4 * Copyright (C) 1995-99 Simon G. Vogl
5 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
6 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
7 * Michael Lawnick <michael.lawnick.ext@nsn.com>
9 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
16 * This program is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
21 #define pr_fmt(fmt) "i2c-core: " fmt
23 #include <dt-bindings/i2c/i2c.h>
24 #include <linux/acpi.h>
25 #include <linux/clk/clk-conf.h>
26 #include <linux/completion.h>
27 #include <linux/delay.h>
28 #include <linux/err.h>
29 #include <linux/errno.h>
30 #include <linux/gpio/consumer.h>
31 #include <linux/i2c.h>
32 #include <linux/i2c-smbus.h>
33 #include <linux/idr.h>
34 #include <linux/init.h>
35 #include <linux/interrupt.h>
36 #include <linux/irqflags.h>
37 #include <linux/jump_label.h>
38 #include <linux/kernel.h>
39 #include <linux/module.h>
40 #include <linux/mutex.h>
41 #include <linux/of_device.h>
43 #include <linux/of_irq.h>
44 #include <linux/pm_domain.h>
45 #include <linux/pm_runtime.h>
46 #include <linux/pm_wakeirq.h>
47 #include <linux/property.h>
48 #include <linux/rwsem.h>
49 #include <linux/slab.h>
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/i2c.h>
56 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
57 #define I2C_ADDR_OFFSET_SLAVE 0x1000
59 #define I2C_ADDR_7BITS_MAX 0x77
60 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
62 #define I2C_ADDR_DEVICE_ID 0x7c
65 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
66 * deletion of detected devices are serialized
68 static DEFINE_MUTEX(core_lock);
69 static DEFINE_IDR(i2c_adapter_idr);
71 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
73 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
74 static bool is_registered;
76 int i2c_transfer_trace_reg(void)
78 static_branch_inc(&i2c_trace_msg_key);
82 void i2c_transfer_trace_unreg(void)
84 static_branch_dec(&i2c_trace_msg_key);
87 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
88 const struct i2c_client *client)
94 if (strcmp(client->name, id->name) == 0)
100 EXPORT_SYMBOL_GPL(i2c_match_id);
102 static int i2c_device_match(struct device *dev, struct device_driver *drv)
104 struct i2c_client *client = i2c_verify_client(dev);
105 struct i2c_driver *driver;
108 /* Attempt an OF style match */
109 if (i2c_of_match_device(drv->of_match_table, client))
112 /* Then ACPI style match */
113 if (acpi_driver_match_device(dev, drv))
116 driver = to_i2c_driver(drv);
118 /* Finally an I2C match */
119 if (i2c_match_id(driver->id_table, client))
125 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
127 struct i2c_client *client = to_i2c_client(dev);
130 rc = of_device_uevent_modalias(dev, env);
134 rc = acpi_device_uevent_modalias(dev, env);
138 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
141 /* i2c bus recovery routines */
142 static int get_scl_gpio_value(struct i2c_adapter *adap)
144 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
147 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
149 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
152 static int get_sda_gpio_value(struct i2c_adapter *adap)
154 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
157 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
159 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
162 static int i2c_generic_bus_free(struct i2c_adapter *adap)
164 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
165 int ret = -EOPNOTSUPP;
167 if (bri->get_bus_free)
168 ret = bri->get_bus_free(adap);
169 else if (bri->get_sda)
170 ret = bri->get_sda(adap);
175 return ret ? 0 : -EBUSY;
179 * We are generating clock pulses. ndelay() determines durating of clk pulses.
180 * We will generate clock with rate 100 KHz and so duration of both clock levels
181 * is: delay in ns = (10^6 / 100) / 2
183 #define RECOVERY_NDELAY 5000
184 #define RECOVERY_CLK_CNT 9
186 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
188 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
189 int i = 0, scl = 1, ret = 0;
191 if (bri->prepare_recovery)
192 bri->prepare_recovery(adap);
195 * If we can set SDA, we will always create a STOP to ensure additional
196 * pulses will do no harm. This is achieved by letting SDA follow SCL
197 * half a cycle later. Check the 'incomplete_write_byte' fault injector
198 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
199 * here for simplicity.
201 bri->set_scl(adap, scl);
202 ndelay(RECOVERY_NDELAY);
204 bri->set_sda(adap, scl);
205 ndelay(RECOVERY_NDELAY / 2);
208 * By this time SCL is high, as we need to give 9 falling-rising edges
210 while (i++ < RECOVERY_CLK_CNT * 2) {
212 /* SCL shouldn't be low here */
213 if (!bri->get_scl(adap)) {
215 "SCL is stuck low, exit recovery\n");
222 bri->set_scl(adap, scl);
223 /* Creating STOP again, see above */
225 /* Honour minimum tsu:sto */
226 ndelay(RECOVERY_NDELAY);
228 /* Honour minimum tf and thd:dat */
229 ndelay(RECOVERY_NDELAY / 2);
232 bri->set_sda(adap, scl);
233 ndelay(RECOVERY_NDELAY / 2);
236 ret = i2c_generic_bus_free(adap);
242 /* If we can't check bus status, assume recovery worked */
243 if (ret == -EOPNOTSUPP)
246 if (bri->unprepare_recovery)
247 bri->unprepare_recovery(adap);
251 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
253 int i2c_recover_bus(struct i2c_adapter *adap)
255 if (!adap->bus_recovery_info)
258 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
259 return adap->bus_recovery_info->recover_bus(adap);
261 EXPORT_SYMBOL_GPL(i2c_recover_bus);
263 static void i2c_init_recovery(struct i2c_adapter *adap)
265 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
266 char *err_str, *err_level = KERN_ERR;
271 if (!bri->recover_bus) {
272 err_str = "no suitable method provided";
273 err_level = KERN_DEBUG;
277 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
278 bri->get_scl = get_scl_gpio_value;
279 bri->set_scl = set_scl_gpio_value;
280 if (bri->sda_gpiod) {
281 bri->get_sda = get_sda_gpio_value;
282 /* FIXME: add proper flag instead of '0' once available */
283 if (gpiod_get_direction(bri->sda_gpiod) == 0)
284 bri->set_sda = set_sda_gpio_value;
289 if (bri->recover_bus == i2c_generic_scl_recovery) {
290 /* Generic SCL recovery */
291 if (!bri->set_scl || !bri->get_scl) {
292 err_str = "no {get|set}_scl() found";
295 if (!bri->set_sda && !bri->get_sda) {
296 err_str = "either get_sda() or set_sda() needed";
303 dev_printk(err_level, &adap->dev, "Not using recovery: %s\n", err_str);
304 adap->bus_recovery_info = NULL;
307 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
309 struct i2c_adapter *adap = client->adapter;
312 if (!adap->host_notify_domain)
315 if (client->flags & I2C_CLIENT_TEN)
318 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
320 return irq > 0 ? irq : -ENXIO;
323 static int i2c_device_probe(struct device *dev)
325 struct i2c_client *client = i2c_verify_client(dev);
326 struct i2c_driver *driver;
332 driver = to_i2c_driver(dev->driver);
334 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
337 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
338 dev_dbg(dev, "Using Host Notify IRQ\n");
339 /* Keep adapter active when Host Notify is required */
340 pm_runtime_get_sync(&client->adapter->dev);
341 irq = i2c_smbus_host_notify_to_irq(client);
342 } else if (dev->of_node) {
343 irq = of_irq_get_byname(dev->of_node, "irq");
344 if (irq == -EINVAL || irq == -ENODATA)
345 irq = of_irq_get(dev->of_node, 0);
346 } else if (ACPI_COMPANION(dev)) {
347 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
349 if (irq == -EPROBE_DEFER)
359 * An I2C ID table is not mandatory, if and only if, a suitable OF
360 * or ACPI ID table is supplied for the probing device.
