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/irqflags.h>
35 #include <linux/jump_label.h>
36 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/mutex.h>
39 #include <linux/of_device.h>
41 #include <linux/of_irq.h>
42 #include <linux/pm_domain.h>
43 #include <linux/pm_runtime.h>
44 #include <linux/pm_wakeirq.h>
45 #include <linux/property.h>
46 #include <linux/rwsem.h>
47 #include <linux/slab.h>
51 #define CREATE_TRACE_POINTS
52 #include <trace/events/i2c.h>
54 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
55 #define I2C_ADDR_OFFSET_SLAVE 0x1000
57 #define I2C_ADDR_7BITS_MAX 0x77
58 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
61 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
62 * deletion of detected devices, and attach_adapter calls are serialized
64 static DEFINE_MUTEX(core_lock);
65 static DEFINE_IDR(i2c_adapter_idr);
67 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
69 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
70 static bool is_registered;
72 int i2c_transfer_trace_reg(void)
74 static_key_slow_inc(&i2c_trace_msg);
78 void i2c_transfer_trace_unreg(void)
80 static_key_slow_dec(&i2c_trace_msg);
83 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
84 const struct i2c_client *client)
90 if (strcmp(client->name, id->name) == 0)
96 EXPORT_SYMBOL_GPL(i2c_match_id);
98 static int i2c_device_match(struct device *dev, struct device_driver *drv)
100 struct i2c_client *client = i2c_verify_client(dev);
101 struct i2c_driver *driver;
104 /* Attempt an OF style match */
105 if (i2c_of_match_device(drv->of_match_table, client))
108 /* Then ACPI style match */
109 if (acpi_driver_match_device(dev, drv))
112 driver = to_i2c_driver(drv);
114 /* Finally an I2C match */
115 if (i2c_match_id(driver->id_table, client))
121 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
123 struct i2c_client *client = to_i2c_client(dev);
126 rc = acpi_device_uevent_modalias(dev, env);
130 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
133 /* i2c bus recovery routines */
134 static int get_scl_gpio_value(struct i2c_adapter *adap)
136 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
139 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
141 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
144 static int get_sda_gpio_value(struct i2c_adapter *adap)
146 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
149 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
151 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
152 struct device *dev = &adap->dev;
155 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
156 GPIOF_OUT_INIT_HIGH, "i2c-scl");
158 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
163 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
164 /* work without SDA polling */
165 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
174 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
176 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
179 gpio_free(bri->sda_gpio);
181 gpio_free(bri->scl_gpio);
185 * We are generating clock pulses. ndelay() determines durating of clk pulses.
186 * We will generate clock with rate 100 KHz and so duration of both clock levels
187 * is: delay in ns = (10^6 / 100) / 2
189 #define RECOVERY_NDELAY 5000
190 #define RECOVERY_CLK_CNT 9
192 static int i2c_generic_recovery(struct i2c_adapter *adap)
194 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
195 int i = 0, val = 1, ret = 0;
197 if (bri->prepare_recovery)
198 bri->prepare_recovery(adap);
200 bri->set_scl(adap, val);
201 ndelay(RECOVERY_NDELAY);
204 * By this time SCL is high, as we need to give 9 falling-rising edges
206 while (i++ < RECOVERY_CLK_CNT * 2) {
208 /* Break if SDA is high */
209 if (bri->get_sda && bri->get_sda(adap))
211 /* SCL shouldn't be low here */
212 if (!bri->get_scl(adap)) {
214 "SCL is stuck low, exit recovery\n");
221 bri->set_scl(adap, val);
222 ndelay(RECOVERY_NDELAY);
225 if (bri->unprepare_recovery)
226 bri->unprepare_recovery(adap);
231 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
233 return i2c_generic_recovery(adap);
235 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
237 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
241 ret = i2c_get_gpios_for_recovery(adap);
245 ret = i2c_generic_recovery(adap);
246 i2c_put_gpios_for_recovery(adap);
250 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
252 int i2c_recover_bus(struct i2c_adapter *adap)
254 if (!adap->bus_recovery_info)
257 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
258 return adap->bus_recovery_info->recover_bus(adap);
260 EXPORT_SYMBOL_GPL(i2c_recover_bus);
262 static void i2c_init_recovery(struct i2c_adapter *adap)
264 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
270 if (!bri->recover_bus) {
271 err_str = "no recover_bus() found";
275 /* Generic GPIO recovery */
276 if (bri->recover_bus == i2c_generic_gpio_recovery) {
277 if (!gpio_is_valid(bri->scl_gpio)) {
278 err_str = "invalid SCL gpio";
282 if (gpio_is_valid(bri->sda_gpio))
283 bri->get_sda = get_sda_gpio_value;
287 bri->get_scl = get_scl_gpio_value;
