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>
27 #include <linux/module.h>
28 #include <linux/kernel.h>
29 #include <linux/delay.h>
30 #include <linux/errno.h>
31 #include <linux/gpio.h>
32 #include <linux/slab.h>
33 #include <linux/i2c.h>
34 #include <linux/init.h>
35 #include <linux/idr.h>
36 #include <linux/mutex.h>
38 #include <linux/of_device.h>
39 #include <linux/of_irq.h>
40 #include <linux/completion.h>
41 #include <linux/hardirq.h>
42 #include <linux/irqflags.h>
43 #include <linux/rwsem.h>
44 #include <linux/pm_runtime.h>
45 #include <linux/acpi.h>
46 #include <asm/uaccess.h>
51 /* core_lock protects i2c_adapter_idr, and guarantees
52 that device detection, deletion of detected devices, and attach_adapter
53 calls are serialized */
54 static DEFINE_MUTEX(core_lock);
55 static DEFINE_IDR(i2c_adapter_idr);
57 static struct device_type i2c_client_type;
58 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
60 /* ------------------------------------------------------------------------- */
62 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
63 const struct i2c_client *client)
66 if (strcmp(client->name, id->name) == 0)
73 static int i2c_device_match(struct device *dev, struct device_driver *drv)
75 struct i2c_client *client = i2c_verify_client(dev);
76 struct i2c_driver *driver;
81 /* Attempt an OF style match */
82 if (of_driver_match_device(dev, drv))
85 /* Then ACPI style match */
86 if (acpi_driver_match_device(dev, drv))
89 driver = to_i2c_driver(drv);
90 /* match on an id table if there is one */
92 return i2c_match_id(driver->id_table, client) != NULL;
98 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
99 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
101 struct i2c_client *client = to_i2c_client(dev);
104 rc = acpi_device_uevent_modalias(dev, env);
108 if (add_uevent_var(env, "MODALIAS=%s%s",
109 I2C_MODULE_PREFIX, client->name))
111 dev_dbg(dev, "uevent\n");
115 /* i2c bus recovery routines */
116 static int get_scl_gpio_value(struct i2c_adapter *adap)
118 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
121 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
123 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
126 static int get_sda_gpio_value(struct i2c_adapter *adap)
128 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
131 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
133 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
134 struct device *dev = &adap->dev;
137 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
138 GPIOF_OUT_INIT_HIGH, "i2c-scl");
140 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
145 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
146 /* work without SDA polling */
147 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
156 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
158 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
161 gpio_free(bri->sda_gpio);
163 gpio_free(bri->scl_gpio);
167 * We are generating clock pulses. ndelay() determines durating of clk pulses.
168 * We will generate clock with rate 100 KHz and so duration of both clock levels
169 * is: delay in ns = (10^6 / 100) / 2
171 #define RECOVERY_NDELAY 5000
172 #define RECOVERY_CLK_CNT 9
174 static int i2c_generic_recovery(struct i2c_adapter *adap)
176 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
177 int i = 0, val = 1, ret = 0;
179 if (bri->prepare_recovery)
180 bri->prepare_recovery(bri);
183 * By this time SCL is high, as we need to give 9 falling-rising edges
185 while (i++ < RECOVERY_CLK_CNT * 2) {
187 /* Break if SDA is high */
188 if (bri->get_sda && bri->get_sda(adap))
190 /* SCL shouldn't be low here */
191 if (!bri->get_scl(adap)) {
193 "SCL is stuck low, exit recovery\n");
200 bri->set_scl(adap, val);
201 ndelay(RECOVERY_NDELAY);
204 if (bri->unprepare_recovery)
205 bri->unprepare_recovery(bri);
210 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
212 adap->bus_recovery_info->set_scl(adap, 1);
213 return i2c_generic_recovery(adap);
216 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
220 ret = i2c_get_gpios_for_recovery(adap);
224 ret = i2c_generic_recovery(adap);
225 i2c_put_gpios_for_recovery(adap);
230 int i2c_recover_bus(struct i2c_adapter *adap)
232 if (!adap->bus_recovery_info)
235 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
236 return adap->bus_recovery_info->recover_bus(adap);
239 static int i2c_device_probe(struct device *dev)
241 struct i2c_client *client = i2c_verify_client(dev);
242 struct i2c_driver *driver;
248 driver = to_i2c_driver(dev->driver);
249 if (!driver->probe || !driver->id_table)
252 if (!device_can_wakeup(&client->dev))
253 device_init_wakeup(&client->dev,
254 client->flags & I2C_CLIENT_WAKE);
255 dev_dbg(dev, "probe\n");
257 acpi_dev_pm_attach(&client->dev, true);
258 status = driver->probe(client, i2c_match_id(driver->id_table, client));
260 acpi_dev_pm_detach(&client->dev, true);
265 static int i2c_device_remove(struct device *dev)
267 struct i2c_client *client = i2c_verify_client(dev);
268 struct i2c_driver *driver;
271 if (!client || !dev->driver)
274 driver = to_i2c_driver(dev->driver);
275 if (driver->remove) {
276 dev_dbg(dev, "remove\n");
277 status = driver->remove(client);
280 acpi_dev_pm_detach(&client->dev, true);
284 static void i2c_device_shutdown(struct device *dev)
286 struct i2c_client *client = i2c_verify_client(dev);
287 struct i2c_driver *driver;
289 if (!client || !dev->driver)
291 driver = to_i2c_driver(dev->driver);
292 if (driver->shutdown)
293 driver->shutdown(client);
296 #ifdef CONFIG_PM_SLEEP
297 static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg)
299 struct i2c_client *client = i2c_verify_client(dev);
300 struct i2c_driver *driver;
302 if (!client || !dev->driver)
304 driver = to_i2c_driver(dev->driver);
305 if (!driver->suspend)
307 return driver->suspend(client, mesg);
310 static int i2c_legacy_resume(struct device *dev)
312 struct i2c_client *client = i2c_verify_client(dev);
313 struct i2c_driver *driver;
315 if (!client || !dev->driver)
317 driver = to_i2c_driver(dev->driver);
320 return driver->resume(client);
323 static int i2c_device_pm_suspend(struct device *dev)
325 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
328 return pm_generic_suspend(dev);
330 return i2c_legacy_suspend(dev, PMSG_SUSPEND);
333 static int i2c_device_pm_resume(struct device *dev)
335 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
338 return pm_generic_resume(dev);
340 return i2c_legacy_resume(dev);
343 static int i2c_device_pm_freeze(struct device *dev)
345 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
348 return pm_generic_freeze(dev);
350 return i2c_legacy_suspend(dev, PMSG_FREEZE);
353 static int i2c_device_pm_thaw(struct device *dev)
355 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
358 return pm_generic_thaw(dev);
360 return i2c_legacy_resume(dev);
363 static int i2c_device_pm_poweroff(struct device *dev)
365 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
368 return pm_generic_poweroff(dev);
370 return i2c_legacy_suspend(dev, PMSG_HIBERNATE);
373 static int i2c_device_pm_restore(struct device *dev)
375 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
378 return pm_generic_restore(dev);
380 return i2c_legacy_resume(dev);
382 #else /* !CONFIG_PM_SLEEP */
383 #define i2c_device_pm_suspend NULL
384 #define i2c_device_pm_resume NULL
385 #define i2c_device_pm_freeze NULL
386 #define i2c_device_pm_thaw NULL
387 #define i2c_device_pm_poweroff NULL
388 #define i2c_device_pm_restore NULL
389 #endif /* !CONFIG_PM_SLEEP */
391 static void i2c_client_dev_release(struct device *dev)
393 kfree(to_i2c_client(dev));
397 show_name(struct device *dev, struct device_attribute *attr, char *buf)
399 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
400 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
404 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
406 struct i2c_client *client = to_i2c_client(dev);
409 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
413 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
416 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
417 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
419 static struct attribute *i2c_dev_attrs[] = {
421 /* modalias helps coldplug: modprobe $(cat .../modalias) */
422 &dev_attr_modalias.attr,
426 static struct attribute_group i2c_dev_attr_group = {
427 .attrs = i2c_dev_attrs,
430 static const struct attribute_group *i2c_dev_attr_groups[] = {
435 static const struct dev_pm_ops i2c_device_pm_ops = {
436 .suspend = i2c_device_pm_suspend,
437 .resume = i2c_device_pm_resume,
438 .freeze = i2c_device_pm_freeze,
439 .thaw = i2c_device_pm_thaw,
440 .poweroff = i2c_device_pm_poweroff,
441 .restore = i2c_device_pm_restore,
443 pm_generic_runtime_suspend,
444 pm_generic_runtime_resume,
449 struct bus_type i2c_bus_type = {
451 .match = i2c_device_match,
452 .probe = i2c_device_probe,
453 .remove = i2c_device_remove,
454 .shutdown = i2c_device_shutdown,
455 .pm = &i2c_device_pm_ops,
457 EXPORT_SYMBOL_GPL(i2c_bus_type);
459 static struct device_type i2c_client_type = {
460 .groups = i2c_dev_attr_groups,
461 .uevent = i2c_device_uevent,
462 .release = i2c_client_dev_release,
467 * i2c_verify_client - return parameter as i2c_client, or NULL
468 * @dev: device, probably from some driver model iterator
470 * When traversing the driver model tree, perhaps using driver model
471 * iterators like @device_for_each_child(), you can't assume very much
472 * about the nodes you find. Use this function to avoid oopses caused
473 * by wrongly treating some non-I2C device as an i2c_client.
