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.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
19 /* ------------------------------------------------------------------------- */
21 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
22 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
23 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
24 Jean Delvare <jdelvare@suse.de>
25 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
26 Michael Lawnick <michael.lawnick.ext@nsn.com>
27 OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
28 (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
29 (c) 2013 Wolfram Sang <wsa@the-dreams.de>
32 #include <linux/module.h>
33 #include <linux/kernel.h>
34 #include <linux/delay.h>
35 #include <linux/errno.h>
36 #include <linux/gpio.h>
37 #include <linux/slab.h>
38 #include <linux/i2c.h>
39 #include <linux/init.h>
40 #include <linux/idr.h>
41 #include <linux/mutex.h>
43 #include <linux/of_device.h>
44 #include <linux/of_irq.h>
45 #include <linux/completion.h>
46 #include <linux/hardirq.h>
47 #include <linux/irqflags.h>
48 #include <linux/rwsem.h>
49 #include <linux/pm_runtime.h>
50 #include <linux/acpi.h>
51 #include <linux/jump_label.h>
52 #include <asm/uaccess.h>
56 #define CREATE_TRACE_POINTS
57 #include <trace/events/i2c.h>
59 /* core_lock protects i2c_adapter_idr, and guarantees
60 that device detection, deletion of detected devices, and attach_adapter
61 calls are serialized */
62 static DEFINE_MUTEX(core_lock);
63 static DEFINE_IDR(i2c_adapter_idr);
65 static struct device_type i2c_client_type;
66 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
68 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
70 void i2c_transfer_trace_reg(void)
72 static_key_slow_inc(&i2c_trace_msg);
75 void i2c_transfer_trace_unreg(void)
77 static_key_slow_dec(&i2c_trace_msg);
80 /* ------------------------------------------------------------------------- */
82 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
83 const struct i2c_client *client)
86 if (strcmp(client->name, id->name) == 0)
93 static int i2c_device_match(struct device *dev, struct device_driver *drv)
95 struct i2c_client *client = i2c_verify_client(dev);
96 struct i2c_driver *driver;
101 /* Attempt an OF style match */
102 if (of_driver_match_device(dev, drv))
105 /* Then ACPI style match */
106 if (acpi_driver_match_device(dev, drv))
109 driver = to_i2c_driver(drv);
110 /* match on an id table if there is one */
111 if (driver->id_table)
112 return i2c_match_id(driver->id_table, client) != NULL;
118 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
119 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
121 struct i2c_client *client = to_i2c_client(dev);
124 rc = acpi_device_uevent_modalias(dev, env);
128 if (add_uevent_var(env, "MODALIAS=%s%s",
129 I2C_MODULE_PREFIX, client->name))
131 dev_dbg(dev, "uevent\n");
135 /* i2c bus recovery routines */
136 static int get_scl_gpio_value(struct i2c_adapter *adap)
138 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
141 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
143 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
146 static int get_sda_gpio_value(struct i2c_adapter *adap)
148 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
151 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
153 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
154 struct device *dev = &adap->dev;
157 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
158 GPIOF_OUT_INIT_HIGH, "i2c-scl");
160 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
165 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
166 /* work without SDA polling */
167 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
176 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
178 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
181 gpio_free(bri->sda_gpio);
183 gpio_free(bri->scl_gpio);
187 * We are generating clock pulses. ndelay() determines durating of clk pulses.
188 * We will generate clock with rate 100 KHz and so duration of both clock levels
189 * is: delay in ns = (10^6 / 100) / 2
191 #define RECOVERY_NDELAY 5000
192 #define RECOVERY_CLK_CNT 9
194 static int i2c_generic_recovery(struct i2c_adapter *adap)
196 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
197 int i = 0, val = 1, ret = 0;
199 if (bri->prepare_recovery)
200 bri->prepare_recovery(bri);
203 * By this time SCL is high, as we need to give 9 falling-rising edges
205 while (i++ < RECOVERY_CLK_CNT * 2) {
207 /* Break if SDA is high */
208 if (bri->get_sda && bri->get_sda(adap))
210 /* SCL shouldn't be low here */
211 if (!bri->get_scl(adap)) {
213 "SCL is stuck low, exit recovery\n");
220 bri->set_scl(adap, val);
221 ndelay(RECOVERY_NDELAY);
224 if (bri->unprepare_recovery)
225 bri->unprepare_recovery(bri);
230 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
232 adap->bus_recovery_info->set_scl(adap, 1);
233 return i2c_generic_recovery(adap);
236 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
240 ret = i2c_get_gpios_for_recovery(adap);
244 ret = i2c_generic_recovery(adap);
245 i2c_put_gpios_for_recovery(adap);
250 int i2c_recover_bus(struct i2c_adapter *adap)
252 if (!adap->bus_recovery_info)
255 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
256 return adap->bus_recovery_info->recover_bus(adap);
259 static int i2c_device_probe(struct device *dev)
261 struct i2c_client *client = i2c_verify_client(dev);
262 struct i2c_driver *driver;
268 driver = to_i2c_driver(dev->driver);
269 if (!driver->probe || !driver->id_table)
272 if (!device_can_wakeup(&client->dev))
273 device_init_wakeup(&client->dev,
274 client->flags & I2C_CLIENT_WAKE);
275 dev_dbg(dev, "probe\n");
277 acpi_dev_pm_attach(&client->dev, true);
278 status = driver->probe(client, i2c_match_id(driver->id_table, client));
280 acpi_dev_pm_detach(&client->dev, true);
285 static int i2c_device_remove(struct device *dev)
287 struct i2c_client *client = i2c_verify_client(dev);
288 struct i2c_driver *driver;
291 if (!client || !dev->driver)
294 driver = to_i2c_driver(dev->driver);
295 if (driver->remove) {
296 dev_dbg(dev, "remove\n");
297 status = driver->remove(client);
300 acpi_dev_pm_detach(&client->dev, true);
304 static void i2c_device_shutdown(struct device *dev)
306 struct i2c_client *client = i2c_verify_client(dev);
307 struct i2c_driver *driver;
309 if (!client || !dev->driver)
311 driver = to_i2c_driver(dev->driver);
312 if (driver->shutdown)
313 driver->shutdown(client);
316 #ifdef CONFIG_PM_SLEEP
317 static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg)
319 struct i2c_client *client = i2c_verify_client(dev);
320 struct i2c_driver *driver;
322 if (!client || !dev->driver)
324 driver = to_i2c_driver(dev->driver);
325 if (!driver->suspend)
327 return driver->suspend(client, mesg);
330 static int i2c_legacy_resume(struct device *dev)
332 struct i2c_client *client = i2c_verify_client(dev);
333 struct i2c_driver *driver;
335 if (!client || !dev->driver)
337 driver = to_i2c_driver(dev->driver);
340 return driver->resume(client);
343 static int i2c_device_pm_suspend(struct device *dev)
345 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
348 return pm_generic_suspend(dev);
350 return i2c_legacy_suspend(dev, PMSG_SUSPEND);
353 static int i2c_device_pm_resume(struct device *dev)
355 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
358 return pm_generic_resume(dev);
360 return i2c_legacy_resume(dev);
