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);
1429 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1431 unsigned int depth = 0;
1433 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1438 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1441 * Let users instantiate I2C devices through sysfs. This can be used when
1442 * platform initialization code doesn't contain the proper data for
1443 * whatever reason. Also useful for drivers that do device detection and
1444 * detection fails, either because the device uses an unexpected address,
1445 * or this is a compatible device with different ID register values.
1447 * Parameter checking may look overzealous, but we really don't want
1448 * the user to provide incorrect parameters.
1451 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
1452 const char *buf, size_t count)
1454 struct i2c_adapter *adap = to_i2c_adapter(dev);
1455 struct i2c_board_info info;
1456 struct i2c_client *client;
1460 memset(&info, 0, sizeof(struct i2c_board_info));
1462 blank = strchr(buf, ' ');
1464 dev_err(dev, "%s: Missing parameters\n", "new_device");
1467 if (blank - buf > I2C_NAME_SIZE - 1) {
1468 dev_err(dev, "%s: Invalid device name\n", "new_device");
1471 memcpy(info.type, buf, blank - buf);
1473 /* Parse remaining parameters, reject extra parameters */
1474 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1476 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1479 if (res > 1 && end != '\n') {
1480 dev_err(dev, "%s: Extra parameters\n", "new_device");
1484 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1485 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1486 info.flags |= I2C_CLIENT_TEN;
1489 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1490 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1491 info.flags |= I2C_CLIENT_SLAVE;
1494 client = i2c_new_device(adap, &info);
1498 /* Keep track of the added device */
1499 mutex_lock(&adap->userspace_clients_lock);
1500 list_add_tail(&client->detected, &adap->userspace_clients);
1501 mutex_unlock(&adap->userspace_clients_lock);
1502 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1503 info.type, info.addr);
1507 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1510 * And of course let the users delete the devices they instantiated, if
1511 * they got it wrong. This interface can only be used to delete devices
1512 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1513 * don't delete devices to which some kernel code still has references.
1515 * Parameter checking may look overzealous, but we really don't want
1516 * the user to delete the wrong device.
1519 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1520 const char *buf, size_t count)
1522 struct i2c_adapter *adap = to_i2c_adapter(dev);
1523 struct i2c_client *client, *next;
1524 unsigned short addr;
1528 /* Parse parameters, reject extra parameters */
1529 res = sscanf(buf, "%hi%c", &addr, &end);
1531 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1534 if (res > 1 && end != '\n') {
1535 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1539 /* Make sure the device was added through sysfs */
1541 mutex_lock_nested(&adap->userspace_clients_lock,
1542 i2c_adapter_depth(adap));
1543 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1545 if (i2c_encode_flags_to_addr(client) == addr) {
1546 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1547 "delete_device", client->name, client->addr);
1549 list_del(&client->detected);
1550 i2c_unregister_device(client);
1555 mutex_unlock(&adap->userspace_clients_lock);
1558 dev_err(dev, "%s: Can't find device in list\n",
1562 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1563 i2c_sysfs_delete_device);
1565 static struct attribute *i2c_adapter_attrs[] = {
1566 &dev_attr_name.attr,
1567 &dev_attr_new_device.attr,
1568 &dev_attr_delete_device.attr,
1571 ATTRIBUTE_GROUPS(i2c_adapter);
1573 struct device_type i2c_adapter_type = {
1574 .groups = i2c_adapter_groups,
1575 .release = i2c_adapter_dev_release,
1577 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1580 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1581 * @dev: device, probably from some driver model iterator
1583 * When traversing the driver model tree, perhaps using driver model
1584 * iterators like @device_for_each_child(), you can't assume very much
1585 * about the nodes you find. Use this function to avoid oopses caused
1586 * by wrongly treating some non-I2C device as an i2c_adapter.
1588 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1590 return (dev->type == &i2c_adapter_type)
1591 ? to_i2c_adapter(dev)
1594 EXPORT_SYMBOL(i2c_verify_adapter);
1596 #ifdef CONFIG_I2C_COMPAT
1597 static struct class_compat *i2c_adapter_compat_class;
1600 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1602 struct i2c_devinfo *devinfo;
1604 down_read(&__i2c_board_lock);
1605 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1606 if (devinfo->busnum == adapter->nr
1607 && !i2c_new_device(adapter,
1608 &devinfo->board_info))
1609 dev_err(&adapter->dev,
1610 "Can't create device at 0x%02x\n",
1611 devinfo->board_info.addr);
1613 up_read(&__i2c_board_lock);
1616 /* OF support code */
1618 #if IS_ENABLED(CONFIG_OF)
1619 static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
1620 struct device_node *node)
1622 struct i2c_client *result;
1623 struct i2c_board_info info = {};
1624 struct dev_archdata dev_ad = {};
1625 const __be32 *addr_be;
1629 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1631 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
1632 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
1634 return ERR_PTR(-EINVAL);
1637 addr_be = of_get_property(node, "reg", &len);
1638 if (!addr_be || (len < sizeof(*addr_be))) {
1639 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
1641 return ERR_PTR(-EINVAL);
1644 addr = be32_to_cpup(addr_be);
1645 if (addr & I2C_TEN_BIT_ADDRESS) {
1646 addr &= ~I2C_TEN_BIT_ADDRESS;
1647 info.flags |= I2C_CLIENT_TEN;
1650 if (addr & I2C_OWN_SLAVE_ADDRESS) {
1651 addr &= ~I2C_OWN_SLAVE_ADDRESS;
1652 info.flags |= I2C_CLIENT_SLAVE;
1655 if (i2c_check_addr_validity(addr, info.flags)) {
1656 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1657 info.addr, node->full_name);
1658 return ERR_PTR(-EINVAL);
1662 info.of_node = of_node_get(node);
1663 info.archdata = &dev_ad;
1665 if (of_get_property(node, "wakeup-source", NULL))
1666 info.flags |= I2C_CLIENT_WAKE;
1668 result = i2c_new_device(adap, &info);
1669 if (result == NULL) {
1670 dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
1673 return ERR_PTR(-EINVAL);
1678 static void of_i2c_register_devices(struct i2c_adapter *adap)
1680 struct device_node *node;