288 bri->set_scl = set_scl_gpio_value;
289 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
290 /* Generic SCL recovery */
291 if (!bri->set_scl || !bri->get_scl) {
292 err_str = "no {get|set}_scl() found";
299 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
300 adap->bus_recovery_info = NULL;
303 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
305 struct i2c_adapter *adap = client->adapter;
308 if (!adap->host_notify_domain)
311 if (client->flags & I2C_CLIENT_TEN)
314 irq = irq_find_mapping(adap->host_notify_domain, client->addr);
316 irq = irq_create_mapping(adap->host_notify_domain,
319 return irq > 0 ? irq : -ENXIO;
322 static int i2c_device_probe(struct device *dev)
324 struct i2c_client *client = i2c_verify_client(dev);
325 struct i2c_driver *driver;
331 driver = to_i2c_driver(dev->driver);
333 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
336 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
337 dev_dbg(dev, "Using Host Notify IRQ\n");
338 irq = i2c_smbus_host_notify_to_irq(client);
339 } else if (dev->of_node) {
340 irq = of_irq_get_byname(dev->of_node, "irq");
341 if (irq == -EINVAL || irq == -ENODATA)
342 irq = of_irq_get(dev->of_node, 0);
343 } else if (ACPI_COMPANION(dev)) {
344 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
346 if (irq == -EPROBE_DEFER)
356 * An I2C ID table is not mandatory, if and only if, a suitable OF
357 * or ACPI ID table is supplied for the probing device.
359 if (!driver->id_table &&
360 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
361 !i2c_of_match_device(dev->driver->of_match_table, client))
364 if (client->flags & I2C_CLIENT_WAKE) {
365 int wakeirq = -ENOENT;
368 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
369 if (wakeirq == -EPROBE_DEFER)
373 device_init_wakeup(&client->dev, true);
375 if (wakeirq > 0 && wakeirq != client->irq)
376 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
377 else if (client->irq > 0)
378 status = dev_pm_set_wake_irq(dev, client->irq);
383 dev_warn(&client->dev, "failed to set up wakeup irq\n");
386 dev_dbg(dev, "probe\n");
388 status = of_clk_set_defaults(dev->of_node, false);
390 goto err_clear_wakeup_irq;
392 status = dev_pm_domain_attach(&client->dev, true);
393 if (status == -EPROBE_DEFER)
394 goto err_clear_wakeup_irq;
397 * When there are no more users of probe(),
398 * rename probe_new to probe.
400 if (driver->probe_new)
401 status = driver->probe_new(client);
402 else if (driver->probe)
403 status = driver->probe(client,
404 i2c_match_id(driver->id_table, client));
409 goto err_detach_pm_domain;
413 err_detach_pm_domain:
414 dev_pm_domain_detach(&client->dev, true);
415 err_clear_wakeup_irq:
416 dev_pm_clear_wake_irq(&client->dev);
417 device_init_wakeup(&client->dev, false);
421 static int i2c_device_remove(struct device *dev)
423 struct i2c_client *client = i2c_verify_client(dev);
424 struct i2c_driver *driver;
427 if (!client || !dev->driver)
430 driver = to_i2c_driver(dev->driver);
431 if (driver->remove) {
432 dev_dbg(dev, "remove\n");
433 status = driver->remove(client);
436 dev_pm_domain_detach(&client->dev, true);
438 dev_pm_clear_wake_irq(&client->dev);
439 device_init_wakeup(&client->dev, false);
444 static void i2c_device_shutdown(struct device *dev)
446 struct i2c_client *client = i2c_verify_client(dev);
447 struct i2c_driver *driver;
449 if (!client || !dev->driver)
451 driver = to_i2c_driver(dev->driver);
452 if (driver->shutdown)
453 driver->shutdown(client);
456 static void i2c_client_dev_release(struct device *dev)
458 kfree(to_i2c_client(dev));
462 show_name(struct device *dev, struct device_attribute *attr, char *buf)
464 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
465 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
467 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
470 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
472 struct i2c_client *client = to_i2c_client(dev);
475 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
479 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
481 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
483 static struct attribute *i2c_dev_attrs[] = {
485 /* modalias helps coldplug: modprobe $(cat .../modalias) */
486 &dev_attr_modalias.attr,
489 ATTRIBUTE_GROUPS(i2c_dev);
491 struct bus_type i2c_bus_type = {
493 .match = i2c_device_match,
494 .probe = i2c_device_probe,
495 .remove = i2c_device_remove,
496 .shutdown = i2c_device_shutdown,
498 EXPORT_SYMBOL_GPL(i2c_bus_type);
500 struct device_type i2c_client_type = {
501 .groups = i2c_dev_groups,
502 .uevent = i2c_device_uevent,
503 .release = i2c_client_dev_release,
505 EXPORT_SYMBOL_GPL(i2c_client_type);
509 * i2c_verify_client - return parameter as i2c_client, or NULL
510 * @dev: device, probably from some driver model iterator
512 * When traversing the driver model tree, perhaps using driver model
513 * iterators like @device_for_each_child(), you can't assume very much
514 * about the nodes you find. Use this function to avoid oopses caused
515 * by wrongly treating some non-I2C device as an i2c_client.