363 static int i2c_device_pm_freeze(struct device *dev)
365 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
368 return pm_generic_freeze(dev);
370 return i2c_legacy_suspend(dev, PMSG_FREEZE);
373 static int i2c_device_pm_thaw(struct device *dev)
375 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
378 return pm_generic_thaw(dev);
380 return i2c_legacy_resume(dev);
383 static int i2c_device_pm_poweroff(struct device *dev)
385 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
388 return pm_generic_poweroff(dev);
390 return i2c_legacy_suspend(dev, PMSG_HIBERNATE);
393 static int i2c_device_pm_restore(struct device *dev)
395 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
398 return pm_generic_restore(dev);
400 return i2c_legacy_resume(dev);
402 #else /* !CONFIG_PM_SLEEP */
403 #define i2c_device_pm_suspend NULL
404 #define i2c_device_pm_resume NULL
405 #define i2c_device_pm_freeze NULL
406 #define i2c_device_pm_thaw NULL
407 #define i2c_device_pm_poweroff NULL
408 #define i2c_device_pm_restore NULL
409 #endif /* !CONFIG_PM_SLEEP */
411 static void i2c_client_dev_release(struct device *dev)
413 kfree(to_i2c_client(dev));
417 show_name(struct device *dev, struct device_attribute *attr, char *buf)
419 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
420 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
424 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
426 struct i2c_client *client = to_i2c_client(dev);
429 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
433 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
436 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
437 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
439 static struct attribute *i2c_dev_attrs[] = {
441 /* modalias helps coldplug: modprobe $(cat .../modalias) */
442 &dev_attr_modalias.attr,
446 static struct attribute_group i2c_dev_attr_group = {
447 .attrs = i2c_dev_attrs,
450 static const struct attribute_group *i2c_dev_attr_groups[] = {
455 static const struct dev_pm_ops i2c_device_pm_ops = {
456 .suspend = i2c_device_pm_suspend,
457 .resume = i2c_device_pm_resume,
458 .freeze = i2c_device_pm_freeze,
459 .thaw = i2c_device_pm_thaw,
460 .poweroff = i2c_device_pm_poweroff,
461 .restore = i2c_device_pm_restore,
463 pm_generic_runtime_suspend,
464 pm_generic_runtime_resume,
469 struct bus_type i2c_bus_type = {
471 .match = i2c_device_match,
472 .probe = i2c_device_probe,
473 .remove = i2c_device_remove,
474 .shutdown = i2c_device_shutdown,
475 .pm = &i2c_device_pm_ops,
477 EXPORT_SYMBOL_GPL(i2c_bus_type);
479 static struct device_type i2c_client_type = {
480 .groups = i2c_dev_attr_groups,
481 .uevent = i2c_device_uevent,
482 .release = i2c_client_dev_release,
487 * i2c_verify_client - return parameter as i2c_client, or NULL
488 * @dev: device, probably from some driver model iterator
490 * When traversing the driver model tree, perhaps using driver model
491 * iterators like @device_for_each_child(), you can't assume very much
492 * about the nodes you find. Use this function to avoid oopses caused
493 * by wrongly treating some non-I2C device as an i2c_client.
495 struct i2c_client *i2c_verify_client(struct device *dev)
497 return (dev->type == &i2c_client_type)
501 EXPORT_SYMBOL(i2c_verify_client);
504 /* This is a permissive address validity check, I2C address map constraints
505 * are purposely not enforced, except for the general call address. */
506 static int i2c_check_client_addr_validity(const struct i2c_client *client)
508 if (client->flags & I2C_CLIENT_TEN) {
509 /* 10-bit address, all values are valid */
510 if (client->addr > 0x3ff)
513 /* 7-bit address, reject the general call address */
514 if (client->addr == 0x00 || client->addr > 0x7f)
520 /* And this is a strict address validity check, used when probing. If a
521 * device uses a reserved address, then it shouldn't be probed. 7-bit
522 * addressing is assumed, 10-bit address devices are rare and should be
523 * explicitly enumerated. */
524 static int i2c_check_addr_validity(unsigned short addr)
527 * Reserved addresses per I2C specification:
528 * 0x00 General call address / START byte
530 * 0x02 Reserved for different bus format
531 * 0x03 Reserved for future purposes
532 * 0x04-0x07 Hs-mode master code
533 * 0x78-0x7b 10-bit slave addressing
534 * 0x7c-0x7f Reserved for future purposes
536 if (addr < 0x08 || addr > 0x77)
541 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
543 struct i2c_client *client = i2c_verify_client(dev);
544 int addr = *(int *)addrp;
546 if (client && client->addr == addr)
551 /* walk up mux tree */
552 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
554 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
557 result = device_for_each_child(&adapter->dev, &addr,
558 __i2c_check_addr_busy);
560 if (!result && parent)
561 result = i2c_check_mux_parents(parent, addr);
566 /* recurse down mux tree */
567 static int i2c_check_mux_children(struct device *dev, void *addrp)
571 if (dev->type == &i2c_adapter_type)
572 result = device_for_each_child(dev, addrp,
573 i2c_check_mux_children);
575 result = __i2c_check_addr_busy(dev, addrp);
580 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
582 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
586 result = i2c_check_mux_parents(parent, addr);
589 result = device_for_each_child(&adapter->dev, &addr,
590 i2c_check_mux_children);
596 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
597 * @adapter: Target I2C bus segment
599 void i2c_lock_adapter(struct i2c_adapter *adapter)
601 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
604 i2c_lock_adapter(parent);
606 rt_mutex_lock(&adapter->bus_lock);
608 EXPORT_SYMBOL_GPL(i2c_lock_adapter);
611 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
612 * @adapter: Target I2C bus segment
614 static int i2c_trylock_adapter(struct i2c_adapter *adapter)
616 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
619 return i2c_trylock_adapter(parent);
621 return rt_mutex_trylock(&adapter->bus_lock);
625 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
626 * @adapter: Target I2C bus segment
628 void i2c_unlock_adapter(struct i2c_adapter *adapter)
630 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
633 i2c_unlock_adapter(parent);
635 rt_mutex_unlock(&adapter->bus_lock);
637 EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
639 static void i2c_dev_set_name(struct i2c_adapter *adap,
640 struct i2c_client *client)
642 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
645 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
649 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
650 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
651 client->addr | ((client->flags & I2C_CLIENT_TEN)
656 * i2c_new_device - instantiate an i2c device
657 * @adap: the adapter managing the device
658 * @info: describes one I2C device; bus_num is ignored
661 * Create an i2c device. Binding is handled through driver model
662 * probe()/remove() methods. A driver may be bound to this device when we
663 * return from this function, or any later moment (e.g. maybe hotplugging will
664 * load the driver module). This call is not appropriate for use by mainboard
665 * initialization logic, which usually runs during an arch_initcall() long
666 * before any i2c_adapter could exist.
668 * This returns the new i2c client, which may be saved for later use with
669 * i2c_unregister_device(); or NULL to indicate an error.
