4 * Copyright (C) 1995-99 Simon G. Vogl
5 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
6 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
7 * Michael Lawnick <michael.lawnick.ext@nsn.com>
9 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
16 * This program is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
21 #define pr_fmt(fmt) "i2c-core: " fmt
23 #include <dt-bindings/i2c/i2c.h>
24 #include <linux/acpi.h>
25 #include <linux/clk/clk-conf.h>
26 #include <linux/completion.h>
27 #include <linux/delay.h>
28 #include <linux/err.h>
29 #include <linux/errno.h>
30 #include <linux/gpio.h>
31 #include <linux/i2c.h>
32 #include <linux/idr.h>
33 #include <linux/init.h>
34 #include <linux/interrupt.h>
35 #include <linux/irqflags.h>
36 #include <linux/jump_label.h>
37 #include <linux/kernel.h>
38 #include <linux/module.h>
39 #include <linux/mutex.h>
40 #include <linux/of_device.h>
42 #include <linux/of_irq.h>
43 #include <linux/pm_domain.h>
44 #include <linux/pm_runtime.h>
45 #include <linux/pm_wakeirq.h>
46 #include <linux/property.h>
47 #include <linux/rwsem.h>
48 #include <linux/slab.h>
52 #define CREATE_TRACE_POINTS
53 #include <trace/events/i2c.h>
55 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
56 #define I2C_ADDR_OFFSET_SLAVE 0x1000
58 #define I2C_ADDR_7BITS_MAX 0x77
59 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
62 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
63 * deletion of detected devices, and attach_adapter calls are serialized
65 static DEFINE_MUTEX(core_lock);
66 static DEFINE_IDR(i2c_adapter_idr);
68 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
70 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
71 static bool is_registered;
73 int i2c_transfer_trace_reg(void)
75 static_key_slow_inc(&i2c_trace_msg);
79 void i2c_transfer_trace_unreg(void)
81 static_key_slow_dec(&i2c_trace_msg);
84 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
85 const struct i2c_client *client)
91 if (strcmp(client->name, id->name) == 0)
97 EXPORT_SYMBOL_GPL(i2c_match_id);
99 static int i2c_device_match(struct device *dev, struct device_driver *drv)
101 struct i2c_client *client = i2c_verify_client(dev);
102 struct i2c_driver *driver;
105 /* Attempt an OF style match */
106 if (i2c_of_match_device(drv->of_match_table, client))
109 /* Then ACPI style match */
110 if (acpi_driver_match_device(dev, drv))
113 driver = to_i2c_driver(drv);
115 /* Finally an I2C match */
116 if (i2c_match_id(driver->id_table, client))
122 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
124 struct i2c_client *client = to_i2c_client(dev);
127 rc = acpi_device_uevent_modalias(dev, env);
131 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
134 /* i2c bus recovery routines */
135 static int get_scl_gpio_value(struct i2c_adapter *adap)
137 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
140 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
142 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
145 static int get_sda_gpio_value(struct i2c_adapter *adap)
147 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
150 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
152 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
153 struct device *dev = &adap->dev;
156 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
157 GPIOF_OUT_INIT_HIGH, "i2c-scl");
159 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
164 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
165 /* work without SDA polling */
166 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
175 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
177 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
180 gpio_free(bri->sda_gpio);
182 gpio_free(bri->scl_gpio);
186 * We are generating clock pulses. ndelay() determines durating of clk pulses.
187 * We will generate clock with rate 100 KHz and so duration of both clock levels
188 * is: delay in ns = (10^6 / 100) / 2
190 #define RECOVERY_NDELAY 5000
191 #define RECOVERY_CLK_CNT 9
193 static int i2c_generic_recovery(struct i2c_adapter *adap)
195 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
196 int i = 0, val = 1, ret = 0;
198 if (bri->prepare_recovery)
199 bri->prepare_recovery(adap);
201 bri->set_scl(adap, val);
202 ndelay(RECOVERY_NDELAY);
205 * By this time SCL is high, as we need to give 9 falling-rising edges
207 while (i++ < RECOVERY_CLK_CNT * 2) {
209 /* Break if SDA is high */
210 if (bri->get_sda && bri->get_sda(adap))
212 /* SCL shouldn't be low here */
213 if (!bri->get_scl(adap)) {
215 "SCL is stuck low, exit recovery\n");
222 bri->set_scl(adap, val);
223 ndelay(RECOVERY_NDELAY);
226 if (bri->unprepare_recovery)
227 bri->unprepare_recovery(adap);
232 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
234 return i2c_generic_recovery(adap);
236 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
238 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
242 ret = i2c_get_gpios_for_recovery(adap);
246 ret = i2c_generic_recovery(adap);
247 i2c_put_gpios_for_recovery(adap);
251 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
253 int i2c_recover_bus(struct i2c_adapter *adap)
255 if (!adap->bus_recovery_info)
258 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
259 return adap->bus_recovery_info->recover_bus(adap);
261 EXPORT_SYMBOL_GPL(i2c_recover_bus);
263 static void i2c_init_recovery(struct i2c_adapter *adap)
265 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
266 char *err_str, *err_level = KERN_ERR;
271 if (!bri->recover_bus) {
272 err_str = "no suitable method provided";
273 err_level = KERN_DEBUG;
277 /* Generic GPIO recovery */
278 if (bri->recover_bus == i2c_generic_gpio_recovery) {
279 if (!gpio_is_valid(bri->scl_gpio)) {
280 err_str = "invalid SCL gpio";
284 if (gpio_is_valid(bri->sda_gpio))
285 bri->get_sda = get_sda_gpio_value;
289 bri->get_scl = get_scl_gpio_value;
290 bri->set_scl = set_scl_gpio_value;
291 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
292 /* Generic SCL recovery */
293 if (!bri->set_scl || !bri->get_scl) {
294 err_str = "no {get|set}_scl() found";
301 dev_printk(err_level, &adap->dev, "Not using recovery: %s\n", err_str);
302 adap->bus_recovery_info = NULL;
305 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
307 struct i2c_adapter *adap = client->adapter;
310 if (!adap->host_notify_domain)
313 if (client->flags & I2C_CLIENT_TEN)
316 irq = irq_find_mapping(adap->host_notify_domain, client->addr);
318 irq = irq_create_mapping(adap->host_notify_domain,
321 return irq > 0 ? irq : -ENXIO;
324 static int i2c_device_probe(struct device *dev)
326 struct i2c_client *client = i2c_verify_client(dev);
327 struct i2c_driver *driver;
333 driver = to_i2c_driver(dev->driver);
335 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
338 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
339 dev_dbg(dev, "Using Host Notify IRQ\n");
340 irq = i2c_smbus_host_notify_to_irq(client);
341 } else if (dev->of_node) {
342 irq = of_irq_get_byname(dev->of_node, "irq");
343 if (irq == -EINVAL || irq == -ENODATA)
344 irq = of_irq_get(dev->of_node, 0);
345 } else if (ACPI_COMPANION(dev)) {
346 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
348 if (irq == -EPROBE_DEFER)
358 * An I2C ID table is not mandatory, if and only if, a suitable OF
359 * or ACPI ID table is supplied for the probing device.