362 if (!driver->id_table &&
363 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
364 !i2c_of_match_device(dev->driver->of_match_table, client))
367 if (client->flags & I2C_CLIENT_WAKE) {
368 int wakeirq = -ENOENT;
371 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
372 if (wakeirq == -EPROBE_DEFER)
376 device_init_wakeup(&client->dev, true);
378 if (wakeirq > 0 && wakeirq != client->irq)
379 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
380 else if (client->irq > 0)
381 status = dev_pm_set_wake_irq(dev, client->irq);
386 dev_warn(&client->dev, "failed to set up wakeup irq\n");
389 dev_dbg(dev, "probe\n");
391 status = of_clk_set_defaults(dev->of_node, false);
393 goto err_clear_wakeup_irq;
395 status = dev_pm_domain_attach(&client->dev, true);
397 goto err_clear_wakeup_irq;
400 * When there are no more users of probe(),
401 * rename probe_new to probe.
403 if (driver->probe_new)
404 status = driver->probe_new(client);
405 else if (driver->probe)
406 status = driver->probe(client,
407 i2c_match_id(driver->id_table, client));
412 goto err_detach_pm_domain;
416 err_detach_pm_domain:
417 dev_pm_domain_detach(&client->dev, true);
418 err_clear_wakeup_irq:
419 dev_pm_clear_wake_irq(&client->dev);
420 device_init_wakeup(&client->dev, false);
424 static int i2c_device_remove(struct device *dev)
426 struct i2c_client *client = i2c_verify_client(dev);
427 struct i2c_driver *driver;
430 if (!client || !dev->driver)
433 driver = to_i2c_driver(dev->driver);
434 if (driver->remove) {
435 dev_dbg(dev, "remove\n");
436 status = driver->remove(client);
439 dev_pm_domain_detach(&client->dev, true);
441 dev_pm_clear_wake_irq(&client->dev);
442 device_init_wakeup(&client->dev, false);
444 client->irq = client->init_irq;
445 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
446 pm_runtime_put(&client->adapter->dev);
451 static void i2c_device_shutdown(struct device *dev)
453 struct i2c_client *client = i2c_verify_client(dev);
454 struct i2c_driver *driver;
456 if (!client || !dev->driver)
458 driver = to_i2c_driver(dev->driver);
459 if (driver->shutdown)
460 driver->shutdown(client);
461 else if (client->irq > 0)
462 disable_irq(client->irq);
465 static void i2c_client_dev_release(struct device *dev)
467 kfree(to_i2c_client(dev));
471 show_name(struct device *dev, struct device_attribute *attr, char *buf)
473 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
474 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
476 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
479 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
481 struct i2c_client *client = to_i2c_client(dev);
484 len = of_device_modalias(dev, buf, PAGE_SIZE);
488 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
492 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
494 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
496 static struct attribute *i2c_dev_attrs[] = {
498 /* modalias helps coldplug: modprobe $(cat .../modalias) */
499 &dev_attr_modalias.attr,
502 ATTRIBUTE_GROUPS(i2c_dev);
504 struct bus_type i2c_bus_type = {
506 .match = i2c_device_match,
507 .probe = i2c_device_probe,
508 .remove = i2c_device_remove,
509 .shutdown = i2c_device_shutdown,
511 EXPORT_SYMBOL_GPL(i2c_bus_type);
513 struct device_type i2c_client_type = {
514 .groups = i2c_dev_groups,
515 .uevent = i2c_device_uevent,
516 .release = i2c_client_dev_release,
518 EXPORT_SYMBOL_GPL(i2c_client_type);
522 * i2c_verify_client - return parameter as i2c_client, or NULL
523 * @dev: device, probably from some driver model iterator
525 * When traversing the driver model tree, perhaps using driver model
526 * iterators like @device_for_each_child(), you can't assume very much
527 * about the nodes you find. Use this function to avoid oopses caused
528 * by wrongly treating some non-I2C device as an i2c_client.