672 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
674 struct i2c_client *client;
677 client = kzalloc(sizeof *client, GFP_KERNEL);
681 client->adapter = adap;
683 client->dev.platform_data = info->platform_data;
686 client->dev.archdata = *info->archdata;
688 client->flags = info->flags;
689 client->addr = info->addr;
690 client->irq = info->irq;
692 strlcpy(client->name, info->type, sizeof(client->name));
694 /* Check for address validity */
695 status = i2c_check_client_addr_validity(client);
697 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
698 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
702 /* Check for address business */
703 status = i2c_check_addr_busy(adap, client->addr);
707 client->dev.parent = &client->adapter->dev;
708 client->dev.bus = &i2c_bus_type;
709 client->dev.type = &i2c_client_type;
710 client->dev.of_node = info->of_node;
711 ACPI_COMPANION_SET(&client->dev, info->acpi_node.companion);
713 i2c_dev_set_name(adap, client);
714 status = device_register(&client->dev);
718 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
719 client->name, dev_name(&client->dev));
724 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
725 "(%d)\n", client->name, client->addr, status);
730 EXPORT_SYMBOL_GPL(i2c_new_device);
734 * i2c_unregister_device - reverse effect of i2c_new_device()
735 * @client: value returned from i2c_new_device()
738 void i2c_unregister_device(struct i2c_client *client)
740 device_unregister(&client->dev);
742 EXPORT_SYMBOL_GPL(i2c_unregister_device);
745 static const struct i2c_device_id dummy_id[] = {
750 static int dummy_probe(struct i2c_client *client,
751 const struct i2c_device_id *id)
756 static int dummy_remove(struct i2c_client *client)
761 static struct i2c_driver dummy_driver = {
762 .driver.name = "dummy",
763 .probe = dummy_probe,
764 .remove = dummy_remove,
765 .id_table = dummy_id,
769 * i2c_new_dummy - return a new i2c device bound to a dummy driver
770 * @adapter: the adapter managing the device
771 * @address: seven bit address to be used
774 * This returns an I2C client bound to the "dummy" driver, intended for use
775 * with devices that consume multiple addresses. Examples of such chips
776 * include various EEPROMS (like 24c04 and 24c08 models).
778 * These dummy devices have two main uses. First, most I2C and SMBus calls
779 * except i2c_transfer() need a client handle; the dummy will be that handle.
780 * And second, this prevents the specified address from being bound to a
783 * This returns the new i2c client, which should be saved for later use with
784 * i2c_unregister_device(); or NULL to indicate an error.
786 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
788 struct i2c_board_info info = {
789 I2C_BOARD_INFO("dummy", address),
792 return i2c_new_device(adapter, &info);
794 EXPORT_SYMBOL_GPL(i2c_new_dummy);
796 /* ------------------------------------------------------------------------- */
798 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
800 static void i2c_adapter_dev_release(struct device *dev)
802 struct i2c_adapter *adap = to_i2c_adapter(dev);
803 complete(&adap->dev_released);
807 * This function is only needed for mutex_lock_nested, so it is never
808 * called unless locking correctness checking is enabled. Thus we
809 * make it inline to avoid a compiler warning. That's what gcc ends up
812 static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
814 unsigned int depth = 0;
816 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
823 * Let users instantiate I2C devices through sysfs. This can be used when
824 * platform initialization code doesn't contain the proper data for
825 * whatever reason. Also useful for drivers that do device detection and
826 * detection fails, either because the device uses an unexpected address,
827 * or this is a compatible device with different ID register values.
829 * Parameter checking may look overzealous, but we really don't want
830 * the user to provide incorrect parameters.
833 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
834 const char *buf, size_t count)
836 struct i2c_adapter *adap = to_i2c_adapter(dev);
837 struct i2c_board_info info;
838 struct i2c_client *client;
842 memset(&info, 0, sizeof(struct i2c_board_info));
844 blank = strchr(buf, ' ');
846 dev_err(dev, "%s: Missing parameters\n", "new_device");
849 if (blank - buf > I2C_NAME_SIZE - 1) {
850 dev_err(dev, "%s: Invalid device name\n", "new_device");
853 memcpy(info.type, buf, blank - buf);
855 /* Parse remaining parameters, reject extra parameters */
856 res = sscanf(++blank, "%hi%c", &info.addr, &end);
858 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
861 if (res > 1 && end != '\n') {
862 dev_err(dev, "%s: Extra parameters\n", "new_device");
866 client = i2c_new_device(adap, &info);
870 /* Keep track of the added device */
871 mutex_lock(&adap->userspace_clients_lock);
872 list_add_tail(&client->detected, &adap->userspace_clients);
873 mutex_unlock(&adap->userspace_clients_lock);
874 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
875 info.type, info.addr);
881 * And of course let the users delete the devices they instantiated, if
882 * they got it wrong. This interface can only be used to delete devices
883 * instantiated by i2c_sysfs_new_device above. This guarantees that we
884 * don't delete devices to which some kernel code still has references.
886 * Parameter checking may look overzealous, but we really don't want
887 * the user to delete the wrong device.
890 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
891 const char *buf, size_t count)
893 struct i2c_adapter *adap = to_i2c_adapter(dev);
894 struct i2c_client *client, *next;
899 /* Parse parameters, reject extra parameters */
900 res = sscanf(buf, "%hi%c", &addr, &end);
902 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
905 if (res > 1 && end != '\n') {
906 dev_err(dev, "%s: Extra parameters\n", "delete_device");
910 /* Make sure the device was added through sysfs */
912 mutex_lock_nested(&adap->userspace_clients_lock,
913 i2c_adapter_depth(adap));
914 list_for_each_entry_safe(client, next, &adap->userspace_clients,
916 if (client->addr == addr) {
917 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
918 "delete_device", client->name, client->addr);
920 list_del(&client->detected);
921 i2c_unregister_device(client);
926 mutex_unlock(&adap->userspace_clients_lock);
929 dev_err(dev, "%s: Can't find device in list\n",
934 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
935 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
936 i2c_sysfs_delete_device);
938 static struct attribute *i2c_adapter_attrs[] = {
940 &dev_attr_new_device.attr,
941 &dev_attr_delete_device.attr,
945 static struct attribute_group i2c_adapter_attr_group = {
946 .attrs = i2c_adapter_attrs,
949 static const struct attribute_group *i2c_adapter_attr_groups[] = {
950 &i2c_adapter_attr_group,
954 struct device_type i2c_adapter_type = {
955 .groups = i2c_adapter_attr_groups,
956 .release = i2c_adapter_dev_release,
958 EXPORT_SYMBOL_GPL(i2c_adapter_type);
961 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
962 * @dev: device, probably from some driver model iterator
964 * When traversing the driver model tree, perhaps using driver model
965 * iterators like @device_for_each_child(), you can't assume very much
966 * about the nodes you find. Use this function to avoid oopses caused
967 * by wrongly treating some non-I2C device as an i2c_adapter.