1682 /* Only register child devices if the adapter has a node pointer set */
1683 if (!adap->dev.of_node)
1686 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
1688 for_each_available_child_of_node(adap->dev.of_node, node) {
1689 if (of_node_test_and_set_flag(node, OF_POPULATED))
1691 of_i2c_register_device(adap, node);
1695 static int of_dev_node_match(struct device *dev, void *data)
1697 return dev->of_node == data;
1700 /* must call put_device() when done with returned i2c_client device */
1701 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1704 struct i2c_client *client;
1706 dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1710 client = i2c_verify_client(dev);
1716 EXPORT_SYMBOL(of_find_i2c_device_by_node);
1718 /* must call put_device() when done with returned i2c_adapter device */
1719 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1722 struct i2c_adapter *adapter;
1724 dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1728 adapter = i2c_verify_adapter(dev);
1734 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1736 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
1737 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
1739 struct i2c_adapter *adapter;
1741 adapter = of_find_i2c_adapter_by_node(node);
1745 if (!try_module_get(adapter->owner)) {
1746 put_device(&adapter->dev);
1752 EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
1754 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
1755 #endif /* CONFIG_OF */
1757 static int i2c_do_add_adapter(struct i2c_driver *driver,
1758 struct i2c_adapter *adap)
1760 /* Detect supported devices on that bus, and instantiate them */
1761 i2c_detect(adap, driver);
1763 /* Let legacy drivers scan this bus for matching devices */
1764 if (driver->attach_adapter) {
1765 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1766 driver->driver.name);
1767 dev_warn(&adap->dev,
1768 "Please use another way to instantiate your i2c_client\n");
1769 /* We ignore the return code; if it fails, too bad */
1770 driver->attach_adapter(adap);
1775 static int __process_new_adapter(struct device_driver *d, void *data)
1777 return i2c_do_add_adapter(to_i2c_driver(d), data);
1780 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1781 .lock_bus = i2c_adapter_lock_bus,
1782 .trylock_bus = i2c_adapter_trylock_bus,
1783 .unlock_bus = i2c_adapter_unlock_bus,
1786 static int i2c_register_adapter(struct i2c_adapter *adap)
1790 /* Can't register until after driver model init */
1791 if (WARN_ON(!is_registered)) {
1797 if (WARN(!adap->name[0], "i2c adapter has no name"))
1801 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1805 if (!adap->lock_ops)
1806 adap->lock_ops = &i2c_adapter_lock_ops;
1808 rt_mutex_init(&adap->bus_lock);
1809 rt_mutex_init(&adap->mux_lock);
1810 mutex_init(&adap->userspace_clients_lock);
1811 INIT_LIST_HEAD(&adap->userspace_clients);
1813 /* Set default timeout to 1 second if not already set */
1814 if (adap->timeout == 0)
1817 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1818 adap->dev.bus = &i2c_bus_type;
1819 adap->dev.type = &i2c_adapter_type;
1820 res = device_register(&adap->dev);
1822 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1826 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1828 pm_runtime_no_callbacks(&adap->dev);
1829 pm_suspend_ignore_children(&adap->dev, true);
1830 pm_runtime_enable(&adap->dev);
1832 #ifdef CONFIG_I2C_COMPAT
1833 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1836 dev_warn(&adap->dev,
1837 "Failed to create compatibility class link\n");
1840 i2c_init_recovery(adap);
1842 /* create pre-declared device nodes */
1843 of_i2c_register_devices(adap);
1844 i2c_acpi_register_devices(adap);
1845 i2c_acpi_install_space_handler(adap);
1847 if (adap->nr < __i2c_first_dynamic_bus_num)
1848 i2c_scan_static_board_info(adap);
1850 /* Notify drivers */
1851 mutex_lock(&core_lock);
1852 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1853 mutex_unlock(&core_lock);
1858 mutex_lock(&core_lock);
1859 idr_remove(&i2c_adapter_idr, adap->nr);
1860 mutex_unlock(&core_lock);
1865 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1866 * @adap: the adapter to register (with adap->nr initialized)
1867 * Context: can sleep
1869 * See i2c_add_numbered_adapter() for details.
1871 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1875 mutex_lock(&core_lock);
1876 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1877 mutex_unlock(&core_lock);
1878 if (WARN(id < 0, "couldn't get idr"))
1879 return id == -ENOSPC ? -EBUSY : id;
1881 return i2c_register_adapter(adap);
1885 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1886 * @adapter: the adapter to add
1887 * Context: can sleep
1889 * This routine is used to declare an I2C adapter when its bus number
1890 * doesn't matter or when its bus number is specified by an dt alias.
1891 * Examples of bases when the bus number doesn't matter: I2C adapters
1892 * dynamically added by USB links or PCI plugin cards.
1894 * When this returns zero, a new bus number was allocated and stored
1895 * in adap->nr, and the specified adapter became available for clients.
1896 * Otherwise, a negative errno value is returned.
1898 int i2c_add_adapter(struct i2c_adapter *adapter)
1900 struct device *dev = &adapter->dev;
1904 id = of_alias_get_id(dev->of_node, "i2c");
1907 return __i2c_add_numbered_adapter(adapter);
1911 mutex_lock(&core_lock);
1912 id = idr_alloc(&i2c_adapter_idr, adapter,
1913 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1914 mutex_unlock(&core_lock);
1915 if (WARN(id < 0, "couldn't get idr"))
1920 return i2c_register_adapter(adapter);
1922 EXPORT_SYMBOL(i2c_add_adapter);
1925 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1926 * @adap: the adapter to register (with adap->nr initialized)
1927 * Context: can sleep
1929 * This routine is used to declare an I2C adapter when its bus number
1930 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1931 * or otherwise built in to the system's mainboard, and where i2c_board_info
1932 * is used to properly configure I2C devices.
1934 * If the requested bus number is set to -1, then this function will behave
1935 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1937 * If no devices have pre-been declared for this bus, then be sure to
1938 * register the adapter before any dynamically allocated ones. Otherwise
1939 * the required bus ID may not be available.
1941 * When this returns zero, the specified adapter became available for
1942 * clients using the bus number provided in adap->nr. Also, the table
1943 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1944 * and the appropriate driver model device nodes are created. Otherwise, a
1945 * negative errno value is returned.