361 if (!driver->id_table &&
362 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
363 !i2c_of_match_device(dev->driver->of_match_table, client))
366 if (client->flags & I2C_CLIENT_WAKE) {
367 int wakeirq = -ENOENT;
370 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
371 if (wakeirq == -EPROBE_DEFER)
375 device_init_wakeup(&client->dev, true);
377 if (wakeirq > 0 && wakeirq != client->irq)
378 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
379 else if (client->irq > 0)
380 status = dev_pm_set_wake_irq(dev, client->irq);
385 dev_warn(&client->dev, "failed to set up wakeup irq\n");
388 dev_dbg(dev, "probe\n");
390 status = of_clk_set_defaults(dev->of_node, false);
392 goto err_clear_wakeup_irq;
394 status = dev_pm_domain_attach(&client->dev, true);
395 if (status == -EPROBE_DEFER)
396 goto err_clear_wakeup_irq;
399 * When there are no more users of probe(),
400 * rename probe_new to probe.
402 if (driver->probe_new)
403 status = driver->probe_new(client);
404 else if (driver->probe)
405 status = driver->probe(client,
406 i2c_match_id(driver->id_table, client));
411 goto err_detach_pm_domain;
415 err_detach_pm_domain:
416 dev_pm_domain_detach(&client->dev, true);
417 err_clear_wakeup_irq:
418 dev_pm_clear_wake_irq(&client->dev);
419 device_init_wakeup(&client->dev, false);
423 static int i2c_device_remove(struct device *dev)
425 struct i2c_client *client = i2c_verify_client(dev);
426 struct i2c_driver *driver;
429 if (!client || !dev->driver)
432 driver = to_i2c_driver(dev->driver);
433 if (driver->remove) {
434 dev_dbg(dev, "remove\n");
435 status = driver->remove(client);
438 dev_pm_domain_detach(&client->dev, true);
440 dev_pm_clear_wake_irq(&client->dev);
441 device_init_wakeup(&client->dev, false);
446 static void i2c_device_shutdown(struct device *dev)
448 struct i2c_client *client = i2c_verify_client(dev);
449 struct i2c_driver *driver;
451 if (!client || !dev->driver)
453 driver = to_i2c_driver(dev->driver);
454 if (driver->shutdown)
455 driver->shutdown(client);
456 else if (client->irq > 0)
457 disable_irq(client->irq);
460 static void i2c_client_dev_release(struct device *dev)
462 kfree(to_i2c_client(dev));
466 show_name(struct device *dev, struct device_attribute *attr, char *buf)
468 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
469 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
471 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
474 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
476 struct i2c_client *client = to_i2c_client(dev);
479 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
483 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
485 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
487 static struct attribute *i2c_dev_attrs[] = {
489 /* modalias helps coldplug: modprobe $(cat .../modalias) */
490 &dev_attr_modalias.attr,
493 ATTRIBUTE_GROUPS(i2c_dev);
495 struct bus_type i2c_bus_type = {
497 .match = i2c_device_match,
498 .probe = i2c_device_probe,
499 .remove = i2c_device_remove,
500 .shutdown = i2c_device_shutdown,
502 EXPORT_SYMBOL_GPL(i2c_bus_type);
504 struct device_type i2c_client_type = {
505 .groups = i2c_dev_groups,
506 .uevent = i2c_device_uevent,
507 .release = i2c_client_dev_release,
509 EXPORT_SYMBOL_GPL(i2c_client_type);
513 * i2c_verify_client - return parameter as i2c_client, or NULL
514 * @dev: device, probably from some driver model iterator
516 * When traversing the driver model tree, perhaps using driver model
517 * iterators like @device_for_each_child(), you can't assume very much
518 * about the nodes you find. Use this function to avoid oopses caused
519 * by wrongly treating some non-I2C device as an i2c_client.
