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@kernel.org>
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
189 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
190 * here for simplicity.
192 bri->set_scl(adap, scl);
193 ndelay(RECOVERY_NDELAY);
195 bri->set_sda(adap, scl);
196 ndelay(RECOVERY_NDELAY / 2);
199 * By this time SCL is high, as we need to give 9 falling-rising edges
201 while (i++ < RECOVERY_CLK_CNT * 2) {
203 /* SCL shouldn't be low here */
204 if (!bri->get_scl(adap)) {
206 "SCL is stuck low, exit recovery\n");
213 bri->set_scl(adap, scl);
214 /* Creating STOP again, see above */
216 /* Honour minimum tsu:sto */
217 ndelay(RECOVERY_NDELAY);
219 /* Honour minimum tf and thd:dat */
220 ndelay(RECOVERY_NDELAY / 2);
223 bri->set_sda(adap, scl);
224 ndelay(RECOVERY_NDELAY / 2);
227 ret = i2c_generic_bus_free(adap);
233 /* If we can't check bus status, assume recovery worked */
234 if (ret == -EOPNOTSUPP)
237 if (bri->unprepare_recovery)
238 bri->unprepare_recovery(adap);
242 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
244 int i2c_recover_bus(struct i2c_adapter *adap)
246 if (!adap->bus_recovery_info)
249 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
250 return adap->bus_recovery_info->recover_bus(adap);
252 EXPORT_SYMBOL_GPL(i2c_recover_bus);
254 static void i2c_init_recovery(struct i2c_adapter *adap)
256 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
262 if (!bri->recover_bus) {
263 err_str = "no recover_bus() found";
267 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
268 bri->get_scl = get_scl_gpio_value;
269 bri->set_scl = set_scl_gpio_value;
270 if (bri->sda_gpiod) {
271 bri->get_sda = get_sda_gpio_value;
272 /* FIXME: add proper flag instead of '0' once available */
273 if (gpiod_get_direction(bri->sda_gpiod) == 0)
274 bri->set_sda = set_sda_gpio_value;
279 if (bri->recover_bus == i2c_generic_scl_recovery) {
280 /* Generic SCL recovery */
281 if (!bri->set_scl || !bri->get_scl) {
282 err_str = "no {get|set}_scl() found";
285 if (!bri->set_sda && !bri->get_sda) {
286 err_str = "either get_sda() or set_sda() needed";
293 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
294 adap->bus_recovery_info = NULL;
297 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
299 struct i2c_adapter *adap = client->adapter;
302 if (!adap->host_notify_domain)
305 if (client->flags & I2C_CLIENT_TEN)
308 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
310 return irq > 0 ? irq : -ENXIO;
313 static int i2c_device_probe(struct device *dev)
315 struct i2c_client *client = i2c_verify_client(dev);
316 struct i2c_driver *driver;
322 driver = to_i2c_driver(dev->driver);
324 client->irq = client->init_irq;
326 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
329 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
330 dev_dbg(dev, "Using Host Notify IRQ\n");
331 /* Keep adapter active when Host Notify is required */
332 pm_runtime_get_sync(&client->adapter->dev);
333 irq = i2c_smbus_host_notify_to_irq(client);
334 } else if (dev->of_node) {
335 irq = of_irq_get_byname(dev->of_node, "irq");
336 if (irq == -EINVAL || irq == -ENODATA)
337 irq = of_irq_get(dev->of_node, 0);
338 } else if (ACPI_COMPANION(dev)) {
339 irq = i2c_acpi_get_irq(client);
341 if (irq == -EPROBE_DEFER) {
343 goto put_sync_adapter;
353 * An I2C ID table is not mandatory, if and only if, a suitable OF
354 * or ACPI ID table is supplied for the probing device.
356 if (!driver->id_table &&
357 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
358 !i2c_of_match_device(dev->driver->of_match_table, client)) {
360 goto put_sync_adapter;
363 if (client->flags & I2C_CLIENT_WAKE) {
366 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
367 if (wakeirq == -EPROBE_DEFER) {
369 goto put_sync_adapter;
372 device_init_wakeup(&client->dev, true);
374 if (wakeirq > 0 && wakeirq != client->irq)
375 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
376 else if (client->irq > 0)
377 status = dev_pm_set_wake_irq(dev, client->irq);
382 dev_warn(&client->dev, "failed to set up wakeup irq\n");
385 dev_dbg(dev, "probe\n");
387 status = of_clk_set_defaults(dev->of_node, false);
389 goto err_clear_wakeup_irq;
391 status = dev_pm_domain_attach(&client->dev, true);
393 goto err_clear_wakeup_irq;
396 * When there are no more users of probe(),
397 * rename probe_new to probe.
