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/clk/clk-conf.h>
46 #include <linux/completion.h>
47 #include <linux/hardirq.h>
48 #include <linux/irqflags.h>
49 #include <linux/rwsem.h>
50 #include <linux/pm_runtime.h>
51 #include <linux/acpi.h>
52 #include <linux/jump_label.h>
53 #include <asm/uaccess.h>
57 #define CREATE_TRACE_POINTS
58 #include <trace/events/i2c.h>
60 /* core_lock protects i2c_adapter_idr, and guarantees
61 that device detection, deletion of detected devices, and attach_adapter
62 calls are serialized */
63 static DEFINE_MUTEX(core_lock);
64 static DEFINE_IDR(i2c_adapter_idr);
66 static struct device_type i2c_client_type;
67 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
69 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
71 void i2c_transfer_trace_reg(void)
73 static_key_slow_inc(&i2c_trace_msg);
76 void i2c_transfer_trace_unreg(void)
78 static_key_slow_dec(&i2c_trace_msg);
81 /* ------------------------------------------------------------------------- */
83 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
84 const struct i2c_client *client)
87 if (strcmp(client->name, id->name) == 0)
94 static int i2c_device_match(struct device *dev, struct device_driver *drv)
96 struct i2c_client *client = i2c_verify_client(dev);
97 struct i2c_driver *driver;
102 /* Attempt an OF style match */
103 if (of_driver_match_device(dev, drv))
106 /* Then ACPI style match */
107 if (acpi_driver_match_device(dev, drv))
110 driver = to_i2c_driver(drv);
111 /* match on an id table if there is one */
112 if (driver->id_table)
113 return i2c_match_id(driver->id_table, client) != NULL;
119 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
120 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
122 struct i2c_client *client = to_i2c_client(dev);
125 rc = acpi_device_uevent_modalias(dev, env);
129 if (add_uevent_var(env, "MODALIAS=%s%s",
130 I2C_MODULE_PREFIX, client->name))
132 dev_dbg(dev, "uevent\n");
136 /* i2c bus recovery routines */
137 static int get_scl_gpio_value(struct i2c_adapter *adap)
139 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
142 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
144 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
147 static int get_sda_gpio_value(struct i2c_adapter *adap)
149 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
152 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
154 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
155 struct device *dev = &adap->dev;
158 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
159 GPIOF_OUT_INIT_HIGH, "i2c-scl");
161 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
166 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
167 /* work without SDA polling */
168 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
177 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
179 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
182 gpio_free(bri->sda_gpio);
184 gpio_free(bri->scl_gpio);
188 * We are generating clock pulses. ndelay() determines durating of clk pulses.
189 * We will generate clock with rate 100 KHz and so duration of both clock levels
190 * is: delay in ns = (10^6 / 100) / 2
192 #define RECOVERY_NDELAY 5000
193 #define RECOVERY_CLK_CNT 9
195 static int i2c_generic_recovery(struct i2c_adapter *adap)
197 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
198 int i = 0, val = 1, ret = 0;
200 if (bri->prepare_recovery)
201 bri->prepare_recovery(bri);
204 * By this time SCL is high, as we need to give 9 falling-rising edges
206 while (i++ < RECOVERY_CLK_CNT * 2) {
208 /* Break if SDA is high */
209 if (bri->get_sda && bri->get_sda(adap))
211 /* SCL shouldn't be low here */
212 if (!bri->get_scl(adap)) {
214 "SCL is stuck low, exit recovery\n");
221 bri->set_scl(adap, val);
222 ndelay(RECOVERY_NDELAY);
225 if (bri->unprepare_recovery)
226 bri->unprepare_recovery(bri);
231 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
233 adap->bus_recovery_info->set_scl(adap, 1);
234 return i2c_generic_recovery(adap);
237 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
241 ret = i2c_get_gpios_for_recovery(adap);
245 ret = i2c_generic_recovery(adap);
246 i2c_put_gpios_for_recovery(adap);
251 int i2c_recover_bus(struct i2c_adapter *adap)
253 if (!adap->bus_recovery_info)
256 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
257 return adap->bus_recovery_info->recover_bus(adap);
260 static int i2c_device_probe(struct device *dev)
262 struct i2c_client *client = i2c_verify_client(dev);
263 struct i2c_driver *driver;
269 driver = to_i2c_driver(dev->driver);
270 if (!driver->probe || !driver->id_table)
273 if (!device_can_wakeup(&client->dev))
274 device_init_wakeup(&client->dev,
275 client->flags & I2C_CLIENT_WAKE);
276 dev_dbg(dev, "probe\n");
278 status = of_clk_set_defaults(dev->of_node, false);
282 acpi_dev_pm_attach(&client->dev, true);
283 status = driver->probe(client, i2c_match_id(driver->id_table, client));
285 acpi_dev_pm_detach(&client->dev, true);
290 static int i2c_device_remove(struct device *dev)
292 struct i2c_client *client = i2c_verify_client(dev);
293 struct i2c_driver *driver;
296 if (!client || !dev->driver)
299 driver = to_i2c_driver(dev->driver);
300 if (driver->remove) {
301 dev_dbg(dev, "remove\n");
302 status = driver->remove(client);
305 acpi_dev_pm_detach(&client->dev, true);
309 static void i2c_device_shutdown(struct device *dev)
311 struct i2c_client *client = i2c_verify_client(dev);
312 struct i2c_driver *driver;
314 if (!client || !dev->driver)
316 driver = to_i2c_driver(dev->driver);
317 if (driver->shutdown)
318 driver->shutdown(client);
321 #ifdef CONFIG_PM_SLEEP
322 static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg)
324 struct i2c_client *client = i2c_verify_client(dev);
325 struct i2c_driver *driver;
327 if (!client || !dev->driver)
329 driver = to_i2c_driver(dev->driver);
330 if (!driver->suspend)
332 return driver->suspend(client, mesg);
335 static int i2c_legacy_resume(struct device *dev)
337 struct i2c_client *client = i2c_verify_client(dev);
338 struct i2c_driver *driver;
340 if (!client || !dev->driver)
342 driver = to_i2c_driver(dev->driver);
345 return driver->resume(client);
348 static int i2c_device_pm_suspend(struct device *dev)
350 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
353 return pm_generic_suspend(dev);
355 return i2c_legacy_suspend(dev, PMSG_SUSPEND);
358 static int i2c_device_pm_resume(struct device *dev)
360 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
363 return pm_generic_resume(dev);
365 return i2c_legacy_resume(dev);
368 static int i2c_device_pm_freeze(struct device *dev)
370 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
373 return pm_generic_freeze(dev);
375 return i2c_legacy_suspend(dev, PMSG_FREEZE);
378 static int i2c_device_pm_thaw(struct device *dev)
380 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
383 return pm_generic_thaw(dev);
385 return i2c_legacy_resume(dev);
388 static int i2c_device_pm_poweroff(struct device *dev)
390 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
393 return pm_generic_poweroff(dev);
395 return i2c_legacy_suspend(dev, PMSG_HIBERNATE);
398 static int i2c_device_pm_restore(struct device *dev)
400 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
403 return pm_generic_restore(dev);
405 return i2c_legacy_resume(dev);
407 #else /* !CONFIG_PM_SLEEP */
408 #define i2c_device_pm_suspend NULL
409 #define i2c_device_pm_resume NULL
410 #define i2c_device_pm_freeze NULL
411 #define i2c_device_pm_thaw NULL
412 #define i2c_device_pm_poweroff NULL
413 #define i2c_device_pm_restore NULL
414 #endif /* !CONFIG_PM_SLEEP */
416 static void i2c_client_dev_release(struct device *dev)
418 kfree(to_i2c_client(dev));
422 show_name(struct device *dev, struct device_attribute *attr, char *buf)
424 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
425 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
429 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
431 struct i2c_client *client = to_i2c_client(dev);
434 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
438 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
441 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
442 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
444 static struct attribute *i2c_dev_attrs[] = {
446 /* modalias helps coldplug: modprobe $(cat .../modalias) */
447 &dev_attr_modalias.attr,
451 static struct attribute_group i2c_dev_attr_group = {
452 .attrs = i2c_dev_attrs,
455 static const struct attribute_group *i2c_dev_attr_groups[] = {
460 static const struct dev_pm_ops i2c_device_pm_ops = {
461 .suspend = i2c_device_pm_suspend,
462 .resume = i2c_device_pm_resume,
463 .freeze = i2c_device_pm_freeze,
464 .thaw = i2c_device_pm_thaw,
465 .poweroff = i2c_device_pm_poweroff,
466 .restore = i2c_device_pm_restore,
468 pm_generic_runtime_suspend,
469 pm_generic_runtime_resume,
474 struct bus_type i2c_bus_type = {
476 .match = i2c_device_match,
477 .probe = i2c_device_probe,
478 .remove = i2c_device_remove,
479 .shutdown = i2c_device_shutdown,
480 .pm = &i2c_device_pm_ops,
482 EXPORT_SYMBOL_GPL(i2c_bus_type);
484 static struct device_type i2c_client_type = {
485 .groups = i2c_dev_attr_groups,
486 .uevent = i2c_device_uevent,
487 .release = i2c_client_dev_release,
492 * i2c_verify_client - return parameter as i2c_client, or NULL
493 * @dev: device, probably from some driver model iterator
495 * When traversing the driver model tree, perhaps using driver model
496 * iterators like @device_for_each_child(), you can't assume very much
497 * about the nodes you find. Use this function to avoid oopses caused
498 * by wrongly treating some non-I2C device as an i2c_client.
