timeout to 1 second if not already set */
1819 if (adap->timeout == 0)
1822 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1823 adap->dev.bus = &i2c_bus_type;
1824 adap->dev.type = &i2c_adapter_type;
1825 res = device_register(&adap->dev);
1827 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1831 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1833 pm_runtime_no_callbacks(&adap->dev);
1834 pm_suspend_ignore_children(&adap->dev, true);
1835 pm_runtime_enable(&adap->dev);
1837 #ifdef CONFIG_I2C_COMPAT
1838 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1841 dev_warn(&adap->dev,
1842 "Failed to create compatibility class link\n");
1845 i2c_init_recovery(adap);
1847 /* create pre-declared device nodes */
1848 of_i2c_register_devices(adap);
1849 i2c_acpi_register_devices(adap);
1850 i2c_acpi_install_space_handler(adap);
1852 if (adap->nr < __i2c_first_dynamic_bus_num)
1853 i2c_scan_static_board_info(adap);
1855 /* Notify drivers */
1856 mutex_lock(&core_lock);
1857 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1858 mutex_unlock(&core_lock);
1863 mutex_lock(&core_lock);
1864 idr_remove(&i2c_adapter_idr, adap->nr);
1865 mutex_unlock(&core_lock);
1870 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1871 * @adap: the adapter to register (with adap->nr initialized)
1872 * Context: can sleep
1874 * See i2c_add_numbered_adapter() for details.
1876 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1880 mutex_lock(&core_lock);
1881 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1882 mutex_unlock(&core_lock);
1883 if (WARN(id < 0, "couldn't get idr"))
1884 return id == -ENOSPC ? -EBUSY : id;
1886 return i2c_register_adapter(adap);
1890 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1891 * @adapter: the adapter to add
1892 * Context: can sleep
1894 * This routine is used to declare an I2C adapter when its bus number
1895 * doesn't matter or when its bus number is specified by an dt alias.
1896 * Examples of bases when the bus number doesn't matter: I2C adapters
1897 * dynamically added by USB links or PCI plugin cards.
1899 * When this returns zero, a new bus number was allocated and stored
1900 * in adap->nr, and the specified adapter became available for clients.
1901 * Otherwise, a negative errno value is returned.
1903 int i2c_add_adapter(struct i2c_adapter *adapter)
1905 struct device *dev = &adapter->dev;
1909 id = of_alias_get_id(dev->of_node, "i2c");
1912 return __i2c_add_numbered_adapter(adapter);
1916 mutex_lock(&core_lock);
1917 id = idr_alloc(&i2c_adapter_idr, adapter,
1918 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1919 mutex_unlock(&core_lock);
1920 if (WARN(id < 0, "couldn't get idr"))
1925 return i2c_register_adapter(adapter);
1927 EXPORT_SYMBOL(i2c_add_adapter);
1930 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1931 * @adap: the adapter to register (with adap->nr initialized)
1932 * Context: can sleep
1934 * This routine is used to declare an I2C adapter when its bus number
1935 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1936 * or otherwise built in to the system's mainboard, and where i2c_board_info
1937 * is used to properly configure I2C devices.
1939 * If the requested bus number is set to -1, then this function will behave
1940 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1942 * If no devices have pre-been declared for this bus, then be sure to
1943 * register the adapter before any dynamically allocated ones. Otherwise
1944 * the required bus ID may not be available.
1946 * When this returns zero, the specified adapter became available for
1947 * clients using the bus number provided in adap->nr. Also, the table
1948 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1949 * and the appropriate driver model device nodes are created. Otherwise, a
1950 * negative errno value is returned.
1952 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1954 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1955 return i2c_add_adapter(adap);
1957 return __i2c_add_numbered_adapter(adap);
1959 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1961 static void i2c_do_del_adapter(struct i2c_driver *driver,
1962 struct i2c_adapter *adapter)
1964 struct i2c_client *client, *_n;
1966 /* Remove the devices we created ourselves as the result of hardware
1967 * probing (using a driver's detect method) */
1968 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1969 if (client->adapter == adapter) {
1970 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1971 client->name, client->addr);
1972 list_del(&client->detected);
1973 i2c_unregister_device(client);
1978 static int __unregister_client(struct device *dev, void *dummy)
1980 struct i2c_client *client = i2c_verify_client(dev);
1981 if (client && strcmp(client->name, "dummy"))
1982 i2c_unregister_device(client);
1986 static int __unregister_dummy(struct device *dev, void *dummy)
1988 struct i2c_client *client = i2c_verify_client(dev);
1990 i2c_unregister_device(client);
1994 static int __process_removed_adapter(struct device_driver *d, void *data)
1996 i2c_do_del_adapter(to_i2c_driver(d), data);
2001 * i2c_del_adapter - unregister I2C adapter
2002 * @adap: the adapter being unregistered
2003 * Context: can sleep
2005 * This unregisters an I2C adapter which was previously registered
2006 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
2008 void i2c_del_adapter(struct i2c_adapter *adap)
2010 struct i2c_adapter *found;
2011 struct i2c_client *client, *next;
2013 /* First make sure that this adapter was ever added */
2014 mutex_lock(&core_lock);
2015 found = idr_find(&i2c_adapter_idr, adap->nr);
2016 mutex_unlock(&core_lock);
2017 if (found != adap) {
2018 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
2022 i2c_acpi_remove_space_handler(adap);
2023 /* Tell drivers about this removal */
2024 mutex_lock(&core_lock);
2025 bus_for_each_drv(&i2c_bus_type, NULL, adap,
2026 __process_removed_adapter);
2027 mutex_unlock(&core_lock);
2029 /* Remove devices instantiated from sysfs */