1947 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1949 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1950 return i2c_add_adapter(adap);
1952 return __i2c_add_numbered_adapter(adap);
1954 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1956 static void i2c_do_del_adapter(struct i2c_driver *driver,
1957 struct i2c_adapter *adapter)
1959 struct i2c_client *client, *_n;
1961 /* Remove the devices we created ourselves as the result of hardware
1962 * probing (using a driver's detect method) */
1963 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1964 if (client->adapter == adapter) {
1965 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1966 client->name, client->addr);
1967 list_del(&client->detected);
1968 i2c_unregister_device(client);
1973 static int __unregister_client(struct device *dev, void *dummy)
1975 struct i2c_client *client = i2c_verify_client(dev);
1976 if (client && strcmp(client->name, "dummy"))
1977 i2c_unregister_device(client);
1981 static int __unregister_dummy(struct device *dev, void *dummy)
1983 struct i2c_client *client = i2c_verify_client(dev);
1985 i2c_unregister_device(client);
1989 static int __process_removed_adapter(struct device_driver *d, void *data)
1991 i2c_do_del_adapter(to_i2c_driver(d), data);
1996 * i2c_del_adapter - unregister I2C adapter
1997 * @adap: the adapter being unregistered
1998 * Context: can sleep
2000 * This unregisters an I2C adapter which was previously registered
2001 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
2003 void i2c_del_adapter(struct i2c_adapter *adap)
2005 struct i2c_adapter *found;
2006 struct i2c_client *client, *next;
2008 /* First make sure that this adapter was ever added */
2009 mutex_lock(&core_lock);
2010 found = idr_find(&i2c_adapter_idr, adap->nr);
2011 mutex_unlock(&core_lock);
2012 if (found != adap) {
2013 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
2017 i2c_acpi_remove_space_handler(adap);
2018 /* Tell drivers about this removal */
2019 mutex_lock(&core_lock);
2020 bus_for_each_drv(&i2c_bus_type, NULL, adap,
2021 __process_removed_adapter);
2022 mutex_unlock(&core_lock);
2024 /* Remove devices instantiated from sysfs */
2025 mutex_lock_nested(&adap->userspace_clients_lock,
2026 i2c_adapter_depth(adap));
2027 list_for_each_entry_safe(client, next, &adap->userspace_clients,
2029 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
2031 list_del(&client->detected);
2032 i2c_unregister_device(client);
2034 mutex_unlock(&adap->userspace_clients_lock);
2036 /* Detach any active clients. This can't fail, thus we do not
2037 * check the returned value. This is a two-pass process, because
2038 * we can't remove the dummy devices during the first pass: they
2039 * could have been instantiated by real devices wishing to clean
2040 * them up properly, so we give them a chance to do that first. */
2041 device_for_each_child(&adap->dev, NULL, __unregister_client);
2042 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
2044 #ifdef CONFIG_I2C_COMPAT
2045 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
2049 /* device name is gone after device_unregister */
2050 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
2052 pm_runtime_disable(&adap->dev);
2054 /* wait until all references to the device are gone
2056 * FIXME: This is old code and should ideally be replaced by an
2057 * alternative which results in decoupling the lifetime of the struct
2058 * device from the i2c_adapter, like spi or netdev do. Any solution
2059 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
2061 init_completion(&adap->dev_released);
2062 device_unregister(&adap->dev);
2063 wait_for_completion(&adap->dev_released);
2066 mutex_lock(&core_lock);
2067 idr_remove(&i2c_adapter_idr, adap->nr);
2068 mutex_unlock(&core_lock);
2070 /* Clear the device structure in case this adapter is ever going to be
2072 memset(&adap->dev, 0, sizeof(adap->dev));
2074 EXPORT_SYMBOL(i2c_del_adapter);
2077 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
2078 * @dev: The device to scan for I2C timing properties
2079 * @t: the i2c_timings struct to be filled with values
2080 * @use_defaults: bool to use sane defaults derived from the I2C specification
2081 * when properties are not found, otherwise use 0
2083 * Scan the device for the generic I2C properties describing timing parameters
2084 * for the signal and fill the given struct with the results. If a property was
2085 * not found and use_defaults was true, then maximum timings are assumed which
2086 * are derived from the I2C specification. If use_defaults is not used, the
2087 * results will be 0, so drivers can apply their own defaults later. The latter
2088 * is mainly intended for avoiding regressions of existing drivers which want
2089 * to switch to this function. New drivers almost always should use the defaults.
2092 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
2096 memset(t, 0, sizeof(*t));
2098 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
2099 if (ret && use_defaults)
2100 t->bus_freq_hz = 100000;
2102 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
2103 if (ret && use_defaults) {
2104 if (t->bus_freq_hz <= 100000)
2105 t->scl_rise_ns = 1000;
2106 else if (t->bus_freq_hz <= 400000)
2107 t->scl_rise_ns = 300;
2109 t->scl_rise_ns = 120;
2112 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
2113 if (ret && use_defaults) {
2114 if (t->bus_freq_hz <= 400000)
2115 t->scl_fall_ns = 300;
2117 t->scl_fall_ns = 120;
2120 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
2122 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
2123 if (ret && use_defaults)
2124 t->sda_fall_ns = t->scl_fall_ns;
2126 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
2128 /* ------------------------------------------------------------------------- */
2130 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
2134 mutex_lock(&core_lock);
2135 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
2136 mutex_unlock(&core_lock);
2140 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
2142 static int __process_new_driver(struct device *dev, void *data)
2144 if (dev->type != &i2c_adapter_type)
2146 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
2150 * An i2c_driver is used with one or more i2c_client (device) nodes to access
2151 * i2c slave chips, on a bus instance associated with some i2c_adapter.
2154 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
2158 /* Can't register until after driver model init */
2159 if (WARN_ON(!is_registered))
2162 /* add the driver to the list of i2c drivers in the driver core */
2163 driver->driver.owner = owner;
2164 driver->driver.bus = &i2c_bus_type;
2166 /* When registration returns, the driver core
2167 * will have called probe() for all matching-but-unbound devices.
