1 // SPDX-License-Identifier: GPL-2.0-or-later
5 * Copyright (C) 1995-99 Simon G. Vogl
6 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
7 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
8 * Michael Lawnick <michael.lawnick.ext@nsn.com>
10 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
13 #define pr_fmt(fmt) "i2c-core: " fmt
15 #include <dt-bindings/i2c/i2c.h>
16 #include <linux/acpi.h>
17 #include <linux/clk/clk-conf.h>
18 #include <linux/completion.h>
19 #include <linux/delay.h>
20 #include <linux/err.h>
21 #include <linux/errno.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/i2c.h>
24 #include <linux/i2c-smbus.h>
25 #include <linux/idr.h>
26 #include <linux/init.h>
27 #include <linux/irqflags.h>
28 #include <linux/jump_label.h>
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/mutex.h>
32 #include <linux/of_device.h>
34 #include <linux/of_irq.h>
35 #include <linux/pm_domain.h>
36 #include <linux/pm_runtime.h>
37 #include <linux/pm_wakeirq.h>
38 #include <linux/property.h>
39 #include <linux/rwsem.h>
40 #include <linux/slab.h>
44 #define CREATE_TRACE_POINTS
45 #include <trace/events/i2c.h>
47 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
48 #define I2C_ADDR_OFFSET_SLAVE 0x1000
50 #define I2C_ADDR_7BITS_MAX 0x77
51 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
53 #define I2C_ADDR_DEVICE_ID 0x7c
56 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
57 * deletion of detected devices are serialized
59 static DEFINE_MUTEX(core_lock);
60 static DEFINE_IDR(i2c_adapter_idr);
62 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
64 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
65 static bool is_registered;
67 int i2c_transfer_trace_reg(void)
69 static_branch_inc(&i2c_trace_msg_key);
73 void i2c_transfer_trace_unreg(void)
75 static_branch_dec(&i2c_trace_msg_key);
78 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
79 const struct i2c_client *client)
85 if (strcmp(client->name, id->name) == 0)
91 EXPORT_SYMBOL_GPL(i2c_match_id);
93 static int i2c_device_match(struct device *dev, struct device_driver *drv)
95 struct i2c_client *client = i2c_verify_client(dev);
96 struct i2c_driver *driver;
99 /* Attempt an OF style match */
100 if (i2c_of_match_device(drv->of_match_table, client))
103 /* Then ACPI style match */
104 if (acpi_driver_match_device(dev, drv))
107 driver = to_i2c_driver(drv);
109 /* Finally an I2C match */
110 if (i2c_match_id(driver->id_table, client))
116 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
118 struct i2c_client *client = to_i2c_client(dev);
121 rc = of_device_uevent_modalias(dev, env);
125 rc = acpi_device_uevent_modalias(dev, env);
129 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
132 /* i2c bus recovery routines */
133 static int get_scl_gpio_value(struct i2c_adapter *adap)
135 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
138 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
140 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
143 static int get_sda_gpio_value(struct i2c_adapter *adap)
145 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
148 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
150 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
153 static int i2c_generic_bus_free(struct i2c_adapter *adap)
155 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
156 int ret = -EOPNOTSUPP;
158 if (bri->get_bus_free)
159 ret = bri->get_bus_free(adap);
160 else if (bri->get_sda)
161 ret = bri->get_sda(adap);
166 return ret ? 0 : -EBUSY;
170 * We are generating clock pulses. ndelay() determines durating of clk pulses.
171 * We will generate clock with rate 100 KHz and so duration of both clock levels
172 * is: delay in ns = (10^6 / 100) / 2
174 #define RECOVERY_NDELAY 5000
175 #define RECOVERY_CLK_CNT 9
177 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
179 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
180 int i = 0, scl = 1, ret = 0;
182 if (bri->prepare_recovery)
183 bri->prepare_recovery(adap);
186 * If we can set SDA, we will always create a STOP to ensure additional
187 * pulses will do no harm. This is achieved by letting SDA follow SCL
188 * half a cycle later. Check the 'incomplete_write_byte' fault injector
191 bri->set_scl(adap, scl);
192 ndelay(RECOVERY_NDELAY / 2);
194 bri->set_sda(adap, scl);
195 ndelay(RECOVERY_NDELAY / 2);
198 * By this time SCL is high, as we need to give 9 falling-rising edges
200 while (i++ < RECOVERY_CLK_CNT * 2) {
202 /* SCL shouldn't be low here */
203 if (!bri->get_scl(adap)) {
205 "SCL is stuck low, exit recovery\n");
212 bri->set_scl(adap, scl);
213 /* Creating STOP again, see above */
214 ndelay(RECOVERY_NDELAY / 2);
216 bri->set_sda(adap, scl);
217 ndelay(RECOVERY_NDELAY / 2);
220 ret = i2c_generic_bus_free(adap);
226 /* If we can't check bus status, assume recovery worked */
227 if (ret == -EOPNOTSUPP)
230 if (bri->unprepare_recovery)
231 bri->unprepare_recovery(adap);
235 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
237 int i2c_recover_bus(struct i2c_adapter *adap)
239 if (!adap->bus_recovery_info)
242 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
243 return adap->bus_recovery_info->recover_bus(adap);
245 EXPORT_SYMBOL_GPL(i2c_recover_bus);
247 static void i2c_init_recovery(struct i2c_adapter *adap)
249 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
255 if (!bri->recover_bus) {
256 err_str = "no recover_bus() found";
260 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
261 bri->get_scl = get_scl_gpio_value;
262 bri->set_scl = set_scl_gpio_value;
263 if (bri->sda_gpiod) {
264 bri->get_sda = get_sda_gpio_value;
265 /* FIXME: add proper flag instead of '0' once available */
266 if (gpiod_get_direction(bri->sda_gpiod) == 0)
267 bri->set_sda = set_sda_gpio_value;
272 if (bri->recover_bus == i2c_generic_scl_recovery) {
273 /* Generic SCL recovery */
274 if (!bri->set_scl || !bri->get_scl) {
275 err_str = "no {get|set}_scl() found";
278 if (!bri->set_sda && !bri->get_sda) {
279 err_str = "either get_sda() or set_sda() needed";
286 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
287 adap->bus_recovery_info = NULL;
290 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
292 struct i2c_adapter *adap = client->adapter;
295 if (!adap->host_notify_domain)
298 if (client->flags & I2C_CLIENT_TEN)
301 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
303 return irq > 0 ? irq : -ENXIO;
306 static int i2c_device_probe(struct device *dev)
308 struct i2c_client *client = i2c_verify_client(dev);
309 struct i2c_driver *driver;
315 driver = to_i2c_driver(dev->driver);
317 client->irq = client->init_irq;
319 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
322 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
323 dev_dbg(dev, "Using Host Notify IRQ\n");
324 /* Keep adapter active when Host Notify is required */
325 pm_runtime_get_sync(&client->adapter->dev);
326 irq = i2c_smbus_host_notify_to_irq(client);
327 } else if (dev->of_node) {
328 irq = of_irq_get_byname(dev->of_node, "irq");
329 if (irq == -EINVAL || irq == -ENODATA)
330 irq = of_irq_get(dev->of_node, 0);
331 } else if (ACPI_COMPANION(dev)) {
332 irq = i2c_acpi_get_irq(client);
334 if (irq == -EPROBE_DEFER)
344 * An I2C ID table is not mandatory, if and only if, a suitable OF
345 * or ACPI ID table is supplied for the probing device.