517 struct i2c_client *i2c_verify_client(struct device *dev)
519 return (dev->type == &i2c_client_type)
523 EXPORT_SYMBOL(i2c_verify_client);
526 /* Return a unique address which takes the flags of the client into account */
527 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
529 unsigned short addr = client->addr;
531 /* For some client flags, add an arbitrary offset to avoid collisions */
532 if (client->flags & I2C_CLIENT_TEN)
533 addr |= I2C_ADDR_OFFSET_TEN_BIT;
535 if (client->flags & I2C_CLIENT_SLAVE)
536 addr |= I2C_ADDR_OFFSET_SLAVE;
541 /* This is a permissive address validity check, I2C address map constraints
542 * are purposely not enforced, except for the general call address. */
543 int i2c_check_addr_validity(unsigned addr, unsigned short flags)
545 if (flags & I2C_CLIENT_TEN) {
546 /* 10-bit address, all values are valid */
550 /* 7-bit address, reject the general call address */
551 if (addr == 0x00 || addr > 0x7f)
557 /* And this is a strict address validity check, used when probing. If a
558 * device uses a reserved address, then it shouldn't be probed. 7-bit
559 * addressing is assumed, 10-bit address devices are rare and should be
560 * explicitly enumerated. */
561 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
564 * Reserved addresses per I2C specification:
565 * 0x00 General call address / START byte
567 * 0x02 Reserved for different bus format
568 * 0x03 Reserved for future purposes
569 * 0x04-0x07 Hs-mode master code
570 * 0x78-0x7b 10-bit slave addressing
571 * 0x7c-0x7f Reserved for future purposes
573 if (addr < 0x08 || addr > 0x77)
578 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
580 struct i2c_client *client = i2c_verify_client(dev);
581 int addr = *(int *)addrp;
583 if (client && i2c_encode_flags_to_addr(client) == addr)
588 /* walk up mux tree */
589 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
591 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
594 result = device_for_each_child(&adapter->dev, &addr,
595 __i2c_check_addr_busy);
597 if (!result && parent)
598 result = i2c_check_mux_parents(parent, addr);
603 /* recurse down mux tree */
604 static int i2c_check_mux_children(struct device *dev, void *addrp)
608 if (dev->type == &i2c_adapter_type)
609 result = device_for_each_child(dev, addrp,
610 i2c_check_mux_children);
612 result = __i2c_check_addr_busy(dev, addrp);
617 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
619 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
623 result = i2c_check_mux_parents(parent, addr);
626 result = device_for_each_child(&adapter->dev, &addr,
627 i2c_check_mux_children);
633 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
634 * @adapter: Target I2C bus segment
635 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
636 * locks only this branch in the adapter tree
638 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
641 rt_mutex_lock(&adapter->bus_lock);
645 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
646 * @adapter: Target I2C bus segment
647 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
648 * trylocks only this branch in the adapter tree
650 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
653 return rt_mutex_trylock(&adapter->bus_lock);
657 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
658 * @adapter: Target I2C bus segment
659 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
660 * unlocks only this branch in the adapter tree
662 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
665 rt_mutex_unlock(&adapter->bus_lock);
668 static void i2c_dev_set_name(struct i2c_adapter *adap,
669 struct i2c_client *client)
671 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
674 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
678 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
679 i2c_encode_flags_to_addr(client));
682 static int i2c_dev_irq_from_resources(const struct resource *resources,
683 unsigned int num_resources)
685 struct irq_data *irqd;
688 for (i = 0; i < num_resources; i++) {
689 const struct resource *r = &resources[i];
691 if (resource_type(r) != IORESOURCE_IRQ)
694 if (r->flags & IORESOURCE_BITS) {
695 irqd = irq_get_irq_data(r->start);
699 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
709 * i2c_new_device - instantiate an i2c device
710 * @adap: the adapter managing the device
711 * @info: describes one I2C device; bus_num is ignored
714 * Create an i2c device. Binding is handled through driver model
715 * probe()/remove() methods. A driver may be bound to this device when we
716 * return from this function, or any later moment (e.g. maybe hotplugging will
717 * load the driver module). This call is not appropriate for use by mainboard
718 * initialization logic, which usually runs during an arch_initcall() long
719 * before any i2c_adapter could exist.