530 struct i2c_client *i2c_verify_client(struct device *dev)
532 return (dev->type == &i2c_client_type)
536 EXPORT_SYMBOL(i2c_verify_client);
539 /* Return a unique address which takes the flags of the client into account */
540 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
542 unsigned short addr = client->addr;
544 /* For some client flags, add an arbitrary offset to avoid collisions */
545 if (client->flags & I2C_CLIENT_TEN)
546 addr |= I2C_ADDR_OFFSET_TEN_BIT;
548 if (client->flags & I2C_CLIENT_SLAVE)
549 addr |= I2C_ADDR_OFFSET_SLAVE;
554 /* This is a permissive address validity check, I2C address map constraints
555 * are purposely not enforced, except for the general call address. */
556 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
558 if (flags & I2C_CLIENT_TEN) {
559 /* 10-bit address, all values are valid */
563 /* 7-bit address, reject the general call address */
564 if (addr == 0x00 || addr > 0x7f)
570 /* And this is a strict address validity check, used when probing. If a
571 * device uses a reserved address, then it shouldn't be probed. 7-bit
572 * addressing is assumed, 10-bit address devices are rare and should be
573 * explicitly enumerated. */
574 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
577 * Reserved addresses per I2C specification:
578 * 0x00 General call address / START byte
580 * 0x02 Reserved for different bus format
581 * 0x03 Reserved for future purposes
582 * 0x04-0x07 Hs-mode master code
583 * 0x78-0x7b 10-bit slave addressing
584 * 0x7c-0x7f Reserved for future purposes
586 if (addr < 0x08 || addr > 0x77)
591 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
593 struct i2c_client *client = i2c_verify_client(dev);
594 int addr = *(int *)addrp;
596 if (client && i2c_encode_flags_to_addr(client) == addr)
601 /* walk up mux tree */
602 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
604 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
607 result = device_for_each_child(&adapter->dev, &addr,
608 __i2c_check_addr_busy);
610 if (!result && parent)
611 result = i2c_check_mux_parents(parent, addr);
616 /* recurse down mux tree */
617 static int i2c_check_mux_children(struct device *dev, void *addrp)
621 if (dev->type == &i2c_adapter_type)
622 result = device_for_each_child(dev, addrp,
623 i2c_check_mux_children);
625 result = __i2c_check_addr_busy(dev, addrp);
630 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
632 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
636 result = i2c_check_mux_parents(parent, addr);
639 result = device_for_each_child(&adapter->dev, &addr,
640 i2c_check_mux_children);
646 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
647 * @adapter: Target I2C bus segment
648 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
649 * locks only this branch in the adapter tree
651 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
654 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
658 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
659 * @adapter: Target I2C bus segment
660 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
661 * trylocks only this branch in the adapter tree
663 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
666 return rt_mutex_trylock(&adapter->bus_lock);
670 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
671 * @adapter: Target I2C bus segment
672 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
673 * unlocks only this branch in the adapter tree
675 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
678 rt_mutex_unlock(&adapter->bus_lock);
681 static void i2c_dev_set_name(struct i2c_adapter *adap,
682 struct i2c_client *client,
683 struct i2c_board_info const *info)
685 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
687 if (info && info->dev_name) {
688 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
693 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
697 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
698 i2c_encode_flags_to_addr(client));
701 static int i2c_dev_irq_from_resources(const struct resource *resources,
702 unsigned int num_resources)
704 struct irq_data *irqd;
707 for (i = 0; i < num_resources; i++) {
708 const struct resource *r = &resources[i];
710 if (resource_type(r) != IORESOURCE_IRQ)
713 if (r->flags & IORESOURCE_BITS) {
714 irqd = irq_get_irq_data(r->start);
718 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
728 * i2c_new_device - instantiate an i2c device
729 * @adap: the adapter managing the device
730 * @info: describes one I2C device; bus_num is ignored
733 * Create an i2c device. Binding is handled through driver model
734 * probe()/remove() methods. A driver may be bound to this device when we
735 * return from this function, or any later moment (e.g. maybe hotplugging will
736 * load the driver module). This call is not appropriate for use by mainboard
737 * initialization logic, which usually runs during an arch_initcall() long
738 * before any i2c_adapter could exist.
740 * This returns the new i2c client, which may be saved for later use with
741 * i2c_unregister_device(); or NULL to indicate an error.
744 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
746 struct i2c_client *client;
749 client = kzalloc(sizeof *client, GFP_KERNEL);
753 client->adapter = adap;
755 client->dev.platform_data = info->platform_data;
756 client->flags = info->flags;
757 client->addr = info->addr;
759 client->init_irq = info->irq;
760 if (!client->init_irq)
761 client->init_irq = i2c_dev_irq_from_resources(info->resources,
762 info->num_resources);
763 client->irq = client->init_irq;
765 strlcpy(client->name, info->type, sizeof(client->name));
767 status = i2c_check_addr_validity(client->addr, client->flags);
769 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
770 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
774 /* Check for address business */
775 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
779 client->dev.parent = &client->adapter->dev;
780 client->dev.bus = &i2c_bus_type;
781 client->dev.type = &i2c_client_type;
782 client->dev.of_node = of_node_get(info->of_node);
783 client->dev.fwnode = info->fwnode;
785 i2c_dev_set_name(adap, client, info);
787 if (info->properties) {
788 status = device_add_properties(&client->dev, info->properties);
791 "Failed to add properties to client %s: %d\n",
792 client->name, status);
793 goto out_err_put_of_node;
797 status = device_register(&client->dev);
801 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
802 client->name, dev_name(&client->dev));
807 if (info->properties)
808 device_remove_properties(&client->dev);
810 of_node_put(info->of_node);
813 "Failed to register i2c client %s at 0x%02x (%d)\n",
814 client->name, client->addr, status);
819 EXPORT_SYMBOL_GPL(i2c_new_device);
823 * i2c_unregister_device - reverse effect of i2c_new_device()
824 * @client: value returned from i2c_new_device()
827 void i2c_unregister_device(struct i2c_client *client)
832 if (client->dev.of_node) {
833 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
834 of_node_put(client->dev.of_node);
837 if (ACPI_COMPANION(&client->dev))
838 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
839 device_unregister(&client->dev);
841 EXPORT_SYMBOL_GPL(i2c_unregister_device);
844 static const struct i2c_device_id dummy_id[] = {
849 static int dummy_probe(struct i2c_client *client,
850 const struct i2c_device_id *id)
855 static int dummy_remove(struct i2c_client *client)
860 static struct i2c_driver dummy_driver = {
861 .driver.name = "dummy",
862 .probe = dummy_probe,
863 .remove = dummy_remove,
864 .id_table = dummy_id,
868 * i2c_new_dummy - return a new i2c device bound to a dummy driver
869 * @adapter: the adapter managing the device
870 * @address: seven bit address to be used
873 * This returns an I2C client bound to the "dummy" driver, intended for use
874 * with devices that consume multiple addresses. Examples of such chips
875 * include various EEPROMS (like 24c04 and 24c08 models).
877 * These dummy devices have two main uses. First, most I2C and SMBus calls
878 * except i2c_transfer() need a client handle; the dummy will be that handle.
879 * And second, this prevents the specified address from being bound to a
882 * This returns the new i2c client, which should be saved for later use with
883 * i2c_unregister_device(); or NULL to indicate an error.
885 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
887 struct i2c_board_info info = {
888 I2C_BOARD_INFO("dummy", address),
891 return i2c_new_device(adapter, &info);
893 EXPORT_SYMBOL_GPL(i2c_new_dummy);
896 * i2c_new_secondary_device - Helper to get the instantiated secondary address
897 * and create the associated device
898 * @client: Handle to the primary client
899 * @name: Handle to specify which secondary address to get
900 * @default_addr: Used as a fallback if no secondary address was specified
903 * I2C clients can be composed of multiple I2C slaves bound together in a single
904 * component. The I2C client driver then binds to the master I2C slave and needs
905 * to create I2C dummy clients to communicate with all the other slaves.