521 struct i2c_client *i2c_verify_client(struct device *dev)
523 return (dev->type == &i2c_client_type)
527 EXPORT_SYMBOL(i2c_verify_client);
530 /* Return a unique address which takes the flags of the client into account */
531 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
533 unsigned short addr = client->addr;
535 /* For some client flags, add an arbitrary offset to avoid collisions */
536 if (client->flags & I2C_CLIENT_TEN)
537 addr |= I2C_ADDR_OFFSET_TEN_BIT;
539 if (client->flags & I2C_CLIENT_SLAVE)
540 addr |= I2C_ADDR_OFFSET_SLAVE;
545 /* This is a permissive address validity check, I2C address map constraints
546 * are purposely not enforced, except for the general call address. */
547 int i2c_check_addr_validity(unsigned addr, unsigned short flags)
549 if (flags & I2C_CLIENT_TEN) {
550 /* 10-bit address, all values are valid */
554 /* 7-bit address, reject the general call address */
555 if (addr == 0x00 || addr > 0x7f)
561 /* And this is a strict address validity check, used when probing. If a
562 * device uses a reserved address, then it shouldn't be probed. 7-bit
563 * addressing is assumed, 10-bit address devices are rare and should be
564 * explicitly enumerated. */
565 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
568 * Reserved addresses per I2C specification:
569 * 0x00 General call address / START byte
571 * 0x02 Reserved for different bus format
572 * 0x03 Reserved for future purposes
573 * 0x04-0x07 Hs-mode master code
574 * 0x78-0x7b 10-bit slave addressing
575 * 0x7c-0x7f Reserved for future purposes
577 if (addr < 0x08 || addr > 0x77)
582 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
584 struct i2c_client *client = i2c_verify_client(dev);
585 int addr = *(int *)addrp;
587 if (client && i2c_encode_flags_to_addr(client) == addr)
592 /* walk up mux tree */
593 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
595 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
598 result = device_for_each_child(&adapter->dev, &addr,
599 __i2c_check_addr_busy);
601 if (!result && parent)
602 result = i2c_check_mux_parents(parent, addr);
607 /* recurse down mux tree */
608 static int i2c_check_mux_children(struct device *dev, void *addrp)
612 if (dev->type == &i2c_adapter_type)
613 result = device_for_each_child(dev, addrp,
614 i2c_check_mux_children);
616 result = __i2c_check_addr_busy(dev, addrp);
621 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
623 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
627 result = i2c_check_mux_parents(parent, addr);
630 result = device_for_each_child(&adapter->dev, &addr,
631 i2c_check_mux_children);
637 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
638 * @adapter: Target I2C bus segment
639 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
640 * locks only this branch in the adapter tree
642 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
645 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
649 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
650 * @adapter: Target I2C bus segment
651 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
652 * trylocks only this branch in the adapter tree
654 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
657 return rt_mutex_trylock(&adapter->bus_lock);
661 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
662 * @adapter: Target I2C bus segment
663 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
664 * unlocks only this branch in the adapter tree
666 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
669 rt_mutex_unlock(&adapter->bus_lock);
672 static void i2c_dev_set_name(struct i2c_adapter *adap,
673 struct i2c_client *client)
675 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
678 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
682 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
683 i2c_encode_flags_to_addr(client));
686 static int i2c_dev_irq_from_resources(const struct resource *resources,
687 unsigned int num_resources)
689 struct irq_data *irqd;
692 for (i = 0; i < num_resources; i++) {
693 const struct resource *r = &resources[i];
695 if (resource_type(r) != IORESOURCE_IRQ)
698 if (r->flags & IORESOURCE_BITS) {
699 irqd = irq_get_irq_data(r->start);
703 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
713 * i2c_new_device - instantiate an i2c device
714 * @adap: the adapter managing the device
715 * @info: describes one I2C device; bus_num is ignored
718 * Create an i2c device. Binding is handled through driver model
719 * probe()/remove() methods. A driver may be bound to this device when we
720 * return from this function, or any later moment (e.g. maybe hotplugging will
721 * load the driver module). This call is not appropriate for use by mainboard
722 * initialization logic, which usually runs during an arch_initcall() long
723 * before any i2c_adapter could exist.
725 * This returns the new i2c client, which may be saved for later use with
726 * i2c_unregister_device(); or NULL to indicate an error.
729 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
731 struct i2c_client *client;
734 client = kzalloc(sizeof *client, GFP_KERNEL);
738 client->adapter = adap;
740 client->dev.platform_data = info->platform_data;
743 client->dev.archdata = *info->archdata;
745 client->flags = info->flags;
746 client->addr = info->addr;
748 client->irq = info->irq;
750 client->irq = i2c_dev_irq_from_resources(info->resources,
751 info->num_resources);
753 strlcpy(client->name, info->type, sizeof(client->name));
755 status = i2c_check_addr_validity(client->addr, client->flags);
757 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
758 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
762 /* Check for address business */
763 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
767 client->dev.parent = &client->adapter->dev;
768 client->dev.bus = &i2c_bus_type;
769 client->dev.type = &i2c_client_type;
770 client->dev.of_node = info->of_node;
771 client->dev.fwnode = info->fwnode;
773 i2c_dev_set_name(adap, client);
775 if (info->properties) {
776 status = device_add_properties(&client->dev, info->properties);
779 "Failed to add properties to client %s: %d\n",
780 client->name, status);
785 status = device_register(&client->dev);
789 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
790 client->name, dev_name(&client->dev));
795 if (info->properties)
796 device_remove_properties(&client->dev);
799 "Failed to register i2c client %s at 0x%02x (%d)\n",
800 client->name, client->addr, status);
805 EXPORT_SYMBOL_GPL(i2c_new_device);
809 * i2c_unregister_device - reverse effect of i2c_new_device()
810 * @client: value returned from i2c_new_device()
813 void i2c_unregister_device(struct i2c_client *client)
815 if (client->dev.of_node) {
816 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
817 of_node_put(client->dev.of_node);
820 if (ACPI_COMPANION(&client->dev))
821 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
822 device_unregister(&client->dev);
824 EXPORT_SYMBOL_GPL(i2c_unregister_device);
827 static const struct i2c_device_id dummy_id[] = {
832 static int dummy_probe(struct i2c_client *client,
833 const struct i2c_device_id *id)
838 static int dummy_remove(struct i2c_client *client)
843 static struct i2c_driver dummy_driver = {
844 .driver.name = "dummy",
845 .probe = dummy_probe,
846 .remove = dummy_remove,
847 .id_table = dummy_id,
851 * i2c_new_dummy - return a new i2c device bound to a dummy driver
852 * @adapter: the adapter managing the device
853 * @address: seven bit address to be used
856 * This returns an I2C client bound to the "dummy" driver, intended for use
857 * with devices that consume multiple addresses. Examples of such chips
858 * include various EEPROMS (like 24c04 and 24c08 models).
860 * These dummy devices have two main uses. First, most I2C and SMBus calls
861 * except i2c_transfer() need a client handle; the dummy will be that handle.
862 * And second, this prevents the specified address from being bound to a
865 * This returns the new i2c client, which should be saved for later use with
866 * i2c_unregister_device(); or NULL to indicate an error.
868 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
870 struct i2c_board_info info = {
871 I2C_BOARD_INFO("dummy", address),
874 return i2c_new_device(adapter, &info);
876 EXPORT_SYMBOL_GPL(i2c_new_dummy);
879 * i2c_new_secondary_device - Helper to get the instantiated secondary address
880 * and create the associated device
881 * @client: Handle to the primary client
882 * @name: Handle to specify which secondary address to get
883 * @default_addr: Used as a fallback if no secondary address was specified
886 * I2C clients can be composed of multiple I2C slaves bound together in a single
887 * component. The I2C client driver then binds to the master I2C slave and needs
888 * to create I2C dummy clients to communicate with all the other slaves.
890 * This function creates and returns an I2C dummy client whose I2C address is
891 * retrieved from the platform firmware based on the given slave name. If no
892 * address is specified by the firmware default_addr is used.
894 * On DT-based platforms the address is retrieved from the "reg" property entry
895 * cell whose "reg-names" value matches the slave name.