475 struct i2c_client *i2c_verify_client(struct device *dev)
477 return (dev->type == &i2c_client_type)
481 EXPORT_SYMBOL(i2c_verify_client);
484 /* This is a permissive address validity check, I2C address map constraints
485 * are purposely not enforced, except for the general call address. */
486 static int i2c_check_client_addr_validity(const struct i2c_client *client)
488 if (client->flags & I2C_CLIENT_TEN) {
489 /* 10-bit address, all values are valid */
490 if (client->addr > 0x3ff)
493 /* 7-bit address, reject the general call address */
494 if (client->addr == 0x00 || client->addr > 0x7f)
500 /* And this is a strict address validity check, used when probing. If a
501 * device uses a reserved address, then it shouldn't be probed. 7-bit
502 * addressing is assumed, 10-bit address devices are rare and should be
503 * explicitly enumerated. */
504 static int i2c_check_addr_validity(unsigned short addr)
507 * Reserved addresses per I2C specification:
508 * 0x00 General call address / START byte
510 * 0x02 Reserved for different bus format
511 * 0x03 Reserved for future purposes
512 * 0x04-0x07 Hs-mode master code
513 * 0x78-0x7b 10-bit slave addressing
514 * 0x7c-0x7f Reserved for future purposes
516 if (addr < 0x08 || addr > 0x77)
521 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
523 struct i2c_client *client = i2c_verify_client(dev);
524 int addr = *(int *)addrp;
526 if (client && client->addr == addr)
531 /* walk up mux tree */
532 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
534 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
537 result = device_for_each_child(&adapter->dev, &addr,
538 __i2c_check_addr_busy);
540 if (!result && parent)
541 result = i2c_check_mux_parents(parent, addr);
546 /* recurse down mux tree */
547 static int i2c_check_mux_children(struct device *dev, void *addrp)
551 if (dev->type == &i2c_adapter_type)
552 result = device_for_each_child(dev, addrp,
553 i2c_check_mux_children);
555 result = __i2c_check_addr_busy(dev, addrp);
560 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
562 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
566 result = i2c_check_mux_parents(parent, addr);
569 result = device_for_each_child(&adapter->dev, &addr,
570 i2c_check_mux_children);
576 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
577 * @adapter: Target I2C bus segment
579 void i2c_lock_adapter(struct i2c_adapter *adapter)
581 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
584 i2c_lock_adapter(parent);
586 rt_mutex_lock(&adapter->bus_lock);
588 EXPORT_SYMBOL_GPL(i2c_lock_adapter);
591 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
592 * @adapter: Target I2C bus segment
594 static int i2c_trylock_adapter(struct i2c_adapter *adapter)
596 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
599 return i2c_trylock_adapter(parent);
601 return rt_mutex_trylock(&adapter->bus_lock);
605 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
606 * @adapter: Target I2C bus segment
608 void i2c_unlock_adapter(struct i2c_adapter *adapter)
610 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
613 i2c_unlock_adapter(parent);
615 rt_mutex_unlock(&adapter->bus_lock);
617 EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
619 static void i2c_dev_set_name(struct i2c_adapter *adap,
620 struct i2c_client *client)
622 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
625 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
629 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
630 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
631 client->addr | ((client->flags & I2C_CLIENT_TEN)
636 * i2c_new_device - instantiate an i2c device
637 * @adap: the adapter managing the device
638 * @info: describes one I2C device; bus_num is ignored
641 * Create an i2c device. Binding is handled through driver model
642 * probe()/remove() methods. A driver may be bound to this device when we
643 * return from this function, or any later moment (e.g. maybe hotplugging will
644 * load the driver module). This call is not appropriate for use by mainboard
645 * initialization logic, which usually runs during an arch_initcall() long
646 * before any i2c_adapter could exist.
648 * This returns the new i2c client, which may be saved for later use with
649 * i2c_unregister_device(); or NULL to indicate an error.
652 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
654 struct i2c_client *client;
657 client = kzalloc(sizeof *client, GFP_KERNEL);
661 client->adapter = adap;
663 client->dev.platform_data = info->platform_data;
666 client->dev.archdata = *info->archdata;
668 client->flags = info->flags;
669 client->addr = info->addr;
670 client->irq = info->irq;
672 strlcpy(client->name, info->type, sizeof(client->name));
674 /* Check for address validity */
675 status = i2c_check_client_addr_validity(client);
677 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
678 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
682 /* Check for address business */
683 status = i2c_check_addr_busy(adap, client->addr);
687 client->dev.parent = &client->adapter->dev;
688 client->dev.bus = &i2c_bus_type;
689 client->dev.type = &i2c_client_type;
690 client->dev.of_node = info->of_node;
691 ACPI_COMPANION_SET(&client->dev, info->acpi_node.companion);
693 i2c_dev_set_name(adap, client);
694 status = device_register(&client->dev);
698 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
699 client->name, dev_name(&client->dev));
704 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
705 "(%d)\n", client->name, client->addr, status);
710 EXPORT_SYMBOL_GPL(i2c_new_device);
714 * i2c_unregister_device - reverse effect of i2c_new_device()
715 * @client: value returned from i2c_new_device()
718 void i2c_unregister_device(struct i2c_client *client)
720 device_unregister(&client->dev);
722 EXPORT_SYMBOL_GPL(i2c_unregister_device);
725 static const struct i2c_device_id dummy_id[] = {
730 static int dummy_probe(struct i2c_client *client,
731 const struct i2c_device_id *id)
736 static int dummy_remove(struct i2c_client *client)
741 static struct i2c_driver dummy_driver = {
742 .driver.name = "dummy",
743 .probe = dummy_probe,
744 .remove = dummy_remove,
745 .id_table = dummy_id,
749 * i2c_new_dummy - return a new i2c device bound to a dummy driver
750 * @adapter: the adapter managing the device
751 * @address: seven bit address to be used
754 * This returns an I2C client bound to the "dummy" driver, intended for use
755 * with devices that consume multiple addresses. Examples of such chips
756 * include various EEPROMS (like 24c04 and 24c08 models).