2030 mutex_lock_nested(&adap->userspace_clients_lock,
2031 i2c_adapter_depth(adap));
2032 list_for_each_entry_safe(client, next, &adap->userspace_clients,
2034 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
2036 list_del(&client->detected);
2037 i2c_unregister_device(client);
2039 mutex_unlock(&adap->userspace_clients_lock);
2041 /* Detach any active clients. This can't fail, thus we do not
2042 * check the returned value. This is a two-pass process, because
2043 * we can't remove the dummy devices during the first pass: they
2044 * could have been instantiated by real devices wishing to clean
2045 * them up properly, so we give them a chance to do that first. */
2046 device_for_each_child(&adap->dev, NULL, __unregister_client);
2047 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
2049 #ifdef CONFIG_I2C_COMPAT
2050 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
2054 /* device name is gone after device_unregister */
2055 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
2057 pm_runtime_disable(&adap->dev);
2059 /* wait until all references to the device are gone
2061 * FIXME: This is old code and should ideally be replaced by an
2062 * alternative which results in decoupling the lifetime of the struct
2063 * device from the i2c_adapter, like spi or netdev do. Any solution
2064 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
2066 init_completion(&adap->dev_released);
2067 device_unregister(&adap->dev);
2068 wait_for_completion(&adap->dev_released);
2071 mutex_lock(&core_lock);
2072 idr_remove(&i2c_adapter_idr, adap->nr);
2073 mutex_unlock(&core_lock);
2075 /* Clear the device structure in case this adapter is ever going to be
2077 memset(&adap->dev, 0, sizeof(adap->dev));
2079 EXPORT_SYMBOL(i2c_del_adapter);
2082 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
2083 * @dev: The device to scan for I2C timing properties
2084 * @t: the i2c_timings struct to be filled with values
2085 * @use_defaults: bool to use sane defaults derived from the I2C specification
2086 * when properties are not found, otherwise use 0
2088 * Scan the device for the generic I2C properties describing timing parameters
2089 * for the signal and fill the given struct with the results. If a property was
2090 * not found and use_defaults was true, then maximum timings are assumed which
2091 * are derived from the I2C specification. If use_defaults is not used, the
2092 * results will be 0, so drivers can apply their own defaults later. The latter
2093 * is mainly intended for avoiding regressions of existing drivers which want
2094 * to switch to this function. New drivers almost always should use the defaults.
2097 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
2101 memset(t, 0, sizeof(*t));
2103 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
2104 if (ret && use_defaults)
2105 t->bus_freq_hz = 100000;
2107 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
2108 if (ret && use_defaults) {
2109 if (t->bus_freq_hz <= 100000)
2110 t->scl_rise_ns = 1000;
2111 else if (t->bus_freq_hz <= 400000)
2112 t->scl_rise_ns = 300;
2114 t->scl_rise_ns = 120;
2117 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
2118 if (ret && use_defaults) {
2119 if (t->bus_freq_hz <= 400000)
2120 t->scl_fall_ns = 300;
2122 t->scl_fall_ns = 120;
2125 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
2127 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
2128 if (ret && use_defaults)
2129 t->sda_fall_ns = t->scl_fall_ns;
2131 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
2133 /* ------------------------------------------------------------------------- */
2135 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
2139 mutex_lock(&core_lock);
2140 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
2141 mutex_unlock(&core_lock);
2145 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
2147 static int __process_new_driver(struct device *dev, void *data)
2149 if (dev->type != &i2c_adapter_type)
2151 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
2155 * An i2c_driver is used with one or more i2c_client (device) nodes to access
2156 * i2c slave chips, on a bus instance associated with some i2c_adapter.
2159 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
2163 /* Can't register until after driver model init */
2164 if (WARN_ON(!is_registered))
2167 /* add the driver to the list of i2c drivers in the driver core */
2168 driver->driver.owner = owner;
2169 driver->driver.bus = &i2c_bus_type;
2171 /* When registration returns, the driver core
2172 * will have called probe() for all matching-but-unbound devices.
2174 res = driver_register(&driver->driver);
2178 pr_debug("driver [%s] registered\n", driver->driver.name);
2180 INIT_LIST_HEAD(&driver->clients);
2181 /* Walk the adapters that are already present */
2182 i2c_for_each_dev(driver, __process_new_driver);
2186 EXPORT_SYMBOL(i2c_register_driver);
2188 static int __process_removed_driver(struct device *dev, void *data)
2190 if (dev->type == &i2c_adapter_type)
2191 i2c_do_del_adapter(data, to_i2c_adapter(dev));
2196 * i2c_del_driver - unregister I2C driver
2197 * @driver: the driver being unregistered
2198 * Context: can sleep
2200 void i2c_del_driver(struct i2c_driver *driver)
2202 i2c_for_each_dev(driver, __process_removed_driver);
2204 driver_unregister(&driver->driver);
2205 pr_debug("driver [%s] unregistered\n", driver->driver.name);
2207 EXPORT_SYMBOL(i2c_del_driver);
2209 /* ------------------------------------------------------------------------- */
2212 * i2c_use_client - increments the reference count of the i2c client structure
2213 * @client: the client being referenced
2215 * Each live reference to a client should be refcounted. The driver model does
2216 * that automatically as part of driver binding, so that most drivers don't
2217 * need to do this explicitly: they hold a reference until they're unbound
2220 * A pointer to the client with the incremented reference counter is returned.