897 * This returns the new i2c client, which should be saved for later use with
898 * i2c_unregister_device(); or NULL to indicate an error.
900 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
904 struct device_node *np = client->dev.of_node;
905 u32 addr = default_addr;
909 i = of_property_match_string(np, "reg-names", name);
911 of_property_read_u32_index(np, "reg", i, &addr);
914 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
915 return i2c_new_dummy(client->adapter, addr);
917 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
919 /* ------------------------------------------------------------------------- */
921 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
923 static void i2c_adapter_dev_release(struct device *dev)
925 struct i2c_adapter *adap = to_i2c_adapter(dev);
926 complete(&adap->dev_released);
929 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
931 unsigned int depth = 0;
933 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
936 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
937 "adapter depth exceeds lockdep subclass limit\n");
941 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
944 * Let users instantiate I2C devices through sysfs. This can be used when
945 * platform initialization code doesn't contain the proper data for
946 * whatever reason. Also useful for drivers that do device detection and
947 * detection fails, either because the device uses an unexpected address,
948 * or this is a compatible device with different ID register values.
950 * Parameter checking may look overzealous, but we really don't want
951 * the user to provide incorrect parameters.
954 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
955 const char *buf, size_t count)
957 struct i2c_adapter *adap = to_i2c_adapter(dev);
958 struct i2c_board_info info;
959 struct i2c_client *client;
963 memset(&info, 0, sizeof(struct i2c_board_info));
965 blank = strchr(buf, ' ');
967 dev_err(dev, "%s: Missing parameters\n", "new_device");
970 if (blank - buf > I2C_NAME_SIZE - 1) {
971 dev_err(dev, "%s: Invalid device name\n", "new_device");
974 memcpy(info.type, buf, blank - buf);
976 /* Parse remaining parameters, reject extra parameters */
977 res = sscanf(++blank, "%hi%c", &info.addr, &end);
979 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
982 if (res > 1 && end != '\n') {
983 dev_err(dev, "%s: Extra parameters\n", "new_device");
987 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
988 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
989 info.flags |= I2C_CLIENT_TEN;
992 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
993 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
994 info.flags |= I2C_CLIENT_SLAVE;
997 client = i2c_new_device(adap, &info);
1001 /* Keep track of the added device */
1002 mutex_lock(&adap->userspace_clients_lock);
1003 list_add_tail(&client->detected, &adap->userspace_clients);
1004 mutex_unlock(&adap->userspace_clients_lock);
1005 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1006 info.type, info.addr);
1010 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1013 * And of course let the users delete the devices they instantiated, if
1014 * they got it wrong. This interface can only be used to delete devices
1015 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1016 * don't delete devices to which some kernel code still has references.
1018 * Parameter checking may look overzealous, but we really don't want
1019 * the user to delete the wrong device.
1022 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1023 const char *buf, size_t count)
1025 struct i2c_adapter *adap = to_i2c_adapter(dev);
1026 struct i2c_client *client, *next;
1027 unsigned short addr;
1031 /* Parse parameters, reject extra parameters */
1032 res = sscanf(buf, "%hi%c", &addr, &end);
1034 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1037 if (res > 1 && end != '\n') {
1038 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1042 /* Make sure the device was added through sysfs */
1044 mutex_lock_nested(&adap->userspace_clients_lock,
1045 i2c_adapter_depth(adap));
1046 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1048 if (i2c_encode_flags_to_addr(client) == addr) {
1049 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1050 "delete_device", client->name, client->addr);
1052 list_del(&client->detected);
1053 i2c_unregister_device(client);
1058 mutex_unlock(&adap->userspace_clients_lock);
1061 dev_err(dev, "%s: Can't find device in list\n",
1065 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1066 i2c_sysfs_delete_device);
1068 static struct attribute *i2c_adapter_attrs[] = {
1069 &dev_attr_name.attr,
1070 &dev_attr_new_device.attr,
1071 &dev_attr_delete_device.attr,
1074 ATTRIBUTE_GROUPS(i2c_adapter);
1076 struct device_type i2c_adapter_type = {
1077 .groups = i2c_adapter_groups,
1078 .release = i2c_adapter_dev_release,
1080 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1083 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1084 * @dev: device, probably from some driver model iterator
1086 * When traversing the driver model tree, perhaps using driver model
1087 * iterators like @device_for_each_child(), you can't assume very much
1088 * about the nodes you find. Use this function to avoid oopses caused
1089 * by wrongly treating some non-I2C device as an i2c_adapter.
1091 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1093 return (dev->type == &i2c_adapter_type)
1094 ? to_i2c_adapter(dev)
1097 EXPORT_SYMBOL(i2c_verify_adapter);
1099 #ifdef CONFIG_I2C_COMPAT
1100 static struct class_compat *i2c_adapter_compat_class;
1103 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1105 struct i2c_devinfo *devinfo;
1107 down_read(&__i2c_board_lock);
1108 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1109 if (devinfo->busnum == adapter->nr
1110 && !i2c_new_device(adapter,
1111 &devinfo->board_info))
1112 dev_err(&adapter->dev,
1113 "Can't create device at 0x%02x\n",
1114 devinfo->board_info.addr);
1116 up_read(&__i2c_board_lock);
1119 static int i2c_do_add_adapter(struct i2c_driver *driver,
1120 struct i2c_adapter *adap)
1122 /* Detect supported devices on that bus, and instantiate them */
1123 i2c_detect(adap, driver);
1125 /* Let legacy drivers scan this bus for matching devices */
1126 if (driver->attach_adapter) {
1127 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1128 driver->driver.name);
1129 dev_warn(&adap->dev,
1130 "Please use another way to instantiate your i2c_client\n");
1131 /* We ignore the return code; if it fails, too bad */
1132 driver->attach_adapter(adap);
1137 static int __process_new_adapter(struct device_driver *d, void *data)
1139 return i2c_do_add_adapter(to_i2c_driver(d), data);
1142 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1143 .lock_bus = i2c_adapter_lock_bus,
1144 .trylock_bus = i2c_adapter_trylock_bus,
1145 .unlock_bus = i2c_adapter_unlock_bus,
1148 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1150 struct irq_domain *domain = adap->host_notify_domain;
1151 irq_hw_number_t hwirq;
1156 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1157 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1159 irq_domain_remove(domain);
1160 adap->host_notify_domain = NULL;
1163 static int i2c_host_notify_irq_map(struct irq_domain *h,
1165 irq_hw_number_t hw_irq_num)
1167 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1172 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1173 .map = i2c_host_notify_irq_map,
1176 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1178 struct irq_domain *domain;
1180 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1183 domain = irq_domain_create_linear(adap->dev.fwnode,
1184 I2C_ADDR_7BITS_COUNT,
1185 &i2c_host_notify_irq_ops, adap);
1189 adap->host_notify_domain = domain;
1195 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1197 * @adap: the adapter
1198 * @addr: the I2C address of the notifying device
1199 * Context: can't sleep
1201 * Helper function to be called from an I2C bus driver's interrupt
1202 * handler. It will schedule the Host Notify IRQ.