758 * These dummy devices have two main uses. First, most I2C and SMBus calls
759 * except i2c_transfer() need a client handle; the dummy will be that handle.
760 * And second, this prevents the specified address from being bound to a
763 * This returns the new i2c client, which should be saved for later use with
764 * i2c_unregister_device(); or NULL to indicate an error.
766 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
768 struct i2c_board_info info = {
769 I2C_BOARD_INFO("dummy", address),
772 return i2c_new_device(adapter, &info);
774 EXPORT_SYMBOL_GPL(i2c_new_dummy);
776 /* ------------------------------------------------------------------------- */
778 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
780 static void i2c_adapter_dev_release(struct device *dev)
782 struct i2c_adapter *adap = to_i2c_adapter(dev);
783 complete(&adap->dev_released);
787 * This function is only needed for mutex_lock_nested, so it is never
788 * called unless locking correctness checking is enabled. Thus we
789 * make it inline to avoid a compiler warning. That's what gcc ends up
792 static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
794 unsigned int depth = 0;
796 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
803 * Let users instantiate I2C devices through sysfs. This can be used when
804 * platform initialization code doesn't contain the proper data for
805 * whatever reason. Also useful for drivers that do device detection and
806 * detection fails, either because the device uses an unexpected address,
807 * or this is a compatible device with different ID register values.
809 * Parameter checking may look overzealous, but we really don't want
810 * the user to provide incorrect parameters.
813 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
814 const char *buf, size_t count)
816 struct i2c_adapter *adap = to_i2c_adapter(dev);
817 struct i2c_board_info info;
818 struct i2c_client *client;
822 memset(&info, 0, sizeof(struct i2c_board_info));
824 blank = strchr(buf, ' ');
826 dev_err(dev, "%s: Missing parameters\n", "new_device");
829 if (blank - buf > I2C_NAME_SIZE - 1) {
830 dev_err(dev, "%s: Invalid device name\n", "new_device");
833 memcpy(info.type, buf, blank - buf);
835 /* Parse remaining parameters, reject extra parameters */
836 res = sscanf(++blank, "%hi%c", &info.addr, &end);
838 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
841 if (res > 1 && end != '\n') {
842 dev_err(dev, "%s: Extra parameters\n", "new_device");
846 client = i2c_new_device(adap, &info);
850 /* Keep track of the added device */
851 mutex_lock(&adap->userspace_clients_lock);
852 list_add_tail(&client->detected, &adap->userspace_clients);
853 mutex_unlock(&adap->userspace_clients_lock);
854 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
855 info.type, info.addr);
861 * And of course let the users delete the devices they instantiated, if
862 * they got it wrong. This interface can only be used to delete devices
863 * instantiated by i2c_sysfs_new_device above. This guarantees that we
864 * don't delete devices to which some kernel code still has references.
866 * Parameter checking may look overzealous, but we really don't want
867 * the user to delete the wrong device.
870 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
871 const char *buf, size_t count)
873 struct i2c_adapter *adap = to_i2c_adapter(dev);
874 struct i2c_client *client, *next;
879 /* Parse parameters, reject extra parameters */
880 res = sscanf(buf, "%hi%c", &addr, &end);
882 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
885 if (res > 1 && end != '\n') {
886 dev_err(dev, "%s: Extra parameters\n", "delete_device");
890 /* Make sure the device was added through sysfs */
892 mutex_lock_nested(&adap->userspace_clients_lock,
893 i2c_adapter_depth(adap));
894 list_for_each_entry_safe(client, next, &adap->userspace_clients,
896 if (client->addr == addr) {
897 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
898 "delete_device", client->name, client->addr);
900 list_del(&client->detected);
901 i2c_unregister_device(client);
906 mutex_unlock(&adap->userspace_clients_lock);
909 dev_err(dev, "%s: Can't find device in list\n",
914 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
915 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
916 i2c_sysfs_delete_device);
918 static struct attribute *i2c_adapter_attrs[] = {
920 &dev_attr_new_device.attr,
921 &dev_attr_delete_device.attr,
925 static struct attribute_group i2c_adapter_attr_group = {
926 .attrs = i2c_adapter_attrs,
929 static const struct attribute_group *i2c_adapter_attr_groups[] = {
930 &i2c_adapter_attr_group,
934 struct device_type i2c_adapter_type = {
935 .groups = i2c_adapter_attr_groups,
936 .release = i2c_adapter_dev_release,
938 EXPORT_SYMBOL_GPL(i2c_adapter_type);
941 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
942 * @dev: device, probably from some driver model iterator
944 * When traversing the driver model tree, perhaps using driver model
945 * iterators like @device_for_each_child(), you can't assume very much
946 * about the nodes you find. Use this function to avoid oopses caused
947 * by wrongly treating some non-I2C device as an i2c_adapter.