907 * This function creates and returns an I2C dummy client whose I2C address is
908 * retrieved from the platform firmware based on the given slave name. If no
909 * address is specified by the firmware default_addr is used.
911 * On DT-based platforms the address is retrieved from the "reg" property entry
912 * cell whose "reg-names" value matches the slave name.
914 * This returns the new i2c client, which should be saved for later use with
915 * i2c_unregister_device(); or NULL to indicate an error.
917 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
921 struct device_node *np = client->dev.of_node;
922 u32 addr = default_addr;
926 i = of_property_match_string(np, "reg-names", name);
928 of_property_read_u32_index(np, "reg", i, &addr);
931 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
932 return i2c_new_dummy(client->adapter, addr);
934 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
936 /* ------------------------------------------------------------------------- */
938 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
940 static void i2c_adapter_dev_release(struct device *dev)
942 struct i2c_adapter *adap = to_i2c_adapter(dev);
943 complete(&adap->dev_released);
946 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
948 unsigned int depth = 0;
950 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
953 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
954 "adapter depth exceeds lockdep subclass limit\n");
958 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
961 * Let users instantiate I2C devices through sysfs. This can be used when
962 * platform initialization code doesn't contain the proper data for
963 * whatever reason. Also useful for drivers that do device detection and
964 * detection fails, either because the device uses an unexpected address,
965 * or this is a compatible device with different ID register values.
967 * Parameter checking may look overzealous, but we really don't want
968 * the user to provide incorrect parameters.
971 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
972 const char *buf, size_t count)
974 struct i2c_adapter *adap = to_i2c_adapter(dev);
975 struct i2c_board_info info;
976 struct i2c_client *client;
980 memset(&info, 0, sizeof(struct i2c_board_info));
982 blank = strchr(buf, ' ');
984 dev_err(dev, "%s: Missing parameters\n", "new_device");
987 if (blank - buf > I2C_NAME_SIZE - 1) {
988 dev_err(dev, "%s: Invalid device name\n", "new_device");
991 memcpy(info.type, buf, blank - buf);
993 /* Parse remaining parameters, reject extra parameters */
994 res = sscanf(++blank, "%hi%c", &info.addr, &end);
996 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
999 if (res > 1 && end != '\n') {
1000 dev_err(dev, "%s: Extra parameters\n", "new_device");
1004 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1005 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1006 info.flags |= I2C_CLIENT_TEN;
1009 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1010 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1011 info.flags |= I2C_CLIENT_SLAVE;
1014 client = i2c_new_device(adap, &info);
1018 /* Keep track of the added device */
1019 mutex_lock(&adap->userspace_clients_lock);
1020 list_add_tail(&client->detected, &adap->userspace_clients);
1021 mutex_unlock(&adap->userspace_clients_lock);
1022 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1023 info.type, info.addr);
1027 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1030 * And of course let the users delete the devices they instantiated, if
1031 * they got it wrong. This interface can only be used to delete devices
1032 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1033 * don't delete devices to which some kernel code still has references.
1035 * Parameter checking may look overzealous, but we really don't want
1036 * the user to delete the wrong device.
1039 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1040 const char *buf, size_t count)
1042 struct i2c_adapter *adap = to_i2c_adapter(dev);
1043 struct i2c_client *client, *next;
1044 unsigned short addr;
1048 /* Parse parameters, reject extra parameters */
1049 res = sscanf(buf, "%hi%c", &addr, &end);
1051 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1054 if (res > 1 && end != '\n') {
1055 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1059 /* Make sure the device was added through sysfs */
1061 mutex_lock_nested(&adap->userspace_clients_lock,
1062 i2c_adapter_depth(adap));
1063 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1065 if (i2c_encode_flags_to_addr(client) == addr) {
1066 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1067 "delete_device", client->name, client->addr);
1069 list_del(&client->detected);
1070 i2c_unregister_device(client);
1075 mutex_unlock(&adap->userspace_clients_lock);
1078 dev_err(dev, "%s: Can't find device in list\n",
1082 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1083 i2c_sysfs_delete_device);
1085 static struct attribute *i2c_adapter_attrs[] = {
1086 &dev_attr_name.attr,
1087 &dev_attr_new_device.attr,
1088 &dev_attr_delete_device.attr,
1091 ATTRIBUTE_GROUPS(i2c_adapter);
1093 struct device_type i2c_adapter_type = {
1094 .groups = i2c_adapter_groups,
1095 .release = i2c_adapter_dev_release,
1097 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1100 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1101 * @dev: device, probably from some driver model iterator
1103 * When traversing the driver model tree, perhaps using driver model
1104 * iterators like @device_for_each_child(), you can't assume very much
1105 * about the nodes you find. Use this function to avoid oopses caused
1106 * by wrongly treating some non-I2C device as an i2c_adapter.
1108 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1110 return (dev->type == &i2c_adapter_type)
1111 ? to_i2c_adapter(dev)
1114 EXPORT_SYMBOL(i2c_verify_adapter);
1116 #ifdef CONFIG_I2C_COMPAT
1117 static struct class_compat *i2c_adapter_compat_class;
1120 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1122 struct i2c_devinfo *devinfo;
1124 down_read(&__i2c_board_lock);
1125 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1126 if (devinfo->busnum == adapter->nr
1127 && !i2c_new_device(adapter,
1128 &devinfo->board_info))
1129 dev_err(&adapter->dev,
1130 "Can't create device at 0x%02x\n",
1131 devinfo->board_info.addr);
1133 up_read(&__i2c_board_lock);
1136 static int i2c_do_add_adapter(struct i2c_driver *driver,
1137 struct i2c_adapter *adap)
1139 /* Detect supported devices on that bus, and instantiate them */
1140 i2c_detect(adap, driver);
1145 static int __process_new_adapter(struct device_driver *d, void *data)
1147 return i2c_do_add_adapter(to_i2c_driver(d), data);
1150 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1151 .lock_bus = i2c_adapter_lock_bus,
1152 .trylock_bus = i2c_adapter_trylock_bus,
1153 .unlock_bus = i2c_adapter_unlock_bus,
1156 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1158 struct irq_domain *domain = adap->host_notify_domain;
1159 irq_hw_number_t hwirq;
1164 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1165 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1167 irq_domain_remove(domain);
1168 adap->host_notify_domain = NULL;
1171 static int i2c_host_notify_irq_map(struct irq_domain *h,
1173 irq_hw_number_t hw_irq_num)
1175 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1180 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1181 .map = i2c_host_notify_irq_map,
1184 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1186 struct irq_domain *domain;
1188 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1191 domain = irq_domain_create_linear(adap->dev.fwnode,
1192 I2C_ADDR_7BITS_COUNT,
1193 &i2c_host_notify_irq_ops, adap);
1197 adap->host_notify_domain = domain;
1203 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1205 * @adap: the adapter
1206 * @addr: the I2C address of the notifying device
1207 * Context: can't sleep
1209 * Helper function to be called from an I2C bus driver's interrupt
1210 * handler. It will schedule the Host Notify IRQ.