1204 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1211 irq = irq_find_mapping(adap->host_notify_domain, addr);
1215 generic_handle_irq(irq);
1219 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1221 static int i2c_register_adapter(struct i2c_adapter *adap)
1225 /* Can't register until after driver model init */
1226 if (WARN_ON(!is_registered)) {
1232 if (WARN(!adap->name[0], "i2c adapter has no name"))
1236 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1240 if (!adap->lock_ops)
1241 adap->lock_ops = &i2c_adapter_lock_ops;
1243 rt_mutex_init(&adap->bus_lock);
1244 rt_mutex_init(&adap->mux_lock);
1245 mutex_init(&adap->userspace_clients_lock);
1246 INIT_LIST_HEAD(&adap->userspace_clients);
1248 /* Set default timeout to 1 second if not already set */
1249 if (adap->timeout == 0)
1252 /* register soft irqs for Host Notify */
1253 res = i2c_setup_host_notify_irq_domain(adap);
1255 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1260 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1261 adap->dev.bus = &i2c_bus_type;
1262 adap->dev.type = &i2c_adapter_type;
1263 res = device_register(&adap->dev);
1265 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1269 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1271 pm_runtime_no_callbacks(&adap->dev);
1272 pm_suspend_ignore_children(&adap->dev, true);
1273 pm_runtime_enable(&adap->dev);
1275 #ifdef CONFIG_I2C_COMPAT
1276 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1279 dev_warn(&adap->dev,
1280 "Failed to create compatibility class link\n");
1283 i2c_init_recovery(adap);
1285 /* create pre-declared device nodes */
1286 of_i2c_register_devices(adap);
1287 i2c_acpi_install_space_handler(adap);
1288 i2c_acpi_register_devices(adap);
1290 if (adap->nr < __i2c_first_dynamic_bus_num)
1291 i2c_scan_static_board_info(adap);
1293 /* Notify drivers */
1294 mutex_lock(&core_lock);
1295 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1296 mutex_unlock(&core_lock);
1301 mutex_lock(&core_lock);
1302 idr_remove(&i2c_adapter_idr, adap->nr);
1303 mutex_unlock(&core_lock);
1308 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1309 * @adap: the adapter to register (with adap->nr initialized)
1310 * Context: can sleep
1312 * See i2c_add_numbered_adapter() for details.
1314 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1318 mutex_lock(&core_lock);
1319 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1320 mutex_unlock(&core_lock);
1321 if (WARN(id < 0, "couldn't get idr"))
1322 return id == -ENOSPC ? -EBUSY : id;
1324 return i2c_register_adapter(adap);
1328 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1329 * @adapter: the adapter to add
1330 * Context: can sleep
1332 * This routine is used to declare an I2C adapter when its bus number
1333 * doesn't matter or when its bus number is specified by an dt alias.
1334 * Examples of bases when the bus number doesn't matter: I2C adapters
1335 * dynamically added by USB links or PCI plugin cards.
1337 * When this returns zero, a new bus number was allocated and stored
1338 * in adap->nr, and the specified adapter became available for clients.
1339 * Otherwise, a negative errno value is returned.
1341 int i2c_add_adapter(struct i2c_adapter *adapter)
1343 struct device *dev = &adapter->dev;
1347 id = of_alias_get_id(dev->of_node, "i2c");
1350 return __i2c_add_numbered_adapter(adapter);
1354 mutex_lock(&core_lock);
1355 id = idr_alloc(&i2c_adapter_idr, adapter,
1356 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1357 mutex_unlock(&core_lock);
1358 if (WARN(id < 0, "couldn't get idr"))
1363 return i2c_register_adapter(adapter);
1365 EXPORT_SYMBOL(i2c_add_adapter);
1368 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1369 * @adap: the adapter to register (with adap->nr initialized)
1370 * Context: can sleep
1372 * This routine is used to declare an I2C adapter when its bus number
1373 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1374 * or otherwise built in to the system's mainboard, and where i2c_board_info
1375 * is used to properly configure I2C devices.
1377 * If the requested bus number is set to -1, then this function will behave
1378 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1380 * If no devices have pre-been declared for this bus, then be sure to
1381 * register the adapter before any dynamically allocated ones. Otherwise
1382 * the required bus ID may not be available.
1384 * When this returns zero, the specified adapter became available for
1385 * clients using the bus number provided in adap->nr. Also, the table
1386 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1387 * and the appropriate driver model device nodes are created. Otherwise, a
1388 * negative errno value is returned.