2222 struct i2c_client *i2c_use_client(struct i2c_client *client)
2224 if (client && get_device(&client->dev))
2228 EXPORT_SYMBOL(i2c_use_client);
2231 * i2c_release_client - release a use of the i2c client structure
2232 * @client: the client being no longer referenced
2234 * Must be called when a user of a client is finished with it.
2236 void i2c_release_client(struct i2c_client *client)
2239 put_device(&client->dev);
2241 EXPORT_SYMBOL(i2c_release_client);
2243 struct i2c_cmd_arg {
2248 static int i2c_cmd(struct device *dev, void *_arg)
2250 struct i2c_client *client = i2c_verify_client(dev);
2251 struct i2c_cmd_arg *arg = _arg;
2252 struct i2c_driver *driver;
2254 if (!client || !client->dev.driver)
2257 driver = to_i2c_driver(client->dev.driver);
2258 if (driver->command)
2259 driver->command(client, arg->cmd, arg->arg);
2263 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2265 struct i2c_cmd_arg cmd_arg;
2269 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2271 EXPORT_SYMBOL(i2c_clients_command);
2273 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2274 static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
2277 struct of_reconfig_data *rd = arg;
2278 struct i2c_adapter *adap;
2279 struct i2c_client *client;
2281 switch (of_reconfig_get_state_change(action, rd)) {
2282 case OF_RECONFIG_CHANGE_ADD:
2283 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
2285 return NOTIFY_OK; /* not for us */
2287 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
2288 put_device(&adap->dev);
2292 client = of_i2c_register_device(adap, rd->dn);
2293 put_device(&adap->dev);
2295 if (IS_ERR(client)) {
2296 dev_err(&adap->dev, "failed to create client for '%s'\n",
2298 return notifier_from_errno(PTR_ERR(client));
2301 case OF_RECONFIG_CHANGE_REMOVE:
2302 /* already depopulated? */
2303 if (!of_node_check_flag(rd->dn, OF_POPULATED))
2306 /* find our device by node */
2307 client = of_find_i2c_device_by_node(rd->dn);
2309 return NOTIFY_OK; /* no? not meant for us */
2311 /* unregister takes one ref away */
2312 i2c_unregister_device(client);
2314 /* and put the reference of the find */
2315 put_device(&client->dev);
2321 static struct notifier_block i2c_of_notifier = {
2322 .notifier_call = of_i2c_notify,
2325 extern struct notifier_block i2c_of_notifier;
2326 #endif /* CONFIG_OF_DYNAMIC */
2328 static int __init i2c_init(void)
2332 retval = of_alias_get_highest_id("i2c");
2334 down_write(&__i2c_board_lock);
2335 if (retval >= __i2c_first_dynamic_bus_num)
2336 __i2c_first_dynamic_bus_num = retval + 1;
2337 up_write(&__i2c_board_lock);
2339 retval = bus_register(&i2c_bus_type);
2343 is_registered = true;
2345 #ifdef CONFIG_I2C_COMPAT
2346 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2347 if (!i2c_adapter_compat_class) {
2352 retval = i2c_add_driver(&dummy_driver);
2356 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2357 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2358 if (IS_ENABLED(CONFIG_ACPI))
2359 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2364 #ifdef CONFIG_I2C_COMPAT
2365 class_compat_unregister(i2c_adapter_compat_class);
2368 is_registered = false;
2369 bus_unregister(&i2c_bus_type);
2373 static void __exit i2c_exit(void)
2375 if (IS_ENABLED(CONFIG_ACPI))
2376 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2377 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2378 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2379 i2c_del_driver(&dummy_driver);
2380 #ifdef CONFIG_I2C_COMPAT
2381 class_compat_unregister(i2c_adapter_compat_class);
2383 bus_unregister(&i2c_bus_type);
2384 tracepoint_synchronize_unregister();
2387 /* We must initialize early, because some subsystems register i2c drivers
2388 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2390 postcore_initcall(i2c_init);
2391 module_exit(i2c_exit);
2393 /* ----------------------------------------------------
2394 * the functional interface to the i2c busses.
2395 * ----------------------------------------------------
2398 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2399 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2401 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2403 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2404 err_msg, msg->addr, msg->len,
2405 msg->flags & I2C_M_RD ? "read" : "write");
2409 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2411 const struct i2c_adapter_quirks *q = adap->quirks;
2412 int max_num = q->max_num_msgs, i;
2413 bool do_len_check = true;
2415 if (q->flags & I2C_AQ_COMB) {
2418 /* special checks for combined messages */
2420 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2421 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2423 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2424 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2426 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2427 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2429 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2430 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2432 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2433 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2435 do_len_check = false;
2439 if (i2c_quirk_exceeded(num, max_num))
2440 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2442 for (i = 0; i < num; i++) {
2443 u16 len = msgs[i].len;
2445 if (msgs[i].flags & I2C_M_RD) {
2446 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2447 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2449 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2450 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2458 * __i2c_transfer - unlocked flavor of i2c_transfer
2459 * @adap: Handle to I2C bus
2460 * @msgs: One or more messages to execute before STOP is issued to
2461 * terminate the operation; each message begins with a START.