721 * This returns the new i2c client, which may be saved for later use with
722 * i2c_unregister_device(); or NULL to indicate an error.
725 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
727 struct i2c_client *client;
730 client = kzalloc(sizeof *client, GFP_KERNEL);
734 client->adapter = adap;
736 client->dev.platform_data = info->platform_data;
739 client->dev.archdata = *info->archdata;
741 client->flags = info->flags;
742 client->addr = info->addr;
744 client->irq = info->irq;
746 client->irq = i2c_dev_irq_from_resources(info->resources,
747 info->num_resources);
749 strlcpy(client->name, info->type, sizeof(client->name));
751 status = i2c_check_addr_validity(client->addr, client->flags);
753 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
754 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
758 /* Check for address business */
759 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
763 client->dev.parent = &client->adapter->dev;
764 client->dev.bus = &i2c_bus_type;
765 client->dev.type = &i2c_client_type;
766 client->dev.of_node = info->of_node;
767 client->dev.fwnode = info->fwnode;
769 i2c_dev_set_name(adap, client);
771 if (info->properties) {
772 status = device_add_properties(&client->dev, info->properties);
775 "Failed to add properties to client %s: %d\n",
776 client->name, status);
781 status = device_register(&client->dev);
785 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
786 client->name, dev_name(&client->dev));
791 if (info->properties)
792 device_remove_properties(&client->dev);
795 "Failed to register i2c client %s at 0x%02x (%d)\n",
796 client->name, client->addr, status);
801 EXPORT_SYMBOL_GPL(i2c_new_device);
805 * i2c_unregister_device - reverse effect of i2c_new_device()
806 * @client: value returned from i2c_new_device()
809 void i2c_unregister_device(struct i2c_client *client)
811 if (client->dev.of_node)
812 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
813 if (ACPI_COMPANION(&client->dev))
814 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
815 device_unregister(&client->dev);
817 EXPORT_SYMBOL_GPL(i2c_unregister_device);
820 static const struct i2c_device_id dummy_id[] = {
825 static int dummy_probe(struct i2c_client *client,
826 const struct i2c_device_id *id)
831 static int dummy_remove(struct i2c_client *client)
836 static struct i2c_driver dummy_driver = {
837 .driver.name = "dummy",
838 .probe = dummy_probe,
839 .remove = dummy_remove,
840 .id_table = dummy_id,
844 * i2c_new_dummy - return a new i2c device bound to a dummy driver
845 * @adapter: the adapter managing the device
846 * @address: seven bit address to be used
849 * This returns an I2C client bound to the "dummy" driver, intended for use
850 * with devices that consume multiple addresses. Examples of such chips
851 * include various EEPROMS (like 24c04 and 24c08 models).
853 * These dummy devices have two main uses. First, most I2C and SMBus calls
854 * except i2c_transfer() need a client handle; the dummy will be that handle.
855 * And second, this prevents the specified address from being bound to a
858 * This returns the new i2c client, which should be saved for later use with
859 * i2c_unregister_device(); or NULL to indicate an error.