500 struct i2c_client *i2c_verify_client(struct device *dev)
502 return (dev->type == &i2c_client_type)
506 EXPORT_SYMBOL(i2c_verify_client);
509 /* This is a permissive address validity check, I2C address map constraints
510 * are purposely not enforced, except for the general call address. */
511 static int i2c_check_client_addr_validity(const struct i2c_client *client)
513 if (client->flags & I2C_CLIENT_TEN) {
514 /* 10-bit address, all values are valid */
515 if (client->addr > 0x3ff)
518 /* 7-bit address, reject the general call address */
519 if (client->addr == 0x00 || client->addr > 0x7f)
525 /* And this is a strict address validity check, used when probing. If a
526 * device uses a reserved address, then it shouldn't be probed. 7-bit
527 * addressing is assumed, 10-bit address devices are rare and should be
528 * explicitly enumerated. */
529 static int i2c_check_addr_validity(unsigned short addr)
532 * Reserved addresses per I2C specification:
533 * 0x00 General call address / START byte
535 * 0x02 Reserved for different bus format
536 * 0x03 Reserved for future purposes
537 * 0x04-0x07 Hs-mode master code
538 * 0x78-0x7b 10-bit slave addressing
539 * 0x7c-0x7f Reserved for future purposes
541 if (addr < 0x08 || addr > 0x77)
546 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
548 struct i2c_client *client = i2c_verify_client(dev);
549 int addr = *(int *)addrp;
551 if (client && client->addr == addr)
556 /* walk up mux tree */
557 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
559 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
562 result = device_for_each_child(&adapter->dev, &addr,
563 __i2c_check_addr_busy);
565 if (!result && parent)
566 result = i2c_check_mux_parents(parent, addr);
571 /* recurse down mux tree */
572 static int i2c_check_mux_children(struct device *dev, void *addrp)
576 if (dev->type == &i2c_adapter_type)
577 result = device_for_each_child(dev, addrp,
578 i2c_check_mux_children);
580 result = __i2c_check_addr_busy(dev, addrp);
585 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
587 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
591 result = i2c_check_mux_parents(parent, addr);
594 result = device_for_each_child(&adapter->dev, &addr,
595 i2c_check_mux_children);
601 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
602 * @adapter: Target I2C bus segment
604 void i2c_lock_adapter(struct i2c_adapter *adapter)
606 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
609 i2c_lock_adapter(parent);
611 rt_mutex_lock(&adapter->bus_lock);
613 EXPORT_SYMBOL_GPL(i2c_lock_adapter);
616 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
617 * @adapter: Target I2C bus segment
619 static int i2c_trylock_adapter(struct i2c_adapter *adapter)
621 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
624 return i2c_trylock_adapter(parent);
626 return rt_mutex_trylock(&adapter->bus_lock);
630 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
631 * @adapter: Target I2C bus segment
633 void i2c_unlock_adapter(struct i2c_adapter *adapter)
635 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
638 i2c_unlock_adapter(parent);
640 rt_mutex_unlock(&adapter->bus_lock);
642 EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
644 static void i2c_dev_set_name(struct i2c_adapter *adap,
645 struct i2c_client *client)
647 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
650 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
654 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
655 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
656 client->addr | ((client->flags & I2C_CLIENT_TEN)
661 * i2c_new_device - instantiate an i2c device
662 * @adap: the adapter managing the device
663 * @info: describes one I2C device; bus_num is ignored
666 * Create an i2c device. Binding is handled through driver model
667 * probe()/remove() methods. A driver may be bound to this device when we
668 * return from this function, or any later moment (e.g. maybe hotplugging will
669 * load the driver module). This call is not appropriate for use by mainboard
670 * initialization logic, which usually runs during an arch_initcall() long
671 * before any i2c_adapter could exist.
673 * This returns the new i2c client, which may be saved for later use with
674 * i2c_unregister_device(); or NULL to indicate an error.
677 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
679 struct i2c_client *client;
682 client = kzalloc(sizeof *client, GFP_KERNEL);
686 client->adapter = adap;
688 client->dev.platform_data = info->platform_data;
691 client->dev.archdata = *info->archdata;
693 client->flags = info->flags;
694 client->addr = info->addr;
695 client->irq = info->irq;
697 strlcpy(client->name, info->type, sizeof(client->name));
699 /* Check for address validity */
700 status = i2c_check_client_addr_validity(client);
702 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
703 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
707 /* Check for address business */
708 status = i2c_check_addr_busy(adap, client->addr);
712 client->dev.parent = &client->adapter->dev;
713 client->dev.bus = &i2c_bus_type;
714 client->dev.type = &i2c_client_type;
715 client->dev.of_node = info->of_node;
716 ACPI_COMPANION_SET(&client->dev, info->acpi_node.companion);
718 i2c_dev_set_name(adap, client);
719 status = device_register(&client->dev);
723 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
724 client->name, dev_name(&client->dev));
729 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
730 "(%d)\n", client->name, client->addr, status);
735 EXPORT_SYMBOL_GPL(i2c_new_device);
739 * i2c_unregister_device - reverse effect of i2c_new_device()
740 * @client: value returned from i2c_new_device()
743 void i2c_unregister_device(struct i2c_client *client)
745 device_unregister(&client->dev);
747 EXPORT_SYMBOL_GPL(i2c_unregister_device);
750 static const struct i2c_device_id dummy_id[] = {
755 static int dummy_probe(struct i2c_client *client,
756 const struct i2c_device_id *id)
761 static int dummy_remove(struct i2c_client *client)
766 static struct i2c_driver dummy_driver = {
767 .driver.name = "dummy",
768 .probe = dummy_probe,
769 .remove = dummy_remove,
770 .id_table = dummy_id,
774 * i2c_new_dummy - return a new i2c device bound to a dummy driver
775 * @adapter: the adapter managing the device
776 * @address: seven bit address to be used
779 * This returns an I2C client bound to the "dummy" driver, intended for use
780 * with devices that consume multiple addresses. Examples of such chips
781 * include various EEPROMS (like 24c04 and 24c08 models).