2462 * @num: Number of messages to be executed.
2464 * Returns negative errno, else the number of messages executed.
2466 * Adapter lock must be held when calling this function. No debug logging
2467 * takes place. adap->algo->master_xfer existence isn't checked.
2469 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2471 unsigned long orig_jiffies;
2474 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2477 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
2478 * enabled. This is an efficient way of keeping the for-loop from
2479 * being executed when not needed.
2481 if (static_key_false(&i2c_trace_msg)) {
2483 for (i = 0; i < num; i++)
2484 if (msgs[i].flags & I2C_M_RD)
2485 trace_i2c_read(adap, &msgs[i], i);
2487 trace_i2c_write(adap, &msgs[i], i);
2490 /* Retry automatically on arbitration loss */
2491 orig_jiffies = jiffies;
2492 for (ret = 0, try = 0; try <= adap->retries; try++) {
2493 ret = adap->algo->master_xfer(adap, msgs, num);
2496 if (time_after(jiffies, orig_jiffies + adap->timeout))
2500 if (static_key_false(&i2c_trace_msg)) {
2502 for (i = 0; i < ret; i++)
2503 if (msgs[i].flags & I2C_M_RD)
2504 trace_i2c_reply(adap, &msgs[i], i);
2505 trace_i2c_result(adap, i, ret);
2510 EXPORT_SYMBOL(__i2c_transfer);
2513 * i2c_transfer - execute a single or combined I2C message
2514 * @adap: Handle to I2C bus
2515 * @msgs: One or more messages to execute before STOP is issued to
2516 * terminate the operation; each message begins with a START.
2517 * @num: Number of messages to be executed.
2519 * Returns negative errno, else the number of messages executed.
2521 * Note that there is no requirement that each message be sent to
2522 * the same slave address, although that is the most common model.
2524 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2528 /* REVISIT the fault reporting model here is weak:
2530 * - When we get an error after receiving N bytes from a slave,
2531 * there is no way to report "N".
2533 * - When we get a NAK after transmitting N bytes to a slave,
2534 * there is no way to report "N" ... or to let the master
2535 * continue executing the rest of this combined message, if
2536 * that's the appropriate response.
2538 * - When for example "num" is two and we successfully complete
2539 * the first message but get an error part way through the
2540 * second, it's unclear whether that should be reported as
2541 * one (discarding status on the second message) or errno
2542 * (discarding status on the first one).
2545 if (adap->algo->master_xfer) {
2547 for (ret = 0; ret < num; ret++) {
2549 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
2550 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
2551 msgs[ret].addr, msgs[ret].len,
2552 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
2556 if (in_atomic() || irqs_disabled()) {
2557 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
2559 /* I2C activity is ongoing. */
2562 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
2565 ret = __i2c_transfer(adap, msgs, num);
2566 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2570 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2574 EXPORT_SYMBOL(i2c_transfer);
2577 * i2c_master_send - issue a single I2C message in master transmit mode
2578 * @client: Handle to slave device
2579 * @buf: Data that will be written to the slave
2580 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2582 * Returns negative errno, or else the number of bytes written.
2584 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
2587 struct i2c_adapter *adap = client->adapter;
2590 msg.addr = client->addr;
2591 msg.flags = client->flags & I2C_M_TEN;
2593 msg.buf = (char *)buf;
2595 ret = i2c_transfer(adap, &msg, 1);
2598 * If everything went ok (i.e. 1 msg transmitted), return #bytes
2599 * transmitted, else error code.
2601 return (ret == 1) ? count : ret;
2603 EXPORT_SYMBOL(i2c_master_send);
2606 * i2c_master_recv - issue a single I2C message in master receive mode
2607 * @client: Handle to slave device
2608 * @buf: Where to store data read from slave
2609 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2611 * Returns negative errno, or else the number of bytes read.
2613 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
2615 struct i2c_adapter *adap = client->adapter;
2619 msg.addr = client->addr;
2620 msg.flags = client->flags & I2C_M_TEN;
2621 msg.flags |= I2C_M_RD;
2625 ret = i2c_transfer(adap, &msg, 1);
2628 * If everything went ok (i.e. 1 msg received), return #bytes received,
2631 return (ret == 1) ? count : ret;
2633 EXPORT_SYMBOL(i2c_master_recv);
2635 /* ----------------------------------------------------
2636 * the i2c address scanning function
2637 * Will not work for 10-bit addresses!
2638 * ----------------------------------------------------
2642 * Legacy default probe function, mostly relevant for SMBus. The default
2643 * probe method is a quick write, but it is known to corrupt the 24RF08
2644 * EEPROMs due to a state machine bug, and could also irreversibly
2645 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2646 * we use a short byte read instead. Also, some bus drivers don't implement
2647 * quick write, so we fallback to a byte read in that case too.