969 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
971 return (dev->type == &i2c_adapter_type)
972 ? to_i2c_adapter(dev)
975 EXPORT_SYMBOL(i2c_verify_adapter);
977 #ifdef CONFIG_I2C_COMPAT
978 static struct class_compat *i2c_adapter_compat_class;
981 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
983 struct i2c_devinfo *devinfo;
985 down_read(&__i2c_board_lock);
986 list_for_each_entry(devinfo, &__i2c_board_list, list) {
987 if (devinfo->busnum == adapter->nr
988 && !i2c_new_device(adapter,
989 &devinfo->board_info))
990 dev_err(&adapter->dev,
991 "Can't create device at 0x%02x\n",
992 devinfo->board_info.addr);
994 up_read(&__i2c_board_lock);
997 /* OF support code */
999 #if IS_ENABLED(CONFIG_OF)
1000 static void of_i2c_register_devices(struct i2c_adapter *adap)
1003 struct device_node *node;
1005 /* Only register child devices if the adapter has a node pointer set */
1006 if (!adap->dev.of_node)
1009 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
1011 for_each_available_child_of_node(adap->dev.of_node, node) {
1012 struct i2c_board_info info = {};
1013 struct dev_archdata dev_ad = {};
1017 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1019 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
1020 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
1025 addr = of_get_property(node, "reg", &len);
1026 if (!addr || (len < sizeof(int))) {
1027 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
1032 info.addr = be32_to_cpup(addr);
1033 if (info.addr > (1 << 10) - 1) {
1034 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1035 info.addr, node->full_name);
1039 info.irq = irq_of_parse_and_map(node, 0);
1040 info.of_node = of_node_get(node);
1041 info.archdata = &dev_ad;
1043 if (of_get_property(node, "wakeup-source", NULL))
1044 info.flags |= I2C_CLIENT_WAKE;
1046 request_module("%s%s", I2C_MODULE_PREFIX, info.type);
1048 result = i2c_new_device(adap, &info);
1049 if (result == NULL) {
1050 dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
1053 irq_dispose_mapping(info.irq);
1059 static int of_dev_node_match(struct device *dev, void *data)
1061 return dev->of_node == data;
1064 /* must call put_device() when done with returned i2c_client device */
1065 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1069 dev = bus_find_device(&i2c_bus_type, NULL, node,
1074 return i2c_verify_client(dev);
1076 EXPORT_SYMBOL(of_find_i2c_device_by_node);
1078 /* must call put_device() when done with returned i2c_adapter device */
1079 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1083 dev = bus_find_device(&i2c_bus_type, NULL, node,
1088 return i2c_verify_adapter(dev);
1090 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1092 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
1093 #endif /* CONFIG_OF */
1095 static int i2c_do_add_adapter(struct i2c_driver *driver,
1096 struct i2c_adapter *adap)
1098 /* Detect supported devices on that bus, and instantiate them */
1099 i2c_detect(adap, driver);
1101 /* Let legacy drivers scan this bus for matching devices */
1102 if (driver->attach_adapter) {
1103 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1104 driver->driver.name);
1105 dev_warn(&adap->dev, "Please use another way to instantiate "
1106 "your i2c_client\n");
1107 /* We ignore the return code; if it fails, too bad */
1108 driver->attach_adapter(adap);
1113 static int __process_new_adapter(struct device_driver *d, void *data)
1115 return i2c_do_add_adapter(to_i2c_driver(d), data);
1118 static int i2c_register_adapter(struct i2c_adapter *adap)
1122 /* Can't register until after driver model init */
1123 if (unlikely(WARN_ON(!i2c_bus_type.p))) {
1129 if (unlikely(adap->name[0] == '\0')) {
1130 pr_err("i2c-core: Attempt to register an adapter with "
1134 if (unlikely(!adap->algo)) {
1135 pr_err("i2c-core: Attempt to register adapter '%s' with "
1136 "no algo!\n", adap->name);
1140 rt_mutex_init(&adap->bus_lock);
1141 mutex_init(&adap->userspace_clients_lock);
1142 INIT_LIST_HEAD(&adap->userspace_clients);
1144 /* Set default timeout to 1 second if not already set */
1145 if (adap->timeout == 0)
1148 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1149 adap->dev.bus = &i2c_bus_type;
1150 adap->dev.type = &i2c_adapter_type;
1151 res = device_register(&adap->dev);
1155 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1157 #ifdef CONFIG_I2C_COMPAT
1158 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1161 dev_warn(&adap->dev,
1162 "Failed to create compatibility class link\n");
1165 /* bus recovery specific initialization */
1166 if (adap->bus_recovery_info) {
1167 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
1169 if (!bri->recover_bus) {
1170 dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
1171 adap->bus_recovery_info = NULL;
1175 /* Generic GPIO recovery */
1176 if (bri->recover_bus == i2c_generic_gpio_recovery) {
1177 if (!gpio_is_valid(bri->scl_gpio)) {
1178 dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
1179 adap->bus_recovery_info = NULL;
1183 if (gpio_is_valid(bri->sda_gpio))
1184 bri->get_sda = get_sda_gpio_value;
1186 bri->get_sda = NULL;
1188 bri->get_scl = get_scl_gpio_value;
1189 bri->set_scl = set_scl_gpio_value;
1190 } else if (!bri->set_scl || !bri->get_scl) {
1191 /* Generic SCL recovery */
1192 dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
1193 adap->bus_recovery_info = NULL;
1198 /* create pre-declared device nodes */
1199 of_i2c_register_devices(adap);
1200 acpi_i2c_register_devices(adap);
1201 acpi_i2c_install_space_handler(adap);
1203 if (adap->nr < __i2c_first_dynamic_bus_num)
1204 i2c_scan_static_board_info(adap);
1206 /* Notify drivers */
1207 mutex_lock(&core_lock);
1208 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1209 mutex_unlock(&core_lock);
1214 mutex_lock(&core_lock);
1215 idr_remove(&i2c_adapter_idr, adap->nr);
1216 mutex_unlock(&core_lock);
1221 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1222 * @adap: the adapter to register (with adap->nr initialized)
1223 * Context: can sleep
1225 * See i2c_add_numbered_adapter() for details.
1227 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1231 mutex_lock(&core_lock);
1232 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
1234 mutex_unlock(&core_lock);
1236 return id == -ENOSPC ? -EBUSY : id;
1238 return i2c_register_adapter(adap);
1242 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1243 * @adapter: the adapter to add
1244 * Context: can sleep
1246 * This routine is used to declare an I2C adapter when its bus number
1247 * doesn't matter or when its bus number is specified by an dt alias.
1248 * Examples of bases when the bus number doesn't matter: I2C adapters
1249 * dynamically added by USB links or PCI plugin cards.
1251 * When this returns zero, a new bus number was allocated and stored
1252 * in adap->nr, and the specified adapter became available for clients.
1253 * Otherwise, a negative errno value is returned.
1255 int i2c_add_adapter(struct i2c_adapter *adapter)
1257 struct device *dev = &adapter->dev;
1261 id = of_alias_get_id(dev->of_node, "i2c");
1264 return __i2c_add_numbered_adapter(adapter);
1268 mutex_lock(&core_lock);
1269 id = idr_alloc(&i2c_adapter_idr, adapter,
1270 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1271 mutex_unlock(&core_lock);
1277 return i2c_register_adapter(adapter);
1279 EXPORT_SYMBOL(i2c_add_adapter);
1282 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1283 * @adap: the adapter to register (with adap->nr initialized)
1284 * Context: can sleep
1286 * This routine is used to declare an I2C adapter when its bus number
1287 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1288 * or otherwise built in to the system's mainboard, and where i2c_board_info
1289 * is used to properly configure I2C devices.
1291 * If the requested bus number is set to -1, then this function will behave
1292 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1294 * If no devices have pre-been declared for this bus, then be sure to
1295 * register the adapter before any dynamically allocated ones. Otherwise
1296 * the required bus ID may not be available.
1298 * When this returns zero, the specified adapter became available for
1299 * clients using the bus number provided in adap->nr. Also, the table
1300 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1301 * and the appropriate driver model device nodes are created. Otherwise, a
1302 * negative errno value is returned.