861 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
863 struct i2c_board_info info = {
864 I2C_BOARD_INFO("dummy", address),
867 return i2c_new_device(adapter, &info);
869 EXPORT_SYMBOL_GPL(i2c_new_dummy);
872 * i2c_new_secondary_device - Helper to get the instantiated secondary address
873 * and create the associated device
874 * @client: Handle to the primary client
875 * @name: Handle to specify which secondary address to get
876 * @default_addr: Used as a fallback if no secondary address was specified
879 * I2C clients can be composed of multiple I2C slaves bound together in a single
880 * component. The I2C client driver then binds to the master I2C slave and needs
881 * to create I2C dummy clients to communicate with all the other slaves.
883 * This function creates and returns an I2C dummy client whose I2C address is
884 * retrieved from the platform firmware based on the given slave name. If no
885 * address is specified by the firmware default_addr is used.
887 * On DT-based platforms the address is retrieved from the "reg" property entry
888 * cell whose "reg-names" value matches the slave name.
890 * This returns the new i2c client, which should be saved for later use with
891 * i2c_unregister_device(); or NULL to indicate an error.
893 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
897 struct device_node *np = client->dev.of_node;
898 u32 addr = default_addr;
902 i = of_property_match_string(np, "reg-names", name);
904 of_property_read_u32_index(np, "reg", i, &addr);
907 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
908 return i2c_new_dummy(client->adapter, addr);
910 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
912 /* ------------------------------------------------------------------------- */
914 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
916 static void i2c_adapter_dev_release(struct device *dev)
918 struct i2c_adapter *adap = to_i2c_adapter(dev);
919 complete(&adap->dev_released);
922 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
924 unsigned int depth = 0;
926 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
929 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
930 "adapter depth exceeds lockdep subclass limit\n");
934 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
937 * Let users instantiate I2C devices through sysfs. This can be used when
938 * platform initialization code doesn't contain the proper data for
939 * whatever reason. Also useful for drivers that do device detection and
940 * detection fails, either because the device uses an unexpected address,
941 * or this is a compatible device with different ID register values.
943 * Parameter checking may look overzealous, but we really don't want
944 * the user to provide incorrect parameters.
947 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
948 const char *buf, size_t count)
950 struct i2c_adapter *adap = to_i2c_adapter(dev);
951 struct i2c_board_info info;
952 struct i2c_client *client;
956 memset(&info, 0, sizeof(struct i2c_board_info));
958 blank = strchr(buf, ' ');
960 dev_err(dev, "%s: Missing parameters\n", "new_device");
963 if (blank - buf > I2C_NAME_SIZE - 1) {
964 dev_err(dev, "%s: Invalid device name\n", "new_device");
967 memcpy(info.type, buf, blank - buf);
969 /* Parse remaining parameters, reject extra parameters */
970 res = sscanf(++blank, "%hi%c", &info.addr, &end);
972 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
975 if (res > 1 && end != '\n') {
976 dev_err(dev, "%s: Extra parameters\n", "new_device");
980 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
981 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
982 info.flags |= I2C_CLIENT_TEN;
985 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
986 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
987 info.flags |= I2C_CLIENT_SLAVE;
990 client = i2c_new_device(adap, &info);
994 /* Keep track of the added device */
995 mutex_lock(&adap->userspace_clients_lock);
996 list_add_tail(&client->detected, &adap->userspace_clients);
997 mutex_unlock(&adap->userspace_clients_lock);
998 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
999 info.type, info.addr);
1003 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1006 * And of course let the users delete the devices they instantiated, if
1007 * they got it wrong. This interface can only be used to delete devices
1008 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1009 * don't delete devices to which some kernel code still has references.
1011 * Parameter checking may look overzealous, but we really don't want
1012 * the user to delete the wrong device.
1015 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1016 const char *buf, size_t count)
1018 struct i2c_adapter *adap = to_i2c_adapter(dev);
1019 struct i2c_client *client, *next;
1020 unsigned short addr;
1024 /* Parse parameters, reject extra parameters */
1025 res = sscanf(buf, "%hi%c", &addr, &end);
1027 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1030 if (res > 1 && end != '\n') {
1031 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1035 /* Make sure the device was added through sysfs */
1037 mutex_lock_nested(&adap->userspace_clients_lock,
1038 i2c_adapter_depth(adap));
1039 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1041 if (i2c_encode_flags_to_addr(client) == addr) {
1042 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1043 "delete_device", client->name, client->addr);
1045 list_del(&client->detected);
1046 i2c_unregister_device(client);
1051 mutex_unlock(&adap->userspace_clients_lock);
1054 dev_err(dev, "%s: Can't find device in list\n",
1058 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1059 i2c_sysfs_delete_device);
1061 static struct attribute *i2c_adapter_attrs[] = {
1062 &dev_attr_name.attr,
1063 &dev_attr_new_device.attr,
1064 &dev_attr_delete_device.attr,
1067 ATTRIBUTE_GROUPS(i2c_adapter);
1069 struct device_type i2c_adapter_type = {
1070 .groups = i2c_adapter_groups,
1071 .release = i2c_adapter_dev_release,
1073 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1076 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1077 * @dev: device, probably from some driver model iterator
1079 * When traversing the driver model tree, perhaps using driver model
1080 * iterators like @device_for_each_child(), you can't assume very much
1081 * about the nodes you find. Use this function to avoid oopses caused
1082 * by wrongly treating some non-I2C device as an i2c_adapter.