399 if (driver->probe_new)
400 status = driver->probe_new(client);
401 else if (driver->probe)
402 status = driver->probe(client,
403 i2c_match_id(driver->id_table, client));
408 goto err_detach_pm_domain;
412 err_detach_pm_domain:
413 dev_pm_domain_detach(&client->dev, true);
414 err_clear_wakeup_irq:
415 dev_pm_clear_wake_irq(&client->dev);
416 device_init_wakeup(&client->dev, false);
418 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
419 pm_runtime_put_sync(&client->adapter->dev);
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);
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);
463 static void i2c_client_dev_release(struct device *dev)
465 kfree(to_i2c_client(dev));
469 name_show(struct device *dev, struct device_attribute *attr, char *buf)
471 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
472 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
474 static DEVICE_ATTR_RO(name);
477 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
479 struct i2c_client *client = to_i2c_client(dev);
482 len = of_device_modalias(dev, buf, PAGE_SIZE);
486 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
490 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
492 static DEVICE_ATTR_RO(modalias);
494 static struct attribute *i2c_dev_attrs[] = {
496 /* modalias helps coldplug: modprobe $(cat .../modalias) */
497 &dev_attr_modalias.attr,
500 ATTRIBUTE_GROUPS(i2c_dev);
502 struct bus_type i2c_bus_type = {
504 .match = i2c_device_match,
505 .probe = i2c_device_probe,
506 .remove = i2c_device_remove,
507 .shutdown = i2c_device_shutdown,
509 EXPORT_SYMBOL_GPL(i2c_bus_type);
511 struct device_type i2c_client_type = {
512 .groups = i2c_dev_groups,
513 .uevent = i2c_device_uevent,
514 .release = i2c_client_dev_release,
516 EXPORT_SYMBOL_GPL(i2c_client_type);
520 * i2c_verify_client - return parameter as i2c_client, or NULL
521 * @dev: device, probably from some driver model iterator
523 * When traversing the driver model tree, perhaps using driver model
524 * iterators like @device_for_each_child(), you can't assume very much
525 * about the nodes you find. Use this function to avoid oopses caused
526 * by wrongly treating some non-I2C device as an i2c_client.
528 struct i2c_client *i2c_verify_client(struct device *dev)
530 return (dev->type == &i2c_client_type)
534 EXPORT_SYMBOL(i2c_verify_client);
537 /* Return a unique address which takes the flags of the client into account */
538 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
540 unsigned short addr = client->addr;
542 /* For some client flags, add an arbitrary offset to avoid collisions */
543 if (client->flags & I2C_CLIENT_TEN)
544 addr |= I2C_ADDR_OFFSET_TEN_BIT;
546 if (client->flags & I2C_CLIENT_SLAVE)
547 addr |= I2C_ADDR_OFFSET_SLAVE;
552 /* This is a permissive address validity check, I2C address map constraints
553 * are purposely not enforced, except for the general call address. */
554 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
556 if (flags & I2C_CLIENT_TEN) {
557 /* 10-bit address, all values are valid */
561 /* 7-bit address, reject the general call address */
562 if (addr == 0x00 || addr > 0x7f)
568 /* And this is a strict address validity check, used when probing. If a
569 * device uses a reserved address, then it shouldn't be probed. 7-bit
570 * addressing is assumed, 10-bit address devices are rare and should be
571 * explicitly enumerated. */
572 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
575 * Reserved addresses per I2C specification:
576 * 0x00 General call address / START byte
578 * 0x02 Reserved for different bus format
579 * 0x03 Reserved for future purposes
580 * 0x04-0x07 Hs-mode master code
581 * 0x78-0x7b 10-bit slave addressing
582 * 0x7c-0x7f Reserved for future purposes
584 if (addr < 0x08 || addr > 0x77)
589 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
591 struct i2c_client *client = i2c_verify_client(dev);
592 int addr = *(int *)addrp;
594 if (client && i2c_encode_flags_to_addr(client) == addr)
599 /* walk up mux tree */
600 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
602 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
605 result = device_for_each_child(&adapter->dev, &addr,
606 __i2c_check_addr_busy);
608 if (!result && parent)
609 result = i2c_check_mux_parents(parent, addr);
614 /* recurse down mux tree */
615 static int i2c_check_mux_children(struct device *dev, void *addrp)
619 if (dev->type == &i2c_adapter_type)
620 result = device_for_each_child(dev, addrp,
621 i2c_check_mux_children);
623 result = __i2c_check_addr_busy(dev, addrp);
628 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
630 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
634 result = i2c_check_mux_parents(parent, addr);
637 result = device_for_each_child(&adapter->dev, &addr,
638 i2c_check_mux_children);
644 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
645 * @adapter: Target I2C bus segment
646 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
647 * locks only this branch in the adapter tree
649 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
652 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
656 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
657 * @adapter: Target I2C bus segment
658 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
659 * trylocks only this branch in the adapter tree
661 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
664 return rt_mutex_trylock(&adapter->bus_lock);
668 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
669 * @adapter: Target I2C bus segment
670 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
671 * unlocks only this branch in the adapter tree
673 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
676 rt_mutex_unlock(&adapter->bus_lock);
679 static void i2c_dev_set_name(struct i2c_adapter *adap,
680 struct i2c_client *client,
681 struct i2c_board_info const *info)
683 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
685 if (info && info->dev_name) {
686 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
691 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
695 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
696 i2c_encode_flags_to_addr(client));
699 int i2c_dev_irq_from_resources(const struct resource *resources,
700 unsigned int num_resources)
702 struct irq_data *irqd;
705 for (i = 0; i < num_resources; i++) {
706 const struct resource *r = &resources[i];
708 if (resource_type(r) != IORESOURCE_IRQ)
711 if (r->flags & IORESOURCE_BITS) {
712 irqd = irq_get_irq_data(r->start);
716 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
726 * i2c_new_client_device - instantiate an i2c device
727 * @adap: the adapter managing the device
728 * @info: describes one I2C device; bus_num is ignored
731 * Create an i2c device. Binding is handled through driver model
732 * probe()/remove() methods. A driver may be bound to this device when we
733 * return from this function, or any later moment (e.g. maybe hotplugging will
734 * load the driver module). This call is not appropriate for use by mainboard
735 * initialization logic, which usually runs during an arch_initcall() long
736 * before any i2c_adapter could exist.
738 * This returns the new i2c client, which may be saved for later use with
739 * i2c_unregister_device(); or an ERR_PTR to describe the error.