1304 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1306 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1307 return i2c_add_adapter(adap);
1309 return __i2c_add_numbered_adapter(adap);
1311 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1313 static void i2c_do_del_adapter(struct i2c_driver *driver,
1314 struct i2c_adapter *adapter)
1316 struct i2c_client *client, *_n;
1318 /* Remove the devices we created ourselves as the result of hardware
1319 * probing (using a driver's detect method) */
1320 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1321 if (client->adapter == adapter) {
1322 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1323 client->name, client->addr);
1324 list_del(&client->detected);
1325 i2c_unregister_device(client);
1330 static int __unregister_client(struct device *dev, void *dummy)
1332 struct i2c_client *client = i2c_verify_client(dev);
1333 if (client && strcmp(client->name, "dummy"))
1334 i2c_unregister_device(client);
1338 static int __unregister_dummy(struct device *dev, void *dummy)
1340 struct i2c_client *client = i2c_verify_client(dev);
1342 i2c_unregister_device(client);
1346 static int __process_removed_adapter(struct device_driver *d, void *data)
1348 i2c_do_del_adapter(to_i2c_driver(d), data);
1353 * i2c_del_adapter - unregister I2C adapter
1354 * @adap: the adapter being unregistered
1355 * Context: can sleep
1357 * This unregisters an I2C adapter which was previously registered
1358 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1360 void i2c_del_adapter(struct i2c_adapter *adap)
1362 struct i2c_adapter *found;
1363 struct i2c_client *client, *next;
1365 /* First make sure that this adapter was ever added */
1366 mutex_lock(&core_lock);
1367 found = idr_find(&i2c_adapter_idr, adap->nr);
1368 mutex_unlock(&core_lock);
1369 if (found != adap) {
1370 pr_debug("i2c-core: attempting to delete unregistered "
1371 "adapter [%s]\n", adap->name);
1375 acpi_i2c_remove_space_handler(adap);
1376 /* Tell drivers about this removal */
1377 mutex_lock(&core_lock);
1378 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1379 __process_removed_adapter);
1380 mutex_unlock(&core_lock);
1382 /* Remove devices instantiated from sysfs */
1383 mutex_lock_nested(&adap->userspace_clients_lock,
1384 i2c_adapter_depth(adap));
1385 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1387 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1389 list_del(&client->detected);
1390 i2c_unregister_device(client);
1392 mutex_unlock(&adap->userspace_clients_lock);
1394 /* Detach any active clients. This can't fail, thus we do not
1395 * check the returned value. This is a two-pass process, because
1396 * we can't remove the dummy devices during the first pass: they
1397 * could have been instantiated by real devices wishing to clean
1398 * them up properly, so we give them a chance to do that first. */
1399 device_for_each_child(&adap->dev, NULL, __unregister_client);
1400 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1402 #ifdef CONFIG_I2C_COMPAT
1403 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1407 /* device name is gone after device_unregister */
1408 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1410 /* clean up the sysfs representation */
1411 init_completion(&adap->dev_released);
1412 device_unregister(&adap->dev);
1414 /* wait for sysfs to drop all references */
1415 wait_for_completion(&adap->dev_released);
1418 mutex_lock(&core_lock);
1419 idr_remove(&i2c_adapter_idr, adap->nr);
1420 mutex_unlock(&core_lock);
1422 /* Clear the device structure in case this adapter is ever going to be
1424 memset(&adap->dev, 0, sizeof(adap->dev));
1426 EXPORT_SYMBOL(i2c_del_adapter);
1428 /* ------------------------------------------------------------------------- */
1430 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1434 mutex_lock(&core_lock);
1435 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1436 mutex_unlock(&core_lock);
1440 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1442 static int __process_new_driver(struct device *dev, void *data)
1444 if (dev->type != &i2c_adapter_type)
1446 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1450 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1451 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1454 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1458 /* Can't register until after driver model init */
1459 if (unlikely(WARN_ON(!i2c_bus_type.p)))
1462 /* add the driver to the list of i2c drivers in the driver core */
1463 driver->driver.owner = owner;
1464 driver->driver.bus = &i2c_bus_type;
1466 /* When registration returns, the driver core
1467 * will have called probe() for all matching-but-unbound devices.
1469 res = driver_register(&driver->driver);
1473 /* Drivers should switch to dev_pm_ops instead. */
1474 if (driver->suspend)
1475 pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
1476 driver->driver.name);
1478 pr_warn("i2c-core: driver [%s] using legacy resume method\n",
1479 driver->driver.name);
1481 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
1483 INIT_LIST_HEAD(&driver->clients);
1484 /* Walk the adapters that are already present */
1485 i2c_for_each_dev(driver, __process_new_driver);
1489 EXPORT_SYMBOL(i2c_register_driver);
1491 static int __process_removed_driver(struct device *dev, void *data)
1493 if (dev->type == &i2c_adapter_type)
1494 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1499 * i2c_del_driver - unregister I2C driver
1500 * @driver: the driver being unregistered
1501 * Context: can sleep
1503 void i2c_del_driver(struct i2c_driver *driver)
1505 i2c_for_each_dev(driver, __process_removed_driver);
1507 driver_unregister(&driver->driver);
1508 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
1510 EXPORT_SYMBOL(i2c_del_driver);
1512 /* ------------------------------------------------------------------------- */
1515 * i2c_use_client - increments the reference count of the i2c client structure
1516 * @client: the client being referenced
1518 * Each live reference to a client should be refcounted. The driver model does
1519 * that automatically as part of driver binding, so that most drivers don't
1520 * need to do this explicitly: they hold a reference until they're unbound
1523 * A pointer to the client with the incremented reference counter is returned.
1525 struct i2c_client *i2c_use_client(struct i2c_client *client)
1527 if (client && get_device(&client->dev))
1531 EXPORT_SYMBOL(i2c_use_client);
1534 * i2c_release_client - release a use of the i2c client structure
1535 * @client: the client being no longer referenced
1537 * Must be called when a user of a client is finished with it.
1539 void i2c_release_client(struct i2c_client *client)
1542 put_device(&client->dev);
1544 EXPORT_SYMBOL(i2c_release_client);
1546 struct i2c_cmd_arg {
1551 static int i2c_cmd(struct device *dev, void *_arg)
1553 struct i2c_client *client = i2c_verify_client(dev);
1554 struct i2c_cmd_arg *arg = _arg;
1555 struct i2c_driver *driver;
1557 if (!client || !client->dev.driver)
1560 driver = to_i2c_driver(client->dev.driver);
1561 if (driver->command)
1562 driver->command(client, arg->cmd, arg->arg);
1566 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1568 struct i2c_cmd_arg cmd_arg;
1572 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1574 EXPORT_SYMBOL(i2c_clients_command);
1576 static int __init i2c_init(void)
1580 retval = bus_register(&i2c_bus_type);
1583 #ifdef CONFIG_I2C_COMPAT
1584 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1585 if (!i2c_adapter_compat_class) {
1590 retval = i2c_add_driver(&dummy_driver);
1596 #ifdef CONFIG_I2C_COMPAT
1597 class_compat_unregister(i2c_adapter_compat_class);
1600 bus_unregister(&i2c_bus_type);
1604 static void __exit i2c_exit(void)
1606 i2c_del_driver(&dummy_driver);
1607 #ifdef CONFIG_I2C_COMPAT
1608 class_compat_unregister(i2c_adapter_compat_class);
1610 bus_unregister(&i2c_bus_type);
1611 tracepoint_synchronize_unregister();
1614 /* We must initialize early, because some subsystems register i2c drivers
1615 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1617 postcore_initcall(i2c_init);
1618 module_exit(i2c_exit);
1620 /* ----------------------------------------------------
1621 * the functional interface to the i2c busses.
1622 * ----------------------------------------------------
1626 * __i2c_transfer - unlocked flavor of i2c_transfer
1627 * @adap: Handle to I2C bus
1628 * @msgs: One or more messages to execute before STOP is issued to
1629 * terminate the operation; each message begins with a START.
1630 * @num: Number of messages to be executed.
1632 * Returns negative errno, else the number of messages executed.
1634 * Adapter lock must be held when calling this function. No debug logging
1635 * takes place. adap->algo->master_xfer existence isn't checked.