347 if (!driver->id_table &&
348 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
349 !i2c_of_match_device(dev->driver->of_match_table, client))
352 if (client->flags & I2C_CLIENT_WAKE) {
355 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
356 if (wakeirq == -EPROBE_DEFER)
359 device_init_wakeup(&client->dev, true);
361 if (wakeirq > 0 && wakeirq != client->irq)
362 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
363 else if (client->irq > 0)
364 status = dev_pm_set_wake_irq(dev, client->irq);
369 dev_warn(&client->dev, "failed to set up wakeup irq\n");
372 dev_dbg(dev, "probe\n");
374 status = of_clk_set_defaults(dev->of_node, false);
376 goto err_clear_wakeup_irq;
378 status = dev_pm_domain_attach(&client->dev, true);
380 goto err_clear_wakeup_irq;
383 * When there are no more users of probe(),
384 * rename probe_new to probe.
386 if (driver->probe_new)
387 status = driver->probe_new(client);
388 else if (driver->probe)
389 status = driver->probe(client,
390 i2c_match_id(driver->id_table, client));
395 goto err_detach_pm_domain;
399 err_detach_pm_domain:
400 dev_pm_domain_detach(&client->dev, true);
401 err_clear_wakeup_irq:
402 dev_pm_clear_wake_irq(&client->dev);
403 device_init_wakeup(&client->dev, false);
407 static int i2c_device_remove(struct device *dev)
409 struct i2c_client *client = i2c_verify_client(dev);
410 struct i2c_driver *driver;
413 if (!client || !dev->driver)
416 driver = to_i2c_driver(dev->driver);
417 if (driver->remove) {
418 dev_dbg(dev, "remove\n");
419 status = driver->remove(client);
422 dev_pm_domain_detach(&client->dev, true);
424 dev_pm_clear_wake_irq(&client->dev);
425 device_init_wakeup(&client->dev, false);
428 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
429 pm_runtime_put(&client->adapter->dev);
434 static void i2c_device_shutdown(struct device *dev)
436 struct i2c_client *client = i2c_verify_client(dev);
437 struct i2c_driver *driver;
439 if (!client || !dev->driver)
441 driver = to_i2c_driver(dev->driver);
442 if (driver->shutdown)
443 driver->shutdown(client);
446 static void i2c_client_dev_release(struct device *dev)
448 kfree(to_i2c_client(dev));
452 show_name(struct device *dev, struct device_attribute *attr, char *buf)
454 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
455 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
457 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
460 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
462 struct i2c_client *client = to_i2c_client(dev);
465 len = of_device_modalias(dev, buf, PAGE_SIZE);
469 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
473 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
475 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
477 static struct attribute *i2c_dev_attrs[] = {
479 /* modalias helps coldplug: modprobe $(cat .../modalias) */
480 &dev_attr_modalias.attr,
483 ATTRIBUTE_GROUPS(i2c_dev);
485 struct bus_type i2c_bus_type = {
487 .match = i2c_device_match,
488 .probe = i2c_device_probe,
489 .remove = i2c_device_remove,
490 .shutdown = i2c_device_shutdown,
492 EXPORT_SYMBOL_GPL(i2c_bus_type);
494 struct device_type i2c_client_type = {
495 .groups = i2c_dev_groups,
496 .uevent = i2c_device_uevent,
497 .release = i2c_client_dev_release,
499 EXPORT_SYMBOL_GPL(i2c_client_type);
503 * i2c_verify_client - return parameter as i2c_client, or NULL
504 * @dev: device, probably from some driver model iterator
506 * When traversing the driver model tree, perhaps using driver model
507 * iterators like @device_for_each_child(), you can't assume very much
508 * about the nodes you find. Use this function to avoid oopses caused
509 * by wrongly treating some non-I2C device as an i2c_client.
511 struct i2c_client *i2c_verify_client(struct device *dev)
513 return (dev->type == &i2c_client_type)
517 EXPORT_SYMBOL(i2c_verify_client);
520 /* Return a unique address which takes the flags of the client into account */
521 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
523 unsigned short addr = client->addr;
525 /* For some client flags, add an arbitrary offset to avoid collisions */
526 if (client->flags & I2C_CLIENT_TEN)
527 addr |= I2C_ADDR_OFFSET_TEN_BIT;
529 if (client->flags & I2C_CLIENT_SLAVE)
530 addr |= I2C_ADDR_OFFSET_SLAVE;
535 /* This is a permissive address validity check, I2C address map constraints
536 * are purposely not enforced, except for the general call address. */
537 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
539 if (flags & I2C_CLIENT_TEN) {
540 /* 10-bit address, all values are valid */
544 /* 7-bit address, reject the general call address */
545 if (addr == 0x00 || addr > 0x7f)
551 /* And this is a strict address validity check, used when probing. If a
552 * device uses a reserved address, then it shouldn't be probed. 7-bit
553 * addressing is assumed, 10-bit address devices are rare and should be
554 * explicitly enumerated. */
555 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
558 * Reserved addresses per I2C specification:
559 * 0x00 General call address / START byte
561 * 0x02 Reserved for different bus format
562 * 0x03 Reserved for future purposes
563 * 0x04-0x07 Hs-mode master code
564 * 0x78-0x7b 10-bit slave addressing
565 * 0x7c-0x7f Reserved for future purposes
567 if (addr < 0x08 || addr > 0x77)
572 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
574 struct i2c_client *client = i2c_verify_client(dev);
575 int addr = *(int *)addrp;
577 if (client && i2c_encode_flags_to_addr(client) == addr)
582 /* walk up mux tree */
583 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
585 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
588 result = device_for_each_child(&adapter->dev, &addr,
589 __i2c_check_addr_busy);
591 if (!result && parent)
592 result = i2c_check_mux_parents(parent, addr);
597 /* recurse down mux tree */
598 static int i2c_check_mux_children(struct device *dev, void *addrp)
602 if (dev->type == &i2c_adapter_type)
603 result = device_for_each_child(dev, addrp,
604 i2c_check_mux_children);
606 result = __i2c_check_addr_busy(dev, addrp);
611 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
613 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
617 result = i2c_check_mux_parents(parent, addr);
620 result = device_for_each_child(&adapter->dev, &addr,
621 i2c_check_mux_children);
627 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
628 * @adapter: Target I2C bus segment
629 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
630 * locks only this branch in the adapter tree
632 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
635 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
639 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
640 * @adapter: Target I2C bus segment
641 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
642 * trylocks only this branch in the adapter tree