1212 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1219 irq = irq_find_mapping(adap->host_notify_domain, addr);
1223 generic_handle_irq(irq);
1227 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1229 static int i2c_register_adapter(struct i2c_adapter *adap)
1233 /* Can't register until after driver model init */
1234 if (WARN_ON(!is_registered)) {
1240 if (WARN(!adap->name[0], "i2c adapter has no name"))
1244 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1248 if (!adap->lock_ops)
1249 adap->lock_ops = &i2c_adapter_lock_ops;
1251 rt_mutex_init(&adap->bus_lock);
1252 rt_mutex_init(&adap->mux_lock);
1253 mutex_init(&adap->userspace_clients_lock);
1254 INIT_LIST_HEAD(&adap->userspace_clients);
1256 /* Set default timeout to 1 second if not already set */
1257 if (adap->timeout == 0)
1260 /* register soft irqs for Host Notify */
1261 res = i2c_setup_host_notify_irq_domain(adap);
1263 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1268 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1269 adap->dev.bus = &i2c_bus_type;
1270 adap->dev.type = &i2c_adapter_type;
1271 res = device_register(&adap->dev);
1273 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1277 res = of_i2c_setup_smbus_alert(adap);
1281 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1283 pm_runtime_no_callbacks(&adap->dev);
1284 pm_suspend_ignore_children(&adap->dev, true);
1285 pm_runtime_enable(&adap->dev);
1287 #ifdef CONFIG_I2C_COMPAT
1288 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1291 dev_warn(&adap->dev,
1292 "Failed to create compatibility class link\n");
1295 i2c_init_recovery(adap);
1297 /* create pre-declared device nodes */
1298 of_i2c_register_devices(adap);
1299 i2c_acpi_install_space_handler(adap);
1300 i2c_acpi_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 init_completion(&adap->dev_released);
1314 device_unregister(&adap->dev);
1315 wait_for_completion(&adap->dev_released);
1317 mutex_lock(&core_lock);
1318 idr_remove(&i2c_adapter_idr, adap->nr);
1319 mutex_unlock(&core_lock);
1324 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1325 * @adap: the adapter to register (with adap->nr initialized)
1326 * Context: can sleep
1328 * See i2c_add_numbered_adapter() for details.
1330 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1334 mutex_lock(&core_lock);
1335 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1336 mutex_unlock(&core_lock);
1337 if (WARN(id < 0, "couldn't get idr"))
1338 return id == -ENOSPC ? -EBUSY : id;
1340 return i2c_register_adapter(adap);
1344 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1345 * @adapter: the adapter to add
1346 * Context: can sleep
1348 * This routine is used to declare an I2C adapter when its bus number
1349 * doesn't matter or when its bus number is specified by an dt alias.
1350 * Examples of bases when the bus number doesn't matter: I2C adapters
1351 * dynamically added by USB links or PCI plugin cards.
1353 * When this returns zero, a new bus number was allocated and stored
1354 * in adap->nr, and the specified adapter became available for clients.
1355 * Otherwise, a negative errno value is returned.
1357 int i2c_add_adapter(struct i2c_adapter *adapter)
1359 struct device *dev = &adapter->dev;
1363 id = of_alias_get_id(dev->of_node, "i2c");
1366 return __i2c_add_numbered_adapter(adapter);
1370 mutex_lock(&core_lock);
1371 id = idr_alloc(&i2c_adapter_idr, adapter,
1372 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1373 mutex_unlock(&core_lock);
1374 if (WARN(id < 0, "couldn't get idr"))
1379 return i2c_register_adapter(adapter);
1381 EXPORT_SYMBOL(i2c_add_adapter);
1384 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1385 * @adap: the adapter to register (with adap->nr initialized)
1386 * Context: can sleep
1388 * This routine is used to declare an I2C adapter when its bus number
1389 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1390 * or otherwise built in to the system's mainboard, and where i2c_board_info
1391 * is used to properly configure I2C devices.
1393 * If the requested bus number is set to -1, then this function will behave
1394 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1396 * If no devices have pre-been declared for this bus, then be sure to
1397 * register the adapter before any dynamically allocated ones. Otherwise
1398 * the required bus ID may not be available.
1400 * When this returns zero, the specified adapter became available for
1401 * clients using the bus number provided in adap->nr. Also, the table
1402 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1403 * and the appropriate driver model device nodes are created. Otherwise, a
1404 * negative errno value is returned.