783 * These dummy devices have two main uses. First, most I2C and SMBus calls
784 * except i2c_transfer() need a client handle; the dummy will be that handle.
785 * And second, this prevents the specified address from being bound to a
788 * This returns the new i2c client, which should be saved for later use with
789 * i2c_unregister_device(); or NULL to indicate an error.
791 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
793 struct i2c_board_info info = {
794 I2C_BOARD_INFO("dummy", address),
797 return i2c_new_device(adapter, &info);
799 EXPORT_SYMBOL_GPL(i2c_new_dummy);
801 /* ------------------------------------------------------------------------- */
803 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
805 static void i2c_adapter_dev_release(struct device *dev)
807 struct i2c_adapter *adap = to_i2c_adapter(dev);
808 complete(&adap->dev_released);
812 * This function is only needed for mutex_lock_nested, so it is never
813 * called unless locking correctness checking is enabled. Thus we
814 * make it inline to avoid a compiler warning. That's what gcc ends up
817 static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
819 unsigned int depth = 0;
821 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
828 * Let users instantiate I2C devices through sysfs. This can be used when
829 * platform initialization code doesn't contain the proper data for
830 * whatever reason. Also useful for drivers that do device detection and
831 * detection fails, either because the device uses an unexpected address,
832 * or this is a compatible device with different ID register values.
834 * Parameter checking may look overzealous, but we really don't want
835 * the user to provide incorrect parameters.
838 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
839 const char *buf, size_t count)
841 struct i2c_adapter *adap = to_i2c_adapter(dev);
842 struct i2c_board_info info;
843 struct i2c_client *client;
847 memset(&info, 0, sizeof(struct i2c_board_info));
849 blank = strchr(buf, ' ');
851 dev_err(dev, "%s: Missing parameters\n", "new_device");
854 if (blank - buf > I2C_NAME_SIZE - 1) {
855 dev_err(dev, "%s: Invalid device name\n", "new_device");
858 memcpy(info.type, buf, blank - buf);
860 /* Parse remaining parameters, reject extra parameters */
861 res = sscanf(++blank, "%hi%c", &info.addr, &end);
863 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
866 if (res > 1 && end != '\n') {
867 dev_err(dev, "%s: Extra parameters\n", "new_device");
871 client = i2c_new_device(adap, &info);
875 /* Keep track of the added device */
876 mutex_lock(&adap->userspace_clients_lock);
877 list_add_tail(&client->detected, &adap->userspace_clients);
878 mutex_unlock(&adap->userspace_clients_lock);
879 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
880 info.type, info.addr);
886 * And of course let the users delete the devices they instantiated, if
887 * they got it wrong. This interface can only be used to delete devices
888 * instantiated by i2c_sysfs_new_device above. This guarantees that we
889 * don't delete devices to which some kernel code still has references.
891 * Parameter checking may look overzealous, but we really don't want
892 * the user to delete the wrong device.
895 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
896 const char *buf, size_t count)
898 struct i2c_adapter *adap = to_i2c_adapter(dev);
899 struct i2c_client *client, *next;
904 /* Parse parameters, reject extra parameters */
905 res = sscanf(buf, "%hi%c", &addr, &end);
907 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
910 if (res > 1 && end != '\n') {
911 dev_err(dev, "%s: Extra parameters\n", "delete_device");
915 /* Make sure the device was added through sysfs */
917 mutex_lock_nested(&adap->userspace_clients_lock,
918 i2c_adapter_depth(adap));
919 list_for_each_entry_safe(client, next, &adap->userspace_clients,
921 if (client->addr == addr) {
922 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
923 "delete_device", client->name, client->addr);
925 list_del(&client->detected);
926 i2c_unregister_device(client);
931 mutex_unlock(&adap->userspace_clients_lock);
934 dev_err(dev, "%s: Can't find device in list\n",
939 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
940 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
941 i2c_sysfs_delete_device);
943 static struct attribute *i2c_adapter_attrs[] = {
945 &dev_attr_new_device.attr,
946 &dev_attr_delete_device.attr,
950 static struct attribute_group i2c_adapter_attr_group = {
951 .attrs = i2c_adapter_attrs,
954 static const struct attribute_group *i2c_adapter_attr_groups[] = {
955 &i2c_adapter_attr_group,
959 struct device_type i2c_adapter_type = {
960 .groups = i2c_adapter_attr_groups,
961 .release = i2c_adapter_dev_release,
963 EXPORT_SYMBOL_GPL(i2c_adapter_type);
966 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
967 * @dev: device, probably from some driver model iterator
969 * When traversing the driver model tree, perhaps using driver model
970 * iterators like @device_for_each_child(), you can't assume very much
971 * about the nodes you find. Use this function to avoid oopses caused
972 * by wrongly treating some non-I2C device as an i2c_adapter.
974 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
976 return (dev->type == &i2c_adapter_type)
977 ? to_i2c_adapter(dev)
980 EXPORT_SYMBOL(i2c_verify_adapter);
982 #ifdef CONFIG_I2C_COMPAT
983 static struct class_compat *i2c_adapter_compat_class;
986 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
988 struct i2c_devinfo *devinfo;
990 down_read(&__i2c_board_lock);
991 list_for_each_entry(devinfo, &__i2c_board_list, list) {
992 if (devinfo->busnum == adapter->nr
993 && !i2c_new_device(adapter,
994 &devinfo->board_info))
995 dev_err(&adapter->dev,
996 "Can't create device at 0x%02x\n",
997 devinfo->board_info.addr);
999 up_read(&__i2c_board_lock);
1002 /* OF support code */
1004 #if IS_ENABLED(CONFIG_OF)
1005 static void of_i2c_register_devices(struct i2c_adapter *adap)
1008 struct device_node *node;
1010 /* Only register child devices if the adapter has a node pointer set */
1011 if (!adap->dev.of_node)
1014 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
1016 for_each_available_child_of_node(adap->dev.of_node, node) {
1017 struct i2c_board_info info = {};
1018 struct dev_archdata dev_ad = {};
1022 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1024 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
1025 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
1030 addr = of_get_property(node, "reg", &len);
1031 if (!addr || (len < sizeof(int))) {
1032 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
1037 info.addr = be32_to_cpup(addr);
1038 if (info.addr > (1 << 10) - 1) {
1039 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1040 info.addr, node->full_name);
1044 info.irq = irq_of_parse_and_map(node, 0);
1045 info.of_node = of_node_get(node);
1046 info.archdata = &dev_ad;
1048 if (of_get_property(node, "wakeup-source", NULL))
1049 info.flags |= I2C_CLIENT_WAKE;
1051 request_module("%s%s", I2C_MODULE_PREFIX, info.type);
1053 result = i2c_new_device(adap, &info);
1054 if (result == NULL) {
1055 dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
1058 irq_dispose_mapping(info.irq);
1064 static int of_dev_node_match(struct device *dev, void *data)
1066 return dev->of_node == data;
1069 /* must call put_device() when done with returned i2c_client device */
1070 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1074 dev = bus_find_device(&i2c_bus_type, NULL, node,
1079 return i2c_verify_client(dev);
1081 EXPORT_SYMBOL(of_find_i2c_device_by_node);
1083 /* must call put_device() when done with returned i2c_adapter device */
1084 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1088 dev = bus_find_device(&i2c_bus_type, NULL, node,
1093 return i2c_verify_adapter(dev);
1095 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1097 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
1098 #endif /* CONFIG_OF */
1100 /* ACPI support code */
1102 #if IS_ENABLED(CONFIG_ACPI)
1103 static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
1105 struct i2c_board_info *info = data;
1107 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1108 struct acpi_resource_i2c_serialbus *sb;
1110 sb = &ares->data.i2c_serial_bus;
1111 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
1112 info->addr = sb->slave_address;
1113 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
1114 info->flags |= I2C_CLIENT_TEN;
1116 } else if (info->irq < 0) {
1119 if (acpi_dev_resource_interrupt(ares, 0, &r))
1120 info->irq = r.start;
1123 /* Tell the ACPI core to skip this resource */
1127 static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
1128 void *data, void **return_value)
1130 struct i2c_adapter *adapter = data;
1131 struct list_head resource_list;
1132 struct i2c_board_info info;
1133 struct acpi_device *adev;
1136 if (acpi_bus_get_device(handle, &adev))
1138 if (acpi_bus_get_status(adev) || !adev->status.present)
1141 memset(&info, 0, sizeof(info));
1142 info.acpi_node.companion = adev;
1145 INIT_LIST_HEAD(&resource_list);
1146 ret = acpi_dev_get_resources(adev, &resource_list,
1147 acpi_i2c_add_resource, &info);
1148 acpi_dev_free_resource_list(&resource_list);
1150 if (ret < 0 || !info.addr)
1153 adev->power.flags.ignore_parent = true;
1154 strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
1155 if (!i2c_new_device(adapter, &info)) {
1156 adev->power.flags.ignore_parent = false;
1157 dev_err(&adapter->dev,
1158 "failed to add I2C device %s from ACPI\n",
1159 dev_name(&adev->dev));
1166 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
1167 * @adap: pointer to adapter
1169 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
1170 * namespace. When a device is found it will be added to the Linux device
1171 * model and bound to the corresponding ACPI handle.