2169 res = driver_register(&driver->driver);
2173 pr_debug("driver [%s] registered\n", driver->driver.name);
2175 INIT_LIST_HEAD(&driver->clients);
2176 /* Walk the adapters that are already present */
2177 i2c_for_each_dev(driver, __process_new_driver);
2181 EXPORT_SYMBOL(i2c_register_driver);
2183 static int __process_removed_driver(struct device *dev, void *data)
2185 if (dev->type == &i2c_adapter_type)
2186 i2c_do_del_adapter(data, to_i2c_adapter(dev));
2191 * i2c_del_driver - unregister I2C driver
2192 * @driver: the driver being unregistered
2193 * Context: can sleep
2195 void i2c_del_driver(struct i2c_driver *driver)
2197 i2c_for_each_dev(driver, __process_removed_driver);
2199 driver_unregister(&driver->driver);
2200 pr_debug("driver [%s] unregistered\n", driver->driver.name);
2202 EXPORT_SYMBOL(i2c_del_driver);
2204 /* ------------------------------------------------------------------------- */
2207 * i2c_use_client - increments the reference count of the i2c client structure
2208 * @client: the client being referenced
2210 * Each live reference to a client should be refcounted. The driver model does
2211 * that automatically as part of driver binding, so that most drivers don't
2212 * need to do this explicitly: they hold a reference until they're unbound
2215 * A pointer to the client with the incremented reference counter is returned.
2217 struct i2c_client *i2c_use_client(struct i2c_client *client)
2219 if (client && get_device(&client->dev))
2223 EXPORT_SYMBOL(i2c_use_client);
2226 * i2c_release_client - release a use of the i2c client structure
2227 * @client: the client being no longer referenced
2229 * Must be called when a user of a client is finished with it.
2231 void i2c_release_client(struct i2c_client *client)
2234 put_device(&client->dev);
2236 EXPORT_SYMBOL(i2c_release_client);
2238 struct i2c_cmd_arg {
2243 static int i2c_cmd(struct device *dev, void *_arg)
2245 struct i2c_client *client = i2c_verify_client(dev);
2246 struct i2c_cmd_arg *arg = _arg;
2247 struct i2c_driver *driver;
2249 if (!client || !client->dev.driver)
2252 driver = to_i2c_driver(client->dev.driver);
2253 if (driver->command)
2254 driver->command(client, arg->cmd, arg->arg);
2258 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2260 struct i2c_cmd_arg cmd_arg;
2264 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2266 EXPORT_SYMBOL(i2c_clients_command);
2268 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2269 static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
2272 struct of_reconfig_data *rd = arg;
2273 struct i2c_adapter *adap;
2274 struct i2c_client *client;
2276 switch (of_reconfig_get_state_change(action, rd)) {
2277 case OF_RECONFIG_CHANGE_ADD:
2278 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
2280 return NOTIFY_OK; /* not for us */
2282 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
2283 put_device(&adap->dev);
2287 client = of_i2c_register_device(adap, rd->dn);
2288 put_device(&adap->dev);
2290 if (IS_ERR(client)) {
2291 dev_err(&adap->dev, "failed to create client for '%s'\n",
2293 return notifier_from_errno(PTR_ERR(client));
2296 case OF_RECONFIG_CHANGE_REMOVE:
2297 /* already depopulated? */
2298 if (!of_node_check_flag(rd->dn, OF_POPULATED))
2301 /* find our device by node */
2302 client = of_find_i2c_device_by_node(rd->dn);
2304 return NOTIFY_OK; /* no? not meant for us */
2306 /* unregister takes one ref away */
2307 i2c_unregister_device(client);
2309 /* and put the reference of the find */
2310 put_device(&client->dev);
2316 static struct notifier_block i2c_of_notifier = {
2317 .notifier_call = of_i2c_notify,
2320 extern struct notifier_block i2c_of_notifier;
2321 #endif /* CONFIG_OF_DYNAMIC */
2323 static int __init i2c_init(void)
2327 retval = of_alias_get_highest_id("i2c");
2329 down_write(&__i2c_board_lock);
2330 if (retval >= __i2c_first_dynamic_bus_num)
2331 __i2c_first_dynamic_bus_num = retval + 1;
2332 up_write(&__i2c_board_lock);
2334 retval = bus_register(&i2c_bus_type);
2338 is_registered = true;
2340 #ifdef CONFIG_I2C_COMPAT
2341 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2342 if (!i2c_adapter_compat_class) {
2347 retval = i2c_add_driver(&dummy_driver);
2351 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2352 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2353 if (IS_ENABLED(CONFIG_ACPI))
2354 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2359 #ifdef CONFIG_I2C_COMPAT
2360 class_compat_unregister(i2c_adapter_compat_class);
2363 is_registered = false;
2364 bus_unregister(&i2c_bus_type);
2368 static void __exit i2c_exit(void)
2370 if (IS_ENABLED(CONFIG_ACPI))
2371 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2372 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2373 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2374 i2c_del_driver(&dummy_driver);
2375 #ifdef CONFIG_I2C_COMPAT
2376 class_compat_unregister(i2c_adapter_compat_class);
2378 bus_unregister(&i2c_bus_type);
2379 tracepoint_synchronize_unregister();
2382 /* We must initialize early, because some subsystems register i2c drivers
2383 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2385 postcore_initcall(i2c_init);
2386 module_exit(i2c_exit);
2388 /* ----------------------------------------------------
2389 * the functional interface to the i2c busses.
2390 * ----------------------------------------------------
2393 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2394 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2396 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2398 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2399 err_msg, msg->addr, msg->len,
2400 msg->flags & I2C_M_RD ? "read" : "write");
2404 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2406 const struct i2c_adapter_quirks *q = adap->quirks;
2407 int max_num = q->max_num_msgs, i;
2408 bool do_len_check = true;
2410 if (q->flags & I2C_AQ_COMB) {
2413 /* special checks for combined messages */
2415 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2416 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2418 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2419 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2421 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2422 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2424 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2425 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2427 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2428 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2430 do_len_check = false;
2434 if (i2c_quirk_exceeded(num, max_num))
2435 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2437 for (i = 0; i < num; i++) {
2438 u16 len = msgs[i].len;
2440 if (msgs[i].flags & I2C_M_RD) {
2441 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2442 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2444 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2445 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2453 * __i2c_transfer - unlocked flavor of i2c_transfer
2454 * @adap: Handle to I2C bus
2455 * @msgs: One or more messages to execute before STOP is issued to
2456 * terminate the operation; each message begins with a START.
2457 * @num: Number of messages to be executed.
2459 * Returns negative errno, else the number of messages executed.
2461 * Adapter lock must be held when calling this function. No debug logging
2462 * takes place. adap->algo->master_xfer existence isn't checked.