2648 * On x86, there is another special case for FSC hardware monitoring chips,
2649 * which want regular byte reads (address 0x73.) Fortunately, these are the
2650 * only known chips using this I2C address on PC hardware.
2651 * Returns 1 if probe succeeded, 0 if not.
2653 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2656 union i2c_smbus_data dummy;
2659 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2660 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2661 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2662 I2C_SMBUS_BYTE_DATA, &dummy);
2665 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2666 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2667 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2668 I2C_SMBUS_QUICK, NULL);
2669 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2670 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2671 I2C_SMBUS_BYTE, &dummy);
2673 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2681 static int i2c_detect_address(struct i2c_client *temp_client,
2682 struct i2c_driver *driver)
2684 struct i2c_board_info info;
2685 struct i2c_adapter *adapter = temp_client->adapter;
2686 int addr = temp_client->addr;
2689 /* Make sure the address is valid */
2690 err = i2c_check_7bit_addr_validity_strict(addr);
2692 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2697 /* Skip if already in use (7 bit, no need to encode flags) */
2698 if (i2c_check_addr_busy(adapter, addr))
2701 /* Make sure there is something at this address */
2702 if (!i2c_default_probe(adapter, addr))
2705 /* Finally call the custom detection function */
2706 memset(&info, 0, sizeof(struct i2c_board_info));
2708 err = driver->detect(temp_client, &info);
2710 /* -ENODEV is returned if the detection fails. We catch it
2711 here as this isn't an error. */
2712 return err == -ENODEV ? 0 : err;
2715 /* Consistency check */
2716 if (info.type[0] == '\0') {
2717 dev_err(&adapter->dev,
2718 "%s detection function provided no name for 0x%x\n",
2719 driver->driver.name, addr);
2721 struct i2c_client *client;
2723 /* Detection succeeded, instantiate the device */
2724 if (adapter->class & I2C_CLASS_DEPRECATED)
2725 dev_warn(&adapter->dev,
2726 "This adapter will soon drop class based instantiation of devices. "
2727 "Please make sure client 0x%02x gets instantiated by other means. "
2728 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2731 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2732 info.type, info.addr);
2733 client = i2c_new_device(adapter, &info);
2735 list_add_tail(&client->detected, &driver->clients);
2737 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2738 info.type, info.addr);
2743 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2745 const unsigned short *address_list;
2746 struct i2c_client *temp_client;
2748 int adap_id = i2c_adapter_id(adapter);
2750 address_list = driver->address_list;
2751 if (!driver->detect || !address_list)
2754 /* Warn that the adapter lost class based instantiation */
2755 if (adapter->class == I2C_CLASS_DEPRECATED) {
2756 dev_dbg(&adapter->dev,
2757 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2758 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2759 driver->driver.name);
2763 /* Stop here if the classes do not match */
2764 if (!(adapter->class & driver->class))
2767 /* Set up a temporary client to help detect callback */
2768 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2771 temp_client->adapter = adapter;
2773 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2774 dev_dbg(&adapter->dev,
2775 "found normal entry for adapter %d, addr 0x%02x\n",
2776 adap_id, address_list[i]);
2777 temp_client->addr = address_list[i];
2778 err = i2c_detect_address(temp_client, driver);
2787 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2789 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2790 I2C_SMBUS_QUICK, NULL) >= 0;
2792 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2795 i2c_new_probed_device(struct i2c_adapter *adap,
2796 struct i2c_board_info *info,
2797 unsigned short const *addr_list,
2798 int (*probe)(struct i2c_adapter *, unsigned short addr))
2803 probe = i2c_default_probe;
2805 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2806 /* Check address validity */
2807 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2808 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2813 /* Check address availability (7 bit, no need to encode flags) */
2814 if (i2c_check_addr_busy(adap, addr_list[i])) {
2816 "Address 0x%02x already in use, not probing\n",
2821 /* Test address responsiveness */
2822 if (probe(adap, addr_list[i]))
2826 if (addr_list[i] == I2C_CLIENT_END) {
2827 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2831 info->addr = addr_list[i];
2832 return i2c_new_device(adap, info);
2834 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2836 struct i2c_adapter *i2c_get_adapter(int nr)
2838 struct i2c_adapter *adapter;
2840 mutex_lock(&core_lock);
2841 adapter = idr_find(&i2c_adapter_idr, nr);
2845 if (try_module_get(adapter->owner))
2846 get_device(&adapter->dev);
2851 mutex_unlock(&core_lock);
2854 EXPORT_SYMBOL(i2c_get_adapter);
2856 void i2c_put_adapter(struct i2c_adapter *adap)
2861 put_device(&adap->dev);
2862 module_put(adap->owner);
2864 EXPORT_SYMBOL(i2c_put_adapter);
2866 /* The SMBus parts */
2868 #define POLY (0x1070U << 3)
2869 static u8 crc8(u16 data)
2873 for (i = 0; i < 8; i++) {
2878 return (u8)(data >> 8);
2881 /* Incremental CRC8 over count bytes in the array pointed to by p */
2882 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
2886 for (i = 0; i < count; i++)
2887 crc = crc8((crc ^ p[i]) << 8);
2891 /* Assume a 7-bit address, which is reasonable for SMBus */
2892 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
2894 /* The address will be sent first */
2895 u8 addr = i2c_8bit_addr_from_msg(msg);
2896 pec = i2c_smbus_pec(pec, &addr, 1);
2898 /* The data buffer follows */
2899 return i2c_smbus_pec(pec, msg->buf, msg->len);
2902 /* Used for write only transactions */
2903 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
2905 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
2909 /* Return <0 on CRC error
2910 If there was a write before this read (most cases) we need to take the
2911 partial CRC from the write part into account.