644 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
647 return rt_mutex_trylock(&adapter->bus_lock);
651 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
652 * @adapter: Target I2C bus segment
653 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
654 * unlocks only this branch in the adapter tree
656 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
659 rt_mutex_unlock(&adapter->bus_lock);
662 static void i2c_dev_set_name(struct i2c_adapter *adap,
663 struct i2c_client *client,
664 struct i2c_board_info const *info)
666 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
668 if (info && info->dev_name) {
669 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
674 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
678 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
679 i2c_encode_flags_to_addr(client));
682 int i2c_dev_irq_from_resources(const struct resource *resources,
683 unsigned int num_resources)
685 struct irq_data *irqd;
688 for (i = 0; i < num_resources; i++) {
689 const struct resource *r = &resources[i];
691 if (resource_type(r) != IORESOURCE_IRQ)
694 if (r->flags & IORESOURCE_BITS) {
695 irqd = irq_get_irq_data(r->start);
699 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
709 * i2c_new_client_device - instantiate an i2c device
710 * @adap: the adapter managing the device
711 * @info: describes one I2C device; bus_num is ignored
714 * Create an i2c device. Binding is handled through driver model
715 * probe()/remove() methods. A driver may be bound to this device when we
716 * return from this function, or any later moment (e.g. maybe hotplugging will
717 * load the driver module). This call is not appropriate for use by mainboard
718 * initialization logic, which usually runs during an arch_initcall() long
719 * before any i2c_adapter could exist.
721 * This returns the new i2c client, which may be saved for later use with
722 * i2c_unregister_device(); or an ERR_PTR to describe the error.
725 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
727 struct i2c_client *client;
730 client = kzalloc(sizeof *client, GFP_KERNEL);
732 return ERR_PTR(-ENOMEM);
734 client->adapter = adap;
736 client->dev.platform_data = info->platform_data;
737 client->flags = info->flags;
738 client->addr = info->addr;
740 client->init_irq = info->irq;
741 if (!client->init_irq)
742 client->init_irq = i2c_dev_irq_from_resources(info->resources,
743 info->num_resources);
745 strlcpy(client->name, info->type, sizeof(client->name));
747 status = i2c_check_addr_validity(client->addr, client->flags);
749 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
750 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
754 /* Check for address business */
755 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
759 client->dev.parent = &client->adapter->dev;
760 client->dev.bus = &i2c_bus_type;
761 client->dev.type = &i2c_client_type;
762 client->dev.of_node = of_node_get(info->of_node);
763 client->dev.fwnode = info->fwnode;
765 i2c_dev_set_name(adap, client, info);
767 if (info->properties) {
768 status = device_add_properties(&client->dev, info->properties);
771 "Failed to add properties to client %s: %d\n",
772 client->name, status);
773 goto out_err_put_of_node;
777 status = device_register(&client->dev);
781 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
782 client->name, dev_name(&client->dev));
787 if (info->properties)
788 device_remove_properties(&client->dev);
790 of_node_put(info->of_node);
793 "Failed to register i2c client %s at 0x%02x (%d)\n",
794 client->name, client->addr, status);
797 return ERR_PTR(status);
799 EXPORT_SYMBOL_GPL(i2c_new_client_device);
802 * i2c_new_device - instantiate an i2c device
803 * @adap: the adapter managing the device
804 * @info: describes one I2C device; bus_num is ignored
807 * This deprecated function has the same functionality as
808 * @i2c_new_client_device, it just returns NULL instead of an ERR_PTR in case of
809 * an error for compatibility with current I2C API. It will be removed once all
810 * users are converted.
812 * This returns the new i2c client, which may be saved for later use with
813 * i2c_unregister_device(); or NULL to indicate an error.
816 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
818 struct i2c_client *ret;
820 ret = i2c_new_client_device(adap, info);
821 return IS_ERR(ret) ? NULL : ret;
823 EXPORT_SYMBOL_GPL(i2c_new_device);
827 * i2c_unregister_device - reverse effect of i2c_new_device()
828 * @client: value returned from i2c_new_device()
831 void i2c_unregister_device(struct i2c_client *client)
833 if (IS_ERR_OR_NULL(client))
836 if (client->dev.of_node) {
837 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
838 of_node_put(client->dev.of_node);
841 if (ACPI_COMPANION(&client->dev))
842 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
843 device_unregister(&client->dev);
845 EXPORT_SYMBOL_GPL(i2c_unregister_device);
848 static const struct i2c_device_id dummy_id[] = {
853 static int dummy_probe(struct i2c_client *client,
854 const struct i2c_device_id *id)
859 static int dummy_remove(struct i2c_client *client)
864 static struct i2c_driver dummy_driver = {
865 .driver.name = "dummy",
866 .probe = dummy_probe,
867 .remove = dummy_remove,
868 .id_table = dummy_id,
872 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
873 * @adapter: the adapter managing the device
874 * @address: seven bit address to be used
877 * This returns an I2C client bound to the "dummy" driver, intended for use
878 * with devices that consume multiple addresses. Examples of such chips
879 * include various EEPROMS (like 24c04 and 24c08 models).
881 * These dummy devices have two main uses. First, most I2C and SMBus calls
882 * except i2c_transfer() need a client handle; the dummy will be that handle.
883 * And second, this prevents the specified address from being bound to a
886 * This returns the new i2c client, which should be saved for later use with
887 * i2c_unregister_device(); or an ERR_PTR to describe the error.
889 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
891 struct i2c_board_info info = {
892 I2C_BOARD_INFO("dummy", address),
895 return i2c_new_client_device(adapter, &info);
897 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
899 struct i2c_dummy_devres {
900 struct i2c_client *client;
903 static void devm_i2c_release_dummy(struct device *dev, void *res)
905 struct i2c_dummy_devres *this = res;
907 i2c_unregister_device(this->client);
911 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
912 * @dev: device the managed resource is bound to
913 * @adapter: the adapter managing the device
914 * @address: seven bit address to be used
917 * This is the device-managed version of @i2c_new_dummy_device. It returns the
918 * new i2c client or an ERR_PTR in case of an error.