1406 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1408 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1409 return i2c_add_adapter(adap);
1411 return __i2c_add_numbered_adapter(adap);
1413 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1415 static void i2c_do_del_adapter(struct i2c_driver *driver,
1416 struct i2c_adapter *adapter)
1418 struct i2c_client *client, *_n;
1420 /* Remove the devices we created ourselves as the result of hardware
1421 * probing (using a driver's detect method) */
1422 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1423 if (client->adapter == adapter) {
1424 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1425 client->name, client->addr);
1426 list_del(&client->detected);
1427 i2c_unregister_device(client);
1432 static int __unregister_client(struct device *dev, void *dummy)
1434 struct i2c_client *client = i2c_verify_client(dev);
1435 if (client && strcmp(client->name, "dummy"))
1436 i2c_unregister_device(client);
1440 static int __unregister_dummy(struct device *dev, void *dummy)
1442 struct i2c_client *client = i2c_verify_client(dev);
1443 i2c_unregister_device(client);
1447 static int __process_removed_adapter(struct device_driver *d, void *data)
1449 i2c_do_del_adapter(to_i2c_driver(d), data);
1454 * i2c_del_adapter - unregister I2C adapter
1455 * @adap: the adapter being unregistered
1456 * Context: can sleep
1458 * This unregisters an I2C adapter which was previously registered
1459 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1461 void i2c_del_adapter(struct i2c_adapter *adap)
1463 struct i2c_adapter *found;
1464 struct i2c_client *client, *next;
1466 /* First make sure that this adapter was ever added */
1467 mutex_lock(&core_lock);
1468 found = idr_find(&i2c_adapter_idr, adap->nr);
1469 mutex_unlock(&core_lock);
1470 if (found != adap) {
1471 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1475 i2c_acpi_remove_space_handler(adap);
1476 /* Tell drivers about this removal */
1477 mutex_lock(&core_lock);
1478 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1479 __process_removed_adapter);
1480 mutex_unlock(&core_lock);
1482 /* Remove devices instantiated from sysfs */
1483 mutex_lock_nested(&adap->userspace_clients_lock,
1484 i2c_adapter_depth(adap));
1485 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1487 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1489 list_del(&client->detected);
1490 i2c_unregister_device(client);
1492 mutex_unlock(&adap->userspace_clients_lock);
1494 /* Detach any active clients. This can't fail, thus we do not
1495 * check the returned value. This is a two-pass process, because
1496 * we can't remove the dummy devices during the first pass: they
1497 * could have been instantiated by real devices wishing to clean
1498 * them up properly, so we give them a chance to do that first. */
1499 device_for_each_child(&adap->dev, NULL, __unregister_client);
1500 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1502 #ifdef CONFIG_I2C_COMPAT
1503 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1507 /* device name is gone after device_unregister */
1508 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1510 pm_runtime_disable(&adap->dev);
1512 i2c_host_notify_irq_teardown(adap);
1514 /* wait until all references to the device are gone
1516 * FIXME: This is old code and should ideally be replaced by an
1517 * alternative which results in decoupling the lifetime of the struct
1518 * device from the i2c_adapter, like spi or netdev do. Any solution
1519 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1521 init_completion(&adap->dev_released);
1522 device_unregister(&adap->dev);
1523 wait_for_completion(&adap->dev_released);
1526 mutex_lock(&core_lock);
1527 idr_remove(&i2c_adapter_idr, adap->nr);
1528 mutex_unlock(&core_lock);
1530 /* Clear the device structure in case this adapter is ever going to be
1532 memset(&adap->dev, 0, sizeof(adap->dev));
1534 EXPORT_SYMBOL(i2c_del_adapter);
1537 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1538 * @dev: The device to scan for I2C timing properties
1539 * @t: the i2c_timings struct to be filled with values
1540 * @use_defaults: bool to use sane defaults derived from the I2C specification
1541 * when properties are not found, otherwise use 0
1543 * Scan the device for the generic I2C properties describing timing parameters
1544 * for the signal and fill the given struct with the results. If a property was
1545 * not found and use_defaults was true, then maximum timings are assumed which
1546 * are derived from the I2C specification. If use_defaults is not used, the
1547 * results will be 0, so drivers can apply their own defaults later. The latter
1548 * is mainly intended for avoiding regressions of existing drivers which want
1549 * to switch to this function. New drivers almost always should use the defaults.
1552 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1556 memset(t, 0, sizeof(*t));
1558 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1559 if (ret && use_defaults)
1560 t->bus_freq_hz = 100000;
1562 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1563 if (ret && use_defaults) {
1564 if (t->bus_freq_hz <= 100000)
1565 t->scl_rise_ns = 1000;
1566 else if (t->bus_freq_hz <= 400000)
1567 t->scl_rise_ns = 300;
1569 t->scl_rise_ns = 120;
1572 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1573 if (ret && use_defaults) {
1574 if (t->bus_freq_hz <= 400000)
1575 t->scl_fall_ns = 300;
1577 t->scl_fall_ns = 120;
1580 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1582 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1583 if (ret && use_defaults)
1584 t->sda_fall_ns = t->scl_fall_ns;
1586 device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1588 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1590 /* ------------------------------------------------------------------------- */
1592 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1596 mutex_lock(&core_lock);
1597 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1598 mutex_unlock(&core_lock);
1602 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1604 static int __process_new_driver(struct device *dev, void *data)
1606 if (dev->type != &i2c_adapter_type)
1608 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1612 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1613 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1616 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1620 /* Can't register until after driver model init */
1621 if (WARN_ON(!is_registered))
1624 /* add the driver to the list of i2c drivers in the driver core */
1625 driver->driver.owner = owner;
1626 driver->driver.bus = &i2c_bus_type;
1627 INIT_LIST_HEAD(&driver->clients);
1629 /* When registration returns, the driver core
1630 * will have called probe() for all matching-but-unbound devices.
1632 res = driver_register(&driver->driver);
1636 pr_debug("driver [%s] registered\n", driver->driver.name);
1638 /* Walk the adapters that are already present */
1639 i2c_for_each_dev(driver, __process_new_driver);
1643 EXPORT_SYMBOL(i2c_register_driver);
1645 static int __process_removed_driver(struct device *dev, void *data)
1647 if (dev->type == &i2c_adapter_type)
1648 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1653 * i2c_del_driver - unregister I2C driver
1654 * @driver: the driver being unregistered
1655 * Context: can sleep
1657 void i2c_del_driver(struct i2c_driver *driver)
1659 i2c_for_each_dev(driver, __process_removed_driver);
1661 driver_unregister(&driver->driver);
1662 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1664 EXPORT_SYMBOL(i2c_del_driver);
1666 /* ------------------------------------------------------------------------- */
1669 * i2c_use_client - increments the reference count of the i2c client structure
1670 * @client: the client being referenced
1672 * Each live reference to a client should be refcounted. The driver model does
1673 * that automatically as part of driver binding, so that most drivers don't
1674 * need to do this explicitly: they hold a reference until they're unbound
1677 * A pointer to the client with the incremented reference counter is returned.
1679 struct i2c_client *i2c_use_client(struct i2c_client *client)
1681 if (client && get_device(&client->dev))
1685 EXPORT_SYMBOL(i2c_use_client);
1688 * i2c_release_client - release a use of the i2c client structure
1689 * @client: the client being no longer referenced
1691 * Must be called when a user of a client is finished with it.