1173 static void acpi_i2c_register_devices(struct i2c_adapter *adap)
1178 if (!adap->dev.parent)
1181 handle = ACPI_HANDLE(adap->dev.parent);
1185 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1186 acpi_i2c_add_device, NULL,
1188 if (ACPI_FAILURE(status))
1189 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
1192 static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
1193 #endif /* CONFIG_ACPI */
1195 static int i2c_do_add_adapter(struct i2c_driver *driver,
1196 struct i2c_adapter *adap)
1198 /* Detect supported devices on that bus, and instantiate them */
1199 i2c_detect(adap, driver);
1201 /* Let legacy drivers scan this bus for matching devices */
1202 if (driver->attach_adapter) {
1203 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1204 driver->driver.name);
1205 dev_warn(&adap->dev, "Please use another way to instantiate "
1206 "your i2c_client\n");
1207 /* We ignore the return code; if it fails, too bad */
1208 driver->attach_adapter(adap);
1213 static int __process_new_adapter(struct device_driver *d, void *data)
1215 return i2c_do_add_adapter(to_i2c_driver(d), data);
1218 static int i2c_register_adapter(struct i2c_adapter *adap)
1222 /* Can't register until after driver model init */
1223 if (unlikely(WARN_ON(!i2c_bus_type.p))) {
1229 if (unlikely(adap->name[0] == '\0')) {
1230 pr_err("i2c-core: Attempt to register an adapter with "
1234 if (unlikely(!adap->algo)) {
1235 pr_err("i2c-core: Attempt to register adapter '%s' with "
1236 "no algo!\n", adap->name);
1240 rt_mutex_init(&adap->bus_lock);
1241 mutex_init(&adap->userspace_clients_lock);
1242 INIT_LIST_HEAD(&adap->userspace_clients);
1244 /* Set default timeout to 1 second if not already set */
1245 if (adap->timeout == 0)
1248 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1249 adap->dev.bus = &i2c_bus_type;
1250 adap->dev.type = &i2c_adapter_type;
1251 res = device_register(&adap->dev);
1255 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1257 #ifdef CONFIG_I2C_COMPAT
1258 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1261 dev_warn(&adap->dev,
1262 "Failed to create compatibility class link\n");
1265 /* bus recovery specific initialization */
1266 if (adap->bus_recovery_info) {
1267 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
1269 if (!bri->recover_bus) {
1270 dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
1271 adap->bus_recovery_info = NULL;
1275 /* Generic GPIO recovery */
1276 if (bri->recover_bus == i2c_generic_gpio_recovery) {
1277 if (!gpio_is_valid(bri->scl_gpio)) {
1278 dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
1279 adap->bus_recovery_info = NULL;
1283 if (gpio_is_valid(bri->sda_gpio))
1284 bri->get_sda = get_sda_gpio_value;
1286 bri->get_sda = NULL;
1288 bri->get_scl = get_scl_gpio_value;
1289 bri->set_scl = set_scl_gpio_value;
1290 } else if (!bri->set_scl || !bri->get_scl) {
1291 /* Generic SCL recovery */
1292 dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
1293 adap->bus_recovery_info = NULL;
1298 /* create pre-declared device nodes */
1299 of_i2c_register_devices(adap);
1300 acpi_i2c_register_devices(adap);
1302 if (adap->nr < __i2c_first_dynamic_bus_num)
1303 i2c_scan_static_board_info(adap);
1305 /* Notify drivers */
1306 mutex_lock(&core_lock);
1307 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1308 mutex_unlock(&core_lock);
1313 mutex_lock(&core_lock);
1314 idr_remove(&i2c_adapter_idr, adap->nr);
1315 mutex_unlock(&core_lock);
1320 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1321 * @adap: the adapter to register (with adap->nr initialized)
1322 * Context: can sleep
1324 * See i2c_add_numbered_adapter() for details.
1326 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1330 mutex_lock(&core_lock);
1331 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
1333 mutex_unlock(&core_lock);
1335 return id == -ENOSPC ? -EBUSY : id;
1337 return i2c_register_adapter(adap);
1341 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1342 * @adapter: the adapter to add
1343 * Context: can sleep
1345 * This routine is used to declare an I2C adapter when its bus number
1346 * doesn't matter or when its bus number is specified by an dt alias.
1347 * Examples of bases when the bus number doesn't matter: I2C adapters
1348 * dynamically added by USB links or PCI plugin cards.
1350 * When this returns zero, a new bus number was allocated and stored
1351 * in adap->nr, and the specified adapter became available for clients.
1352 * Otherwise, a negative errno value is returned.
1354 int i2c_add_adapter(struct i2c_adapter *adapter)
1356 struct device *dev = &adapter->dev;
1360 id = of_alias_get_id(dev->of_node, "i2c");
1363 return __i2c_add_numbered_adapter(adapter);
1367 mutex_lock(&core_lock);
1368 id = idr_alloc(&i2c_adapter_idr, adapter,
1369 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1370 mutex_unlock(&core_lock);
1376 return i2c_register_adapter(adapter);
1378 EXPORT_SYMBOL(i2c_add_adapter);
1381 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1382 * @adap: the adapter to register (with adap->nr initialized)
1383 * Context: can sleep
1385 * This routine is used to declare an I2C adapter when its bus number
1386 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1387 * or otherwise built in to the system's mainboard, and where i2c_board_info
1388 * is used to properly configure I2C devices.
1390 * If the requested bus number is set to -1, then this function will behave
1391 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1393 * If no devices have pre-been declared for this bus, then be sure to
1394 * register the adapter before any dynamically allocated ones. Otherwise
1395 * the required bus ID may not be available.