1637 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1639 unsigned long orig_jiffies;
1642 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1643 * enabled. This is an efficient way of keeping the for-loop from
1644 * being executed when not needed.
1646 if (static_key_false(&i2c_trace_msg)) {
1648 for (i = 0; i < num; i++)
1649 if (msgs[i].flags & I2C_M_RD)
1650 trace_i2c_read(adap, &msgs[i], i);
1652 trace_i2c_write(adap, &msgs[i], i);
1655 /* Retry automatically on arbitration loss */
1656 orig_jiffies = jiffies;
1657 for (ret = 0, try = 0; try <= adap->retries; try++) {
1658 ret = adap->algo->master_xfer(adap, msgs, num);
1661 if (time_after(jiffies, orig_jiffies + adap->timeout))
1665 if (static_key_false(&i2c_trace_msg)) {
1667 for (i = 0; i < ret; i++)
1668 if (msgs[i].flags & I2C_M_RD)
1669 trace_i2c_reply(adap, &msgs[i], i);
1670 trace_i2c_result(adap, i, ret);
1675 EXPORT_SYMBOL(__i2c_transfer);
1678 * i2c_transfer - execute a single or combined I2C message
1679 * @adap: Handle to I2C bus
1680 * @msgs: One or more messages to execute before STOP is issued to
1681 * terminate the operation; each message begins with a START.
1682 * @num: Number of messages to be executed.
1684 * Returns negative errno, else the number of messages executed.
1686 * Note that there is no requirement that each message be sent to
1687 * the same slave address, although that is the most common model.
1689 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1693 /* REVISIT the fault reporting model here is weak:
1695 * - When we get an error after receiving N bytes from a slave,
1696 * there is no way to report "N".
1698 * - When we get a NAK after transmitting N bytes to a slave,
1699 * there is no way to report "N" ... or to let the master
1700 * continue executing the rest of this combined message, if
1701 * that's the appropriate response.
1703 * - When for example "num" is two and we successfully complete
1704 * the first message but get an error part way through the
1705 * second, it's unclear whether that should be reported as
1706 * one (discarding status on the second message) or errno
1707 * (discarding status on the first one).
1710 if (adap->algo->master_xfer) {
1712 for (ret = 0; ret < num; ret++) {
1713 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
1714 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
1715 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
1716 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1720 if (in_atomic() || irqs_disabled()) {
1721 ret = i2c_trylock_adapter(adap);
1723 /* I2C activity is ongoing. */
1726 i2c_lock_adapter(adap);
1729 ret = __i2c_transfer(adap, msgs, num);
1730 i2c_unlock_adapter(adap);
1734 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1738 EXPORT_SYMBOL(i2c_transfer);
1741 * i2c_master_send - issue a single I2C message in master transmit mode
1742 * @client: Handle to slave device
1743 * @buf: Data that will be written to the slave
1744 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1746 * Returns negative errno, or else the number of bytes written.
1748 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1751 struct i2c_adapter *adap = client->adapter;
1754 msg.addr = client->addr;
1755 msg.flags = client->flags & I2C_M_TEN;
1757 msg.buf = (char *)buf;
1759 ret = i2c_transfer(adap, &msg, 1);
1762 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1763 * transmitted, else error code.
1765 return (ret == 1) ? count : ret;
1767 EXPORT_SYMBOL(i2c_master_send);
1770 * i2c_master_recv - issue a single I2C message in master receive mode
1771 * @client: Handle to slave device
1772 * @buf: Where to store data read from slave
1773 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1775 * Returns negative errno, or else the number of bytes read.
1777 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
1779 struct i2c_adapter *adap = client->adapter;
1783 msg.addr = client->addr;
1784 msg.flags = client->flags & I2C_M_TEN;
1785 msg.flags |= I2C_M_RD;
1789 ret = i2c_transfer(adap, &msg, 1);
1792 * If everything went ok (i.e. 1 msg received), return #bytes received,
1795 return (ret == 1) ? count : ret;
1797 EXPORT_SYMBOL(i2c_master_recv);
1799 /* ----------------------------------------------------
1800 * the i2c address scanning function
1801 * Will not work for 10-bit addresses!
1802 * ----------------------------------------------------
1806 * Legacy default probe function, mostly relevant for SMBus. The default
1807 * probe method is a quick write, but it is known to corrupt the 24RF08
1808 * EEPROMs due to a state machine bug, and could also irreversibly
1809 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1810 * we use a short byte read instead. Also, some bus drivers don't implement
1811 * quick write, so we fallback to a byte read in that case too.
1812 * On x86, there is another special case for FSC hardware monitoring chips,
1813 * which want regular byte reads (address 0x73.) Fortunately, these are the
1814 * only known chips using this I2C address on PC hardware.
1815 * Returns 1 if probe succeeded, 0 if not.
1817 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
1820 union i2c_smbus_data dummy;
1823 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
1824 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
1825 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1826 I2C_SMBUS_BYTE_DATA, &dummy);
1829 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
1830 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
1831 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
1832 I2C_SMBUS_QUICK, NULL);
1833 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
1834 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1835 I2C_SMBUS_BYTE, &dummy);
1837 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
1845 static int i2c_detect_address(struct i2c_client *temp_client,
1846 struct i2c_driver *driver)
1848 struct i2c_board_info info;
1849 struct i2c_adapter *adapter = temp_client->adapter;
1850 int addr = temp_client->addr;
1853 /* Make sure the address is valid */
1854 err = i2c_check_addr_validity(addr);
1856 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
1861 /* Skip if already in use */
1862 if (i2c_check_addr_busy(adapter, addr))
1865 /* Make sure there is something at this address */
1866 if (!i2c_default_probe(adapter, addr))
1869 /* Finally call the custom detection function */
1870 memset(&info, 0, sizeof(struct i2c_board_info));
1872 err = driver->detect(temp_client, &info);
1874 /* -ENODEV is returned if the detection fails. We catch it
1875 here as this isn't an error. */
1876 return err == -ENODEV ? 0 : err;
1879 /* Consistency check */
1880 if (info.type[0] == '\0') {
1881 dev_err(&adapter->dev, "%s detection function provided "
1882 "no name for 0x%x\n", driver->driver.name,
1885 struct i2c_client *client;
1887 /* Detection succeeded, instantiate the device */
1888 if (adapter->class & I2C_CLASS_DEPRECATED)
1889 dev_warn(&adapter->dev,
1890 "This adapter will soon drop class based instantiation of devices. "
1891 "Please make sure client 0x%02x gets instantiated by other means. "
1892 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
1895 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
1896 info.type, info.addr);
1897 client = i2c_new_device(adapter, &info);
1899 list_add_tail(&client->detected, &driver->clients);
1901 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
1902 info.type, info.addr);
1907 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
1909 const unsigned short *address_list;
1910 struct i2c_client *temp_client;
1912 int adap_id = i2c_adapter_id(adapter);
1914 address_list = driver->address_list;
1915 if (!driver->detect || !address_list)
1918 /* Warn that the adapter lost class based instantiation */
1919 if (adapter->class == I2C_CLASS_DEPRECATED) {
1920 dev_dbg(&adapter->dev,
1921 "This adapter dropped support for I2C classes and "
1922 "won't auto-detect %s devices anymore. If you need it, check "
1923 "'Documentation/i2c/instantiating-devices' for alternatives.\n",
1924 driver->driver.name);