1693 void i2c_release_client(struct i2c_client *client)
1696 put_device(&client->dev);
1698 EXPORT_SYMBOL(i2c_release_client);
1700 struct i2c_cmd_arg {
1705 static int i2c_cmd(struct device *dev, void *_arg)
1707 struct i2c_client *client = i2c_verify_client(dev);
1708 struct i2c_cmd_arg *arg = _arg;
1709 struct i2c_driver *driver;
1711 if (!client || !client->dev.driver)
1714 driver = to_i2c_driver(client->dev.driver);
1715 if (driver->command)
1716 driver->command(client, arg->cmd, arg->arg);
1720 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1722 struct i2c_cmd_arg cmd_arg;
1726 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1728 EXPORT_SYMBOL(i2c_clients_command);
1730 static int __init i2c_init(void)
1734 retval = of_alias_get_highest_id("i2c");
1736 down_write(&__i2c_board_lock);
1737 if (retval >= __i2c_first_dynamic_bus_num)
1738 __i2c_first_dynamic_bus_num = retval + 1;
1739 up_write(&__i2c_board_lock);
1741 retval = bus_register(&i2c_bus_type);
1745 is_registered = true;
1747 #ifdef CONFIG_I2C_COMPAT
1748 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1749 if (!i2c_adapter_compat_class) {
1754 retval = i2c_add_driver(&dummy_driver);
1758 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1759 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1760 if (IS_ENABLED(CONFIG_ACPI))
1761 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1766 #ifdef CONFIG_I2C_COMPAT
1767 class_compat_unregister(i2c_adapter_compat_class);
1770 is_registered = false;
1771 bus_unregister(&i2c_bus_type);
1775 static void __exit i2c_exit(void)
1777 if (IS_ENABLED(CONFIG_ACPI))
1778 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1779 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1780 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1781 i2c_del_driver(&dummy_driver);
1782 #ifdef CONFIG_I2C_COMPAT
1783 class_compat_unregister(i2c_adapter_compat_class);
1785 bus_unregister(&i2c_bus_type);
1786 tracepoint_synchronize_unregister();
1789 /* We must initialize early, because some subsystems register i2c drivers
1790 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1792 postcore_initcall(i2c_init);
1793 module_exit(i2c_exit);
1795 /* ----------------------------------------------------
1796 * the functional interface to the i2c busses.
1797 * ----------------------------------------------------
1800 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1801 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1803 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1805 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1806 err_msg, msg->addr, msg->len,
1807 msg->flags & I2C_M_RD ? "read" : "write");
1811 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1813 const struct i2c_adapter_quirks *q = adap->quirks;
1814 int max_num = q->max_num_msgs, i;
1815 bool do_len_check = true;
1817 if (q->flags & I2C_AQ_COMB) {
1820 /* special checks for combined messages */
1822 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1823 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1825 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1826 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1828 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1829 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1831 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1832 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1834 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1835 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1837 do_len_check = false;
1841 if (i2c_quirk_exceeded(num, max_num))
1842 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1844 for (i = 0; i < num; i++) {
1845 u16 len = msgs[i].len;
1847 if (msgs[i].flags & I2C_M_RD) {
1848 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1849 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1851 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1852 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1854 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1855 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1857 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1858 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1866 * __i2c_transfer - unlocked flavor of i2c_transfer
1867 * @adap: Handle to I2C bus
1868 * @msgs: One or more messages to execute before STOP is issued to
1869 * terminate the operation; each message begins with a START.
1870 * @num: Number of messages to be executed.
1872 * Returns negative errno, else the number of messages executed.
1874 * Adapter lock must be held when calling this function. No debug logging
1875 * takes place. adap->algo->master_xfer existence isn't checked.
1877 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1879 unsigned long orig_jiffies;
1882 if (WARN_ON(!msgs || num < 1))
1885 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1889 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1890 * enabled. This is an efficient way of keeping the for-loop from
1891 * being executed when not needed.
1893 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1895 for (i = 0; i < num; i++)
1896 if (msgs[i].flags & I2C_M_RD)
1897 trace_i2c_read(adap, &msgs[i], i);
1899 trace_i2c_write(adap, &msgs[i], i);
1902 /* Retry automatically on arbitration loss */
1903 orig_jiffies = jiffies;
1904 for (ret = 0, try = 0; try <= adap->retries; try++) {
1905 ret = adap->algo->master_xfer(adap, msgs, num);
1908 if (time_after(jiffies, orig_jiffies + adap->timeout))
1912 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1914 for (i = 0; i < ret; i++)
1915 if (msgs[i].flags & I2C_M_RD)
1916 trace_i2c_reply(adap, &msgs[i], i);
1917 trace_i2c_result(adap, num, ret);
1922 EXPORT_SYMBOL(__i2c_transfer);
1925 * i2c_transfer - execute a single or combined I2C message
1926 * @adap: Handle to I2C bus
1927 * @msgs: One or more messages to execute before STOP is issued to
1928 * terminate the operation; each message begins with a START.
1929 * @num: Number of messages to be executed.
1931 * Returns negative errno, else the number of messages executed.
1933 * Note that there is no requirement that each message be sent to
1934 * the same slave address, although that is the most common model.
1936 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1940 /* REVISIT the fault reporting model here is weak:
1942 * - When we get an error after receiving N bytes from a slave,
1943 * there is no way to report "N".
1945 * - When we get a NAK after transmitting N bytes to a slave,
1946 * there is no way to report "N" ... or to let the master
1947 * continue executing the rest of this combined message, if
1948 * that's the appropriate response.
1950 * - When for example "num" is two and we successfully complete
1951 * the first message but get an error part way through the
1952 * second, it's unclear whether that should be reported as
1953 * one (discarding status on the second message) or errno
1954 * (discarding status on the first one).
1957 if (adap->algo->master_xfer) {
1959 for (ret = 0; ret < num; ret++) {
1961 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1962 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1963 msgs[ret].addr, msgs[ret].len,
1964 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1968 if (in_atomic() || irqs_disabled()) {
1969 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1971 /* I2C activity is ongoing. */
1974 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1977 ret = __i2c_transfer(adap, msgs, num);
1978 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1982 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1986 EXPORT_SYMBOL(i2c_transfer);
1989 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1991 * @client: Handle to slave device
1992 * @buf: Where the data is stored
1993 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1994 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1996 * Returns negative errno, or else the number of bytes transferred.
1998 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1999 int count, u16 flags)
2002 struct i2c_msg msg = {
2003 .addr = client->addr,
2004 .flags = flags | (client->flags & I2C_M_TEN),
2009 ret = i2c_transfer(client->adapter, &msg, 1);
2012 * If everything went ok (i.e. 1 msg transferred), return #bytes
2013 * transferred, else error code.
2015 return (ret == 1) ? count : ret;
2017 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2020 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2021 * @client: The device to query
2022 * @id: The queried information
2024 * Returns negative errno on error, zero on success.