742 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
744 struct i2c_client *client;
747 client = kzalloc(sizeof *client, GFP_KERNEL);
749 return ERR_PTR(-ENOMEM);
751 client->adapter = adap;
753 client->dev.platform_data = info->platform_data;
754 client->flags = info->flags;
755 client->addr = info->addr;
757 client->init_irq = info->irq;
758 if (!client->init_irq)
759 client->init_irq = i2c_dev_irq_from_resources(info->resources,
760 info->num_resources);
762 strlcpy(client->name, info->type, sizeof(client->name));
764 status = i2c_check_addr_validity(client->addr, client->flags);
766 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
767 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
771 /* Check for address business */
772 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
776 client->dev.parent = &client->adapter->dev;
777 client->dev.bus = &i2c_bus_type;
778 client->dev.type = &i2c_client_type;
779 client->dev.of_node = of_node_get(info->of_node);
780 client->dev.fwnode = info->fwnode;
782 i2c_dev_set_name(adap, client, info);
784 if (info->properties) {
785 status = device_add_properties(&client->dev, info->properties);
788 "Failed to add properties to client %s: %d\n",
789 client->name, status);
790 goto out_err_put_of_node;
794 status = device_register(&client->dev);
798 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
799 client->name, dev_name(&client->dev));
804 if (info->properties)
805 device_remove_properties(&client->dev);
807 of_node_put(info->of_node);
810 "Failed to register i2c client %s at 0x%02x (%d)\n",
811 client->name, client->addr, status);
814 return ERR_PTR(status);
816 EXPORT_SYMBOL_GPL(i2c_new_client_device);
819 * i2c_unregister_device - reverse effect of i2c_new_*_device()
820 * @client: value returned from i2c_new_*_device()
823 void i2c_unregister_device(struct i2c_client *client)
825 if (IS_ERR_OR_NULL(client))
828 if (client->dev.of_node) {
829 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
830 of_node_put(client->dev.of_node);
833 if (ACPI_COMPANION(&client->dev))
834 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
835 device_unregister(&client->dev);
837 EXPORT_SYMBOL_GPL(i2c_unregister_device);
840 static const struct i2c_device_id dummy_id[] = {
845 static int dummy_probe(struct i2c_client *client,
846 const struct i2c_device_id *id)
851 static int dummy_remove(struct i2c_client *client)
856 static struct i2c_driver dummy_driver = {
857 .driver.name = "dummy",
858 .probe = dummy_probe,
859 .remove = dummy_remove,
860 .id_table = dummy_id,
864 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
865 * @adapter: the adapter managing the device
866 * @address: seven bit address to be used
869 * This returns an I2C client bound to the "dummy" driver, intended for use
870 * with devices that consume multiple addresses. Examples of such chips
871 * include various EEPROMS (like 24c04 and 24c08 models).
873 * These dummy devices have two main uses. First, most I2C and SMBus calls
874 * except i2c_transfer() need a client handle; the dummy will be that handle.
875 * And second, this prevents the specified address from being bound to a
878 * This returns the new i2c client, which should be saved for later use with
879 * i2c_unregister_device(); or an ERR_PTR to describe the error.
881 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
883 struct i2c_board_info info = {
884 I2C_BOARD_INFO("dummy", address),
887 return i2c_new_client_device(adapter, &info);
889 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
891 struct i2c_dummy_devres {
892 struct i2c_client *client;
895 static void devm_i2c_release_dummy(struct device *dev, void *res)
897 struct i2c_dummy_devres *this = res;
899 i2c_unregister_device(this->client);
903 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
904 * @dev: device the managed resource is bound to
905 * @adapter: the adapter managing the device
906 * @address: seven bit address to be used
909 * This is the device-managed version of @i2c_new_dummy_device. It returns the
910 * new i2c client or an ERR_PTR in case of an error.
912 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
913 struct i2c_adapter *adapter,
916 struct i2c_dummy_devres *dr;
917 struct i2c_client *client;
919 dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
921 return ERR_PTR(-ENOMEM);
923 client = i2c_new_dummy_device(adapter, address);
924 if (IS_ERR(client)) {
933 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
936 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
937 * and create the associated device
938 * @client: Handle to the primary client
939 * @name: Handle to specify which secondary address to get
940 * @default_addr: Used as a fallback if no secondary address was specified
943 * I2C clients can be composed of multiple I2C slaves bound together in a single
944 * component. The I2C client driver then binds to the master I2C slave and needs
945 * to create I2C dummy clients to communicate with all the other slaves.
947 * This function creates and returns an I2C dummy client whose I2C address is
948 * retrieved from the platform firmware based on the given slave name. If no
949 * address is specified by the firmware default_addr is used.
951 * On DT-based platforms the address is retrieved from the "reg" property entry
952 * cell whose "reg-names" value matches the slave name.
954 * This returns the new i2c client, which should be saved for later use with
955 * i2c_unregister_device(); or an ERR_PTR to describe the error.
957 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
961 struct device_node *np = client->dev.of_node;
962 u32 addr = default_addr;
966 i = of_property_match_string(np, "reg-names", name);
968 of_property_read_u32_index(np, "reg", i, &addr);
971 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
972 return i2c_new_dummy_device(client->adapter, addr);
974 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
976 /* ------------------------------------------------------------------------- */
978 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
980 static void i2c_adapter_dev_release(struct device *dev)
982 struct i2c_adapter *adap = to_i2c_adapter(dev);
983 complete(&adap->dev_released);
986 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
988 unsigned int depth = 0;
990 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
993 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
994 "adapter depth exceeds lockdep subclass limit\n");
998 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1001 * Let users instantiate I2C devices through sysfs. This can be used when
1002 * platform initialization code doesn't contain the proper data for
1003 * whatever reason. Also useful for drivers that do device detection and
1004 * detection fails, either because the device uses an unexpected address,
1005 * or this is a compatible device with different ID register values.
1007 * Parameter checking may look overzealous, but we really don't want
1008 * the user to provide incorrect parameters.