949 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
951 return (dev->type == &i2c_adapter_type)
952 ? to_i2c_adapter(dev)
955 EXPORT_SYMBOL(i2c_verify_adapter);
957 #ifdef CONFIG_I2C_COMPAT
958 static struct class_compat *i2c_adapter_compat_class;
961 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
963 struct i2c_devinfo *devinfo;
965 down_read(&__i2c_board_lock);
966 list_for_each_entry(devinfo, &__i2c_board_list, list) {
967 if (devinfo->busnum == adapter->nr
968 && !i2c_new_device(adapter,
969 &devinfo->board_info))
970 dev_err(&adapter->dev,
971 "Can't create device at 0x%02x\n",
972 devinfo->board_info.addr);
974 up_read(&__i2c_board_lock);
977 /* OF support code */
979 #if IS_ENABLED(CONFIG_OF)
980 static void of_i2c_register_devices(struct i2c_adapter *adap)
983 struct device_node *node;
985 /* Only register child devices if the adapter has a node pointer set */
986 if (!adap->dev.of_node)
989 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
991 for_each_available_child_of_node(adap->dev.of_node, node) {
992 struct i2c_board_info info = {};
993 struct dev_archdata dev_ad = {};
997 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
999 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
1000 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
1005 addr = of_get_property(node, "reg", &len);
1006 if (!addr || (len < sizeof(int))) {
1007 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
1012 info.addr = be32_to_cpup(addr);
1013 if (info.addr > (1 << 10) - 1) {
1014 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1015 info.addr, node->full_name);
1019 info.irq = irq_of_parse_and_map(node, 0);
1020 info.of_node = of_node_get(node);
1021 info.archdata = &dev_ad;
1023 if (of_get_property(node, "wakeup-source", NULL))
1024 info.flags |= I2C_CLIENT_WAKE;
1026 request_module("%s%s", I2C_MODULE_PREFIX, info.type);
1028 result = i2c_new_device(adap, &info);
1029 if (result == NULL) {
1030 dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
1033 irq_dispose_mapping(info.irq);
1039 static int of_dev_node_match(struct device *dev, void *data)
1041 return dev->of_node == data;
1044 /* must call put_device() when done with returned i2c_client device */
1045 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1049 dev = bus_find_device(&i2c_bus_type, NULL, node,
1054 return i2c_verify_client(dev);
1056 EXPORT_SYMBOL(of_find_i2c_device_by_node);
1058 /* must call put_device() when done with returned i2c_adapter device */
1059 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1063 dev = bus_find_device(&i2c_bus_type, NULL, node,
1068 return i2c_verify_adapter(dev);
1070 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1072 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
1073 #endif /* CONFIG_OF */
1075 /* ACPI support code */
1077 #if IS_ENABLED(CONFIG_ACPI)
1078 static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
1080 struct i2c_board_info *info = data;
1082 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1083 struct acpi_resource_i2c_serialbus *sb;
1085 sb = &ares->data.i2c_serial_bus;
1086 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
1087 info->addr = sb->slave_address;
1088 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
1089 info->flags |= I2C_CLIENT_TEN;
1091 } else if (info->irq < 0) {
1094 if (acpi_dev_resource_interrupt(ares, 0, &r))
1095 info->irq = r.start;
1098 /* Tell the ACPI core to skip this resource */
1102 static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
1103 void *data, void **return_value)
1105 struct i2c_adapter *adapter = data;
1106 struct list_head resource_list;
1107 struct i2c_board_info info;
1108 struct acpi_device *adev;
1111 if (acpi_bus_get_device(handle, &adev))
1113 if (acpi_bus_get_status(adev) || !adev->status.present)
1116 memset(&info, 0, sizeof(info));
1117 info.acpi_node.companion = adev;
1120 INIT_LIST_HEAD(&resource_list);
1121 ret = acpi_dev_get_resources(adev, &resource_list,
1122 acpi_i2c_add_resource, &info);
1123 acpi_dev_free_resource_list(&resource_list);
1125 if (ret < 0 || !info.addr)
1128 adev->power.flags.ignore_parent = true;
1129 strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
1130 if (!i2c_new_device(adapter, &info)) {
1131 adev->power.flags.ignore_parent = false;
1132 dev_err(&adapter->dev,
1133 "failed to add I2C device %s from ACPI\n",
1134 dev_name(&adev->dev));
1141 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
1142 * @adap: pointer to adapter
1144 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
1145 * namespace. When a device is found it will be added to the Linux device
1146 * model and bound to the corresponding ACPI handle.
1148 static void acpi_i2c_register_devices(struct i2c_adapter *adap)
1153 if (!adap->dev.parent)
1156 handle = ACPI_HANDLE(adap->dev.parent);
1160 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1161 acpi_i2c_add_device, NULL,
1163 if (ACPI_FAILURE(status))
1164 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
1167 static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
1168 #endif /* CONFIG_ACPI */
1170 static int i2c_do_add_adapter(struct i2c_driver *driver,
1171 struct i2c_adapter *adap)
1173 /* Detect supported devices on that bus, and instantiate them */
1174 i2c_detect(adap, driver);
1176 /* Let legacy drivers scan this bus for matching devices */
1177 if (driver->attach_adapter) {
1178 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1179 driver->driver.name);
1180 dev_warn(&adap->dev, "Please use another way to instantiate "
1181 "your i2c_client\n");
1182 /* We ignore the return code; if it fails, too bad */
1183 driver->attach_adapter(adap);
1188 static int __process_new_adapter(struct device_driver *d, void *data)
1190 return i2c_do_add_adapter(to_i2c_driver(d), data);
1193 static int i2c_register_adapter(struct i2c_adapter *adap)
1197 /* Can't register until after driver model init */
1198 if (unlikely(WARN_ON(!i2c_bus_type.p))) {
1204 if (unlikely(adap->name[0] == '\0')) {
1205 pr_err("i2c-core: Attempt to register an adapter with "
1209 if (unlikely(!adap->algo)) {
1210 pr_err("i2c-core: Attempt to register adapter '%s' with "
1211 "no algo!\n", adap->name);
1215 rt_mutex_init(&adap->bus_lock);
1216 mutex_init(&adap->userspace_clients_lock);
1217 INIT_LIST_HEAD(&adap->userspace_clients);
1219 /* Set default timeout to 1 second if not already set */
1220 if (adap->timeout == 0)
1223 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1224 adap->dev.bus = &i2c_bus_type;
1225 adap->dev.type = &i2c_adapter_type;
1226 res = device_register(&adap->dev);
1230 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1232 #ifdef CONFIG_I2C_COMPAT
1233 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1236 dev_warn(&adap->dev,
1237 "Failed to create compatibility class link\n");
1240 /* bus recovery specific initialization */
1241 if (adap->bus_recovery_info) {
1242 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
1244 if (!bri->recover_bus) {
1245 dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
1246 adap->bus_recovery_info = NULL;
1250 /* Generic GPIO recovery */
1251 if (bri->recover_bus == i2c_generic_gpio_recovery) {
1252 if (!gpio_is_valid(bri->scl_gpio)) {
1253 dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
1254 adap->bus_recovery_info = NULL;
1258 if (gpio_is_valid(bri->sda_gpio))
1259 bri->get_sda = get_sda_gpio_value;
1261 bri->get_sda = NULL;
1263 bri->get_scl = get_scl_gpio_value;
1264 bri->set_scl = set_scl_gpio_value;
1265 } else if (!bri->set_scl || !bri->get_scl) {
1266 /* Generic SCL recovery */
1267 dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
1268 adap->bus_recovery_info = NULL;
1273 /* create pre-declared device nodes */
1274 of_i2c_register_devices(adap);
1275 acpi_i2c_register_devices(adap);
1277 if (adap->nr < __i2c_first_dynamic_bus_num)
1278 i2c_scan_static_board_info(adap);
1280 /* Notify drivers */
1281 mutex_lock(&core_lock);
1282 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1283 mutex_unlock(&core_lock);
1288 mutex_lock(&core_lock);
1289 idr_remove(&i2c_adapter_idr, adap->nr);
1290 mutex_unlock(&core_lock);
1295 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1296 * @adap: the adapter to register (with adap->nr initialized)
1297 * Context: can sleep
1299 * See i2c_add_numbered_adapter() for details.
1301 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1305 mutex_lock(&core_lock);
1306 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
1308 mutex_unlock(&core_lock);
1310 return id == -ENOSPC ? -EBUSY : id;
1312 return i2c_register_adapter(adap);
1316 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1317 * @adapter: the adapter to add
1318 * Context: can sleep
1320 * This routine is used to declare an I2C adapter when its bus number
1321 * doesn't matter or when its bus number is specified by an dt alias.
1322 * Examples of bases when the bus number doesn't matter: I2C adapters
1323 * dynamically added by USB links or PCI plugin cards.
1325 * When this returns zero, a new bus number was allocated and stored
1326 * in adap->nr, and the specified adapter became available for clients.
1327 * Otherwise, a negative errno value is returned.
1329 int i2c_add_adapter(struct i2c_adapter *adapter)
1331 struct device *dev = &adapter->dev;
1335 id = of_alias_get_id(dev->of_node, "i2c");
1338 return __i2c_add_numbered_adapter(adapter);
1342 mutex_lock(&core_lock);
1343 id = idr_alloc(&i2c_adapter_idr, adapter,
1344 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1345 mutex_unlock(&core_lock);
1351 return i2c_register_adapter(adapter);
1353 EXPORT_SYMBOL(i2c_add_adapter);
1356 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1357 * @adap: the adapter to register (with adap->nr initialized)
1358 * Context: can sleep
1360 * This routine is used to declare an I2C adapter when its bus number
1361 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1362 * or otherwise built in to the system's mainboard, and where i2c_board_info
1363 * is used to properly configure I2C devices.