920 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
921 struct i2c_adapter *adapter,
924 struct i2c_dummy_devres *dr;
925 struct i2c_client *client;
927 dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
929 return ERR_PTR(-ENOMEM);
931 client = i2c_new_dummy_device(adapter, address);
932 if (IS_ERR(client)) {
941 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
944 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
945 * and create the associated device
946 * @client: Handle to the primary client
947 * @name: Handle to specify which secondary address to get
948 * @default_addr: Used as a fallback if no secondary address was specified
951 * I2C clients can be composed of multiple I2C slaves bound together in a single
952 * component. The I2C client driver then binds to the master I2C slave and needs
953 * to create I2C dummy clients to communicate with all the other slaves.
955 * This function creates and returns an I2C dummy client whose I2C address is
956 * retrieved from the platform firmware based on the given slave name. If no
957 * address is specified by the firmware default_addr is used.
959 * On DT-based platforms the address is retrieved from the "reg" property entry
960 * cell whose "reg-names" value matches the slave name.
962 * This returns the new i2c client, which should be saved for later use with
963 * i2c_unregister_device(); or an ERR_PTR to describe the error.
965 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
969 struct device_node *np = client->dev.of_node;
970 u32 addr = default_addr;
974 i = of_property_match_string(np, "reg-names", name);
976 of_property_read_u32_index(np, "reg", i, &addr);
979 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
980 return i2c_new_dummy_device(client->adapter, addr);
982 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
984 /* ------------------------------------------------------------------------- */
986 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
988 static void i2c_adapter_dev_release(struct device *dev)
990 struct i2c_adapter *adap = to_i2c_adapter(dev);
991 complete(&adap->dev_released);
994 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
996 unsigned int depth = 0;
998 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1001 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1002 "adapter depth exceeds lockdep subclass limit\n");
1006 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1009 * Let users instantiate I2C devices through sysfs. This can be used when
1010 * platform initialization code doesn't contain the proper data for
1011 * whatever reason. Also useful for drivers that do device detection and
1012 * detection fails, either because the device uses an unexpected address,
1013 * or this is a compatible device with different ID register values.
1015 * Parameter checking may look overzealous, but we really don't want
1016 * the user to provide incorrect parameters.
1019 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
1020 const char *buf, size_t count)
1022 struct i2c_adapter *adap = to_i2c_adapter(dev);
1023 struct i2c_board_info info;
1024 struct i2c_client *client;
1028 memset(&info, 0, sizeof(struct i2c_board_info));
1030 blank = strchr(buf, ' ');
1032 dev_err(dev, "%s: Missing parameters\n", "new_device");
1035 if (blank - buf > I2C_NAME_SIZE - 1) {
1036 dev_err(dev, "%s: Invalid device name\n", "new_device");
1039 memcpy(info.type, buf, blank - buf);
1041 /* Parse remaining parameters, reject extra parameters */
1042 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1044 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1047 if (res > 1 && end != '\n') {
1048 dev_err(dev, "%s: Extra parameters\n", "new_device");
1052 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1053 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1054 info.flags |= I2C_CLIENT_TEN;
1057 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1058 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1059 info.flags |= I2C_CLIENT_SLAVE;
1062 client = i2c_new_client_device(adap, &info);
1064 return PTR_ERR(client);
1066 /* Keep track of the added device */
1067 mutex_lock(&adap->userspace_clients_lock);
1068 list_add_tail(&client->detected, &adap->userspace_clients);
1069 mutex_unlock(&adap->userspace_clients_lock);
1070 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1071 info.type, info.addr);
1075 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1078 * And of course let the users delete the devices they instantiated, if
1079 * they got it wrong. This interface can only be used to delete devices
1080 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1081 * don't delete devices to which some kernel code still has references.
1083 * Parameter checking may look overzealous, but we really don't want
1084 * the user to delete the wrong device.
1087 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1088 const char *buf, size_t count)
1090 struct i2c_adapter *adap = to_i2c_adapter(dev);
1091 struct i2c_client *client, *next;
1092 unsigned short addr;
1096 /* Parse parameters, reject extra parameters */
1097 res = sscanf(buf, "%hi%c", &addr, &end);
1099 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1102 if (res > 1 && end != '\n') {
1103 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1107 /* Make sure the device was added through sysfs */
1109 mutex_lock_nested(&adap->userspace_clients_lock,
1110 i2c_adapter_depth(adap));
1111 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1113 if (i2c_encode_flags_to_addr(client) == addr) {
1114 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1115 "delete_device", client->name, client->addr);
1117 list_del(&client->detected);
1118 i2c_unregister_device(client);
1123 mutex_unlock(&adap->userspace_clients_lock);
1126 dev_err(dev, "%s: Can't find device in list\n",
1130 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1131 i2c_sysfs_delete_device);
1133 static struct attribute *i2c_adapter_attrs[] = {
1134 &dev_attr_name.attr,
1135 &dev_attr_new_device.attr,
1136 &dev_attr_delete_device.attr,
1139 ATTRIBUTE_GROUPS(i2c_adapter);
1141 struct device_type i2c_adapter_type = {
1142 .groups = i2c_adapter_groups,
1143 .release = i2c_adapter_dev_release,
1145 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1148 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1149 * @dev: device, probably from some driver model iterator
1151 * When traversing the driver model tree, perhaps using driver model
1152 * iterators like @device_for_each_child(), you can't assume very much
1153 * about the nodes you find. Use this function to avoid oopses caused
1154 * by wrongly treating some non-I2C device as an i2c_adapter.