1011 new_device_store(struct device *dev, struct device_attribute *attr,
1012 const char *buf, size_t count)
1014 struct i2c_adapter *adap = to_i2c_adapter(dev);
1015 struct i2c_board_info info;
1016 struct i2c_client *client;
1020 memset(&info, 0, sizeof(struct i2c_board_info));
1022 blank = strchr(buf, ' ');
1024 dev_err(dev, "%s: Missing parameters\n", "new_device");
1027 if (blank - buf > I2C_NAME_SIZE - 1) {
1028 dev_err(dev, "%s: Invalid device name\n", "new_device");
1031 memcpy(info.type, buf, blank - buf);
1033 /* Parse remaining parameters, reject extra parameters */
1034 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1036 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1039 if (res > 1 && end != '\n') {
1040 dev_err(dev, "%s: Extra parameters\n", "new_device");
1044 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1045 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1046 info.flags |= I2C_CLIENT_TEN;
1049 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1050 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1051 info.flags |= I2C_CLIENT_SLAVE;
1054 client = i2c_new_client_device(adap, &info);
1056 return PTR_ERR(client);
1058 /* Keep track of the added device */
1059 mutex_lock(&adap->userspace_clients_lock);
1060 list_add_tail(&client->detected, &adap->userspace_clients);
1061 mutex_unlock(&adap->userspace_clients_lock);
1062 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1063 info.type, info.addr);
1067 static DEVICE_ATTR_WO(new_device);
1070 * And of course let the users delete the devices they instantiated, if
1071 * they got it wrong. This interface can only be used to delete devices
1072 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1073 * don't delete devices to which some kernel code still has references.
1075 * Parameter checking may look overzealous, but we really don't want
1076 * the user to delete the wrong device.
1079 delete_device_store(struct device *dev, struct device_attribute *attr,
1080 const char *buf, size_t count)
1082 struct i2c_adapter *adap = to_i2c_adapter(dev);
1083 struct i2c_client *client, *next;
1084 unsigned short addr;
1088 /* Parse parameters, reject extra parameters */
1089 res = sscanf(buf, "%hi%c", &addr, &end);
1091 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1094 if (res > 1 && end != '\n') {
1095 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1099 /* Make sure the device was added through sysfs */
1101 mutex_lock_nested(&adap->userspace_clients_lock,
1102 i2c_adapter_depth(adap));
1103 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1105 if (i2c_encode_flags_to_addr(client) == addr) {
1106 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1107 "delete_device", client->name, client->addr);
1109 list_del(&client->detected);
1110 i2c_unregister_device(client);
1115 mutex_unlock(&adap->userspace_clients_lock);
1118 dev_err(dev, "%s: Can't find device in list\n",
1122 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1123 delete_device_store);
1125 static struct attribute *i2c_adapter_attrs[] = {
1126 &dev_attr_name.attr,
1127 &dev_attr_new_device.attr,
1128 &dev_attr_delete_device.attr,
1131 ATTRIBUTE_GROUPS(i2c_adapter);
1133 struct device_type i2c_adapter_type = {
1134 .groups = i2c_adapter_groups,
1135 .release = i2c_adapter_dev_release,
1137 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1140 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1141 * @dev: device, probably from some driver model iterator
1143 * When traversing the driver model tree, perhaps using driver model
1144 * iterators like @device_for_each_child(), you can't assume very much
1145 * about the nodes you find. Use this function to avoid oopses caused
1146 * by wrongly treating some non-I2C device as an i2c_adapter.
1148 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1150 return (dev->type == &i2c_adapter_type)
1151 ? to_i2c_adapter(dev)
1154 EXPORT_SYMBOL(i2c_verify_adapter);
1156 #ifdef CONFIG_I2C_COMPAT
1157 static struct class_compat *i2c_adapter_compat_class;
1160 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1162 struct i2c_devinfo *devinfo;
1164 down_read(&__i2c_board_lock);
1165 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1166 if (devinfo->busnum == adapter->nr &&
1167 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1168 dev_err(&adapter->dev,
1169 "Can't create device at 0x%02x\n",
1170 devinfo->board_info.addr);
1172 up_read(&__i2c_board_lock);
1175 static int i2c_do_add_adapter(struct i2c_driver *driver,
1176 struct i2c_adapter *adap)
1178 /* Detect supported devices on that bus, and instantiate them */
1179 i2c_detect(adap, driver);
1184 static int __process_new_adapter(struct device_driver *d, void *data)
1186 return i2c_do_add_adapter(to_i2c_driver(d), data);
1189 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1190 .lock_bus = i2c_adapter_lock_bus,
1191 .trylock_bus = i2c_adapter_trylock_bus,
1192 .unlock_bus = i2c_adapter_unlock_bus,
1195 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1197 struct irq_domain *domain = adap->host_notify_domain;
1198 irq_hw_number_t hwirq;
1203 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1204 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1206 irq_domain_remove(domain);
1207 adap->host_notify_domain = NULL;
1210 static int i2c_host_notify_irq_map(struct irq_domain *h,
1212 irq_hw_number_t hw_irq_num)
1214 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1219 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1220 .map = i2c_host_notify_irq_map,
1223 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1225 struct irq_domain *domain;
1227 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1230 domain = irq_domain_create_linear(adap->dev.fwnode,
1231 I2C_ADDR_7BITS_COUNT,
1232 &i2c_host_notify_irq_ops, adap);
1236 adap->host_notify_domain = domain;
1242 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1244 * @adap: the adapter
1245 * @addr: the I2C address of the notifying device
1246 * Context: can't sleep
1248 * Helper function to be called from an I2C bus driver's interrupt
1249 * handler. It will schedule the Host Notify IRQ.