2464 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2466 unsigned long orig_jiffies;
2469 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2472 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
2473 * enabled. This is an efficient way of keeping the for-loop from
2474 * being executed when not needed.
2476 if (static_key_false(&i2c_trace_msg)) {
2478 for (i = 0; i < num; i++)
2479 if (msgs[i].flags & I2C_M_RD)
2480 trace_i2c_read(adap, &msgs[i], i);
2482 trace_i2c_write(adap, &msgs[i], i);
2485 /* Retry automatically on arbitration loss */
2486 orig_jiffies = jiffies;
2487 for (ret = 0, try = 0; try <= adap->retries; try++) {
2488 ret = adap->algo->master_xfer(adap, msgs, num);
2491 if (time_after(jiffies, orig_jiffies + adap->timeout))
2495 if (static_key_false(&i2c_trace_msg)) {
2497 for (i = 0; i < ret; i++)
2498 if (msgs[i].flags & I2C_M_RD)
2499 trace_i2c_reply(adap, &msgs[i], i);
2500 trace_i2c_result(adap, i, ret);
2505 EXPORT_SYMBOL(__i2c_transfer);
2508 * i2c_transfer - execute a single or combined I2C message
2509 * @adap: Handle to I2C bus
2510 * @msgs: One or more messages to execute before STOP is issued to
2511 * terminate the operation; each message begins with a START.
2512 * @num: Number of messages to be executed.
2514 * Returns negative errno, else the number of messages executed.
2516 * Note that there is no requirement that each message be sent to
2517 * the same slave address, although that is the most common model.
2519 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2523 /* REVISIT the fault reporting model here is weak:
2525 * - When we get an error after receiving N bytes from a slave,
2526 * there is no way to report "N".
2528 * - When we get a NAK after transmitting N bytes to a slave,
2529 * there is no way to report "N" ... or to let the master
2530 * continue executing the rest of this combined message, if
2531 * that's the appropriate response.
2533 * - When for example "num" is two and we successfully complete
2534 * the first message but get an error part way through the
2535 * second, it's unclear whether that should be reported as
2536 * one (discarding status on the second message) or errno
2537 * (discarding status on the first one).
2540 if (adap->algo->master_xfer) {
2542 for (ret = 0; ret < num; ret++) {
2544 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
2545 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
2546 msgs[ret].addr, msgs[ret].len,
2547 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
2551 if (in_atomic() || irqs_disabled()) {
2552 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
2554 /* I2C activity is ongoing. */
2557 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
2560 ret = __i2c_transfer(adap, msgs, num);
2561 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2565 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2569 EXPORT_SYMBOL(i2c_transfer);
2572 * i2c_master_send - issue a single I2C message in master transmit mode
2573 * @client: Handle to slave device
2574 * @buf: Data that will be written to the slave
2575 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2577 * Returns negative errno, or else the number of bytes written.
2579 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
2582 struct i2c_adapter *adap = client->adapter;
2585 msg.addr = client->addr;
2586 msg.flags = client->flags & I2C_M_TEN;
2588 msg.buf = (char *)buf;
2590 ret = i2c_transfer(adap, &msg, 1);
2593 * If everything went ok (i.e. 1 msg transmitted), return #bytes
2594 * transmitted, else error code.
2596 return (ret == 1) ? count : ret;
2598 EXPORT_SYMBOL(i2c_master_send);
2601 * i2c_master_recv - issue a single I2C message in master receive mode
2602 * @client: Handle to slave device
2603 * @buf: Where to store data read from slave
2604 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2606 * Returns negative errno, or else the number of bytes read.
2608 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
2610 struct i2c_adapter *adap = client->adapter;
2614 msg.addr = client->addr;
2615 msg.flags = client->flags & I2C_M_TEN;
2616 msg.flags |= I2C_M_RD;
2620 ret = i2c_transfer(adap, &msg, 1);
2623 * If everything went ok (i.e. 1 msg received), return #bytes received,
2626 return (ret == 1) ? count : ret;
2628 EXPORT_SYMBOL(i2c_master_recv);
2630 /* ----------------------------------------------------
2631 * the i2c address scanning function
2632 * Will not work for 10-bit addresses!
2633 * ----------------------------------------------------
2637 * Legacy default probe function, mostly relevant for SMBus. The default
2638 * probe method is a quick write, but it is known to corrupt the 24RF08
2639 * EEPROMs due to a state machine bug, and could also irreversibly
2640 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2641 * we use a short byte read instead. Also, some bus drivers don't implement
2642 * quick write, so we fallback to a byte read in that case too.
2643 * On x86, there is another special case for FSC hardware monitoring chips,
2644 * which want regular byte reads (address 0x73.) Fortunately, these are the
2645 * only known chips using this I2C address on PC hardware.
2646 * Returns 1 if probe succeeded, 0 if not.