1156 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1158 return (dev->type == &i2c_adapter_type)
1159 ? to_i2c_adapter(dev)
1162 EXPORT_SYMBOL(i2c_verify_adapter);
1164 #ifdef CONFIG_I2C_COMPAT
1165 static struct class_compat *i2c_adapter_compat_class;
1168 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1170 struct i2c_devinfo *devinfo;
1172 down_read(&__i2c_board_lock);
1173 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1174 if (devinfo->busnum == adapter->nr
1175 && !i2c_new_device(adapter,
1176 &devinfo->board_info))
1177 dev_err(&adapter->dev,
1178 "Can't create device at 0x%02x\n",
1179 devinfo->board_info.addr);
1181 up_read(&__i2c_board_lock);
1184 static int i2c_do_add_adapter(struct i2c_driver *driver,
1185 struct i2c_adapter *adap)
1187 /* Detect supported devices on that bus, and instantiate them */
1188 i2c_detect(adap, driver);
1193 static int __process_new_adapter(struct device_driver *d, void *data)
1195 return i2c_do_add_adapter(to_i2c_driver(d), data);
1198 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1199 .lock_bus = i2c_adapter_lock_bus,
1200 .trylock_bus = i2c_adapter_trylock_bus,
1201 .unlock_bus = i2c_adapter_unlock_bus,
1204 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1206 struct irq_domain *domain = adap->host_notify_domain;
1207 irq_hw_number_t hwirq;
1212 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1213 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1215 irq_domain_remove(domain);
1216 adap->host_notify_domain = NULL;
1219 static int i2c_host_notify_irq_map(struct irq_domain *h,
1221 irq_hw_number_t hw_irq_num)
1223 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1228 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1229 .map = i2c_host_notify_irq_map,
1232 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1234 struct irq_domain *domain;
1236 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1239 domain = irq_domain_create_linear(adap->dev.fwnode,
1240 I2C_ADDR_7BITS_COUNT,
1241 &i2c_host_notify_irq_ops, adap);
1245 adap->host_notify_domain = domain;
1251 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1253 * @adap: the adapter
1254 * @addr: the I2C address of the notifying device
1255 * Context: can't sleep
1257 * Helper function to be called from an I2C bus driver's interrupt
1258 * handler. It will schedule the Host Notify IRQ.
1260 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1267 irq = irq_find_mapping(adap->host_notify_domain, addr);
1271 generic_handle_irq(irq);
1275 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1277 static int i2c_register_adapter(struct i2c_adapter *adap)
1281 /* Can't register until after driver model init */
1282 if (WARN_ON(!is_registered)) {
1288 if (WARN(!adap->name[0], "i2c adapter has no name"))
1292 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1296 if (!adap->lock_ops)
1297 adap->lock_ops = &i2c_adapter_lock_ops;
1299 adap->locked_flags = 0;
1300 rt_mutex_init(&adap->bus_lock);
1301 rt_mutex_init(&adap->mux_lock);
1302 mutex_init(&adap->userspace_clients_lock);
1303 INIT_LIST_HEAD(&adap->userspace_clients);
1305 /* Set default timeout to 1 second if not already set */
1306 if (adap->timeout == 0)
1309 /* register soft irqs for Host Notify */
1310 res = i2c_setup_host_notify_irq_domain(adap);
1312 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1317 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1318 adap->dev.bus = &i2c_bus_type;
1319 adap->dev.type = &i2c_adapter_type;
1320 res = device_register(&adap->dev);
1322 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1326 res = of_i2c_setup_smbus_alert(adap);
1330 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1332 pm_runtime_no_callbacks(&adap->dev);
1333 pm_suspend_ignore_children(&adap->dev, true);
1334 pm_runtime_enable(&adap->dev);
1336 #ifdef CONFIG_I2C_COMPAT
1337 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1340 dev_warn(&adap->dev,
1341 "Failed to create compatibility class link\n");
1344 i2c_init_recovery(adap);
1346 /* create pre-declared device nodes */
1347 of_i2c_register_devices(adap);
1348 i2c_acpi_register_devices(adap);
1349 i2c_acpi_install_space_handler(adap);
1351 if (adap->nr < __i2c_first_dynamic_bus_num)
1352 i2c_scan_static_board_info(adap);
1354 /* Notify drivers */
1355 mutex_lock(&core_lock);
1356 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1357 mutex_unlock(&core_lock);
1362 init_completion(&adap->dev_released);
1363 device_unregister(&adap->dev);
1364 wait_for_completion(&adap->dev_released);
1366 mutex_lock(&core_lock);
1367 idr_remove(&i2c_adapter_idr, adap->nr);
1368 mutex_unlock(&core_lock);
1373 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1374 * @adap: the adapter to register (with adap->nr initialized)
1375 * Context: can sleep
1377 * See i2c_add_numbered_adapter() for details.
1379 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1383 mutex_lock(&core_lock);
1384 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1385 mutex_unlock(&core_lock);
1386 if (WARN(id < 0, "couldn't get idr"))
1387 return id == -ENOSPC ? -EBUSY : id;
1389 return i2c_register_adapter(adap);
1393 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1394 * @adapter: the adapter to add
1395 * Context: can sleep
1397 * This routine is used to declare an I2C adapter when its bus number
1398 * doesn't matter or when its bus number is specified by an dt alias.
1399 * Examples of bases when the bus number doesn't matter: I2C adapters
1400 * dynamically added by USB links or PCI plugin cards.
1402 * When this returns zero, a new bus number was allocated and stored
1403 * in adap->nr, and the specified adapter became available for clients.
1404 * Otherwise, a negative errno value is returned.
1406 int i2c_add_adapter(struct i2c_adapter *adapter)
1408 struct device *dev = &adapter->dev;
1412 id = of_alias_get_id(dev->of_node, "i2c");
1415 return __i2c_add_numbered_adapter(adapter);
1419 mutex_lock(&core_lock);
1420 id = idr_alloc(&i2c_adapter_idr, adapter,
1421 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1422 mutex_unlock(&core_lock);
1423 if (WARN(id < 0, "couldn't get idr"))
1428 return i2c_register_adapter(adapter);
1430 EXPORT_SYMBOL(i2c_add_adapter);
1433 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1434 * @adap: the adapter to register (with adap->nr initialized)
1435 * Context: can sleep
1437 * This routine is used to declare an I2C adapter when its bus number
1438 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1439 * or otherwise built in to the system's mainboard, and where i2c_board_info
1440 * is used to properly configure I2C devices.
1442 * If the requested bus number is set to -1, then this function will behave
1443 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1445 * If no devices have pre-been declared for this bus, then be sure to
1446 * register the adapter before any dynamically allocated ones. Otherwise
1447 * the required bus ID may not be available.
1449 * When this returns zero, the specified adapter became available for
1450 * clients using the bus number provided in adap->nr. Also, the table
1451 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1452 * and the appropriate driver model device nodes are created. Otherwise, a
1453 * negative errno value is returned.