1251 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1258 irq = irq_find_mapping(adap->host_notify_domain, addr);
1262 generic_handle_irq(irq);
1266 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1268 static int i2c_register_adapter(struct i2c_adapter *adap)
1272 /* Can't register until after driver model init */
1273 if (WARN_ON(!is_registered)) {
1279 if (WARN(!adap->name[0], "i2c adapter has no name"))
1283 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1287 if (!adap->lock_ops)
1288 adap->lock_ops = &i2c_adapter_lock_ops;
1290 adap->locked_flags = 0;
1291 rt_mutex_init(&adap->bus_lock);
1292 rt_mutex_init(&adap->mux_lock);
1293 mutex_init(&adap->userspace_clients_lock);
1294 INIT_LIST_HEAD(&adap->userspace_clients);
1296 /* Set default timeout to 1 second if not already set */
1297 if (adap->timeout == 0)
1300 /* register soft irqs for Host Notify */
1301 res = i2c_setup_host_notify_irq_domain(adap);
1303 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1308 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1309 adap->dev.bus = &i2c_bus_type;
1310 adap->dev.type = &i2c_adapter_type;
1311 res = device_register(&adap->dev);
1313 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1317 res = of_i2c_setup_smbus_alert(adap);
1321 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1323 pm_runtime_no_callbacks(&adap->dev);
1324 pm_suspend_ignore_children(&adap->dev, true);
1325 pm_runtime_enable(&adap->dev);
1327 #ifdef CONFIG_I2C_COMPAT
1328 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1331 dev_warn(&adap->dev,
1332 "Failed to create compatibility class link\n");
1335 i2c_init_recovery(adap);
1337 /* create pre-declared device nodes */
1338 of_i2c_register_devices(adap);
1339 i2c_acpi_register_devices(adap);
1340 i2c_acpi_install_space_handler(adap);
1342 if (adap->nr < __i2c_first_dynamic_bus_num)
1343 i2c_scan_static_board_info(adap);
1345 /* Notify drivers */
1346 mutex_lock(&core_lock);
1347 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1348 mutex_unlock(&core_lock);
1353 init_completion(&adap->dev_released);
1354 device_unregister(&adap->dev);
1355 wait_for_completion(&adap->dev_released);
1357 mutex_lock(&core_lock);
1358 idr_remove(&i2c_adapter_idr, adap->nr);
1359 mutex_unlock(&core_lock);
1364 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1365 * @adap: the adapter to register (with adap->nr initialized)
1366 * Context: can sleep
1368 * See i2c_add_numbered_adapter() for details.
1370 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1374 mutex_lock(&core_lock);
1375 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1376 mutex_unlock(&core_lock);
1377 if (WARN(id < 0, "couldn't get idr"))
1378 return id == -ENOSPC ? -EBUSY : id;
1380 return i2c_register_adapter(adap);
1384 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1385 * @adapter: the adapter to add
1386 * Context: can sleep
1388 * This routine is used to declare an I2C adapter when its bus number
1389 * doesn't matter or when its bus number is specified by an dt alias.
1390 * Examples of bases when the bus number doesn't matter: I2C adapters
1391 * dynamically added by USB links or PCI plugin cards.
1393 * When this returns zero, a new bus number was allocated and stored
1394 * in adap->nr, and the specified adapter became available for clients.
1395 * Otherwise, a negative errno value is returned.
1397 int i2c_add_adapter(struct i2c_adapter *adapter)
1399 struct device *dev = &adapter->dev;
1403 id = of_alias_get_id(dev->of_node, "i2c");
1406 return __i2c_add_numbered_adapter(adapter);
1410 mutex_lock(&core_lock);
1411 id = idr_alloc(&i2c_adapter_idr, adapter,
1412 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1413 mutex_unlock(&core_lock);
1414 if (WARN(id < 0, "couldn't get idr"))
1419 return i2c_register_adapter(adapter);
1421 EXPORT_SYMBOL(i2c_add_adapter);
1424 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1425 * @adap: the adapter to register (with adap->nr initialized)
1426 * Context: can sleep
1428 * This routine is used to declare an I2C adapter when its bus number
1429 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1430 * or otherwise built in to the system's mainboard, and where i2c_board_info
1431 * is used to properly configure I2C devices.
1433 * If the requested bus number is set to -1, then this function will behave
1434 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1436 * If no devices have pre-been declared for this bus, then be sure to
1437 * register the adapter before any dynamically allocated ones. Otherwise
1438 * the required bus ID may not be available.
1440 * When this returns zero, the specified adapter became available for
1441 * clients using the bus number provided in adap->nr. Also, the table
1442 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1443 * and the appropriate driver model device nodes are created. Otherwise, a
1444 * negative errno value is returned.