1928 /* Stop here if the classes do not match */
1929 if (!(adapter->class & driver->class))
1932 /* Set up a temporary client to help detect callback */
1933 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
1936 temp_client->adapter = adapter;
1938 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
1939 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
1940 "addr 0x%02x\n", adap_id, address_list[i]);
1941 temp_client->addr = address_list[i];
1942 err = i2c_detect_address(temp_client, driver);
1951 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
1953 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1954 I2C_SMBUS_QUICK, NULL) >= 0;
1956 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
1959 i2c_new_probed_device(struct i2c_adapter *adap,
1960 struct i2c_board_info *info,
1961 unsigned short const *addr_list,
1962 int (*probe)(struct i2c_adapter *, unsigned short addr))
1967 probe = i2c_default_probe;
1969 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
1970 /* Check address validity */
1971 if (i2c_check_addr_validity(addr_list[i]) < 0) {
1972 dev_warn(&adap->dev, "Invalid 7-bit address "
1973 "0x%02x\n", addr_list[i]);
1977 /* Check address availability */
1978 if (i2c_check_addr_busy(adap, addr_list[i])) {
1979 dev_dbg(&adap->dev, "Address 0x%02x already in "
1980 "use, not probing\n", addr_list[i]);
1984 /* Test address responsiveness */
1985 if (probe(adap, addr_list[i]))
1989 if (addr_list[i] == I2C_CLIENT_END) {
1990 dev_dbg(&adap->dev, "Probing failed, no device found\n");
1994 info->addr = addr_list[i];
1995 return i2c_new_device(adap, info);
1997 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
1999 struct i2c_adapter *i2c_get_adapter(int nr)
2001 struct i2c_adapter *adapter;
2003 mutex_lock(&core_lock);
2004 adapter = idr_find(&i2c_adapter_idr, nr);
2005 if (adapter && !try_module_get(adapter->owner))
2008 mutex_unlock(&core_lock);
2011 EXPORT_SYMBOL(i2c_get_adapter);
2013 void i2c_put_adapter(struct i2c_adapter *adap)
2016 module_put(adap->owner);
2018 EXPORT_SYMBOL(i2c_put_adapter);
2020 /* The SMBus parts */
2022 #define POLY (0x1070U << 3)
2023 static u8 crc8(u16 data)
2027 for (i = 0; i < 8; i++) {
2032 return (u8)(data >> 8);
2035 /* Incremental CRC8 over count bytes in the array pointed to by p */
2036 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
2040 for (i = 0; i < count; i++)
2041 crc = crc8((crc ^ p[i]) << 8);
2045 /* Assume a 7-bit address, which is reasonable for SMBus */
2046 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
2048 /* The address will be sent first */
2049 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
2050 pec = i2c_smbus_pec(pec, &addr, 1);
2052 /* The data buffer follows */
2053 return i2c_smbus_pec(pec, msg->buf, msg->len);
2056 /* Used for write only transactions */
2057 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
2059 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
2063 /* Return <0 on CRC error
2064 If there was a write before this read (most cases) we need to take the
2065 partial CRC from the write part into account.
2066 Note that this function does modify the message (we need to decrease the
2067 message length to hide the CRC byte from the caller). */
2068 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
2070 u8 rpec = msg->buf[--msg->len];
2071 cpec = i2c_smbus_msg_pec(cpec, msg);
2074 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2082 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2083 * @client: Handle to slave device
2085 * This executes the SMBus "receive byte" protocol, returning negative errno
2086 * else the byte received from the device.
2088 s32 i2c_smbus_read_byte(const struct i2c_client *client)
2090 union i2c_smbus_data data;
2093 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2095 I2C_SMBUS_BYTE, &data);
2096 return (status < 0) ? status : data.byte;
2098 EXPORT_SYMBOL(i2c_smbus_read_byte);
2101 * i2c_smbus_write_byte - SMBus "send byte" protocol
2102 * @client: Handle to slave device
2103 * @value: Byte to be sent
2105 * This executes the SMBus "send byte" protocol, returning negative errno
2106 * else zero on success.
2108 s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
2110 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2111 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
2113 EXPORT_SYMBOL(i2c_smbus_write_byte);
2116 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2117 * @client: Handle to slave device
2118 * @command: Byte interpreted by slave
2120 * This executes the SMBus "read byte" protocol, returning negative errno
2121 * else a data byte received from the device.
2123 s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
2125 union i2c_smbus_data data;
2128 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2129 I2C_SMBUS_READ, command,
2130 I2C_SMBUS_BYTE_DATA, &data);
2131 return (status < 0) ? status : data.byte;
2133 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
2136 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2137 * @client: Handle to slave device
2138 * @command: Byte interpreted by slave
2139 * @value: Byte being written
2141 * This executes the SMBus "write byte" protocol, returning negative errno
2142 * else zero on success.
2144 s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
2147 union i2c_smbus_data data;
2149 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2150 I2C_SMBUS_WRITE, command,
2151 I2C_SMBUS_BYTE_DATA, &data);
2153 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
2156 * i2c_smbus_read_word_data - SMBus "read word" protocol
2157 * @client: Handle to slave device
2158 * @command: Byte interpreted by slave
2160 * This executes the SMBus "read word" protocol, returning negative errno
2161 * else a 16-bit unsigned "word" received from the device.
2163 s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
2165 union i2c_smbus_data data;
2168 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2169 I2C_SMBUS_READ, command,
2170 I2C_SMBUS_WORD_DATA, &data);
2171 return (status < 0) ? status : data.word;
2173 EXPORT_SYMBOL(i2c_smbus_read_word_data);
2176 * i2c_smbus_write_word_data - SMBus "write word" protocol
2177 * @client: Handle to slave device
2178 * @command: Byte interpreted by slave
2179 * @value: 16-bit "word" being written
2181 * This executes the SMBus "write word" protocol, returning negative errno
2182 * else zero on success.
2184 s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
2187 union i2c_smbus_data data;
2189 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2190 I2C_SMBUS_WRITE, command,
2191 I2C_SMBUS_WORD_DATA, &data);
2193 EXPORT_SYMBOL(i2c_smbus_write_word_data);
2196 * i2c_smbus_read_block_data - SMBus "block read" protocol
2197 * @client: Handle to slave device
2198 * @command: Byte interpreted by slave
2199 * @values: Byte array into which data will be read; big enough to hold
2200 * the data returned by the slave. SMBus allows at most 32 bytes.
2202 * This executes the SMBus "block read" protocol, returning negative errno
2203 * else the number of data bytes in the slave's response.
2205 * Note that using this function requires that the client's adapter support
2206 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2207 * support this; its emulation through I2C messaging relies on a specific
2208 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2210 s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2213 union i2c_smbus_data data;
2216 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2217 I2C_SMBUS_READ, command,
2218 I2C_SMBUS_BLOCK_DATA, &data);
2222 memcpy(values, &data.block[1], data.block[0]);
2223 return data.block[0];
2225 EXPORT_SYMBOL(i2c_smbus_read_block_data);
2228 * i2c_smbus_write_block_data - SMBus "block write" protocol
2229 * @client: Handle to slave device
2230 * @command: Byte interpreted by slave
2231 * @length: Size of data block; SMBus allows at most 32 bytes
2232 * @values: Byte array which will be written.
2234 * This executes the SMBus "block write" protocol, returning negative errno
2235 * else zero on success.