1455 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1457 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1458 return i2c_add_adapter(adap);
1460 return __i2c_add_numbered_adapter(adap);
1462 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1464 static void i2c_do_del_adapter(struct i2c_driver *driver,
1465 struct i2c_adapter *adapter)
1467 struct i2c_client *client, *_n;
1469 /* Remove the devices we created ourselves as the result of hardware
1470 * probing (using a driver's detect method) */
1471 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1472 if (client->adapter == adapter) {
1473 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1474 client->name, client->addr);
1475 list_del(&client->detected);
1476 i2c_unregister_device(client);
1481 static int __unregister_client(struct device *dev, void *dummy)
1483 struct i2c_client *client = i2c_verify_client(dev);
1484 if (client && strcmp(client->name, "dummy"))
1485 i2c_unregister_device(client);
1489 static int __unregister_dummy(struct device *dev, void *dummy)
1491 struct i2c_client *client = i2c_verify_client(dev);
1492 i2c_unregister_device(client);
1496 static int __process_removed_adapter(struct device_driver *d, void *data)
1498 i2c_do_del_adapter(to_i2c_driver(d), data);
1503 * i2c_del_adapter - unregister I2C adapter
1504 * @adap: the adapter being unregistered
1505 * Context: can sleep
1507 * This unregisters an I2C adapter which was previously registered
1508 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1510 void i2c_del_adapter(struct i2c_adapter *adap)
1512 struct i2c_adapter *found;
1513 struct i2c_client *client, *next;
1515 /* First make sure that this adapter was ever added */
1516 mutex_lock(&core_lock);
1517 found = idr_find(&i2c_adapter_idr, adap->nr);
1518 mutex_unlock(&core_lock);
1519 if (found != adap) {
1520 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1524 i2c_acpi_remove_space_handler(adap);
1525 /* Tell drivers about this removal */
1526 mutex_lock(&core_lock);
1527 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1528 __process_removed_adapter);
1529 mutex_unlock(&core_lock);
1531 /* Remove devices instantiated from sysfs */
1532 mutex_lock_nested(&adap->userspace_clients_lock,
1533 i2c_adapter_depth(adap));
1534 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1536 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1538 list_del(&client->detected);
1539 i2c_unregister_device(client);
1541 mutex_unlock(&adap->userspace_clients_lock);
1543 /* Detach any active clients. This can't fail, thus we do not
1544 * check the returned value. This is a two-pass process, because
1545 * we can't remove the dummy devices during the first pass: they
1546 * could have been instantiated by real devices wishing to clean
1547 * them up properly, so we give them a chance to do that first. */
1548 device_for_each_child(&adap->dev, NULL, __unregister_client);
1549 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1551 #ifdef CONFIG_I2C_COMPAT
1552 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1556 /* device name is gone after device_unregister */
1557 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1559 pm_runtime_disable(&adap->dev);
1561 i2c_host_notify_irq_teardown(adap);
1563 /* wait until all references to the device are gone
1565 * FIXME: This is old code and should ideally be replaced by an
1566 * alternative which results in decoupling the lifetime of the struct
1567 * device from the i2c_adapter, like spi or netdev do. Any solution
1568 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1570 init_completion(&adap->dev_released);
1571 device_unregister(&adap->dev);
1572 wait_for_completion(&adap->dev_released);
1575 mutex_lock(&core_lock);
1576 idr_remove(&i2c_adapter_idr, adap->nr);
1577 mutex_unlock(&core_lock);
1579 /* Clear the device structure in case this adapter is ever going to be
1581 memset(&adap->dev, 0, sizeof(adap->dev));
1583 EXPORT_SYMBOL(i2c_del_adapter);
1586 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1587 * @dev: The device to scan for I2C timing properties
1588 * @t: the i2c_timings struct to be filled with values
1589 * @use_defaults: bool to use sane defaults derived from the I2C specification
1590 * when properties are not found, otherwise use 0
1592 * Scan the device for the generic I2C properties describing timing parameters
1593 * for the signal and fill the given struct with the results. If a property was
1594 * not found and use_defaults was true, then maximum timings are assumed which
1595 * are derived from the I2C specification. If use_defaults is not used, the
1596 * results will be 0, so drivers can apply their own defaults later. The latter
1597 * is mainly intended for avoiding regressions of existing drivers which want
1598 * to switch to this function. New drivers almost always should use the defaults.
1601 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1605 memset(t, 0, sizeof(*t));
1607 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1608 if (ret && use_defaults)
1609 t->bus_freq_hz = 100000;
1611 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1612 if (ret && use_defaults) {
1613 if (t->bus_freq_hz <= 100000)
1614 t->scl_rise_ns = 1000;
1615 else if (t->bus_freq_hz <= 400000)
1616 t->scl_rise_ns = 300;
1618 t->scl_rise_ns = 120;
1621 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1622 if (ret && use_defaults) {
1623 if (t->bus_freq_hz <= 400000)
1624 t->scl_fall_ns = 300;
1626 t->scl_fall_ns = 120;
1629 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1631 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1632 if (ret && use_defaults)
1633 t->sda_fall_ns = t->scl_fall_ns;
1635 device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1637 device_property_read_u32(dev, "i2c-digital-filter-width-ns",
1638 &t->digital_filter_width_ns);
1640 device_property_read_u32(dev, "i2c-analog-filter-cutoff-frequency",
1641 &t->analog_filter_cutoff_freq_hz);
1643 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1645 /* ------------------------------------------------------------------------- */
1647 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1651 mutex_lock(&core_lock);
1652 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1653 mutex_unlock(&core_lock);
1657 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1659 static int __process_new_driver(struct device *dev, void *data)
1661 if (dev->type != &i2c_adapter_type)
1663 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1667 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1668 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1671 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1675 /* Can't register until after driver model init */
1676 if (WARN_ON(!is_registered))
1679 /* add the driver to the list of i2c drivers in the driver core */
1680 driver->driver.owner = owner;
1681 driver->driver.bus = &i2c_bus_type;
1682 INIT_LIST_HEAD(&driver->clients);
1684 /* When registration returns, the driver core
1685 * will have called probe() for all matching-but-unbound devices.