1365 * If the requested bus number is set to -1, then this function will behave
1366 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1368 * If no devices have pre-been declared for this bus, then be sure to
1369 * register the adapter before any dynamically allocated ones. Otherwise
1370 * the required bus ID may not be available.
1372 * When this returns zero, the specified adapter became available for
1373 * clients using the bus number provided in adap->nr. Also, the table
1374 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1375 * and the appropriate driver model device nodes are created. Otherwise, a
1376 * negative errno value is returned.
1378 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1380 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1381 return i2c_add_adapter(adap);
1383 return __i2c_add_numbered_adapter(adap);
1385 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1387 static void i2c_do_del_adapter(struct i2c_driver *driver,
1388 struct i2c_adapter *adapter)
1390 struct i2c_client *client, *_n;
1392 /* Remove the devices we created ourselves as the result of hardware
1393 * probing (using a driver's detect method) */
1394 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1395 if (client->adapter == adapter) {
1396 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1397 client->name, client->addr);
1398 list_del(&client->detected);
1399 i2c_unregister_device(client);
1404 static int __unregister_client(struct device *dev, void *dummy)
1406 struct i2c_client *client = i2c_verify_client(dev);
1407 if (client && strcmp(client->name, "dummy"))
1408 i2c_unregister_device(client);
1412 static int __unregister_dummy(struct device *dev, void *dummy)
1414 struct i2c_client *client = i2c_verify_client(dev);
1416 i2c_unregister_device(client);
1420 static int __process_removed_adapter(struct device_driver *d, void *data)
1422 i2c_do_del_adapter(to_i2c_driver(d), data);
1427 * i2c_del_adapter - unregister I2C adapter
1428 * @adap: the adapter being unregistered
1429 * Context: can sleep
1431 * This unregisters an I2C adapter which was previously registered
1432 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1434 void i2c_del_adapter(struct i2c_adapter *adap)
1436 struct i2c_adapter *found;
1437 struct i2c_client *client, *next;
1439 /* First make sure that this adapter was ever added */
1440 mutex_lock(&core_lock);
1441 found = idr_find(&i2c_adapter_idr, adap->nr);
1442 mutex_unlock(&core_lock);
1443 if (found != adap) {
1444 pr_debug("i2c-core: attempting to delete unregistered "
1445 "adapter [%s]\n", adap->name);
1449 /* Tell drivers about this removal */
1450 mutex_lock(&core_lock);
1451 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1452 __process_removed_adapter);
1453 mutex_unlock(&core_lock);
1455 /* Remove devices instantiated from sysfs */
1456 mutex_lock_nested(&adap->userspace_clients_lock,
1457 i2c_adapter_depth(adap));
1458 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1460 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1462 list_del(&client->detected);
1463 i2c_unregister_device(client);
1465 mutex_unlock(&adap->userspace_clients_lock);
1467 /* Detach any active clients. This can't fail, thus we do not
1468 * check the returned value. This is a two-pass process, because
1469 * we can't remove the dummy devices during the first pass: they
1470 * could have been instantiated by real devices wishing to clean
1471 * them up properly, so we give them a chance to do that first. */
1472 device_for_each_child(&adap->dev, NULL, __unregister_client);
1473 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1475 #ifdef CONFIG_I2C_COMPAT
1476 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1480 /* device name is gone after device_unregister */
1481 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1483 /* clean up the sysfs representation */
1484 init_completion(&adap->dev_released);
1485 device_unregister(&adap->dev);
1487 /* wait for sysfs to drop all references */
1488 wait_for_completion(&adap->dev_released);
1491 mutex_lock(&core_lock);
1492 idr_remove(&i2c_adapter_idr, adap->nr);
1493 mutex_unlock(&core_lock);
1495 /* Clear the device structure in case this adapter is ever going to be
1497 memset(&adap->dev, 0, sizeof(adap->dev));
1499 EXPORT_SYMBOL(i2c_del_adapter);
1501 /* ------------------------------------------------------------------------- */
1503 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1507 mutex_lock(&core_lock);
1508 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1509 mutex_unlock(&core_lock);
1513 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1515 static int __process_new_driver(struct device *dev, void *data)
1517 if (dev->type != &i2c_adapter_type)
1519 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1523 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1524 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1527 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1531 /* Can't register until after driver model init */
1532 if (unlikely(WARN_ON(!i2c_bus_type.p)))
1535 /* add the driver to the list of i2c drivers in the driver core */
1536 driver->driver.owner = owner;
1537 driver->driver.bus = &i2c_bus_type;
1539 /* When registration returns, the driver core
1540 * will have called probe() for all matching-but-unbound devices.
1542 res = driver_register(&driver->driver);
1546 /* Drivers should switch to dev_pm_ops instead. */
1547 if (driver->suspend)
1548 pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
1549 driver->driver.name);
1551 pr_warn("i2c-core: driver [%s] using legacy resume method\n",
1552 driver->driver.name);
1554 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
1556 INIT_LIST_HEAD(&driver->clients);
1557 /* Walk the adapters that are already present */
1558 i2c_for_each_dev(driver, __process_new_driver);
1562 EXPORT_SYMBOL(i2c_register_driver);
1564 static int __process_removed_driver(struct device *dev, void *data)
1566 if (dev->type == &i2c_adapter_type)
1567 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1572 * i2c_del_driver - unregister I2C driver
1573 * @driver: the driver being unregistered
1574 * Context: can sleep
1576 void i2c_del_driver(struct i2c_driver *driver)
1578 i2c_for_each_dev(driver, __process_removed_driver);
1580 driver_unregister(&driver->driver);
1581 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
1583 EXPORT_SYMBOL(i2c_del_driver);
1585 /* ------------------------------------------------------------------------- */
1588 * i2c_use_client - increments the reference count of the i2c client structure
1589 * @client: the client being referenced
1591 * Each live reference to a client should be refcounted. The driver model does
1592 * that automatically as part of driver binding, so that most drivers don't
1593 * need to do this explicitly: they hold a reference until they're unbound
1596 * A pointer to the client with the incremented reference counter is returned.
1598 struct i2c_client *i2c_use_client(struct i2c_client *client)
1600 if (client && get_device(&client->dev))
1604 EXPORT_SYMBOL(i2c_use_client);
1607 * i2c_release_client - release a use of the i2c client structure
1608 * @client: the client being no longer referenced
1610 * Must be called when a user of a client is finished with it.