2237 s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2238 u8 length, const u8 *values)
2240 union i2c_smbus_data data;
2242 if (length > I2C_SMBUS_BLOCK_MAX)
2243 length = I2C_SMBUS_BLOCK_MAX;
2244 data.block[0] = length;
2245 memcpy(&data.block[1], values, length);
2246 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2247 I2C_SMBUS_WRITE, command,
2248 I2C_SMBUS_BLOCK_DATA, &data);
2250 EXPORT_SYMBOL(i2c_smbus_write_block_data);
2252 /* Returns the number of read bytes */
2253 s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2254 u8 length, u8 *values)
2256 union i2c_smbus_data data;
2259 if (length > I2C_SMBUS_BLOCK_MAX)
2260 length = I2C_SMBUS_BLOCK_MAX;
2261 data.block[0] = length;
2262 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2263 I2C_SMBUS_READ, command,
2264 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2268 memcpy(values, &data.block[1], data.block[0]);
2269 return data.block[0];
2271 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
2273 s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2274 u8 length, const u8 *values)
2276 union i2c_smbus_data data;
2278 if (length > I2C_SMBUS_BLOCK_MAX)
2279 length = I2C_SMBUS_BLOCK_MAX;
2280 data.block[0] = length;
2281 memcpy(data.block + 1, values, length);
2282 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2283 I2C_SMBUS_WRITE, command,
2284 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2286 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2288 /* Simulate a SMBus command using the i2c protocol
2289 No checking of parameters is done! */
2290 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
2291 unsigned short flags,
2292 char read_write, u8 command, int size,
2293 union i2c_smbus_data *data)
2295 /* So we need to generate a series of msgs. In the case of writing, we
2296 need to use only one message; when reading, we need two. We initialize
2297 most things with sane defaults, to keep the code below somewhat
2299 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
2300 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2301 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
2305 struct i2c_msg msg[2] = {
2313 .flags = flags | I2C_M_RD,
2319 msgbuf0[0] = command;
2321 case I2C_SMBUS_QUICK:
2323 /* Special case: The read/write field is used as data */
2324 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
2328 case I2C_SMBUS_BYTE:
2329 if (read_write == I2C_SMBUS_READ) {
2330 /* Special case: only a read! */
2331 msg[0].flags = I2C_M_RD | flags;
2335 case I2C_SMBUS_BYTE_DATA:
2336 if (read_write == I2C_SMBUS_READ)
2340 msgbuf0[1] = data->byte;
2343 case I2C_SMBUS_WORD_DATA:
2344 if (read_write == I2C_SMBUS_READ)
2348 msgbuf0[1] = data->word & 0xff;
2349 msgbuf0[2] = data->word >> 8;
2352 case I2C_SMBUS_PROC_CALL:
2353 num = 2; /* Special case */
2354 read_write = I2C_SMBUS_READ;
2357 msgbuf0[1] = data->word & 0xff;
2358 msgbuf0[2] = data->word >> 8;
2360 case I2C_SMBUS_BLOCK_DATA:
2361 if (read_write == I2C_SMBUS_READ) {
2362 msg[1].flags |= I2C_M_RECV_LEN;
2363 msg[1].len = 1; /* block length will be added by
2364 the underlying bus driver */
2366 msg[0].len = data->block[0] + 2;
2367 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
2368 dev_err(&adapter->dev,
2369 "Invalid block write size %d\n",
2373 for (i = 1; i < msg[0].len; i++)
2374 msgbuf0[i] = data->block[i-1];
2377 case I2C_SMBUS_BLOCK_PROC_CALL:
2378 num = 2; /* Another special case */
2379 read_write = I2C_SMBUS_READ;
2380 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
2381 dev_err(&adapter->dev,
2382 "Invalid block write size %d\n",
2386 msg[0].len = data->block[0] + 2;
2387 for (i = 1; i < msg[0].len; i++)
2388 msgbuf0[i] = data->block[i-1];
2389 msg[1].flags |= I2C_M_RECV_LEN;
2390 msg[1].len = 1; /* block length will be added by
2391 the underlying bus driver */
2393 case I2C_SMBUS_I2C_BLOCK_DATA:
2394 if (read_write == I2C_SMBUS_READ) {
2395 msg[1].len = data->block[0];
2397 msg[0].len = data->block[0] + 1;
2398 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
2399 dev_err(&adapter->dev,
2400 "Invalid block write size %d\n",
2404 for (i = 1; i <= data->block[0]; i++)
2405 msgbuf0[i] = data->block[i];
2409 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
2413 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
2414 && size != I2C_SMBUS_I2C_BLOCK_DATA);
2416 /* Compute PEC if first message is a write */
2417 if (!(msg[0].flags & I2C_M_RD)) {
2418 if (num == 1) /* Write only */
2419 i2c_smbus_add_pec(&msg[0]);
2420 else /* Write followed by read */
2421 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
2423 /* Ask for PEC if last message is a read */
2424 if (msg[num-1].flags & I2C_M_RD)
2428 status = i2c_transfer(adapter, msg, num);
2432 /* Check PEC if last message is a read */
2433 if (i && (msg[num-1].flags & I2C_M_RD)) {
2434 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
2439 if (read_write == I2C_SMBUS_READ)
2441 case I2C_SMBUS_BYTE:
2442 data->byte = msgbuf0[0];
2444 case I2C_SMBUS_BYTE_DATA:
2445 data->byte = msgbuf1[0];
2447 case I2C_SMBUS_WORD_DATA:
2448 case I2C_SMBUS_PROC_CALL:
2449 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
2451 case I2C_SMBUS_I2C_BLOCK_DATA:
2452 for (i = 0; i < data->block[0]; i++)
2453 data->block[i+1] = msgbuf1[i];
2455 case I2C_SMBUS_BLOCK_DATA:
2456 case I2C_SMBUS_BLOCK_PROC_CALL:
2457 for (i = 0; i < msgbuf1[0] + 1; i++)
2458 data->block[i] = msgbuf1[i];
2465 * i2c_smbus_xfer - execute SMBus protocol operations
2466 * @adapter: Handle to I2C bus
2467 * @addr: Address of SMBus slave on that bus
2468 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2469 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2470 * @command: Byte interpreted by slave, for protocols which use such bytes
2471 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2472 * @data: Data to be read or written
2474 * This executes an SMBus protocol operation, and returns a negative
2475 * errno code else zero on success.
2477 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
2478 char read_write, u8 command, int protocol,
2479 union i2c_smbus_data *data)
2481 unsigned long orig_jiffies;
2485 /* If enabled, the following two tracepoints are conditional on
2486 * read_write and protocol.
2488 trace_smbus_write(adapter, addr, flags, read_write,
2489 command, protocol, data);
2490 trace_smbus_read(adapter, addr, flags, read_write,
2493 flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
2495 if (adapter->algo->smbus_xfer) {
2496 i2c_lock_adapter(adapter);
2498 /* Retry automatically on arbitration loss */
2499 orig_jiffies = jiffies;
2500 for (res = 0, try = 0; try <= adapter->retries; try++) {
2501 res = adapter->algo->smbus_xfer(adapter, addr, flags,
2502 read_write, command,
2506 if (time_after(jiffies,
2507 orig_jiffies + adapter->timeout))
2510 i2c_unlock_adapter(adapter);
2512 if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
2515 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2516 * implement native support for the SMBus operation.
2520 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
2521 command, protocol, data);
2524 /* If enabled, the reply tracepoint is conditional on read_write. */
2525 trace_smbus_reply(adapter, addr, flags, read_write,
2526 command, protocol, data);
2527 trace_smbus_result(adapter, addr, flags, read_write,
2528 command, protocol, res);
2532 EXPORT_SYMBOL(i2c_smbus_xfer);
2534 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2535 MODULE_DESCRIPTION("I2C-Bus main module");
2536 MODULE_LICENSE("GPL");