2912 Note that this function does modify the message (we need to decrease the
2913 message length to hide the CRC byte from the caller). */
2914 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
2916 u8 rpec = msg->buf[--msg->len];
2917 cpec = i2c_smbus_msg_pec(cpec, msg);
2920 pr_debug("Bad PEC 0x%02x vs. 0x%02x\n",
2928 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2929 * @client: Handle to slave device
2931 * This executes the SMBus "receive byte" protocol, returning negative errno
2932 * else the byte received from the device.
2934 s32 i2c_smbus_read_byte(const struct i2c_client *client)
2936 union i2c_smbus_data data;
2939 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2941 I2C_SMBUS_BYTE, &data);
2942 return (status < 0) ? status : data.byte;
2944 EXPORT_SYMBOL(i2c_smbus_read_byte);
2947 * i2c_smbus_write_byte - SMBus "send byte" protocol
2948 * @client: Handle to slave device
2949 * @value: Byte to be sent
2951 * This executes the SMBus "send byte" protocol, returning negative errno
2952 * else zero on success.
2954 s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
2956 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2957 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
2959 EXPORT_SYMBOL(i2c_smbus_write_byte);
2962 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2963 * @client: Handle to slave device
2964 * @command: Byte interpreted by slave
2966 * This executes the SMBus "read byte" protocol, returning negative errno
2967 * else a data byte received from the device.
2969 s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
2971 union i2c_smbus_data data;
2974 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2975 I2C_SMBUS_READ, command,
2976 I2C_SMBUS_BYTE_DATA, &data);
2977 return (status < 0) ? status : data.byte;
2979 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
2982 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2983 * @client: Handle to slave device
2984 * @command: Byte interpreted by slave
2985 * @value: Byte being written
2987 * This executes the SMBus "write byte" protocol, returning negative errno
2988 * else zero on success.
2990 s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
2993 union i2c_smbus_data data;
2995 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2996 I2C_SMBUS_WRITE, command,
2997 I2C_SMBUS_BYTE_DATA, &data);
2999 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
3002 * i2c_smbus_read_word_data - SMBus "read word" protocol
3003 * @client: Handle to slave device
3004 * @command: Byte interpreted by slave
3006 * This executes the SMBus "read word" protocol, returning negative errno
3007 * else a 16-bit unsigned "word" received from the device.
3009 s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
3011 union i2c_smbus_data data;
3014 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3015 I2C_SMBUS_READ, command,
3016 I2C_SMBUS_WORD_DATA, &data);
3017 return (status < 0) ? status : data.word;
3019 EXPORT_SYMBOL(i2c_smbus_read_word_data);
3022 * i2c_smbus_write_word_data - SMBus "write word" protocol
3023 * @client: Handle to slave device
3024 * @command: Byte interpreted by slave
3025 * @value: 16-bit "word" being written
3027 * This executes the SMBus "write word" protocol, returning negative errno
3028 * else zero on success.
3030 s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
3033 union i2c_smbus_data data;
3035 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3036 I2C_SMBUS_WRITE, command,
3037 I2C_SMBUS_WORD_DATA, &data);
3039 EXPORT_SYMBOL(i2c_smbus_write_word_data);
3042 * i2c_smbus_read_block_data - SMBus "block read" protocol
3043 * @client: Handle to slave device
3044 * @command: Byte interpreted by slave
3045 * @values: Byte array into which data will be read; big enough to hold
3046 * the data returned by the slave. SMBus allows at most 32 bytes.
3048 * This executes the SMBus "block read" protocol, returning negative errno
3049 * else the number of data bytes in the slave's response.
3051 * Note that using this function requires that the client's adapter support
3052 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
3053 * support this; its emulation through I2C messaging relies on a specific
3054 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
3056 s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
3059 union i2c_smbus_data data;
3062 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3063 I2C_SMBUS_READ, command,
3064 I2C_SMBUS_BLOCK_DATA, &data);
3068 memcpy(values, &data.block[1], data.block[0]);
3069 return data.block[0];
3071 EXPORT_SYMBOL(i2c_smbus_read_block_data);
3074 * i2c_smbus_write_block_data - SMBus "block write" protocol
3075 * @client: Handle to slave device
3076 * @command: Byte interpreted by slave
3077 * @length: Size of data block; SMBus allows at most 32 bytes
3078 * @values: Byte array which will be written.
3080 * This executes the SMBus "block write" protocol, returning negative errno
3081 * else zero on success.