1612 void i2c_release_client(struct i2c_client *client)
1615 put_device(&client->dev);
1617 EXPORT_SYMBOL(i2c_release_client);
1619 struct i2c_cmd_arg {
1624 static int i2c_cmd(struct device *dev, void *_arg)
1626 struct i2c_client *client = i2c_verify_client(dev);
1627 struct i2c_cmd_arg *arg = _arg;
1628 struct i2c_driver *driver;
1630 if (!client || !client->dev.driver)
1633 driver = to_i2c_driver(client->dev.driver);
1634 if (driver->command)
1635 driver->command(client, arg->cmd, arg->arg);
1639 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1641 struct i2c_cmd_arg cmd_arg;
1645 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1647 EXPORT_SYMBOL(i2c_clients_command);
1649 static int __init i2c_init(void)
1653 retval = bus_register(&i2c_bus_type);
1656 #ifdef CONFIG_I2C_COMPAT
1657 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1658 if (!i2c_adapter_compat_class) {
1663 retval = i2c_add_driver(&dummy_driver);
1669 #ifdef CONFIG_I2C_COMPAT
1670 class_compat_unregister(i2c_adapter_compat_class);
1673 bus_unregister(&i2c_bus_type);
1677 static void __exit i2c_exit(void)
1679 i2c_del_driver(&dummy_driver);
1680 #ifdef CONFIG_I2C_COMPAT
1681 class_compat_unregister(i2c_adapter_compat_class);
1683 bus_unregister(&i2c_bus_type);
1686 /* We must initialize early, because some subsystems register i2c drivers
1687 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1689 postcore_initcall(i2c_init);
1690 module_exit(i2c_exit);
1692 /* ----------------------------------------------------
1693 * the functional interface to the i2c busses.
1694 * ----------------------------------------------------
1698 * __i2c_transfer - unlocked flavor of i2c_transfer
1699 * @adap: Handle to I2C bus
1700 * @msgs: One or more messages to execute before STOP is issued to
1701 * terminate the operation; each message begins with a START.
1702 * @num: Number of messages to be executed.
1704 * Returns negative errno, else the number of messages executed.
1706 * Adapter lock must be held when calling this function. No debug logging
1707 * takes place. adap->algo->master_xfer existence isn't checked.
1709 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1711 unsigned long orig_jiffies;
1714 /* Retry automatically on arbitration loss */
1715 orig_jiffies = jiffies;
1716 for (ret = 0, try = 0; try <= adap->retries; try++) {
1717 ret = adap->algo->master_xfer(adap, msgs, num);
1720 if (time_after(jiffies, orig_jiffies + adap->timeout))
1726 EXPORT_SYMBOL(__i2c_transfer);
1729 * i2c_transfer - execute a single or combined I2C message
1730 * @adap: Handle to I2C bus
1731 * @msgs: One or more messages to execute before STOP is issued to
1732 * terminate the operation; each message begins with a START.
1733 * @num: Number of messages to be executed.
1735 * Returns negative errno, else the number of messages executed.
1737 * Note that there is no requirement that each message be sent to
1738 * the same slave address, although that is the most common model.
1740 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1744 /* REVISIT the fault reporting model here is weak:
1746 * - When we get an error after receiving N bytes from a slave,
1747 * there is no way to report "N".
1749 * - When we get a NAK after transmitting N bytes to a slave,
1750 * there is no way to report "N" ... or to let the master
1751 * continue executing the rest of this combined message, if
1752 * that's the appropriate response.
1754 * - When for example "num" is two and we successfully complete
1755 * the first message but get an error part way through the
1756 * second, it's unclear whether that should be reported as
1757 * one (discarding status on the second message) or errno
1758 * (discarding status on the first one).
1761 if (adap->algo->master_xfer) {
1763 for (ret = 0; ret < num; ret++) {
1764 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
1765 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
1766 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
1767 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1771 if (in_atomic() || irqs_disabled()) {
1772 ret = i2c_trylock_adapter(adap);
1774 /* I2C activity is ongoing. */
1777 i2c_lock_adapter(adap);
1780 ret = __i2c_transfer(adap, msgs, num);
1781 i2c_unlock_adapter(adap);
1785 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1789 EXPORT_SYMBOL(i2c_transfer);
1792 * i2c_master_send - issue a single I2C message in master transmit mode
1793 * @client: Handle to slave device
1794 * @buf: Data that will be written to the slave
1795 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1797 * Returns negative errno, or else the number of bytes written.
1799 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1802 struct i2c_adapter *adap = client->adapter;
1805 msg.addr = client->addr;
1806 msg.flags = client->flags & I2C_M_TEN;
1808 msg.buf = (char *)buf;
1810 ret = i2c_transfer(adap, &msg, 1);
1813 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1814 * transmitted, else error code.
1816 return (ret == 1) ? count : ret;
1818 EXPORT_SYMBOL(i2c_master_send);
1821 * i2c_master_recv - issue a single I2C message in master receive mode
1822 * @client: Handle to slave device
1823 * @buf: Where to store data read from slave
1824 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1826 * Returns negative errno, or else the number of bytes read.
1828 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
1830 struct i2c_adapter *adap = client->adapter;
1834 msg.addr = client->addr;
1835 msg.flags = client->flags & I2C_M_TEN;
1836 msg.flags |= I2C_M_RD;
1840 ret = i2c_transfer(adap, &msg, 1);
1843 * If everything went ok (i.e. 1 msg received), return #bytes received,
1846 return (ret == 1) ? count : ret;
1848 EXPORT_SYMBOL(i2c_master_recv);
1850 /* ----------------------------------------------------
1851 * the i2c address scanning function
1852 * Will not work for 10-bit addresses!
1853 * ----------------------------------------------------
1857 * Legacy default probe function, mostly relevant for SMBus. The default
1858 * probe method is a quick write, but it is known to corrupt the 24RF08
1859 * EEPROMs due to a state machine bug, and could also irreversibly
1860 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1861 * we use a short byte read instead. Also, some bus drivers don't implement
1862 * quick write, so we fallback to a byte read in that case too.
1863 * On x86, there is another special case for FSC hardware monitoring chips,
1864 * which want regular byte reads (address 0x73.) Fortunately, these are the
1865 * only known chips using this I2C address on PC hardware.
1866 * Returns 1 if probe succeeded, 0 if not.