1397 * When this returns zero, the specified adapter became available for
1398 * clients using the bus number provided in adap->nr. Also, the table
1399 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1400 * and the appropriate driver model device nodes are created. Otherwise, a
1401 * negative errno value is returned.
1403 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1405 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1406 return i2c_add_adapter(adap);
1408 return __i2c_add_numbered_adapter(adap);
1410 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1412 static void i2c_do_del_adapter(struct i2c_driver *driver,
1413 struct i2c_adapter *adapter)
1415 struct i2c_client *client, *_n;
1417 /* Remove the devices we created ourselves as the result of hardware
1418 * probing (using a driver's detect method) */
1419 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1420 if (client->adapter == adapter) {
1421 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1422 client->name, client->addr);
1423 list_del(&client->detected);
1424 i2c_unregister_device(client);
1429 static int __unregister_client(struct device *dev, void *dummy)
1431 struct i2c_client *client = i2c_verify_client(dev);
1432 if (client && strcmp(client->name, "dummy"))
1433 i2c_unregister_device(client);
1437 static int __unregister_dummy(struct device *dev, void *dummy)
1439 struct i2c_client *client = i2c_verify_client(dev);
1441 i2c_unregister_device(client);
1445 static int __process_removed_adapter(struct device_driver *d, void *data)
1447 i2c_do_del_adapter(to_i2c_driver(d), data);
1452 * i2c_del_adapter - unregister I2C adapter
1453 * @adap: the adapter being unregistered
1454 * Context: can sleep
1456 * This unregisters an I2C adapter which was previously registered
1457 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1459 void i2c_del_adapter(struct i2c_adapter *adap)
1461 struct i2c_adapter *found;
1462 struct i2c_client *client, *next;
1464 /* First make sure that this adapter was ever added */
1465 mutex_lock(&core_lock);
1466 found = idr_find(&i2c_adapter_idr, adap->nr);
1467 mutex_unlock(&core_lock);
1468 if (found != adap) {
1469 pr_debug("i2c-core: attempting to delete unregistered "
1470 "adapter [%s]\n", adap->name);
1474 /* Tell drivers about this removal */
1475 mutex_lock(&core_lock);
1476 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1477 __process_removed_adapter);
1478 mutex_unlock(&core_lock);
1480 /* Remove devices instantiated from sysfs */
1481 mutex_lock_nested(&adap->userspace_clients_lock,
1482 i2c_adapter_depth(adap));
1483 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1485 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1487 list_del(&client->detected);
1488 i2c_unregister_device(client);
1490 mutex_unlock(&adap->userspace_clients_lock);
1492 /* Detach any active clients. This can't fail, thus we do not
1493 * check the returned value. This is a two-pass process, because
1494 * we can't remove the dummy devices during the first pass: they
1495 * could have been instantiated by real devices wishing to clean
1496 * them up properly, so we give them a chance to do that first. */
1497 device_for_each_child(&adap->dev, NULL, __unregister_client);
1498 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1500 #ifdef CONFIG_I2C_COMPAT
1501 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1505 /* device name is gone after device_unregister */
1506 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1508 /* clean up the sysfs representation */
1509 init_completion(&adap->dev_released);
1510 device_unregister(&adap->dev);
1512 /* wait for sysfs to drop all references */
1513 wait_for_completion(&adap->dev_released);
1516 mutex_lock(&core_lock);
1517 idr_remove(&i2c_adapter_idr, adap->nr);
1518 mutex_unlock(&core_lock);
1520 /* Clear the device structure in case this adapter is ever going to be
1522 memset(&adap->dev, 0, sizeof(adap->dev));
1524 EXPORT_SYMBOL(i2c_del_adapter);
1526 /* ------------------------------------------------------------------------- */
1528 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1532 mutex_lock(&core_lock);
1533 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1534 mutex_unlock(&core_lock);
1538 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1540 static int __process_new_driver(struct device *dev, void *data)
1542 if (dev->type != &i2c_adapter_type)
1544 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1548 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1549 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1552 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1556 /* Can't register until after driver model init */
1557 if (unlikely(WARN_ON(!i2c_bus_type.p)))
1560 /* add the driver to the list of i2c drivers in the driver core */
1561 driver->driver.owner = owner;
1562 driver->driver.bus = &i2c_bus_type;
1564 /* When registration returns, the driver core
1565 * will have called probe() for all matching-but-unbound devices.
1567 res = driver_register(&driver->driver);
1571 /* Drivers should switch to dev_pm_ops instead. */
1572 if (driver->suspend)
1573 pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
1574 driver->driver.name);
1576 pr_warn("i2c-core: driver [%s] using legacy resume method\n",
1577 driver->driver.name);
1579 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
1581 INIT_LIST_HEAD(&driver->clients);
1582 /* Walk the adapters that are already present */
1583 i2c_for_each_dev(driver, __process_new_driver);
1587 EXPORT_SYMBOL(i2c_register_driver);
1589 static int __process_removed_driver(struct device *dev, void *data)
1591 if (dev->type == &i2c_adapter_type)
1592 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1597 * i2c_del_driver - unregister I2C driver
1598 * @driver: the driver being unregistered
1599 * Context: can sleep
1601 void i2c_del_driver(struct i2c_driver *driver)
1603 i2c_for_each_dev(driver, __process_removed_driver);
1605 driver_unregister(&driver->driver);
1606 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
1608 EXPORT_SYMBOL(i2c_del_driver);
1610 /* ------------------------------------------------------------------------- */
1613 * i2c_use_client - increments the reference count of the i2c client structure
1614 * @client: the client being referenced
1616 * Each live reference to a client should be refcounted. The driver model does
1617 * that automatically as part of driver binding, so that most drivers don't
1618 * need to do this explicitly: they hold a reference until they're unbound
1621 * A pointer to the client with the incremented reference counter is returned.
1623 struct i2c_client *i2c_use_client(struct i2c_client *client)
1625 if (client && get_device(&client->dev))
1629 EXPORT_SYMBOL(i2c_use_client);
1632 * i2c_release_client - release a use of the i2c client structure
1633 * @client: the client being no longer referenced
1635 * Must be called when a user of a client is finished with it.
1637 void i2c_release_client(struct i2c_client *client)
1640 put_device(&client->dev);
1642 EXPORT_SYMBOL(i2c_release_client);
1644 struct i2c_cmd_arg {
1649 static int i2c_cmd(struct device *dev, void *_arg)
1651 struct i2c_client *client = i2c_verify_client(dev);
1652 struct i2c_cmd_arg *arg = _arg;
1653 struct i2c_driver *driver;
1655 if (!client || !client->dev.driver)
1658 driver = to_i2c_driver(client->dev.driver);
1659 if (driver->command)
1660 driver->command(client, arg->cmd, arg->arg);
1664 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1666 struct i2c_cmd_arg cmd_arg;
1670 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1672 EXPORT_SYMBOL(i2c_clients_command);
1674 static int __init i2c_init(void)
1678 retval = bus_register(&i2c_bus_type);
1681 #ifdef CONFIG_I2C_COMPAT
1682 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1683 if (!i2c_adapter_compat_class) {
1688 retval = i2c_add_driver(&dummy_driver);
1694 #ifdef CONFIG_I2C_COMPAT
1695 class_compat_unregister(i2c_adapter_compat_class);
1698 bus_unregister(&i2c_bus_type);
1702 static void __exit i2c_exit(void)
1704 i2c_del_driver(&dummy_driver);
1705 #ifdef CONFIG_I2C_COMPAT
1706 class_compat_unregister(i2c_adapter_compat_class);
1708 bus_unregister(&i2c_bus_type);
1709 tracepoint_synchronize_unregister();
1712 /* We must initialize early, because some subsystems register i2c drivers
1713 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1715 postcore_initcall(i2c_init);
1716 module_exit(i2c_exit);
1718 /* ----------------------------------------------------
1719 * the functional interface to the i2c busses.