1446 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1448 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1449 return i2c_add_adapter(adap);
1451 return __i2c_add_numbered_adapter(adap);
1453 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1455 static void i2c_do_del_adapter(struct i2c_driver *driver,
1456 struct i2c_adapter *adapter)
1458 struct i2c_client *client, *_n;
1460 /* Remove the devices we created ourselves as the result of hardware
1461 * probing (using a driver's detect method) */
1462 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1463 if (client->adapter == adapter) {
1464 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1465 client->name, client->addr);
1466 list_del(&client->detected);
1467 i2c_unregister_device(client);
1472 static int __unregister_client(struct device *dev, void *dummy)
1474 struct i2c_client *client = i2c_verify_client(dev);
1475 if (client && strcmp(client->name, "dummy"))
1476 i2c_unregister_device(client);
1480 static int __unregister_dummy(struct device *dev, void *dummy)
1482 struct i2c_client *client = i2c_verify_client(dev);
1483 i2c_unregister_device(client);
1487 static int __process_removed_adapter(struct device_driver *d, void *data)
1489 i2c_do_del_adapter(to_i2c_driver(d), data);
1494 * i2c_del_adapter - unregister I2C adapter
1495 * @adap: the adapter being unregistered
1496 * Context: can sleep
1498 * This unregisters an I2C adapter which was previously registered
1499 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1501 void i2c_del_adapter(struct i2c_adapter *adap)
1503 struct i2c_adapter *found;
1504 struct i2c_client *client, *next;
1506 /* First make sure that this adapter was ever added */
1507 mutex_lock(&core_lock);
1508 found = idr_find(&i2c_adapter_idr, adap->nr);
1509 mutex_unlock(&core_lock);
1510 if (found != adap) {
1511 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1515 i2c_acpi_remove_space_handler(adap);
1516 /* Tell drivers about this removal */
1517 mutex_lock(&core_lock);
1518 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1519 __process_removed_adapter);
1520 mutex_unlock(&core_lock);
1522 /* Remove devices instantiated from sysfs */
1523 mutex_lock_nested(&adap->userspace_clients_lock,
1524 i2c_adapter_depth(adap));
1525 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1527 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1529 list_del(&client->detected);
1530 i2c_unregister_device(client);
1532 mutex_unlock(&adap->userspace_clients_lock);
1534 /* Detach any active clients. This can't fail, thus we do not
1535 * check the returned value. This is a two-pass process, because
1536 * we can't remove the dummy devices during the first pass: they
1537 * could have been instantiated by real devices wishing to clean
1538 * them up properly, so we give them a chance to do that first. */
1539 device_for_each_child(&adap->dev, NULL, __unregister_client);
1540 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1542 #ifdef CONFIG_I2C_COMPAT
1543 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1547 /* device name is gone after device_unregister */
1548 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1550 pm_runtime_disable(&adap->dev);
1552 i2c_host_notify_irq_teardown(adap);
1554 /* wait until all references to the device are gone
1556 * FIXME: This is old code and should ideally be replaced by an
1557 * alternative which results in decoupling the lifetime of the struct
1558 * device from the i2c_adapter, like spi or netdev do. Any solution
1559 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1561 init_completion(&adap->dev_released);
1562 device_unregister(&adap->dev);
1563 wait_for_completion(&adap->dev_released);
1566 mutex_lock(&core_lock);
1567 idr_remove(&i2c_adapter_idr, adap->nr);
1568 mutex_unlock(&core_lock);
1570 /* Clear the device structure in case this adapter is ever going to be
1572 memset(&adap->dev, 0, sizeof(adap->dev));
1574 EXPORT_SYMBOL(i2c_del_adapter);
1576 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1577 u32 def_val, bool use_def)
1581 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1583 *cur_val_p = def_val;
1585 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1589 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1590 * @dev: The device to scan for I2C timing properties
1591 * @t: the i2c_timings struct to be filled with values
1592 * @use_defaults: bool to use sane defaults derived from the I2C specification
1593 * when properties are not found, otherwise don't update
1595 * Scan the device for the generic I2C properties describing timing parameters
1596 * for the signal and fill the given struct with the results. If a property was
1597 * not found and use_defaults was true, then maximum timings are assumed which
1598 * are derived from the I2C specification. If use_defaults is not used, the
1599 * results will be as before, so drivers can apply their own defaults before
1600 * calling this helper. The latter is mainly intended for avoiding regressions
1601 * of existing drivers which want to switch to this function. New drivers
1602 * almost always should use the defaults.
1604 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1606 bool u = use_defaults;
1609 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1610 I2C_MAX_STANDARD_MODE_FREQ, u);
1612 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1613 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1614 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1616 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1617 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1619 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1620 &t->scl_int_delay_ns, 0, u);
1621 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1623 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1624 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1625 &t->digital_filter_width_ns, 0, u);
1626 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1627 &t->analog_filter_cutoff_freq_hz, 0, u);
1629 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1631 /* ------------------------------------------------------------------------- */
1633 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1637 mutex_lock(&core_lock);
1638 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1639 mutex_unlock(&core_lock);
1643 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1645 static int __process_new_driver(struct device *dev, void *data)
1647 if (dev->type != &i2c_adapter_type)
1649 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1653 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1654 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1657 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1661 /* Can't register until after driver model init */
1662 if (WARN_ON(!is_registered))
1665 /* add the driver to the list of i2c drivers in the driver core */
1666 driver->driver.owner = owner;
1667 driver->driver.bus = &i2c_bus_type;
1668 INIT_LIST_HEAD(&driver->clients);
1670 /* When registration returns, the driver core
1671 * will have called probe() for all matching-but-unbound devices.