3083 s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
3084 u8 length, const u8 *values)
3086 union i2c_smbus_data data;
3088 if (length > I2C_SMBUS_BLOCK_MAX)
3089 length = I2C_SMBUS_BLOCK_MAX;
3090 data.block[0] = length;
3091 memcpy(&data.block[1], values, length);
3092 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3093 I2C_SMBUS_WRITE, command,
3094 I2C_SMBUS_BLOCK_DATA, &data);
3096 EXPORT_SYMBOL(i2c_smbus_write_block_data);
3098 /* Returns the number of read bytes */
3099 s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
3100 u8 length, u8 *values)
3102 union i2c_smbus_data data;
3105 if (length > I2C_SMBUS_BLOCK_MAX)
3106 length = I2C_SMBUS_BLOCK_MAX;
3107 data.block[0] = length;
3108 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3109 I2C_SMBUS_READ, command,
3110 I2C_SMBUS_I2C_BLOCK_DATA, &data);
3114 memcpy(values, &data.block[1], data.block[0]);
3115 return data.block[0];
3117 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
3119 s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
3120 u8 length, const u8 *values)
3122 union i2c_smbus_data data;
3124 if (length > I2C_SMBUS_BLOCK_MAX)
3125 length = I2C_SMBUS_BLOCK_MAX;
3126 data.block[0] = length;
3127 memcpy(data.block + 1, values, length);
3128 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3129 I2C_SMBUS_WRITE, command,
3130 I2C_SMBUS_I2C_BLOCK_DATA, &data);
3132 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
3134 /* Simulate a SMBus command using the i2c protocol
3135 No checking of parameters is done! */
3136 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
3137 unsigned short flags,
3138 char read_write, u8 command, int size,
3139 union i2c_smbus_data *data)
3141 /* So we need to generate a series of msgs. In the case of writing, we
3142 need to use only one message; when reading, we need two. We initialize
3143 most things with sane defaults, to keep the code below somewhat
3145 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
3146 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
3147 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
3151 struct i2c_msg msg[2] = {
3159 .flags = flags | I2C_M_RD,
3165 msgbuf0[0] = command;
3167 case I2C_SMBUS_QUICK:
3169 /* Special case: The read/write field is used as data */
3170 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
3174 case I2C_SMBUS_BYTE:
3175 if (read_write == I2C_SMBUS_READ) {
3176 /* Special case: only a read! */
3177 msg[0].flags = I2C_M_RD | flags;
3181 case I2C_SMBUS_BYTE_DATA:
3182 if (read_write == I2C_SMBUS_READ)
3186 msgbuf0[1] = data->byte;
3189 case I2C_SMBUS_WORD_DATA:
3190 if (read_write == I2C_SMBUS_READ)
3194 msgbuf0[1] = data->word & 0xff;
3195 msgbuf0[2] = data->word >> 8;
3198 case I2C_SMBUS_PROC_CALL:
3199 num = 2; /* Special case */
3200 read_write = I2C_SMBUS_READ;
3203 msgbuf0[1] = data->word & 0xff;
3204 msgbuf0[2] = data->word >> 8;
3206 case I2C_SMBUS_BLOCK_DATA:
3207 if (read_write == I2C_SMBUS_READ) {
3208 msg[1].flags |= I2C_M_RECV_LEN;
3209 msg[1].len = 1; /* block length will be added by
3210 the underlying bus driver */
3212 msg[0].len = data->block[0] + 2;
3213 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
3214 dev_err(&adapter->dev,
3215 "Invalid block write size %d\n",
3219 for (i = 1; i < msg[0].len; i++)
3220 msgbuf0[i] = data->block[i-1];
3223 case I2C_SMBUS_BLOCK_PROC_CALL:
3224 num = 2; /* Another special case */
3225 read_write = I2C_SMBUS_READ;
3226 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
3227 dev_err(&adapter->dev,
3228 "Invalid block write size %d\n",
3232 msg[0].len = data->block[0] + 2;
3233 for (i = 1; i < msg[0].len; i++)
3234 msgbuf0[i] = data->block[i-1];
3235 msg[1].flags |= I2C_M_RECV_LEN;
3236 msg[1].len = 1; /* block length will be added by
3237 the underlying bus driver */
3239 case I2C_SMBUS_I2C_BLOCK_DATA:
3240 if (read_write == I2C_SMBUS_READ) {
3241 msg[1].len = data->block[0];
3243 msg[0].len = data->block[0] + 1;
3244 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
3245 dev_err(&adapter->dev,
3246 "Invalid block write size %d\n",
3250 for (i = 1; i <= data->block[0]; i++)
3251 msgbuf0[i] = data->block[i];
3255 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
3259 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
3260 && size != I2C_SMBUS_I2C_BLOCK_DATA);
3262 /* Compute PEC if first message is a write */
3263 if (!(msg[0].flags & I2C_M_RD)) {
3264 if (num == 1) /* Write only */
3265 i2c_smbus_add_pec(&msg[0]);
3266 else /* Write followed by read */
3267 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
3269 /* Ask for PEC if last message is a read */
3270 if (msg[num-1].flags & I2C_M_RD)
3274 status = i2c_transfer(adapter, msg, num);
3278 /* Check PEC if last message is a read */
3279 if (i && (msg[num-1].flags & I2C_M_RD)) {
3280 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
3285 if (read_write == I2C_SMBUS_READ)
3287 case I2C_SMBUS_BYTE:
3288 data->byte = msgbuf0[0];
3290 case I2C_SMBUS_BYTE_DATA:
3291 data->byte = msgbuf1[0];
3293 case I2C_SMBUS_WORD_DATA:
3294 case I2C_SMBUS_PROC_CALL:
3295 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
3297 case I2C_SMBUS_I2C_BLOCK_DATA:
3298 for (i = 0; i < data->block[0]; i++)
3299 data->block[i+1] = msgbuf1[i];
3301 case I2C_SMBUS_BLOCK_DATA:
3302 case I2C_SMBUS_BLOCK_PROC_CALL:
3303 for (i = 0; i < msgbuf1[0] + 1; i++)
3304 data->block[i] = msgbuf1[i];
3311 * i2c_smbus_xfer - execute SMBus protocol operations
3312 * @adapter: Handle to I2C bus
3313 * @addr: Address of SMBus slave on that bus
3314 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
3315 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
3316 * @command: Byte interpreted by slave, for protocols which use such bytes
3317 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
3318 * @data: Data to be read or written
3320 * This executes an SMBus protocol operation, and returns a negative
3321 * errno code else zero on success.