2026 int i2c_get_device_id(const struct i2c_client *client,
2027 struct i2c_device_identity *id)
2029 struct i2c_adapter *adap = client->adapter;
2030 union i2c_smbus_data raw_id;
2033 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2036 raw_id.block[0] = 3;
2037 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2038 I2C_SMBUS_READ, client->addr << 1,
2039 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2043 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2044 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2045 id->die_revision = raw_id.block[3] & 0x7;
2048 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2050 /* ----------------------------------------------------
2051 * the i2c address scanning function
2052 * Will not work for 10-bit addresses!
2053 * ----------------------------------------------------
2057 * Legacy default probe function, mostly relevant for SMBus. The default
2058 * probe method is a quick write, but it is known to corrupt the 24RF08
2059 * EEPROMs due to a state machine bug, and could also irreversibly
2060 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2061 * we use a short byte read instead. Also, some bus drivers don't implement
2062 * quick write, so we fallback to a byte read in that case too.
2063 * On x86, there is another special case for FSC hardware monitoring chips,
2064 * which want regular byte reads (address 0x73.) Fortunately, these are the
2065 * only known chips using this I2C address on PC hardware.
2066 * Returns 1 if probe succeeded, 0 if not.
2068 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2071 union i2c_smbus_data dummy;
2074 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2075 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2076 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2077 I2C_SMBUS_BYTE_DATA, &dummy);
2080 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2081 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2082 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2083 I2C_SMBUS_QUICK, NULL);
2084 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2085 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2086 I2C_SMBUS_BYTE, &dummy);
2088 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2096 static int i2c_detect_address(struct i2c_client *temp_client,
2097 struct i2c_driver *driver)
2099 struct i2c_board_info info;
2100 struct i2c_adapter *adapter = temp_client->adapter;
2101 int addr = temp_client->addr;
2104 /* Make sure the address is valid */
2105 err = i2c_check_7bit_addr_validity_strict(addr);
2107 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2112 /* Skip if already in use (7 bit, no need to encode flags) */
2113 if (i2c_check_addr_busy(adapter, addr))
2116 /* Make sure there is something at this address */
2117 if (!i2c_default_probe(adapter, addr))
2120 /* Finally call the custom detection function */
2121 memset(&info, 0, sizeof(struct i2c_board_info));
2123 err = driver->detect(temp_client, &info);
2125 /* -ENODEV is returned if the detection fails. We catch it
2126 here as this isn't an error. */
2127 return err == -ENODEV ? 0 : err;
2130 /* Consistency check */
2131 if (info.type[0] == '\0') {
2132 dev_err(&adapter->dev,
2133 "%s detection function provided no name for 0x%x\n",
2134 driver->driver.name, addr);
2136 struct i2c_client *client;
2138 /* Detection succeeded, instantiate the device */
2139 if (adapter->class & I2C_CLASS_DEPRECATED)
2140 dev_warn(&adapter->dev,
2141 "This adapter will soon drop class based instantiation of devices. "
2142 "Please make sure client 0x%02x gets instantiated by other means. "
2143 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2146 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2147 info.type, info.addr);
2148 client = i2c_new_device(adapter, &info);
2150 list_add_tail(&client->detected, &driver->clients);
2152 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2153 info.type, info.addr);
2158 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2160 const unsigned short *address_list;
2161 struct i2c_client *temp_client;
2163 int adap_id = i2c_adapter_id(adapter);
2165 address_list = driver->address_list;
2166 if (!driver->detect || !address_list)
2169 /* Warn that the adapter lost class based instantiation */
2170 if (adapter->class == I2C_CLASS_DEPRECATED) {
2171 dev_dbg(&adapter->dev,
2172 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2173 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2174 driver->driver.name);
2178 /* Stop here if the classes do not match */
2179 if (!(adapter->class & driver->class))
2182 /* Set up a temporary client to help detect callback */
2183 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2186 temp_client->adapter = adapter;
2188 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2189 dev_dbg(&adapter->dev,
2190 "found normal entry for adapter %d, addr 0x%02x\n",
2191 adap_id, address_list[i]);
2192 temp_client->addr = address_list[i];
2193 err = i2c_detect_address(temp_client, driver);
2202 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2204 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2205 I2C_SMBUS_QUICK, NULL) >= 0;
2207 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2210 i2c_new_probed_device(struct i2c_adapter *adap,
2211 struct i2c_board_info *info,
2212 unsigned short const *addr_list,
2213 int (*probe)(struct i2c_adapter *, unsigned short addr))
2218 probe = i2c_default_probe;
2220 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2221 /* Check address validity */
2222 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2223 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2228 /* Check address availability (7 bit, no need to encode flags) */
2229 if (i2c_check_addr_busy(adap, addr_list[i])) {
2231 "Address 0x%02x already in use, not probing\n",
2236 /* Test address responsiveness */
2237 if (probe(adap, addr_list[i]))
2241 if (addr_list[i] == I2C_CLIENT_END) {
2242 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2246 info->addr = addr_list[i];
2247 return i2c_new_device(adap, info);
2249 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2251 struct i2c_adapter *i2c_get_adapter(int nr)
2253 struct i2c_adapter *adapter;
2255 mutex_lock(&core_lock);
2256 adapter = idr_find(&i2c_adapter_idr, nr);
2260 if (try_module_get(adapter->owner))
2261 get_device(&adapter->dev);
2266 mutex_unlock(&core_lock);
2269 EXPORT_SYMBOL(i2c_get_adapter);
2271 void i2c_put_adapter(struct i2c_adapter *adap)
2276 module_put(adap->owner);
2277 /* Should be last, otherwise we risk use-after-free with 'adap' */
2278 put_device(&adap->dev);
2280 EXPORT_SYMBOL(i2c_put_adapter);
2283 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2284 * @msg: the message to be checked
2285 * @threshold: the minimum number of bytes for which using DMA makes sense
2287 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2288 * Or a valid pointer to be used with DMA. After use, release it by
2289 * calling i2c_put_dma_safe_msg_buf().
2291 * This function must only be called from process context!
2293 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2295 if (msg->len < threshold)
2298 if (msg->flags & I2C_M_DMA_SAFE)
2301 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2302 msg->addr, msg->len);
2304 if (msg->flags & I2C_M_RD)
2305 return kzalloc(msg->len, GFP_KERNEL);
2307 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2309 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2312 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2313 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2314 * @msg: the message which the buffer corresponds to
2315 * @xferred: bool saying if the message was transferred
2317 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2319 if (!buf || buf == msg->buf)
2322 if (xferred && msg->flags & I2C_M_RD)
2323 memcpy(msg->buf, buf, msg->len);
2327 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2329 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2330 MODULE_DESCRIPTION("I2C-Bus main module");
2331 MODULE_LICENSE("GPL");