2648 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2651 union i2c_smbus_data dummy;
2654 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2655 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2656 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2657 I2C_SMBUS_BYTE_DATA, &dummy);
2660 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2661 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2662 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2663 I2C_SMBUS_QUICK, NULL);
2664 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2665 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2666 I2C_SMBUS_BYTE, &dummy);
2668 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2676 static int i2c_detect_address(struct i2c_client *temp_client,
2677 struct i2c_driver *driver)
2679 struct i2c_board_info info;
2680 struct i2c_adapter *adapter = temp_client->adapter;
2681 int addr = temp_client->addr;
2684 /* Make sure the address is valid */
2685 err = i2c_check_7bit_addr_validity_strict(addr);
2687 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2692 /* Skip if already in use (7 bit, no need to encode flags) */
2693 if (i2c_check_addr_busy(adapter, addr))
2696 /* Make sure there is something at this address */
2697 if (!i2c_default_probe(adapter, addr))
2700 /* Finally call the custom detection function */
2701 memset(&info, 0, sizeof(struct i2c_board_info));
2703 err = driver->detect(temp_client, &info);
2705 /* -ENODEV is returned if the detection fails. We catch it
2706 here as this isn't an error. */
2707 return err == -ENODEV ? 0 : err;
2710 /* Consistency check */
2711 if (info.type[0] == '\0') {
2712 dev_err(&adapter->dev,
2713 "%s detection function provided no name for 0x%x\n",
2714 driver->driver.name, addr);
2716 struct i2c_client *client;
2718 /* Detection succeeded, instantiate the device */
2719 if (adapter->class & I2C_CLASS_DEPRECATED)
2720 dev_warn(&adapter->dev,
2721 "This adapter will soon drop class based instantiation of devices. "
2722 "Please make sure client 0x%02x gets instantiated by other means. "
2723 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2726 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2727 info.type, info.addr);
2728 client = i2c_new_device(adapter, &info);
2730 list_add_tail(&client->detected, &driver->clients);
2732 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2733 info.type, info.addr);
2738 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2740 const unsigned short *address_list;
2741 struct i2c_client *temp_client;
2743 int adap_id = i2c_adapter_id(adapter);
2745 address_list = driver->address_list;
2746 if (!driver->detect || !address_list)
2749 /* Warn that the adapter lost class based instantiation */
2750 if (adapter->class == I2C_CLASS_DEPRECATED) {
2751 dev_dbg(&adapter->dev,
2752 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2753 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2754 driver->driver.name);
2758 /* Stop here if the classes do not match */
2759 if (!(adapter->class & driver->class))
2762 /* Set up a temporary client to help detect callback */
2763 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2766 temp_client->adapter = adapter;
2768 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2769 dev_dbg(&adapter->dev,
2770 "found normal entry for adapter %d, addr 0x%02x\n",
2771 adap_id, address_list[i]);
2772 temp_client->addr = address_list[i];
2773 err = i2c_detect_address(temp_client, driver);
2782 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2784 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2785 I2C_SMBUS_QUICK, NULL) >= 0;
2787 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2790 i2c_new_probed_device(struct i2c_adapter *adap,
2791 struct i2c_board_info *info,
2792 unsigned short const *addr_list,
2793 int (*probe)(struct i2c_adapter *, unsigned short addr))
2798 probe = i2c_default_probe;
2800 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2801 /* Check address validity */
2802 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2803 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2808 /* Check address availability (7 bit, no need to encode flags) */
2809 if (i2c_check_addr_busy(adap, addr_list[i])) {
2811 "Address 0x%02x already in use, not probing\n",
2816 /* Test address responsiveness */
2817 if (probe(adap, addr_list[i]))
2821 if (addr_list[i] == I2C_CLIENT_END) {
2822 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2826 info->addr = addr_list[i];
2827 return i2c_new_device(adap, info);
2829 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2831 struct i2c_adapter *i2c_get_adapter(int nr)
2833 struct i2c_adapter *adapter;
2835 mutex_lock(&core_lock);
2836 adapter = idr_find(&i2c_adapter_idr, nr);
2840 if (try_module_get(adapter->owner))
2841 get_device(&adapter->dev);
2846 mutex_unlock(&core_lock);
2849 EXPORT_SYMBOL(i2c_get_adapter);
2851 void i2c_put_adapter(struct i2c_adapter *adap)
2856 put_device(&adap->dev);
2857 module_put(adap->owner);
2859 EXPORT_SYMBOL(i2c_put_adapter);
2861 /* The SMBus parts */
2863 #define POLY (0x1070U << 3)
2864 static u8 crc8(u16 data)
2868 for (i = 0; i < 8; i++) {
2873 return (u8)(data >> 8);
2876 /* Incremental CRC8 over count bytes in the array pointed to by p */
2877 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
2881 for (i = 0; i < count; i++)
2882 crc = crc8((crc ^ p[i]) << 8);
2886 /* Assume a 7-bit address, which is reasonable for SMBus */
2887 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
2889 /* The address will be sent first */
2890 u8 addr = i2c_8bit_addr_from_msg(msg);
2891 pec = i2c_smbus_pec(pec, &addr, 1);
2893 /* The data buffer follows */
2894 return i2c_smbus_pec(pec, msg->buf, msg->len);
2897 /* Used for write only transactions */
2898 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
2900 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
2904 /* Return <0 on CRC error
2905 If there was a write before this read (most cases) we need to take the
2906 partial CRC from the write part into account.
2907 Note that this function does modify the message (we need to decrease the
2908 message length to hide the CRC byte from the caller). */
2909 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
2911 u8 rpec = msg->buf[--msg->len];
2912 cpec = i2c_smbus_msg_pec(cpec, msg);
2915 pr_debug("Bad PEC 0x%02x vs. 0x%02x\n",
2923 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2924 * @client: Handle to slave device
2926 * This executes the SMBus "receive byte" protocol, returning negative errno
2927 * else the byte received from the device.
2929 s32 i2c_smbus_read_byte(const struct i2c_client *client)
2931 union i2c_smbus_data data;
2934 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2936 I2C_SMBUS_BYTE, &data);
2937 return (status < 0) ? status : data.byte;
2939 EXPORT_SYMBOL(i2c_smbus_read_byte);
2942 * i2c_smbus_write_byte - SMBus "send byte" protocol
2943 * @client: Handle to slave device
2944 * @value: Byte to be sent
2946 * This executes the SMBus "send byte" protocol, returning negative errno
2947 * else zero on success.
2949 s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
2951 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2952 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
2954 EXPORT_SYMBOL(i2c_smbus_write_byte);
2957 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2958 * @client: Handle to slave device
2959 * @command: Byte interpreted by slave
2961 * This executes the SMBus "read byte" protocol, returning negative errno
2962 * else a data byte received from the device.
2964 s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
2966 union i2c_smbus_data data;
2969 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2970 I2C_SMBUS_READ, command,
2971 I2C_SMBUS_BYTE_DATA, &data);
2972 return (status < 0) ? status : data.byte;
2974 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
2977 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2978 * @client: Handle to slave device
2979 * @command: Byte interpreted by slave
2980 * @value: Byte being written
2982 * This executes the SMBus "write byte" protocol, returning negative errno
2983 * else zero on success.
2985 s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
2988 union i2c_smbus_data data;
2990 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2991 I2C_SMBUS_WRITE, command,
2992 I2C_SMBUS_BYTE_DATA, &data);
2994 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
2997 * i2c_smbus_read_word_data - SMBus "read word" protocol
2998 * @client: Handle to slave device
2999 * @command: Byte interpreted by slave
3001 * This executes the SMBus "read word" protocol, returning negative errno
3002 * else a 16-bit unsigned "word" received from the device.