1720 * ----------------------------------------------------
1724 * __i2c_transfer - unlocked flavor of i2c_transfer
1725 * @adap: Handle to I2C bus
1726 * @msgs: One or more messages to execute before STOP is issued to
1727 * terminate the operation; each message begins with a START.
1728 * @num: Number of messages to be executed.
1730 * Returns negative errno, else the number of messages executed.
1732 * Adapter lock must be held when calling this function. No debug logging
1733 * takes place. adap->algo->master_xfer existence isn't checked.
1735 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1737 unsigned long orig_jiffies;
1740 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1741 * enabled. This is an efficient way of keeping the for-loop from
1742 * being executed when not needed.
1744 if (static_key_false(&i2c_trace_msg)) {
1746 for (i = 0; i < num; i++)
1747 if (msgs[i].flags & I2C_M_RD)
1748 trace_i2c_read(adap, &msgs[i], i);
1750 trace_i2c_write(adap, &msgs[i], i);
1753 /* Retry automatically on arbitration loss */
1754 orig_jiffies = jiffies;
1755 for (ret = 0, try = 0; try <= adap->retries; try++) {
1756 ret = adap->algo->master_xfer(adap, msgs, num);
1759 if (time_after(jiffies, orig_jiffies + adap->timeout))
1763 if (static_key_false(&i2c_trace_msg)) {
1765 for (i = 0; i < ret; i++)
1766 if (msgs[i].flags & I2C_M_RD)
1767 trace_i2c_reply(adap, &msgs[i], i);
1768 trace_i2c_result(adap, i, ret);
1773 EXPORT_SYMBOL(__i2c_transfer);
1776 * i2c_transfer - execute a single or combined I2C message
1777 * @adap: Handle to I2C bus
1778 * @msgs: One or more messages to execute before STOP is issued to
1779 * terminate the operation; each message begins with a START.
1780 * @num: Number of messages to be executed.
1782 * Returns negative errno, else the number of messages executed.
1784 * Note that there is no requirement that each message be sent to
1785 * the same slave address, although that is the most common model.
1787 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1791 /* REVISIT the fault reporting model here is weak:
1793 * - When we get an error after receiving N bytes from a slave,
1794 * there is no way to report "N".
1796 * - When we get a NAK after transmitting N bytes to a slave,
1797 * there is no way to report "N" ... or to let the master
1798 * continue executing the rest of this combined message, if
1799 * that's the appropriate response.
1801 * - When for example "num" is two and we successfully complete
1802 * the first message but get an error part way through the
1803 * second, it's unclear whether that should be reported as
1804 * one (discarding status on the second message) or errno
1805 * (discarding status on the first one).
1808 if (adap->algo->master_xfer) {
1810 for (ret = 0; ret < num; ret++) {
1811 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
1812 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
1813 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
1814 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1818 if (in_atomic() || irqs_disabled()) {
1819 ret = i2c_trylock_adapter(adap);
1821 /* I2C activity is ongoing. */
1824 i2c_lock_adapter(adap);
1827 ret = __i2c_transfer(adap, msgs, num);
1828 i2c_unlock_adapter(adap);
1832 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1836 EXPORT_SYMBOL(i2c_transfer);
1839 * i2c_master_send - issue a single I2C message in master transmit mode
1840 * @client: Handle to slave device
1841 * @buf: Data that will be written to the slave
1842 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1844 * Returns negative errno, or else the number of bytes written.
1846 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1849 struct i2c_adapter *adap = client->adapter;
1852 msg.addr = client->addr;
1853 msg.flags = client->flags & I2C_M_TEN;
1855 msg.buf = (char *)buf;
1857 ret = i2c_transfer(adap, &msg, 1);
1860 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1861 * transmitted, else error code.
1863 return (ret == 1) ? count : ret;
1865 EXPORT_SYMBOL(i2c_master_send);
1868 * i2c_master_recv - issue a single I2C message in master receive mode
1869 * @client: Handle to slave device
1870 * @buf: Where to store data read from slave
1871 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1873 * Returns negative errno, or else the number of bytes read.
1875 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
1877 struct i2c_adapter *adap = client->adapter;
1881 msg.addr = client->addr;
1882 msg.flags = client->flags & I2C_M_TEN;
1883 msg.flags |= I2C_M_RD;
1887 ret = i2c_transfer(adap, &msg, 1);
1890 * If everything went ok (i.e. 1 msg received), return #bytes received,
1893 return (ret == 1) ? count : ret;
1895 EXPORT_SYMBOL(i2c_master_recv);
1897 /* ----------------------------------------------------
1898 * the i2c address scanning function
1899 * Will not work for 10-bit addresses!
1900 * ----------------------------------------------------
1904 * Legacy default probe function, mostly relevant for SMBus. The default
1905 * probe method is a quick write, but it is known to corrupt the 24RF08
1906 * EEPROMs due to a state machine bug, and could also irreversibly
1907 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1908 * we use a short byte read instead. Also, some bus drivers don't implement
1909 * quick write, so we fallback to a byte read in that case too.
1910 * On x86, there is another special case for FSC hardware monitoring chips,
1911 * which want regular byte reads (address 0x73.) Fortunately, these are the
1912 * only known chips using this I2C address on PC hardware.
1913 * Returns 1 if probe succeeded, 0 if not.