1868 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
1871 union i2c_smbus_data dummy;
1874 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
1875 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
1876 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1877 I2C_SMBUS_BYTE_DATA, &dummy);
1880 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
1881 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
1882 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
1883 I2C_SMBUS_QUICK, NULL);
1884 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
1885 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1886 I2C_SMBUS_BYTE, &dummy);
1888 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
1896 static int i2c_detect_address(struct i2c_client *temp_client,
1897 struct i2c_driver *driver)
1899 struct i2c_board_info info;
1900 struct i2c_adapter *adapter = temp_client->adapter;
1901 int addr = temp_client->addr;
1904 /* Make sure the address is valid */
1905 err = i2c_check_addr_validity(addr);
1907 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
1912 /* Skip if already in use */
1913 if (i2c_check_addr_busy(adapter, addr))
1916 /* Make sure there is something at this address */
1917 if (!i2c_default_probe(adapter, addr))
1920 /* Finally call the custom detection function */
1921 memset(&info, 0, sizeof(struct i2c_board_info));
1923 err = driver->detect(temp_client, &info);
1925 /* -ENODEV is returned if the detection fails. We catch it
1926 here as this isn't an error. */
1927 return err == -ENODEV ? 0 : err;
1930 /* Consistency check */
1931 if (info.type[0] == '\0') {
1932 dev_err(&adapter->dev, "%s detection function provided "
1933 "no name for 0x%x\n", driver->driver.name,
1936 struct i2c_client *client;
1938 /* Detection succeeded, instantiate the device */
1939 if (adapter->class & I2C_CLASS_DEPRECATED)
1940 dev_warn(&adapter->dev,
1941 "This adapter will soon drop class based instantiation of devices. "
1942 "Please make sure client 0x%02x gets instantiated by other means. "
1943 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
1946 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
1947 info.type, info.addr);
1948 client = i2c_new_device(adapter, &info);
1950 list_add_tail(&client->detected, &driver->clients);
1952 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
1953 info.type, info.addr);
1958 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
1960 const unsigned short *address_list;
1961 struct i2c_client *temp_client;
1963 int adap_id = i2c_adapter_id(adapter);
1965 address_list = driver->address_list;
1966 if (!driver->detect || !address_list)
1969 /* Stop here if the classes do not match */
1970 if (!(adapter->class & driver->class))
1973 /* Set up a temporary client to help detect callback */
1974 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
1977 temp_client->adapter = adapter;
1979 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
1980 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
1981 "addr 0x%02x\n", adap_id, address_list[i]);
1982 temp_client->addr = address_list[i];
1983 err = i2c_detect_address(temp_client, driver);
1992 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
1994 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1995 I2C_SMBUS_QUICK, NULL) >= 0;
1997 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2000 i2c_new_probed_device(struct i2c_adapter *adap,
2001 struct i2c_board_info *info,
2002 unsigned short const *addr_list,
2003 int (*probe)(struct i2c_adapter *, unsigned short addr))
2008 probe = i2c_default_probe;
2010 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2011 /* Check address validity */
2012 if (i2c_check_addr_validity(addr_list[i]) < 0) {
2013 dev_warn(&adap->dev, "Invalid 7-bit address "
2014 "0x%02x\n", addr_list[i]);
2018 /* Check address availability */
2019 if (i2c_check_addr_busy(adap, addr_list[i])) {
2020 dev_dbg(&adap->dev, "Address 0x%02x already in "
2021 "use, not probing\n", addr_list[i]);
2025 /* Test address responsiveness */
2026 if (probe(adap, addr_list[i]))
2030 if (addr_list[i] == I2C_CLIENT_END) {
2031 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2035 info->addr = addr_list[i];
2036 return i2c_new_device(adap, info);
2038 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2040 struct i2c_adapter *i2c_get_adapter(int nr)
2042 struct i2c_adapter *adapter;
2044 mutex_lock(&core_lock);
2045 adapter = idr_find(&i2c_adapter_idr, nr);
2046 if (adapter && !try_module_get(adapter->owner))
2049 mutex_unlock(&core_lock);
2052 EXPORT_SYMBOL(i2c_get_adapter);
2054 void i2c_put_adapter(struct i2c_adapter *adap)
2057 module_put(adap->owner);
2059 EXPORT_SYMBOL(i2c_put_adapter);
2061 /* The SMBus parts */
2063 #define POLY (0x1070U << 3)
2064 static u8 crc8(u16 data)
2068 for (i = 0; i < 8; i++) {
2073 return (u8)(data >> 8);
2076 /* Incremental CRC8 over count bytes in the array pointed to by p */
2077 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
2081 for (i = 0; i < count; i++)
2082 crc = crc8((crc ^ p[i]) << 8);
2086 /* Assume a 7-bit address, which is reasonable for SMBus */
2087 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
2089 /* The address will be sent first */
2090 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
2091 pec = i2c_smbus_pec(pec, &addr, 1);
2093 /* The data buffer follows */
2094 return i2c_smbus_pec(pec, msg->buf, msg->len);
2097 /* Used for write only transactions */
2098 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
2100 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
2104 /* Return <0 on CRC error
2105 If there was a write before this read (most cases) we need to take the
2106 partial CRC from the write part into account.
2107 Note that this function does modify the message (we need to decrease the
2108 message length to hide the CRC byte from the caller). */
2109 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
2111 u8 rpec = msg->buf[--msg->len];
2112 cpec = i2c_smbus_msg_pec(cpec, msg);
2115 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2123 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2124 * @client: Handle to slave device
2126 * This executes the SMBus "receive byte" protocol, returning negative errno
2127 * else the byte received from the device.
2129 s32 i2c_smbus_read_byte(const struct i2c_client *client)
2131 union i2c_smbus_data data;
2134 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2136 I2C_SMBUS_BYTE, &data);
2137 return (status < 0) ? status : data.byte;
2139 EXPORT_SYMBOL(i2c_smbus_read_byte);
2142 * i2c_smbus_write_byte - SMBus "send byte" protocol
2143 * @client: Handle to slave device
2144 * @value: Byte to be sent
2146 * This executes the SMBus "send byte" protocol, returning negative errno
2147 * else zero on success.
2149 s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
2151 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2152 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
2154 EXPORT_SYMBOL(i2c_smbus_write_byte);
2157 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2158 * @client: Handle to slave device
2159 * @command: Byte interpreted by slave
2161 * This executes the SMBus "read byte" protocol, returning negative errno
2162 * else a data byte received from the device.
2164 s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
2166 union i2c_smbus_data data;
2169 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2170 I2C_SMBUS_READ, command,
2171 I2C_SMBUS_BYTE_DATA, &data);
2172 return (status < 0) ? status : data.byte;
2174 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
2177 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2178 * @client: Handle to slave device
2179 * @command: Byte interpreted by slave
2180 * @value: Byte being written
2182 * This executes the SMBus "write byte" protocol, returning negative errno
2183 * else zero on success.
2185 s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
2188 union i2c_smbus_data data;
2190 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2191 I2C_SMBUS_WRITE, command,
2192 I2C_SMBUS_BYTE_DATA, &data);
2194 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
2197 * i2c_smbus_read_word_data - SMBus "read word" protocol
2198 * @client: Handle to slave device
2199 * @command: Byte interpreted by slave
2201 * This executes the SMBus "read word" protocol, returning negative errno
2202 * else a 16-bit unsigned "word" received from the device.
2204 s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
2206 union i2c_smbus_data data;
2209 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2210 I2C_SMBUS_READ, command,
2211 I2C_SMBUS_WORD_DATA, &data);
2212 return (status < 0) ? status : data.word;
2214 EXPORT_SYMBOL(i2c_smbus_read_word_data);
2217 * i2c_smbus_write_word_data - SMBus "write word" protocol
2218 * @client: Handle to slave device
2219 * @command: Byte interpreted by slave
2220 * @value: 16-bit "word" being written
2222 * This executes the SMBus "write word" protocol, returning negative errno
2223 * else zero on success.
2225 s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
2228 union i2c_smbus_data data;
2230 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2231 I2C_SMBUS_WRITE, command,
2232 I2C_SMBUS_WORD_DATA, &data);
2234 EXPORT_SYMBOL(i2c_smbus_write_word_data);
2237 * i2c_smbus_read_block_data - SMBus "block read" protocol
2238 * @client: Handle to slave device
2239 * @command: Byte interpreted by slave
2240 * @values: Byte array into which data will be read; big enough to hold
2241 * the data returned by the slave. SMBus allows at most 32 bytes.
2243 * This executes the SMBus "block read" protocol, returning negative errno
2244 * else the number of data bytes in the slave's response.
2246 * Note that using this function requires that the client's adapter support
2247 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2248 * support this; its emulation through I2C messaging relies on a specific
2249 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2251 s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2254 union i2c_smbus_data data;
2257 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2258 I2C_SMBUS_READ, command,
2259 I2C_SMBUS_BLOCK_DATA, &data);
2263 memcpy(values, &data.block[1], data.block[0]);
2264 return data.block[0];
2266 EXPORT_SYMBOL(i2c_smbus_read_block_data);
2269 * i2c_smbus_write_block_data - SMBus "block write" protocol
2270 * @client: Handle to slave device
2271 * @command: Byte interpreted by slave
2272 * @length: Size of data block; SMBus allows at most 32 bytes
2273 * @values: Byte array which will be written.