1673 res = driver_register(&driver->driver);
1677 pr_debug("driver [%s] registered\n", driver->driver.name);
1679 /* Walk the adapters that are already present */
1680 i2c_for_each_dev(driver, __process_new_driver);
1684 EXPORT_SYMBOL(i2c_register_driver);
1686 static int __process_removed_driver(struct device *dev, void *data)
1688 if (dev->type == &i2c_adapter_type)
1689 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1694 * i2c_del_driver - unregister I2C driver
1695 * @driver: the driver being unregistered
1696 * Context: can sleep
1698 void i2c_del_driver(struct i2c_driver *driver)
1700 i2c_for_each_dev(driver, __process_removed_driver);
1702 driver_unregister(&driver->driver);
1703 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1705 EXPORT_SYMBOL(i2c_del_driver);
1707 /* ------------------------------------------------------------------------- */
1709 struct i2c_cmd_arg {
1714 static int i2c_cmd(struct device *dev, void *_arg)
1716 struct i2c_client *client = i2c_verify_client(dev);
1717 struct i2c_cmd_arg *arg = _arg;
1718 struct i2c_driver *driver;
1720 if (!client || !client->dev.driver)
1723 driver = to_i2c_driver(client->dev.driver);
1724 if (driver->command)
1725 driver->command(client, arg->cmd, arg->arg);
1729 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1731 struct i2c_cmd_arg cmd_arg;
1735 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1737 EXPORT_SYMBOL(i2c_clients_command);
1739 static int __init i2c_init(void)
1743 retval = of_alias_get_highest_id("i2c");
1745 down_write(&__i2c_board_lock);
1746 if (retval >= __i2c_first_dynamic_bus_num)
1747 __i2c_first_dynamic_bus_num = retval + 1;
1748 up_write(&__i2c_board_lock);
1750 retval = bus_register(&i2c_bus_type);
1754 is_registered = true;
1756 #ifdef CONFIG_I2C_COMPAT
1757 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1758 if (!i2c_adapter_compat_class) {
1763 retval = i2c_add_driver(&dummy_driver);
1767 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1768 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1769 if (IS_ENABLED(CONFIG_ACPI))
1770 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1775 #ifdef CONFIG_I2C_COMPAT
1776 class_compat_unregister(i2c_adapter_compat_class);
1779 is_registered = false;
1780 bus_unregister(&i2c_bus_type);
1784 static void __exit i2c_exit(void)
1786 if (IS_ENABLED(CONFIG_ACPI))
1787 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1788 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1789 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1790 i2c_del_driver(&dummy_driver);
1791 #ifdef CONFIG_I2C_COMPAT
1792 class_compat_unregister(i2c_adapter_compat_class);
1794 bus_unregister(&i2c_bus_type);
1795 tracepoint_synchronize_unregister();
1798 /* We must initialize early, because some subsystems register i2c drivers
1799 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1801 postcore_initcall(i2c_init);
1802 module_exit(i2c_exit);
1804 /* ----------------------------------------------------
1805 * the functional interface to the i2c busses.
1806 * ----------------------------------------------------
1809 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1810 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1812 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1814 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1815 err_msg, msg->addr, msg->len,
1816 msg->flags & I2C_M_RD ? "read" : "write");
1820 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1822 const struct i2c_adapter_quirks *q = adap->quirks;
1823 int max_num = q->max_num_msgs, i;
1824 bool do_len_check = true;
1826 if (q->flags & I2C_AQ_COMB) {
1829 /* special checks for combined messages */
1831 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1832 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1834 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1835 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1837 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1838 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1840 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1841 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1843 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1844 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1846 do_len_check = false;
1850 if (i2c_quirk_exceeded(num, max_num))
1851 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1853 for (i = 0; i < num; i++) {
1854 u16 len = msgs[i].len;
1856 if (msgs[i].flags & I2C_M_RD) {
1857 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1858 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1860 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1861 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1863 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1864 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1866 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1867 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1875 * __i2c_transfer - unlocked flavor of i2c_transfer
1876 * @adap: Handle to I2C bus
1877 * @msgs: One or more messages to execute before STOP is issued to
1878 * terminate the operation; each message begins with a START.
1879 * @num: Number of messages to be executed.
1881 * Returns negative errno, else the number of messages executed.
1883 * Adapter lock must be held when calling this function. No debug logging
1884 * takes place. adap->algo->master_xfer existence isn't checked.
1886 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1888 unsigned long orig_jiffies;
1891 if (WARN_ON(!msgs || num < 1))
1894 ret = __i2c_check_suspended(adap);
1898 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1902 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1903 * enabled. This is an efficient way of keeping the for-loop from
1904 * being executed when not needed.
1906 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1908 for (i = 0; i < num; i++)
1909 if (msgs[i].flags & I2C_M_RD)
1910 trace_i2c_read(adap, &msgs[i], i);
1912 trace_i2c_write(adap, &msgs[i], i);
1915 /* Retry automatically on arbitration loss */
1916 orig_jiffies = jiffies;
1917 for (ret = 0, try = 0; try <= adap->retries; try++) {
1918 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
1919 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
1921 ret = adap->algo->master_xfer(adap, msgs, num);
1925 if (time_after(jiffies, orig_jiffies + adap->timeout))
1929 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1931 for (i = 0; i < ret; i++)
1932 if (msgs[i].flags & I2C_M_RD)
1933 trace_i2c_reply(adap, &msgs[i], i);
1934 trace_i2c_result(adap, num, ret);
1939 EXPORT_SYMBOL(__i2c_transfer);
1942 * i2c_transfer - execute a single or combined I2C message
1943 * @adap: Handle to I2C bus
1944 * @msgs: One or more messages to execute before STOP is issued to
1945 * terminate the operation; each message begins with a START.
1946 * @num: Number of messages to be executed.
1948 * Returns negative errno, else the number of messages executed.
1950 * Note that there is no requirement that each message be sent to
1951 * the same slave address, although that is the most common model.
1953 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1957 if (!adap->algo->master_xfer) {
1958 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1962 /* REVISIT the fault reporting model here is weak:
1964 * - When we get an error after receiving N bytes from a slave,
1965 * there is no way to report "N".
1967 * - When we get a NAK after transmitting N bytes to a slave,
1968 * there is no way to report "N" ... or to let the master
1969 * continue executing the rest of this combined message, if
1970 * that's the appropriate response.
1972 * - When for example "num" is two and we successfully complete
1973 * the first message but get an error part way through the
1974 * second, it's unclear whether that should be reported as
1975 * one (discarding status on the second message) or errno
1976 * (discarding status on the first one).