1915 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
1918 union i2c_smbus_data dummy;
1921 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
1922 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
1923 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1924 I2C_SMBUS_BYTE_DATA, &dummy);
1927 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
1928 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
1929 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
1930 I2C_SMBUS_QUICK, NULL);
1931 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
1932 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1933 I2C_SMBUS_BYTE, &dummy);
1935 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
1943 static int i2c_detect_address(struct i2c_client *temp_client,
1944 struct i2c_driver *driver)
1946 struct i2c_board_info info;
1947 struct i2c_adapter *adapter = temp_client->adapter;
1948 int addr = temp_client->addr;
1951 /* Make sure the address is valid */
1952 err = i2c_check_addr_validity(addr);
1954 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
1959 /* Skip if already in use */
1960 if (i2c_check_addr_busy(adapter, addr))
1963 /* Make sure there is something at this address */
1964 if (!i2c_default_probe(adapter, addr))
1967 /* Finally call the custom detection function */
1968 memset(&info, 0, sizeof(struct i2c_board_info));
1970 err = driver->detect(temp_client, &info);
1972 /* -ENODEV is returned if the detection fails. We catch it
1973 here as this isn't an error. */
1974 return err == -ENODEV ? 0 : err;
1977 /* Consistency check */
1978 if (info.type[0] == '\0') {
1979 dev_err(&adapter->dev, "%s detection function provided "
1980 "no name for 0x%x\n", driver->driver.name,
1983 struct i2c_client *client;
1985 /* Detection succeeded, instantiate the device */
1986 if (adapter->class & I2C_CLASS_DEPRECATED)
1987 dev_warn(&adapter->dev,
1988 "This adapter will soon drop class based instantiation of devices. "
1989 "Please make sure client 0x%02x gets instantiated by other means. "
1990 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
1993 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
1994 info.type, info.addr);
1995 client = i2c_new_device(adapter, &info);
1997 list_add_tail(&client->detected, &driver->clients);
1999 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2000 info.type, info.addr);
2005 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2007 const unsigned short *address_list;
2008 struct i2c_client *temp_client;
2010 int adap_id = i2c_adapter_id(adapter);
2012 address_list = driver->address_list;
2013 if (!driver->detect || !address_list)
2016 /* Stop here if the classes do not match */
2017 if (!(adapter->class & driver->class))
2020 /* Set up a temporary client to help detect callback */
2021 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2024 temp_client->adapter = adapter;
2026 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2027 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
2028 "addr 0x%02x\n", adap_id, address_list[i]);
2029 temp_client->addr = address_list[i];
2030 err = i2c_detect_address(temp_client, driver);
2039 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2041 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2042 I2C_SMBUS_QUICK, NULL) >= 0;
2044 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2047 i2c_new_probed_device(struct i2c_adapter *adap,
2048 struct i2c_board_info *info,
2049 unsigned short const *addr_list,
2050 int (*probe)(struct i2c_adapter *, unsigned short addr))
2055 probe = i2c_default_probe;
2057 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2058 /* Check address validity */
2059 if (i2c_check_addr_validity(addr_list[i]) < 0) {
2060 dev_warn(&adap->dev, "Invalid 7-bit address "
2061 "0x%02x\n", addr_list[i]);
2065 /* Check address availability */
2066 if (i2c_check_addr_busy(adap, addr_list[i])) {
2067 dev_dbg(&adap->dev, "Address 0x%02x already in "
2068 "use, not probing\n", addr_list[i]);
2072 /* Test address responsiveness */
2073 if (probe(adap, addr_list[i]))
2077 if (addr_list[i] == I2C_CLIENT_END) {
2078 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2082 info->addr = addr_list[i];
2083 return i2c_new_device(adap, info);
2085 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2087 struct i2c_adapter *i2c_get_adapter(int nr)
2089 struct i2c_adapter *adapter;
2091 mutex_lock(&core_lock);
2092 adapter = idr_find(&i2c_adapter_idr, nr);
2093 if (adapter && !try_module_get(adapter->owner))
2096 mutex_unlock(&core_lock);
2099 EXPORT_SYMBOL(i2c_get_adapter);
2101 void i2c_put_adapter(struct i2c_adapter *adap)
2104 module_put(adap->owner);
2106 EXPORT_SYMBOL(i2c_put_adapter);
2108 /* The SMBus parts */
2110 #define POLY (0x1070U << 3)
2111 static u8 crc8(u16 data)
2115 for (i = 0; i < 8; i++) {
2120 return (u8)(data >> 8);
2123 /* Incremental CRC8 over count bytes in the array pointed to by p */
2124 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
2128 for (i = 0; i < count; i++)
2129 crc = crc8((crc ^ p[i]) << 8);
2133 /* Assume a 7-bit address, which is reasonable for SMBus */
2134 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
2136 /* The address will be sent first */
2137 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
2138 pec = i2c_smbus_pec(pec, &addr, 1);
2140 /* The data buffer follows */
2141 return i2c_smbus_pec(pec, msg->buf, msg->len);
2144 /* Used for write only transactions */
2145 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
2147 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
2151 /* Return <0 on CRC error
2152 If there was a write before this read (most cases) we need to take the
2153 partial CRC from the write part into account.
2154 Note that this function does modify the message (we need to decrease the
2155 message length to hide the CRC byte from the caller). */
2156 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
2158 u8 rpec = msg->buf[--msg->len];
2159 cpec = i2c_smbus_msg_pec(cpec, msg);
2162 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2170 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2171 * @client: Handle to slave device
2173 * This executes the SMBus "receive byte" protocol, returning negative errno
2174 * else the byte received from the device.
2176 s32 i2c_smbus_read_byte(const struct i2c_client *client)
2178 union i2c_smbus_data data;
2181 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2183 I2C_SMBUS_BYTE, &data);
2184 return (status < 0) ? status : data.byte;
2186 EXPORT_SYMBOL(i2c_smbus_read_byte);
2189 * i2c_smbus_write_byte - SMBus "send byte" protocol
2190 * @client: Handle to slave device
2191 * @value: Byte to be sent
2193 * This executes the SMBus "send byte" protocol, returning negative errno
2194 * else zero on success.
2196 s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
2198 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2199 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
2201 EXPORT_SYMBOL(i2c_smbus_write_byte);
2204 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2205 * @client: Handle to slave device
2206 * @command: Byte interpreted by slave
2208 * This executes the SMBus "read byte" protocol, returning negative errno
2209 * else a data byte received from the device.
2211 s32 i2c_smbus_read_byte_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_BYTE_DATA, &data);
2219 return (status < 0) ? status : data.byte;
2221 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
2224 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2225 * @client: Handle to slave device
2226 * @command: Byte interpreted by slave
2227 * @value: Byte being written
2229 * This executes the SMBus "write byte" protocol, returning negative errno
2230 * else zero on success.
2232 s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
2235 union i2c_smbus_data data;
2237 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2238 I2C_SMBUS_WRITE, command,
2239 I2C_SMBUS_BYTE_DATA, &data);
2241 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
2244 * i2c_smbus_read_word_data - SMBus "read word" protocol
2245 * @client: Handle to slave device
2246 * @command: Byte interpreted by slave
2248 * This executes the SMBus "read word" protocol, returning negative errno
2249 * else a 16-bit unsigned "word" received from the device.
2251 s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
2253 union i2c_smbus_data data;
2256 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2257 I2C_SMBUS_READ, command,
2258 I2C_SMBUS_WORD_DATA, &data);
2259 return (status < 0) ? status : data.word;
2261 EXPORT_SYMBOL(i2c_smbus_read_word_data);
2264 * i2c_smbus_write_word_data - SMBus "write word" protocol
2265 * @client: Handle to slave device
2266 * @command: Byte interpreted by slave
2267 * @value: 16-bit "word" being written
2269 * This executes the SMBus "write word" protocol, returning negative errno
2270 * else zero on success.
2272 s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
2275 union i2c_smbus_data data;
2277 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2278 I2C_SMBUS_WRITE, command,
2279 I2C_SMBUS_WORD_DATA, &data);
2281 EXPORT_SYMBOL(i2c_smbus_write_word_data);
2284 * i2c_smbus_read_block_data - SMBus "block read" protocol
2285 * @client: Handle to slave device
2286 * @command: Byte interpreted by slave
2287 * @values: Byte array into which data will be read; big enough to hold
2288 * the data returned by the slave. SMBus allows at most 32 bytes.
2290 * This executes the SMBus "block read" protocol, returning negative errno
2291 * else the number of data bytes in the slave's response.
2293 * Note that using this function requires that the client's adapter support
2294 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2295 * support this; its emulation through I2C messaging relies on a specific
2296 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2298 s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2301 union i2c_smbus_data data;
2304 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2305 I2C_SMBUS_READ, command,
2306 I2C_SMBUS_BLOCK_DATA, &data);
2310 memcpy(values, &data.block[1], data.block[0]);
2311 return data.block[0];
2313 EXPORT_SYMBOL(i2c_smbus_read_block_data);
2316 * i2c_smbus_write_block_data - SMBus "block write" protocol
2317 * @client: Handle to slave device
2318 * @command: Byte interpreted by slave
2319 * @length: Size of data block; SMBus allows at most 32 bytes
2320 * @values: Byte array which will be written.
2322 * This executes the SMBus "block write" protocol, returning negative errno
2323 * else zero on success.