1687 res = driver_register(&driver->driver);
1691 pr_debug("driver [%s] registered\n", driver->driver.name);
1693 /* Walk the adapters that are already present */
1694 i2c_for_each_dev(driver, __process_new_driver);
1698 EXPORT_SYMBOL(i2c_register_driver);
1700 static int __process_removed_driver(struct device *dev, void *data)
1702 if (dev->type == &i2c_adapter_type)
1703 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1708 * i2c_del_driver - unregister I2C driver
1709 * @driver: the driver being unregistered
1710 * Context: can sleep
1712 void i2c_del_driver(struct i2c_driver *driver)
1714 i2c_for_each_dev(driver, __process_removed_driver);
1716 driver_unregister(&driver->driver);
1717 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1719 EXPORT_SYMBOL(i2c_del_driver);
1721 /* ------------------------------------------------------------------------- */
1723 struct i2c_cmd_arg {
1728 static int i2c_cmd(struct device *dev, void *_arg)
1730 struct i2c_client *client = i2c_verify_client(dev);
1731 struct i2c_cmd_arg *arg = _arg;
1732 struct i2c_driver *driver;
1734 if (!client || !client->dev.driver)
1737 driver = to_i2c_driver(client->dev.driver);
1738 if (driver->command)
1739 driver->command(client, arg->cmd, arg->arg);
1743 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1745 struct i2c_cmd_arg cmd_arg;
1749 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1751 EXPORT_SYMBOL(i2c_clients_command);
1753 static int __init i2c_init(void)
1757 retval = of_alias_get_highest_id("i2c");
1759 down_write(&__i2c_board_lock);
1760 if (retval >= __i2c_first_dynamic_bus_num)
1761 __i2c_first_dynamic_bus_num = retval + 1;
1762 up_write(&__i2c_board_lock);
1764 retval = bus_register(&i2c_bus_type);
1768 is_registered = true;
1770 #ifdef CONFIG_I2C_COMPAT
1771 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1772 if (!i2c_adapter_compat_class) {
1777 retval = i2c_add_driver(&dummy_driver);
1781 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1782 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1783 if (IS_ENABLED(CONFIG_ACPI))
1784 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1789 #ifdef CONFIG_I2C_COMPAT
1790 class_compat_unregister(i2c_adapter_compat_class);
1793 is_registered = false;
1794 bus_unregister(&i2c_bus_type);
1798 static void __exit i2c_exit(void)
1800 if (IS_ENABLED(CONFIG_ACPI))
1801 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1802 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1803 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1804 i2c_del_driver(&dummy_driver);
1805 #ifdef CONFIG_I2C_COMPAT
1806 class_compat_unregister(i2c_adapter_compat_class);
1808 bus_unregister(&i2c_bus_type);
1809 tracepoint_synchronize_unregister();
1812 /* We must initialize early, because some subsystems register i2c drivers
1813 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1815 postcore_initcall(i2c_init);
1816 module_exit(i2c_exit);
1818 /* ----------------------------------------------------
1819 * the functional interface to the i2c busses.
1820 * ----------------------------------------------------
1823 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1824 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1826 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1828 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1829 err_msg, msg->addr, msg->len,
1830 msg->flags & I2C_M_RD ? "read" : "write");
1834 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1836 const struct i2c_adapter_quirks *q = adap->quirks;
1837 int max_num = q->max_num_msgs, i;
1838 bool do_len_check = true;
1840 if (q->flags & I2C_AQ_COMB) {
1843 /* special checks for combined messages */
1845 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1846 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1848 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1849 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1851 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1852 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1854 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1855 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1857 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1858 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1860 do_len_check = false;
1864 if (i2c_quirk_exceeded(num, max_num))
1865 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1867 for (i = 0; i < num; i++) {
1868 u16 len = msgs[i].len;
1870 if (msgs[i].flags & I2C_M_RD) {
1871 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1872 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1874 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1875 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1877 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1878 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1880 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1881 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1889 * __i2c_transfer - unlocked flavor of i2c_transfer
1890 * @adap: Handle to I2C bus
1891 * @msgs: One or more messages to execute before STOP is issued to
1892 * terminate the operation; each message begins with a START.
1893 * @num: Number of messages to be executed.
1895 * Returns negative errno, else the number of messages executed.
1897 * Adapter lock must be held when calling this function. No debug logging
1898 * takes place. adap->algo->master_xfer existence isn't checked.
1900 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1902 unsigned long orig_jiffies;
1905 if (WARN_ON(!msgs || num < 1))
1908 ret = __i2c_check_suspended(adap);
1912 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1916 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1917 * enabled. This is an efficient way of keeping the for-loop from
1918 * being executed when not needed.
1920 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1922 for (i = 0; i < num; i++)
1923 if (msgs[i].flags & I2C_M_RD)
1924 trace_i2c_read(adap, &msgs[i], i);
1926 trace_i2c_write(adap, &msgs[i], i);
1929 /* Retry automatically on arbitration loss */
1930 orig_jiffies = jiffies;
1931 for (ret = 0, try = 0; try <= adap->retries; try++) {
1932 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
1933 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
1935 ret = adap->algo->master_xfer(adap, msgs, num);
1939 if (time_after(jiffies, orig_jiffies + adap->timeout))
1943 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1945 for (i = 0; i < ret; i++)
1946 if (msgs[i].flags & I2C_M_RD)
1947 trace_i2c_reply(adap, &msgs[i], i);
1948 trace_i2c_result(adap, num, ret);
1953 EXPORT_SYMBOL(__i2c_transfer);
1956 * i2c_transfer - execute a single or combined I2C message
1957 * @adap: Handle to I2C bus
1958 * @msgs: One or more messages to execute before STOP is issued to
1959 * terminate the operation; each message begins with a START.
1960 * @num: Number of messages to be executed.
1962 * Returns negative errno, else the number of messages executed.
1964 * Note that there is no requirement that each message be sent to
1965 * the same slave address, although that is the most common model.
1967 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1971 if (!adap->algo->master_xfer) {
1972 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1976 /* REVISIT the fault reporting model here is weak:
1978 * - When we get an error after receiving N bytes from a slave,
1979 * there is no way to report "N".
1981 * - When we get a NAK after transmitting N bytes to a slave,
1982 * there is no way to report "N" ... or to let the master
1983 * continue executing the rest of this combined message, if
1984 * that's the appropriate response.
1986 * - When for example "num" is two and we successfully complete
1987 * the first message but get an error part way through the
1988 * second, it's unclear whether that should be reported as
1989 * one (discarding status on the second message) or errno
1990 * (discarding status on the first one).
1992 ret = __i2c_lock_bus_helper(adap);
1996 ret = __i2c_transfer(adap, msgs, num);
1997 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2001 EXPORT_SYMBOL(i2c_transfer);
2004 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2006 * @client: Handle to slave device
2007 * @buf: Where the data is stored
2008 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2009 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2011 * Returns negative errno, or else the number of bytes transferred.
2013 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2014 int count, u16 flags)
2017 struct i2c_msg msg = {
2018 .addr = client->addr,
2019 .flags = flags | (client->flags & I2C_M_TEN),
2024 ret = i2c_transfer(client->adapter, &msg, 1);
2027 * If everything went ok (i.e. 1 msg transferred), return #bytes
2028 * transferred, else error code.
2030 return (ret == 1) ? count : ret;
2032 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2035 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2036 * @client: The device to query
2037 * @id: The queried information
2039 * Returns negative errno on error, zero on success.
2041 int i2c_get_device_id(const struct i2c_client *client,
2042 struct i2c_device_identity *id)
2044 struct i2c_adapter *adap = client->adapter;
2045 union i2c_smbus_data raw_id;
2048 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2051 raw_id.block[0] = 3;
2052 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2053 I2C_SMBUS_READ, client->addr << 1,
2054 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2058 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2059 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2060 id->die_revision = raw_id.block[3] & 0x7;
2063 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2065 /* ----------------------------------------------------
2066 * the i2c address scanning function
2067 * Will not work for 10-bit addresses!