1390 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1392 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1393 return i2c_add_adapter(adap);
1395 return __i2c_add_numbered_adapter(adap);
1397 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1399 static void i2c_do_del_adapter(struct i2c_driver *driver,
1400 struct i2c_adapter *adapter)
1402 struct i2c_client *client, *_n;
1404 /* Remove the devices we created ourselves as the result of hardware
1405 * probing (using a driver's detect method) */
1406 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1407 if (client->adapter == adapter) {
1408 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1409 client->name, client->addr);
1410 list_del(&client->detected);
1411 i2c_unregister_device(client);
1416 static int __unregister_client(struct device *dev, void *dummy)
1418 struct i2c_client *client = i2c_verify_client(dev);
1419 if (client && strcmp(client->name, "dummy"))
1420 i2c_unregister_device(client);
1424 static int __unregister_dummy(struct device *dev, void *dummy)
1426 struct i2c_client *client = i2c_verify_client(dev);
1428 i2c_unregister_device(client);
1432 static int __process_removed_adapter(struct device_driver *d, void *data)
1434 i2c_do_del_adapter(to_i2c_driver(d), data);
1439 * i2c_del_adapter - unregister I2C adapter
1440 * @adap: the adapter being unregistered
1441 * Context: can sleep
1443 * This unregisters an I2C adapter which was previously registered
1444 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1446 void i2c_del_adapter(struct i2c_adapter *adap)
1448 struct i2c_adapter *found;
1449 struct i2c_client *client, *next;
1451 /* First make sure that this adapter was ever added */
1452 mutex_lock(&core_lock);
1453 found = idr_find(&i2c_adapter_idr, adap->nr);
1454 mutex_unlock(&core_lock);
1455 if (found != adap) {
1456 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1460 i2c_acpi_remove_space_handler(adap);
1461 /* Tell drivers about this removal */
1462 mutex_lock(&core_lock);
1463 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1464 __process_removed_adapter);
1465 mutex_unlock(&core_lock);
1467 /* Remove devices instantiated from sysfs */
1468 mutex_lock_nested(&adap->userspace_clients_lock,
1469 i2c_adapter_depth(adap));
1470 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1472 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1474 list_del(&client->detected);
1475 i2c_unregister_device(client);
1477 mutex_unlock(&adap->userspace_clients_lock);
1479 /* Detach any active clients. This can't fail, thus we do not
1480 * check the returned value. This is a two-pass process, because
1481 * we can't remove the dummy devices during the first pass: they
1482 * could have been instantiated by real devices wishing to clean
1483 * them up properly, so we give them a chance to do that first. */
1484 device_for_each_child(&adap->dev, NULL, __unregister_client);
1485 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1487 #ifdef CONFIG_I2C_COMPAT
1488 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1492 /* device name is gone after device_unregister */
1493 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1495 pm_runtime_disable(&adap->dev);
1497 i2c_host_notify_irq_teardown(adap);
1499 /* wait until all references to the device are gone
1501 * FIXME: This is old code and should ideally be replaced by an
1502 * alternative which results in decoupling the lifetime of the struct
1503 * device from the i2c_adapter, like spi or netdev do. Any solution
1504 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1506 init_completion(&adap->dev_released);
1507 device_unregister(&adap->dev);
1508 wait_for_completion(&adap->dev_released);
1511 mutex_lock(&core_lock);
1512 idr_remove(&i2c_adapter_idr, adap->nr);
1513 mutex_unlock(&core_lock);
1515 /* Clear the device structure in case this adapter is ever going to be
1517 memset(&adap->dev, 0, sizeof(adap->dev));
1519 EXPORT_SYMBOL(i2c_del_adapter);
1522 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1523 * @dev: The device to scan for I2C timing properties
1524 * @t: the i2c_timings struct to be filled with values
1525 * @use_defaults: bool to use sane defaults derived from the I2C specification
1526 * when properties are not found, otherwise use 0
1528 * Scan the device for the generic I2C properties describing timing parameters
1529 * for the signal and fill the given struct with the results. If a property was
1530 * not found and use_defaults was true, then maximum timings are assumed which
1531 * are derived from the I2C specification. If use_defaults is not used, the
1532 * results will be 0, so drivers can apply their own defaults later. The latter
1533 * is mainly intended for avoiding regressions of existing drivers which want
1534 * to switch to this function. New drivers almost always should use the defaults.
1537 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1541 memset(t, 0, sizeof(*t));
1543 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1544 if (ret && use_defaults)
1545 t->bus_freq_hz = 100000;
1547 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1548 if (ret && use_defaults) {
1549 if (t->bus_freq_hz <= 100000)
1550 t->scl_rise_ns = 1000;
1551 else if (t->bus_freq_hz <= 400000)
1552 t->scl_rise_ns = 300;
1554 t->scl_rise_ns = 120;
1557 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1558 if (ret && use_defaults) {
1559 if (t->bus_freq_hz <= 400000)
1560 t->scl_fall_ns = 300;
1562 t->scl_fall_ns = 120;
1565 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1567 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1568 if (ret && use_defaults)
1569 t->sda_fall_ns = t->scl_fall_ns;
1571 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1573 /* ------------------------------------------------------------------------- */
1575 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1579 mutex_lock(&core_lock);
1580 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1581 mutex_unlock(&core_lock);
1585 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1587 static int __process_new_driver(struct device *dev, void *data)
1589 if (dev->type != &i2c_adapter_type)
1591 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1595 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1596 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1599 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1603 /* Can't register until after driver model init */
1604 if (WARN_ON(!is_registered))
1607 /* add the driver to the list of i2c drivers in the driver core */
1608 driver->driver.owner = owner;
1609 driver->driver.bus = &i2c_bus_type;
1610 INIT_LIST_HEAD(&driver->clients);
1612 /* When registration returns, the driver core
1613 * will have called probe() for all matching-but-unbound devices.
1615 res = driver_register(&driver->driver);
1619 pr_debug("driver [%s] registered\n", driver->driver.name);
1621 /* Walk the adapters that are already present */
1622 i2c_for_each_dev(driver, __process_new_driver);
1626 EXPORT_SYMBOL(i2c_register_driver);
1628 static int __process_removed_driver(struct device *dev, void *data)
1630 if (dev->type == &i2c_adapter_type)
1631 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1636 * i2c_del_driver - unregister I2C driver
1637 * @driver: the driver being unregistered
1638 * Context: can sleep
1640 void i2c_del_driver(struct i2c_driver *driver)
1642 i2c_for_each_dev(driver, __process_removed_driver);
1644 driver_unregister(&driver->driver);
1645 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1647 EXPORT_SYMBOL(i2c_del_driver);
1649 /* ------------------------------------------------------------------------- */
1652 * i2c_use_client - increments the reference count of the i2c client structure
1653 * @client: the client being referenced
1655 * Each live reference to a client should be refcounted. The driver model does
1656 * that automatically as part of driver binding, so that most drivers don't
1657 * need to do this explicitly: they hold a reference until they're unbound
1660 * A pointer to the client with the incremented reference counter is returned.
1662 struct i2c_client *i2c_use_client(struct i2c_client *client)
1664 if (client && get_device(&client->dev))
1668 EXPORT_SYMBOL(i2c_use_client);
1671 * i2c_release_client - release a use of the i2c client structure
1672 * @client: the client being no longer referenced
1674 * Must be called when a user of a client is finished with it.