1978 ret = __i2c_lock_bus_helper(adap);
1982 ret = __i2c_transfer(adap, msgs, num);
1983 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1987 EXPORT_SYMBOL(i2c_transfer);
1990 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1992 * @client: Handle to slave device
1993 * @buf: Where the data is stored
1994 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1995 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1997 * Returns negative errno, or else the number of bytes transferred.
1999 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2000 int count, u16 flags)
2003 struct i2c_msg msg = {
2004 .addr = client->addr,
2005 .flags = flags | (client->flags & I2C_M_TEN),
2010 ret = i2c_transfer(client->adapter, &msg, 1);
2013 * If everything went ok (i.e. 1 msg transferred), return #bytes
2014 * transferred, else error code.
2016 return (ret == 1) ? count : ret;
2018 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2021 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2022 * @client: The device to query
2023 * @id: The queried information
2025 * Returns negative errno on error, zero on success.
2027 int i2c_get_device_id(const struct i2c_client *client,
2028 struct i2c_device_identity *id)
2030 struct i2c_adapter *adap = client->adapter;
2031 union i2c_smbus_data raw_id;
2034 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2037 raw_id.block[0] = 3;
2038 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2039 I2C_SMBUS_READ, client->addr << 1,
2040 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2044 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2045 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2046 id->die_revision = raw_id.block[3] & 0x7;
2049 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2051 /* ----------------------------------------------------
2052 * the i2c address scanning function
2053 * Will not work for 10-bit addresses!
2054 * ----------------------------------------------------
2058 * Legacy default probe function, mostly relevant for SMBus. The default
2059 * probe method is a quick write, but it is known to corrupt the 24RF08
2060 * EEPROMs due to a state machine bug, and could also irreversibly
2061 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2062 * we use a short byte read instead. Also, some bus drivers don't implement
2063 * quick write, so we fallback to a byte read in that case too.
2064 * On x86, there is another special case for FSC hardware monitoring chips,
2065 * which want regular byte reads (address 0x73.) Fortunately, these are the
2066 * only known chips using this I2C address on PC hardware.
2067 * Returns 1 if probe succeeded, 0 if not.
2069 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2072 union i2c_smbus_data dummy;
2075 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2076 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2077 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2078 I2C_SMBUS_BYTE_DATA, &dummy);
2081 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2082 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2083 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2084 I2C_SMBUS_QUICK, NULL);
2085 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2086 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2087 I2C_SMBUS_BYTE, &dummy);
2089 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2097 static int i2c_detect_address(struct i2c_client *temp_client,
2098 struct i2c_driver *driver)
2100 struct i2c_board_info info;
2101 struct i2c_adapter *adapter = temp_client->adapter;
2102 int addr = temp_client->addr;
2105 /* Make sure the address is valid */
2106 err = i2c_check_7bit_addr_validity_strict(addr);
2108 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2113 /* Skip if already in use (7 bit, no need to encode flags) */
2114 if (i2c_check_addr_busy(adapter, addr))
2117 /* Make sure there is something at this address */
2118 if (!i2c_default_probe(adapter, addr))
2121 /* Finally call the custom detection function */
2122 memset(&info, 0, sizeof(struct i2c_board_info));
2124 err = driver->detect(temp_client, &info);
2126 /* -ENODEV is returned if the detection fails. We catch it
2127 here as this isn't an error. */
2128 return err == -ENODEV ? 0 : err;
2131 /* Consistency check */
2132 if (info.type[0] == '\0') {
2133 dev_err(&adapter->dev,
2134 "%s detection function provided no name for 0x%x\n",
2135 driver->driver.name, addr);
2137 struct i2c_client *client;
2139 /* Detection succeeded, instantiate the device */
2140 if (adapter->class & I2C_CLASS_DEPRECATED)
2141 dev_warn(&adapter->dev,
2142 "This adapter will soon drop class based instantiation of devices. "
2143 "Please make sure client 0x%02x gets instantiated by other means. "
2144 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2147 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2148 info.type, info.addr);
2149 client = i2c_new_client_device(adapter, &info);
2150 if (!IS_ERR(client))
2151 list_add_tail(&client->detected, &driver->clients);
2153 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2154 info.type, info.addr);
2159 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2161 const unsigned short *address_list;
2162 struct i2c_client *temp_client;
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.rst' 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 i2c_adapter_id(adapter), 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_scanned_device(struct i2c_adapter *adap,
2211 struct i2c_board_info *info,
2212 unsigned short const *addr_list,
2213 int (*probe)(struct i2c_adapter *adap, 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");
2243 return ERR_PTR(-ENODEV);
2246 info->addr = addr_list[i];
2247 return i2c_new_client_device(adap, info);
2249 EXPORT_SYMBOL_GPL(i2c_new_scanned_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 put_device(&adap->dev);
2277 module_put(adap->owner);
2279 EXPORT_SYMBOL(i2c_put_adapter);
2282 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2283 * @msg: the message to be checked
2284 * @threshold: the minimum number of bytes for which using DMA makes sense.
2285 * Should at least be 1.
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 /* also skip 0-length msgs for bogus thresholds of 0 */
2297 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2299 if (msg->len < threshold || msg->len == 0)
2302 if (msg->flags & I2C_M_DMA_SAFE)
2305 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2306 msg->addr, msg->len);
2308 if (msg->flags & I2C_M_RD)
2309 return kzalloc(msg->len, GFP_KERNEL);
2311 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2313 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2316 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2317 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2318 * @msg: the message which the buffer corresponds to
2319 * @xferred: bool saying if the message was transferred
2321 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2323 if (!buf || buf == msg->buf)
2326 if (xferred && msg->flags & I2C_M_RD)
2327 memcpy(msg->buf, buf, msg->len);
2331 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2333 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2334 MODULE_DESCRIPTION("I2C-Bus main module");
2335 MODULE_LICENSE("GPL");