3323 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
3324 char read_write, u8 command, int protocol,
3325 union i2c_smbus_data *data)
3327 unsigned long orig_jiffies;
3331 /* If enabled, the following two tracepoints are conditional on
3332 * read_write and protocol.
3334 trace_smbus_write(adapter, addr, flags, read_write,
3335 command, protocol, data);
3336 trace_smbus_read(adapter, addr, flags, read_write,
3339 flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
3341 if (adapter->algo->smbus_xfer) {
3342 i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
3344 /* Retry automatically on arbitration loss */
3345 orig_jiffies = jiffies;
3346 for (res = 0, try = 0; try <= adapter->retries; try++) {
3347 res = adapter->algo->smbus_xfer(adapter, addr, flags,
3348 read_write, command,
3352 if (time_after(jiffies,
3353 orig_jiffies + adapter->timeout))
3356 i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
3358 if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
3361 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
3362 * implement native support for the SMBus operation.
3366 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
3367 command, protocol, data);
3370 /* If enabled, the reply tracepoint is conditional on read_write. */
3371 trace_smbus_reply(adapter, addr, flags, read_write,
3372 command, protocol, data);
3373 trace_smbus_result(adapter, addr, flags, read_write,
3374 command, protocol, res);
3378 EXPORT_SYMBOL(i2c_smbus_xfer);
3381 * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
3382 * @client: Handle to slave device
3383 * @command: Byte interpreted by slave
3384 * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes
3385 * @values: Byte array into which data will be read; big enough to hold
3386 * the data returned by the slave. SMBus allows at most
3387 * I2C_SMBUS_BLOCK_MAX bytes.
3389 * This executes the SMBus "block read" protocol if supported by the adapter.
3390 * If block read is not supported, it emulates it using either word or byte
3391 * read protocols depending on availability.
3393 * The addresses of the I2C slave device that are accessed with this function
3394 * must be mapped to a linear region, so that a block read will have the same
3395 * effect as a byte read. Before using this function you must double-check
3396 * if the I2C slave does support exchanging a block transfer with a byte
3399 s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
3400 u8 command, u8 length, u8 *values)
3405 if (length > I2C_SMBUS_BLOCK_MAX)
3406 length = I2C_SMBUS_BLOCK_MAX;
3408 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
3409 return i2c_smbus_read_i2c_block_data(client, command, length, values);
3411 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA))
3414 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) {
3415 while ((i + 2) <= length) {
3416 status = i2c_smbus_read_word_data(client, command + i);
3419 values[i] = status & 0xff;
3420 values[i + 1] = status >> 8;
3425 while (i < length) {
3426 status = i2c_smbus_read_byte_data(client, command + i);
3435 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated);
3437 #if IS_ENABLED(CONFIG_I2C_SLAVE)
3438 int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
3442 if (!client || !slave_cb) {
3443 WARN(1, "insufficent data\n");
3447 if (!(client->flags & I2C_CLIENT_SLAVE))
3448 dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n",
3451 if (!(client->flags & I2C_CLIENT_TEN)) {
3452 /* Enforce stricter address checking */
3453 ret = i2c_check_7bit_addr_validity_strict(client->addr);
3455 dev_err(&client->dev, "%s: invalid address\n", __func__);
3460 if (!client->adapter->algo->reg_slave) {
3461 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
3465 client->slave_cb = slave_cb;
3467 i2c_lock_adapter(client->adapter);
3468 ret = client->adapter->algo->reg_slave(client);
3469 i2c_unlock_adapter(client->adapter);
3472 client->slave_cb = NULL;
3473 dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
3478 EXPORT_SYMBOL_GPL(i2c_slave_register);
3480 int i2c_slave_unregister(struct i2c_client *client)
3484 if (!client->adapter->algo->unreg_slave) {
3485 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
3489 i2c_lock_adapter(client->adapter);
3490 ret = client->adapter->algo->unreg_slave(client);
3491 i2c_unlock_adapter(client->adapter);
3494 client->slave_cb = NULL;
3496 dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
3500 EXPORT_SYMBOL_GPL(i2c_slave_unregister);
3503 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
3504 MODULE_DESCRIPTION("I2C-Bus main module");
3505 MODULE_LICENSE("GPL");