1676 void i2c_release_client(struct i2c_client *client)
1679 put_device(&client->dev);
1681 EXPORT_SYMBOL(i2c_release_client);
1683 struct i2c_cmd_arg {
1688 static int i2c_cmd(struct device *dev, void *_arg)
1690 struct i2c_client *client = i2c_verify_client(dev);
1691 struct i2c_cmd_arg *arg = _arg;
1692 struct i2c_driver *driver;
1694 if (!client || !client->dev.driver)
1697 driver = to_i2c_driver(client->dev.driver);
1698 if (driver->command)
1699 driver->command(client, arg->cmd, arg->arg);
1703 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1705 struct i2c_cmd_arg cmd_arg;
1709 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1711 EXPORT_SYMBOL(i2c_clients_command);
1713 static int __init i2c_init(void)
1717 retval = of_alias_get_highest_id("i2c");
1719 down_write(&__i2c_board_lock);
1720 if (retval >= __i2c_first_dynamic_bus_num)
1721 __i2c_first_dynamic_bus_num = retval + 1;
1722 up_write(&__i2c_board_lock);
1724 retval = bus_register(&i2c_bus_type);
1728 is_registered = true;
1730 #ifdef CONFIG_I2C_COMPAT
1731 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1732 if (!i2c_adapter_compat_class) {
1737 retval = i2c_add_driver(&dummy_driver);
1741 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1742 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1743 if (IS_ENABLED(CONFIG_ACPI))
1744 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1749 #ifdef CONFIG_I2C_COMPAT
1750 class_compat_unregister(i2c_adapter_compat_class);
1753 is_registered = false;
1754 bus_unregister(&i2c_bus_type);
1758 static void __exit i2c_exit(void)
1760 if (IS_ENABLED(CONFIG_ACPI))
1761 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1762 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1763 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1764 i2c_del_driver(&dummy_driver);
1765 #ifdef CONFIG_I2C_COMPAT
1766 class_compat_unregister(i2c_adapter_compat_class);
1768 bus_unregister(&i2c_bus_type);
1769 tracepoint_synchronize_unregister();
1772 /* We must initialize early, because some subsystems register i2c drivers
1773 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1775 postcore_initcall(i2c_init);
1776 module_exit(i2c_exit);
1778 /* ----------------------------------------------------
1779 * the functional interface to the i2c busses.
1780 * ----------------------------------------------------
1783 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1784 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1786 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1788 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1789 err_msg, msg->addr, msg->len,
1790 msg->flags & I2C_M_RD ? "read" : "write");
1794 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1796 const struct i2c_adapter_quirks *q = adap->quirks;
1797 int max_num = q->max_num_msgs, i;
1798 bool do_len_check = true;
1800 if (q->flags & I2C_AQ_COMB) {
1803 /* special checks for combined messages */
1805 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1806 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1808 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1809 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1811 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1812 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1814 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1815 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1817 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1818 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1820 do_len_check = false;
1824 if (i2c_quirk_exceeded(num, max_num))
1825 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1827 for (i = 0; i < num; i++) {
1828 u16 len = msgs[i].len;
1830 if (msgs[i].flags & I2C_M_RD) {
1831 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1832 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1834 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1835 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1843 * __i2c_transfer - unlocked flavor of i2c_transfer
1844 * @adap: Handle to I2C bus
1845 * @msgs: One or more messages to execute before STOP is issued to
1846 * terminate the operation; each message begins with a START.
1847 * @num: Number of messages to be executed.
1849 * Returns negative errno, else the number of messages executed.
1851 * Adapter lock must be held when calling this function. No debug logging
1852 * takes place. adap->algo->master_xfer existence isn't checked.
1854 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1856 unsigned long orig_jiffies;
1859 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1862 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1863 * enabled. This is an efficient way of keeping the for-loop from
1864 * being executed when not needed.
1866 if (static_key_false(&i2c_trace_msg)) {
1868 for (i = 0; i < num; i++)
1869 if (msgs[i].flags & I2C_M_RD)
1870 trace_i2c_read(adap, &msgs[i], i);
1872 trace_i2c_write(adap, &msgs[i], i);
1875 /* Retry automatically on arbitration loss */
1876 orig_jiffies = jiffies;
1877 for (ret = 0, try = 0; try <= adap->retries; try++) {
1878 ret = adap->algo->master_xfer(adap, msgs, num);
1881 if (time_after(jiffies, orig_jiffies + adap->timeout))
1885 if (static_key_false(&i2c_trace_msg)) {
1887 for (i = 0; i < ret; i++)
1888 if (msgs[i].flags & I2C_M_RD)
1889 trace_i2c_reply(adap, &msgs[i], i);
1890 trace_i2c_result(adap, i, ret);
1895 EXPORT_SYMBOL(__i2c_transfer);
1898 * i2c_transfer - execute a single or combined I2C message
1899 * @adap: Handle to I2C bus
1900 * @msgs: One or more messages to execute before STOP is issued to
1901 * terminate the operation; each message begins with a START.
1902 * @num: Number of messages to be executed.
1904 * Returns negative errno, else the number of messages executed.
1906 * Note that there is no requirement that each message be sent to
1907 * the same slave address, although that is the most common model.
1909 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1913 /* REVISIT the fault reporting model here is weak:
1915 * - When we get an error after receiving N bytes from a slave,
1916 * there is no way to report "N".
1918 * - When we get a NAK after transmitting N bytes to a slave,
1919 * there is no way to report "N" ... or to let the master
1920 * continue executing the rest of this combined message, if
1921 * that's the appropriate response.
1923 * - When for example "num" is two and we successfully complete
1924 * the first message but get an error part way through the
1925 * second, it's unclear whether that should be reported as
1926 * one (discarding status on the second message) or errno
1927 * (discarding status on the first one).
1930 if (adap->algo->master_xfer) {
1932 for (ret = 0; ret < num; ret++) {
1934 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1935 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1936 msgs[ret].addr, msgs[ret].len,
1937 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1941 if (in_atomic() || irqs_disabled()) {
1942 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1944 /* I2C activity is ongoing. */
1947 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1950 ret = __i2c_transfer(adap, msgs, num);
1951 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1955 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1959 EXPORT_SYMBOL(i2c_transfer);
1962 * i2c_master_send - issue a single I2C message in master transmit mode
1963 * @client: Handle to slave device
1964 * @buf: Data that will be written to the slave
1965 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1967 * Returns negative errno, or else the number of bytes written.