2325 s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2326 u8 length, const u8 *values)
2328 union i2c_smbus_data data;
2330 if (length > I2C_SMBUS_BLOCK_MAX)
2331 length = I2C_SMBUS_BLOCK_MAX;
2332 data.block[0] = length;
2333 memcpy(&data.block[1], values, length);
2334 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2335 I2C_SMBUS_WRITE, command,
2336 I2C_SMBUS_BLOCK_DATA, &data);
2338 EXPORT_SYMBOL(i2c_smbus_write_block_data);
2340 /* Returns the number of read bytes */
2341 s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2342 u8 length, u8 *values)
2344 union i2c_smbus_data data;
2347 if (length > I2C_SMBUS_BLOCK_MAX)
2348 length = I2C_SMBUS_BLOCK_MAX;
2349 data.block[0] = length;
2350 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2351 I2C_SMBUS_READ, command,
2352 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2356 memcpy(values, &data.block[1], data.block[0]);
2357 return data.block[0];
2359 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
2361 s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2362 u8 length, const u8 *values)
2364 union i2c_smbus_data data;
2366 if (length > I2C_SMBUS_BLOCK_MAX)
2367 length = I2C_SMBUS_BLOCK_MAX;
2368 data.block[0] = length;
2369 memcpy(data.block + 1, values, length);
2370 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2371 I2C_SMBUS_WRITE, command,
2372 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2374 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2376 /* Simulate a SMBus command using the i2c protocol
2377 No checking of parameters is done! */
2378 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
2379 unsigned short flags,
2380 char read_write, u8 command, int size,
2381 union i2c_smbus_data *data)
2383 /* So we need to generate a series of msgs. In the case of writing, we
2384 need to use only one message; when reading, we need two. We initialize
2385 most things with sane defaults, to keep the code below somewhat
2387 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
2388 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2389 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
2393 struct i2c_msg msg[2] = {
2401 .flags = flags | I2C_M_RD,
2407 msgbuf0[0] = command;
2409 case I2C_SMBUS_QUICK:
2411 /* Special case: The read/write field is used as data */
2412 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
2416 case I2C_SMBUS_BYTE:
2417 if (read_write == I2C_SMBUS_READ) {
2418 /* Special case: only a read! */
2419 msg[0].flags = I2C_M_RD | flags;
2423 case I2C_SMBUS_BYTE_DATA:
2424 if (read_write == I2C_SMBUS_READ)
2428 msgbuf0[1] = data->byte;
2431 case I2C_SMBUS_WORD_DATA:
2432 if (read_write == I2C_SMBUS_READ)
2436 msgbuf0[1] = data->word & 0xff;
2437 msgbuf0[2] = data->word >> 8;
2440 case I2C_SMBUS_PROC_CALL:
2441 num = 2; /* Special case */
2442 read_write = I2C_SMBUS_READ;
2445 msgbuf0[1] = data->word & 0xff;
2446 msgbuf0[2] = data->word >> 8;
2448 case I2C_SMBUS_BLOCK_DATA:
2449 if (read_write == I2C_SMBUS_READ) {
2450 msg[1].flags |= I2C_M_RECV_LEN;
2451 msg[1].len = 1; /* block length will be added by
2452 the underlying bus driver */
2454 msg[0].len = data->block[0] + 2;
2455 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
2456 dev_err(&adapter->dev,
2457 "Invalid block write size %d\n",
2461 for (i = 1; i < msg[0].len; i++)
2462 msgbuf0[i] = data->block[i-1];
2465 case I2C_SMBUS_BLOCK_PROC_CALL:
2466 num = 2; /* Another special case */
2467 read_write = I2C_SMBUS_READ;
2468 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
2469 dev_err(&adapter->dev,
2470 "Invalid block write size %d\n",
2474 msg[0].len = data->block[0] + 2;
2475 for (i = 1; i < msg[0].len; i++)
2476 msgbuf0[i] = data->block[i-1];
2477 msg[1].flags |= I2C_M_RECV_LEN;
2478 msg[1].len = 1; /* block length will be added by
2479 the underlying bus driver */
2481 case I2C_SMBUS_I2C_BLOCK_DATA:
2482 if (read_write == I2C_SMBUS_READ) {
2483 msg[1].len = data->block[0];
2485 msg[0].len = data->block[0] + 1;
2486 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
2487 dev_err(&adapter->dev,
2488 "Invalid block write size %d\n",
2492 for (i = 1; i <= data->block[0]; i++)
2493 msgbuf0[i] = data->block[i];
2497 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
2501 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
2502 && size != I2C_SMBUS_I2C_BLOCK_DATA);
2504 /* Compute PEC if first message is a write */
2505 if (!(msg[0].flags & I2C_M_RD)) {
2506 if (num == 1) /* Write only */
2507 i2c_smbus_add_pec(&msg[0]);
2508 else /* Write followed by read */
2509 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
2511 /* Ask for PEC if last message is a read */
2512 if (msg[num-1].flags & I2C_M_RD)
2516 status = i2c_transfer(adapter, msg, num);
2520 /* Check PEC if last message is a read */
2521 if (i && (msg[num-1].flags & I2C_M_RD)) {
2522 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
2527 if (read_write == I2C_SMBUS_READ)
2529 case I2C_SMBUS_BYTE:
2530 data->byte = msgbuf0[0];
2532 case I2C_SMBUS_BYTE_DATA:
2533 data->byte = msgbuf1[0];
2535 case I2C_SMBUS_WORD_DATA:
2536 case I2C_SMBUS_PROC_CALL:
2537 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
2539 case I2C_SMBUS_I2C_BLOCK_DATA:
2540 for (i = 0; i < data->block[0]; i++)
2541 data->block[i+1] = msgbuf1[i];
2543 case I2C_SMBUS_BLOCK_DATA:
2544 case I2C_SMBUS_BLOCK_PROC_CALL:
2545 for (i = 0; i < msgbuf1[0] + 1; i++)
2546 data->block[i] = msgbuf1[i];
2553 * i2c_smbus_xfer - execute SMBus protocol operations
2554 * @adapter: Handle to I2C bus
2555 * @addr: Address of SMBus slave on that bus
2556 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2557 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2558 * @command: Byte interpreted by slave, for protocols which use such bytes
2559 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2560 * @data: Data to be read or written
2562 * This executes an SMBus protocol operation, and returns a negative
2563 * errno code else zero on success.
2565 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
2566 char read_write, u8 command, int protocol,
2567 union i2c_smbus_data *data)
2569 unsigned long orig_jiffies;
2573 /* If enabled, the following two tracepoints are conditional on
2574 * read_write and protocol.
2576 trace_smbus_write(adapter, addr, flags, read_write,
2577 command, protocol, data);
2578 trace_smbus_read(adapter, addr, flags, read_write,
2581 flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
2583 if (adapter->algo->smbus_xfer) {
2584 i2c_lock_adapter(adapter);
2586 /* Retry automatically on arbitration loss */
2587 orig_jiffies = jiffies;
2588 for (res = 0, try = 0; try <= adapter->retries; try++) {
2589 res = adapter->algo->smbus_xfer(adapter, addr, flags,
2590 read_write, command,
2594 if (time_after(jiffies,
2595 orig_jiffies + adapter->timeout))
2598 i2c_unlock_adapter(adapter);
2600 if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
2603 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2604 * implement native support for the SMBus operation.
2608 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
2609 command, protocol, data);
2612 /* If enabled, the reply tracepoint is conditional on read_write. */
2613 trace_smbus_reply(adapter, addr, flags, read_write,
2614 command, protocol, data);
2615 trace_smbus_result(adapter, addr, flags, read_write,
2616 command, protocol, res);
2620 EXPORT_SYMBOL(i2c_smbus_xfer);
2622 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2623 MODULE_DESCRIPTION("I2C-Bus main module");
2624 MODULE_LICENSE("GPL");