2068 * ----------------------------------------------------
2072 * Legacy default probe function, mostly relevant for SMBus. The default
2073 * probe method is a quick write, but it is known to corrupt the 24RF08
2074 * EEPROMs due to a state machine bug, and could also irreversibly
2075 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2076 * we use a short byte read instead. Also, some bus drivers don't implement
2077 * quick write, so we fallback to a byte read in that case too.
2078 * On x86, there is another special case for FSC hardware monitoring chips,
2079 * which want regular byte reads (address 0x73.) Fortunately, these are the
2080 * only known chips using this I2C address on PC hardware.
2081 * Returns 1 if probe succeeded, 0 if not.
2083 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2086 union i2c_smbus_data dummy;
2089 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2090 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2091 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2092 I2C_SMBUS_BYTE_DATA, &dummy);
2095 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2096 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2097 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2098 I2C_SMBUS_QUICK, NULL);
2099 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2100 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2101 I2C_SMBUS_BYTE, &dummy);
2103 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2111 static int i2c_detect_address(struct i2c_client *temp_client,
2112 struct i2c_driver *driver)
2114 struct i2c_board_info info;
2115 struct i2c_adapter *adapter = temp_client->adapter;
2116 int addr = temp_client->addr;
2119 /* Make sure the address is valid */
2120 err = i2c_check_7bit_addr_validity_strict(addr);
2122 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2127 /* Skip if already in use (7 bit, no need to encode flags) */
2128 if (i2c_check_addr_busy(adapter, addr))
2131 /* Make sure there is something at this address */
2132 if (!i2c_default_probe(adapter, addr))
2135 /* Finally call the custom detection function */
2136 memset(&info, 0, sizeof(struct i2c_board_info));
2138 err = driver->detect(temp_client, &info);
2140 /* -ENODEV is returned if the detection fails. We catch it
2141 here as this isn't an error. */
2142 return err == -ENODEV ? 0 : err;
2145 /* Consistency check */
2146 if (info.type[0] == '\0') {
2147 dev_err(&adapter->dev,
2148 "%s detection function provided no name for 0x%x\n",
2149 driver->driver.name, addr);
2151 struct i2c_client *client;
2153 /* Detection succeeded, instantiate the device */
2154 if (adapter->class & I2C_CLASS_DEPRECATED)
2155 dev_warn(&adapter->dev,
2156 "This adapter will soon drop class based instantiation of devices. "
2157 "Please make sure client 0x%02x gets instantiated by other means. "
2158 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2161 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2162 info.type, info.addr);
2163 client = i2c_new_device(adapter, &info);
2165 list_add_tail(&client->detected, &driver->clients);
2167 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2168 info.type, info.addr);
2173 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2175 const unsigned short *address_list;
2176 struct i2c_client *temp_client;
2178 int adap_id = i2c_adapter_id(adapter);
2180 address_list = driver->address_list;
2181 if (!driver->detect || !address_list)
2184 /* Warn that the adapter lost class based instantiation */
2185 if (adapter->class == I2C_CLASS_DEPRECATED) {
2186 dev_dbg(&adapter->dev,
2187 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2188 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2189 driver->driver.name);
2193 /* Stop here if the classes do not match */
2194 if (!(adapter->class & driver->class))
2197 /* Set up a temporary client to help detect callback */
2198 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2201 temp_client->adapter = adapter;
2203 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2204 dev_dbg(&adapter->dev,
2205 "found normal entry for adapter %d, addr 0x%02x\n",
2206 adap_id, address_list[i]);
2207 temp_client->addr = address_list[i];
2208 err = i2c_detect_address(temp_client, driver);
2217 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2219 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2220 I2C_SMBUS_QUICK, NULL) >= 0;
2222 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2225 i2c_new_scanned_device(struct i2c_adapter *adap,
2226 struct i2c_board_info *info,
2227 unsigned short const *addr_list,
2228 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2233 probe = i2c_default_probe;
2235 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2236 /* Check address validity */
2237 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2238 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2243 /* Check address availability (7 bit, no need to encode flags) */
2244 if (i2c_check_addr_busy(adap, addr_list[i])) {
2246 "Address 0x%02x already in use, not probing\n",
2251 /* Test address responsiveness */
2252 if (probe(adap, addr_list[i]))
2256 if (addr_list[i] == I2C_CLIENT_END) {
2257 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2258 return ERR_PTR(-ENODEV);
2261 info->addr = addr_list[i];
2262 return i2c_new_client_device(adap, info);
2264 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2267 i2c_new_probed_device(struct i2c_adapter *adap,
2268 struct i2c_board_info *info,
2269 unsigned short const *addr_list,
2270 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2272 struct i2c_client *client;
2274 client = i2c_new_scanned_device(adap, info, addr_list, probe);
2275 return IS_ERR(client) ? NULL : client;
2277 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2279 struct i2c_adapter *i2c_get_adapter(int nr)
2281 struct i2c_adapter *adapter;
2283 mutex_lock(&core_lock);
2284 adapter = idr_find(&i2c_adapter_idr, nr);
2288 if (try_module_get(adapter->owner))
2289 get_device(&adapter->dev);
2294 mutex_unlock(&core_lock);
2297 EXPORT_SYMBOL(i2c_get_adapter);
2299 void i2c_put_adapter(struct i2c_adapter *adap)
2304 put_device(&adap->dev);
2305 module_put(adap->owner);
2307 EXPORT_SYMBOL(i2c_put_adapter);
2310 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2311 * @msg: the message to be checked
2312 * @threshold: the minimum number of bytes for which using DMA makes sense.
2313 * Should at least be 1.
2315 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2316 * Or a valid pointer to be used with DMA. After use, release it by
2317 * calling i2c_put_dma_safe_msg_buf().
2319 * This function must only be called from process context!
2321 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2323 /* also skip 0-length msgs for bogus thresholds of 0 */
2325 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2327 if (msg->len < threshold || msg->len == 0)
2330 if (msg->flags & I2C_M_DMA_SAFE)
2333 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2334 msg->addr, msg->len);
2336 if (msg->flags & I2C_M_RD)
2337 return kzalloc(msg->len, GFP_KERNEL);
2339 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2341 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2344 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2345 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2346 * @msg: the message which the buffer corresponds to
2347 * @xferred: bool saying if the message was transferred
2349 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2351 if (!buf || buf == msg->buf)
2354 if (xferred && msg->flags & I2C_M_RD)
2355 memcpy(msg->buf, buf, msg->len);
2359 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2361 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2362 MODULE_DESCRIPTION("I2C-Bus main module");
2363 MODULE_LICENSE("GPL");