1969 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1972 struct i2c_adapter *adap = client->adapter;
1975 msg.addr = client->addr;
1976 msg.flags = client->flags & I2C_M_TEN;
1978 msg.buf = (char *)buf;
1980 ret = i2c_transfer(adap, &msg, 1);
1983 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1984 * transmitted, else error code.
1986 return (ret == 1) ? count : ret;
1988 EXPORT_SYMBOL(i2c_master_send);
1991 * i2c_master_recv - issue a single I2C message in master receive mode
1992 * @client: Handle to slave device
1993 * @buf: Where to store data read from slave
1994 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1996 * Returns negative errno, or else the number of bytes read.
1998 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
2000 struct i2c_adapter *adap = client->adapter;
2004 msg.addr = client->addr;
2005 msg.flags = client->flags & I2C_M_TEN;
2006 msg.flags |= I2C_M_RD;
2010 ret = i2c_transfer(adap, &msg, 1);
2013 * If everything went ok (i.e. 1 msg received), return #bytes received,
2016 return (ret == 1) ? count : ret;
2018 EXPORT_SYMBOL(i2c_master_recv);
2020 /* ----------------------------------------------------
2021 * the i2c address scanning function
2022 * Will not work for 10-bit addresses!
2023 * ----------------------------------------------------
2027 * Legacy default probe function, mostly relevant for SMBus. The default
2028 * probe method is a quick write, but it is known to corrupt the 24RF08
2029 * EEPROMs due to a state machine bug, and could also irreversibly
2030 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2031 * we use a short byte read instead. Also, some bus drivers don't implement
2032 * quick write, so we fallback to a byte read in that case too.
2033 * On x86, there is another special case for FSC hardware monitoring chips,
2034 * which want regular byte reads (address 0x73.) Fortunately, these are the
2035 * only known chips using this I2C address on PC hardware.
2036 * Returns 1 if probe succeeded, 0 if not.
2038 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2041 union i2c_smbus_data dummy;
2044 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2045 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2046 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2047 I2C_SMBUS_BYTE_DATA, &dummy);
2050 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2051 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2052 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2053 I2C_SMBUS_QUICK, NULL);
2054 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2055 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2056 I2C_SMBUS_BYTE, &dummy);
2058 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2066 static int i2c_detect_address(struct i2c_client *temp_client,
2067 struct i2c_driver *driver)
2069 struct i2c_board_info info;
2070 struct i2c_adapter *adapter = temp_client->adapter;
2071 int addr = temp_client->addr;
2074 /* Make sure the address is valid */
2075 err = i2c_check_7bit_addr_validity_strict(addr);
2077 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2082 /* Skip if already in use (7 bit, no need to encode flags) */
2083 if (i2c_check_addr_busy(adapter, addr))
2086 /* Make sure there is something at this address */
2087 if (!i2c_default_probe(adapter, addr))
2090 /* Finally call the custom detection function */
2091 memset(&info, 0, sizeof(struct i2c_board_info));
2093 err = driver->detect(temp_client, &info);
2095 /* -ENODEV is returned if the detection fails. We catch it
2096 here as this isn't an error. */
2097 return err == -ENODEV ? 0 : err;
2100 /* Consistency check */
2101 if (info.type[0] == '\0') {
2102 dev_err(&adapter->dev,
2103 "%s detection function provided no name for 0x%x\n",
2104 driver->driver.name, addr);
2106 struct i2c_client *client;
2108 /* Detection succeeded, instantiate the device */
2109 if (adapter->class & I2C_CLASS_DEPRECATED)
2110 dev_warn(&adapter->dev,
2111 "This adapter will soon drop class based instantiation of devices. "
2112 "Please make sure client 0x%02x gets instantiated by other means. "
2113 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2116 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2117 info.type, info.addr);
2118 client = i2c_new_device(adapter, &info);
2120 list_add_tail(&client->detected, &driver->clients);
2122 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2123 info.type, info.addr);
2128 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2130 const unsigned short *address_list;
2131 struct i2c_client *temp_client;
2133 int adap_id = i2c_adapter_id(adapter);
2135 address_list = driver->address_list;
2136 if (!driver->detect || !address_list)
2139 /* Warn that the adapter lost class based instantiation */
2140 if (adapter->class == I2C_CLASS_DEPRECATED) {
2141 dev_dbg(&adapter->dev,
2142 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2143 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2144 driver->driver.name);
2148 /* Stop here if the classes do not match */
2149 if (!(adapter->class & driver->class))
2152 /* Set up a temporary client to help detect callback */
2153 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2156 temp_client->adapter = adapter;
2158 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2159 dev_dbg(&adapter->dev,
2160 "found normal entry for adapter %d, addr 0x%02x\n",
2161 adap_id, address_list[i]);
2162 temp_client->addr = address_list[i];
2163 err = i2c_detect_address(temp_client, driver);
2172 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2174 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2175 I2C_SMBUS_QUICK, NULL) >= 0;
2177 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2180 i2c_new_probed_device(struct i2c_adapter *adap,
2181 struct i2c_board_info *info,
2182 unsigned short const *addr_list,
2183 int (*probe)(struct i2c_adapter *, unsigned short addr))
2188 probe = i2c_default_probe;
2190 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2191 /* Check address validity */
2192 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2193 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2198 /* Check address availability (7 bit, no need to encode flags) */
2199 if (i2c_check_addr_busy(adap, addr_list[i])) {
2201 "Address 0x%02x already in use, not probing\n",
2206 /* Test address responsiveness */
2207 if (probe(adap, addr_list[i]))
2211 if (addr_list[i] == I2C_CLIENT_END) {
2212 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2216 info->addr = addr_list[i];
2217 return i2c_new_device(adap, info);
2219 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2221 struct i2c_adapter *i2c_get_adapter(int nr)
2223 struct i2c_adapter *adapter;
2225 mutex_lock(&core_lock);
2226 adapter = idr_find(&i2c_adapter_idr, nr);
2230 if (try_module_get(adapter->owner))
2231 get_device(&adapter->dev);
2236 mutex_unlock(&core_lock);
2239 EXPORT_SYMBOL(i2c_get_adapter);
2241 void i2c_put_adapter(struct i2c_adapter *adap)
2246 put_device(&adap->dev);
2247 module_put(adap->owner);
2249 EXPORT_SYMBOL(i2c_put_adapter);
2251 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2252 MODULE_DESCRIPTION("I2C-Bus main module");
2253 MODULE_LICENSE("GPL");