3004 s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
3006 union i2c_smbus_data data;
3009 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3010 I2C_SMBUS_READ, command,
3011 I2C_SMBUS_WORD_DATA, &data);
3012 return (status < 0) ? status : data.word;
3014 EXPORT_SYMBOL(i2c_smbus_read_word_data);
3017 * i2c_smbus_write_word_data - SMBus "write word" protocol
3018 * @client: Handle to slave device
3019 * @command: Byte interpreted by slave
3020 * @value: 16-bit "word" being written
3022 * This executes the SMBus "write word" protocol, returning negative errno
3023 * else zero on success.
3025 s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
3028 union i2c_smbus_data data;
3030 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3031 I2C_SMBUS_WRITE, command,
3032 I2C_SMBUS_WORD_DATA, &data);
3034 EXPORT_SYMBOL(i2c_smbus_write_word_data);
3037 * i2c_smbus_read_block_data - SMBus "block read" protocol
3038 * @client: Handle to slave device
3039 * @command: Byte interpreted by slave
3040 * @values: Byte array into which data will be read; big enough to hold
3041 * the data returned by the slave. SMBus allows at most 32 bytes.
3043 * This executes the SMBus "block read" protocol, returning negative errno
3044 * else the number of data bytes in the slave's response.
3046 * Note that using this function requires that the client's adapter support
3047 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
3048 * support this; its emulation through I2C messaging relies on a specific
3049 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
3051 s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
3054 union i2c_smbus_data data;
3057 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3058 I2C_SMBUS_READ, command,
3059 I2C_SMBUS_BLOCK_DATA, &data);
3063 memcpy(values, &data.block[1], data.block[0]);
3064 return data.block[0];
3066 EXPORT_SYMBOL(i2c_smbus_read_block_data);
3069 * i2c_smbus_write_block_data - SMBus "block write" protocol
3070 * @client: Handle to slave device
3071 * @command: Byte interpreted by slave
3072 * @length: Size of data block; SMBus allows at most 32 bytes
3073 * @values: Byte array which will be written.
3075 * This executes the SMBus "block write" protocol, returning negative errno
3076 * else zero on success.
3078 s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
3079 u8 length, const u8 *values)
3081 union i2c_smbus_data data;
3083 if (length > I2C_SMBUS_BLOCK_MAX)
3084 length = I2C_SMBUS_BLOCK_MAX;
3085 data.block[0] = length;
3086 memcpy(&data.block[1], values, length);
3087 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3088 I2C_SMBUS_WRITE, command,
3089 I2C_SMBUS_BLOCK_DATA, &data);
3091 EXPORT_SYMBOL(i2c_smbus_write_block_data);
3093 /* Returns the number of read bytes */
3094 s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
3095 u8 length, u8 *values)
3097 union i2c_smbus_data data;
3100 if (length > I2C_SMBUS_BLOCK_MAX)
3101 length = I2C_SMBUS_BLOCK_MAX;
3102 data.block[0] = length;
3103 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3104 I2C_SMBUS_READ, command,
3105 I2C_SMBUS_I2C_BLOCK_DATA, &data);
3109 memcpy(values, &data.block[1], data.block[0]);
3110 return data.block[0];
3112 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
3114 s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
3115 u8 length, const u8 *values)
3117 union i2c_smbus_data data;
3119 if (length > I2C_SMBUS_BLOCK_MAX)
3120 length = I2C_SMBUS_BLOCK_MAX;
3121 data.block[0] = length;
3122 memcpy(data.block + 1, values, length);
3123 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
3124 I2C_SMBUS_WRITE, command,
3125 I2C_SMBUS_I2C_BLOCK_DATA, &data);
3127 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
3129 /* Simulate a SMBus command using the i2c protocol
3130 No checking of parameters is done! */
3131 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
3132 unsigned short flags,
3133 char read_write, u8 command, int size,
3134 union i2c_smbus_data *data)
3136 /* So we need to generate a series of msgs. In the case of writing, we
3137 need to use only one message; when reading, we need two. We initialize
3138 most things with sane defaults, to keep the code below somewhat
3140 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
3141 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
3142 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
3146 struct i2c_msg msg[2] = {
3154 .flags = flags | I2C_M_RD,
3160 msgbuf0[0] = command;
3162 case I2C_SMBUS_QUICK:
3164 /* Special case: The read/write field is used as data */
3165 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
3169 case I2C_SMBUS_BYTE:
3170 if (read_write == I2C_SMBUS_READ) {
3171 /* Special case: only a read! */
3172 msg[0].flags = I2C_M_RD | flags;
3176 case I2C_SMBUS_BYTE_DATA:
3177 if (read_write == I2C_SMBUS_READ)
3181 msgbuf0[1] = data->byte;
3184 case I2C_SMBUS_WORD_DATA:
3185 if (read_write == I2C_SMBUS_READ)
3189 msgbuf0[1] = data->word & 0xff;
3190 msgbuf0[2] = data->word >> 8;
3193 case I2C_SMBUS_PROC_CALL:
3194 num = 2; /* Special case */
3195 read_write = I2C_SMBUS_READ;
3198 msgbuf0[1] = data->word & 0xff;
3199 msgbuf0[2] = data->word >> 8;
3201 case I2C_SMBUS_BLOCK_DATA:
3202 if (read_write == I2C_SMBUS_READ) {
3203 msg[1].flags |= I2C_M_RECV_LEN;
3204 msg[1].len = 1; /* block length will be added by
3205 the underlying bus driver */
3207 msg[0].len = data->block[0] + 2;
3208 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
3209 dev_err(&adapter->dev,
3210 "Invalid block write size %d\n",
3214 for (i = 1; i < msg[0].len; i++)
3215 msgbuf0[i] = data->block[i-1];
3218 case I2C_SMBUS_BLOCK_PROC_CALL:
3219 num = 2; /* Another special case */
3220 read_write = I2C_SMBUS_READ;
3221 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
3222 dev_err(&adapter->dev,
3223 "Invalid block write size %d\n",
3227 msg[0].len = data->block[0] + 2;
3228 for (i = 1; i < msg[0].len; i++)
3229 msgbuf0[i] = data->block[i-1];
3230 msg[1].flags |= I2C_M_RECV_LEN;
3231 msg[1].len = 1; /* block length will be added by
3232 the underlying bus driver */
3234 case I2C_SMBUS_I2C_BLOCK_DATA:
3235 if (read_write == I2C_SMBUS_READ) {
3236 msg[1].len = data->block[0];
3238 msg[0].len = data->block[0] + 1;
3239 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
3240 dev_err(&adapter->dev,
3241 "Invalid block write size %d\n",
3245 for (i = 1; i <= data->block[0]; i++)