2275 * This executes the SMBus "block write" protocol, returning negative errno
2276 * else zero on success.
2278 s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2279 u8 length, const u8 *values)
2281 union i2c_smbus_data data;
2283 if (length > I2C_SMBUS_BLOCK_MAX)
2284 length = I2C_SMBUS_BLOCK_MAX;
2285 data.block[0] = length;
2286 memcpy(&data.block[1], values, length);
2287 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2288 I2C_SMBUS_WRITE, command,
2289 I2C_SMBUS_BLOCK_DATA, &data);
2291 EXPORT_SYMBOL(i2c_smbus_write_block_data);
2293 /* Returns the number of read bytes */
2294 s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2295 u8 length, u8 *values)
2297 union i2c_smbus_data data;
2300 if (length > I2C_SMBUS_BLOCK_MAX)
2301 length = I2C_SMBUS_BLOCK_MAX;
2302 data.block[0] = length;
2303 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2304 I2C_SMBUS_READ, command,
2305 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2309 memcpy(values, &data.block[1], data.block[0]);
2310 return data.block[0];
2312 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
2314 s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2315 u8 length, const u8 *values)
2317 union i2c_smbus_data data;
2319 if (length > I2C_SMBUS_BLOCK_MAX)
2320 length = I2C_SMBUS_BLOCK_MAX;
2321 data.block[0] = length;
2322 memcpy(data.block + 1, values, length);
2323 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2324 I2C_SMBUS_WRITE, command,
2325 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2327 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2329 /* Simulate a SMBus command using the i2c protocol
2330 No checking of parameters is done! */
2331 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
2332 unsigned short flags,
2333 char read_write, u8 command, int size,
2334 union i2c_smbus_data *data)
2336 /* So we need to generate a series of msgs. In the case of writing, we
2337 need to use only one message; when reading, we need two. We initialize
2338 most things with sane defaults, to keep the code below somewhat
2340 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
2341 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2342 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
2346 struct i2c_msg msg[2] = {
2354 .flags = flags | I2C_M_RD,
2360 msgbuf0[0] = command;
2362 case I2C_SMBUS_QUICK:
2364 /* Special case: The read/write field is used as data */
2365 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
2369 case I2C_SMBUS_BYTE:
2370 if (read_write == I2C_SMBUS_READ) {
2371 /* Special case: only a read! */
2372 msg[0].flags = I2C_M_RD | flags;
2376 case I2C_SMBUS_BYTE_DATA:
2377 if (read_write == I2C_SMBUS_READ)
2381 msgbuf0[1] = data->byte;
2384 case I2C_SMBUS_WORD_DATA:
2385 if (read_write == I2C_SMBUS_READ)
2389 msgbuf0[1] = data->word & 0xff;
2390 msgbuf0[2] = data->word >> 8;
2393 case I2C_SMBUS_PROC_CALL:
2394 num = 2; /* Special case */
2395 read_write = I2C_SMBUS_READ;
2398 msgbuf0[1] = data->word & 0xff;
2399 msgbuf0[2] = data->word >> 8;
2401 case I2C_SMBUS_BLOCK_DATA:
2402 if (read_write == I2C_SMBUS_READ) {
2403 msg[1].flags |= I2C_M_RECV_LEN;
2404 msg[1].len = 1; /* block length will be added by
2405 the underlying bus driver */
2407 msg[0].len = data->block[0] + 2;
2408 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
2409 dev_err(&adapter->dev,
2410 "Invalid block write size %d\n",
2414 for (i = 1; i < msg[0].len; i++)
2415 msgbuf0[i] = data->block[i-1];
2418 case I2C_SMBUS_BLOCK_PROC_CALL:
2419 num = 2; /* Another special case */
2420 read_write = I2C_SMBUS_READ;
2421 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
2422 dev_err(&adapter->dev,
2423 "Invalid block write size %d\n",
2427 msg[0].len = data->block[0] + 2;
2428 for (i = 1; i < msg[0].len; i++)
2429 msgbuf0[i] = data->block[i-1];
2430 msg[1].flags |= I2C_M_RECV_LEN;
2431 msg[1].len = 1; /* block length will be added by
2432 the underlying bus driver */
2434 case I2C_SMBUS_I2C_BLOCK_DATA:
2435 if (read_write == I2C_SMBUS_READ) {
2436 msg[1].len = data->block[0];
2438 msg[0].len = data->block[0] + 1;
2439 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
2440 dev_err(&adapter->dev,
2441 "Invalid block write size %d\n",
2445 for (i = 1; i <= data->block[0]; i++)
2446 msgbuf0[i] = data->block[i];
2450 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
2454 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
2455 && size != I2C_SMBUS_I2C_BLOCK_DATA);
2457 /* Compute PEC if first message is a write */
2458 if (!(msg[0].flags & I2C_M_RD)) {
2459 if (num == 1) /* Write only */
2460 i2c_smbus_add_pec(&msg[0]);
2461 else /* Write followed by read */
2462 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
2464 /* Ask for PEC if last message is a read */
2465 if (msg[num-1].flags & I2C_M_RD)
2469 status = i2c_transfer(adapter, msg, num);
2473 /* Check PEC if last message is a read */
2474 if (i && (msg[num-1].flags & I2C_M_RD)) {
2475 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
2480 if (read_write == I2C_SMBUS_READ)
2482 case I2C_SMBUS_BYTE:
2483 data->byte = msgbuf0[0];
2485 case I2C_SMBUS_BYTE_DATA:
2486 data->byte = msgbuf1[0];
2488 case I2C_SMBUS_WORD_DATA:
2489 case I2C_SMBUS_PROC_CALL:
2490 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
2492 case I2C_SMBUS_I2C_BLOCK_DATA:
2493 for (i = 0; i < data->block[0]; i++)
2494 data->block[i+1] = msgbuf1[i];
2496 case I2C_SMBUS_BLOCK_DATA:
2497 case I2C_SMBUS_BLOCK_PROC_CALL:
2498 for (i = 0; i < msgbuf1[0] + 1; i++)
2499 data->block[i] = msgbuf1[i];
2506 * i2c_smbus_xfer - execute SMBus protocol operations
2507 * @adapter: Handle to I2C bus
2508 * @addr: Address of SMBus slave on that bus
2509 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2510 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2511 * @command: Byte interpreted by slave, for protocols which use such bytes
2512 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2513 * @data: Data to be read or written
2515 * This executes an SMBus protocol operation, and returns a negative
2516 * errno code else zero on success.
2518 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
2519 char read_write, u8 command, int protocol,
2520 union i2c_smbus_data *data)
2522 unsigned long orig_jiffies;
2526 flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
2528 if (adapter->algo->smbus_xfer) {
2529 i2c_lock_adapter(adapter);
2531 /* Retry automatically on arbitration loss */
2532 orig_jiffies = jiffies;
2533 for (res = 0, try = 0; try <= adapter->retries; try++) {
2534 res = adapter->algo->smbus_xfer(adapter, addr, flags,
2535 read_write, command,
2539 if (time_after(jiffies,
2540 orig_jiffies + adapter->timeout))
2543 i2c_unlock_adapter(adapter);
2545 if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
2548 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2549 * implement native support for the SMBus operation.
2553 return i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
2554 command, protocol, data);
2556 EXPORT_SYMBOL(i2c_smbus_xfer);
2558 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2559 MODULE_DESCRIPTION("I2C-Bus main module");
2560 MODULE_LICENSE("GPL");