3246 msgbuf0[i] = data->block[i];
3250 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
3254 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
3255 && size != I2C_SMBUS_I2C_BLOCK_DATA);
3257 /* Compute PEC if first message is a write */
3258 if (!(msg[0].flags & I2C_M_RD)) {
3259 if (num == 1) /* Write only */
3260 i2c_smbus_add_pec(&msg[0]);
3261 else /* Write followed by read */
3262 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
3264 /* Ask for PEC if last message is a read */
3265 if (msg[num-1].flags & I2C_M_RD)
3269 status = i2c_transfer(adapter, msg, num);
3273 /* Check PEC if last message is a read */
3274 if (i && (msg[num-1].flags & I2C_M_RD)) {
3275 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
3280 if (read_write == I2C_SMBUS_READ)
3282 case I2C_SMBUS_BYTE:
3283 data->byte = msgbuf0[0];
3285 case I2C_SMBUS_BYTE_DATA:
3286 data->byte = msgbuf1[0];
3288 case I2C_SMBUS_WORD_DATA:
3289 case I2C_SMBUS_PROC_CALL:
3290 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
3292 case I2C_SMBUS_I2C_BLOCK_DATA:
3293 for (i = 0; i < data->block[0]; i++)
3294 data->block[i+1] = msgbuf1[i];
3296 case I2C_SMBUS_BLOCK_DATA:
3297 case I2C_SMBUS_BLOCK_PROC_CALL:
3298 for (i = 0; i < msgbuf1[0] + 1; i++)
3299 data->block[i] = msgbuf1[i];
3306 * i2c_smbus_xfer - execute SMBus protocol operations
3307 * @adapter: Handle to I2C bus
3308 * @addr: Address of SMBus slave on that bus
3309 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
3310 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
3311 * @command: Byte interpreted by slave, for protocols which use such bytes
3312 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
3313 * @data: Data to be read or written
3315 * This executes an SMBus protocol operation, and returns a negative
3316 * errno code else zero on success.
3318 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
3319 char read_write, u8 command, int protocol,
3320 union i2c_smbus_data *data)
3322 unsigned long orig_jiffies;
3326 /* If enabled, the following two tracepoints are conditional on
3327 * read_write and protocol.
3329 trace_smbus_write(adapter, addr, flags, read_write,
3330 command, protocol, data);
3331 trace_smbus_read(adapter, addr, flags, read_write,
3334 flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
3336 if (adapter->algo->smbus_xfer) {
3337 i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
3339 /* Retry automatically on arbitration loss */
3340 orig_jiffies = jiffies;
3341 for (res = 0, try = 0; try <= adapter->retries; try++) {
3342 res = adapter->algo->smbus_xfer(adapter, addr, flags,
3343 read_write, command,
3347 if (time_after(jiffies,
3348 orig_jiffies + adapter->timeout))
3351 i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
3353 if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
3356 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
3357 * implement native support for the SMBus operation.
3361 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
3362 command, protocol, data);
3365 /* If enabled, the reply tracepoint is conditional on read_write. */
3366 trace_smbus_reply(adapter, addr, flags, read_write,
3367 command, protocol, data);
3368 trace_smbus_result(adapter, addr, flags, read_write,
3369 command, protocol, res);
3373 EXPORT_SYMBOL(i2c_smbus_xfer);
3376 * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
3377 * @client: Handle to slave device
3378 * @command: Byte interpreted by slave
3379 * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes
3380 * @values: Byte array into which data will be read; big enough to hold
3381 * the data returned by the slave. SMBus allows at most
3382 * I2C_SMBUS_BLOCK_MAX bytes.
3384 * This executes the SMBus "block read" protocol if supported by the adapter.
3385 * If block read is not supported, it emulates it using either word or byte
3386 * read protocols depending on availability.
3388 * The addresses of the I2C slave device that are accessed with this function
3389 * must be mapped to a linear region, so that a block read will have the same
3390 * effect as a byte read. Before using this function you must double-check
3391 * if the I2C slave does support exchanging a block transfer with a byte
3394 s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
3395 u8 command, u8 length, u8 *values)
3400 if (length > I2C_SMBUS_BLOCK_MAX)
3401 length = I2C_SMBUS_BLOCK_MAX;
3403 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
3404 return i2c_smbus_read_i2c_block_data(client, command, length, values);
3406 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA))
3409 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) {
3410 while ((i + 2) <= length) {
3411 status = i2c_smbus_read_word_data(client, command + i);
3414 values[i] = status & 0xff;
3415 values[i + 1] = status >> 8;
3420 while (i < length) {
3421 status = i2c_smbus_read_byte_data(client, command + i);
3430 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated);
3432 #if IS_ENABLED(CONFIG_I2C_SLAVE)
3433 int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
3437 if (!client || !slave_cb) {
3438 WARN(1, "insufficent data\n");
3442 if (!(client->flags & I2C_CLIENT_SLAVE))
3443 dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n",
3446 if (!(client->flags & I2C_CLIENT_TEN)) {
3447 /* Enforce stricter address checking */
3448 ret = i2c_check_7bit_addr_validity_strict(client->addr);
3450 dev_err(&client->dev, "%s: invalid address\n", __func__);
3455 if (!client->adapter->algo->reg_slave) {
3456 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
3460 client->slave_cb = slave_cb;
3462 i2c_lock_adapter(client->adapter);
3463 ret = client->adapter->algo->reg_slave(client);
3464 i2c_unlock_adapter(client->adapter);
3467 client->slave_cb = NULL;
3468 dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
3473 EXPORT_SYMBOL_GPL(i2c_slave_register);
3475 int i2c_slave_unregister(struct i2c_client *client)
3479 if (!client->adapter->algo->unreg_slave) {
3480 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
3484 i2c_lock_adapter(client->adapter);
3485 ret = client->adapter->algo->unreg_slave(client);
3486 i2c_unlock_adapter(client->adapter);
3489 client->slave_cb = NULL;
3491 dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
3495 EXPORT_SYMBOL_GPL(i2c_slave_unregister);
3498 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
3499 MODULE_DESCRIPTION("I2C-Bus main module");
3500 MODULE_LICENSE("GPL");