1084 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1086 return (dev->type == &i2c_adapter_type)
1087 ? to_i2c_adapter(dev)
1090 EXPORT_SYMBOL(i2c_verify_adapter);
1092 #ifdef CONFIG_I2C_COMPAT
1093 static struct class_compat *i2c_adapter_compat_class;
1096 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1098 struct i2c_devinfo *devinfo;
1100 down_read(&__i2c_board_lock);
1101 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1102 if (devinfo->busnum == adapter->nr
1103 && !i2c_new_device(adapter,
1104 &devinfo->board_info))
1105 dev_err(&adapter->dev,
1106 "Can't create device at 0x%02x\n",
1107 devinfo->board_info.addr);
1109 up_read(&__i2c_board_lock);
1112 static int i2c_do_add_adapter(struct i2c_driver *driver,
1113 struct i2c_adapter *adap)
1115 /* Detect supported devices on that bus, and instantiate them */
1116 i2c_detect(adap, driver);
1118 /* Let legacy drivers scan this bus for matching devices */
1119 if (driver->attach_adapter) {
1120 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1121 driver->driver.name);
1122 dev_warn(&adap->dev,
1123 "Please use another way to instantiate your i2c_client\n");
1124 /* We ignore the return code; if it fails, too bad */
1125 driver->attach_adapter(adap);
1130 static int __process_new_adapter(struct device_driver *d, void *data)
1132 return i2c_do_add_adapter(to_i2c_driver(d), data);
1135 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1136 .lock_bus = i2c_adapter_lock_bus,
1137 .trylock_bus = i2c_adapter_trylock_bus,
1138 .unlock_bus = i2c_adapter_unlock_bus,
1141 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1143 struct irq_domain *domain = adap->host_notify_domain;
1144 irq_hw_number_t hwirq;
1149 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1150 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1152 irq_domain_remove(domain);
1153 adap->host_notify_domain = NULL;
1156 static int i2c_host_notify_irq_map(struct irq_domain *h,
1158 irq_hw_number_t hw_irq_num)
1160 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1165 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1166 .map = i2c_host_notify_irq_map,
1169 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1171 struct irq_domain *domain;
1173 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1176 domain = irq_domain_create_linear(adap->dev.fwnode,
1177 I2C_ADDR_7BITS_COUNT,
1178 &i2c_host_notify_irq_ops, adap);
1182 adap->host_notify_domain = domain;
1188 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1190 * @adap: the adapter
1191 * @addr: the I2C address of the notifying device
1192 * Context: can't sleep
1194 * Helper function to be called from an I2C bus driver's interrupt
1195 * handler. It will schedule the Host Notify IRQ.
1197 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1204 irq = irq_find_mapping(adap->host_notify_domain, addr);
1208 generic_handle_irq(irq);
1212 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1214 static int i2c_register_adapter(struct i2c_adapter *adap)
1218 /* Can't register until after driver model init */
1219 if (WARN_ON(!is_registered)) {
1225 if (WARN(!adap->name[0], "i2c adapter has no name"))
1229 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1233 if (!adap->lock_ops)
1234 adap->lock_ops = &i2c_adapter_lock_ops;
1236 rt_mutex_init(&adap->bus_lock);
1237 rt_mutex_init(&adap->mux_lock);
1238 mutex_init(&adap->userspace_clients_lock);
1239 INIT_LIST_HEAD(&adap->userspace_clients);
1241 /* Set default timeout to 1 second if not already set */
1242 if (adap->timeout == 0)
1245 /* register soft irqs for Host Notify */
1246 res = i2c_setup_host_notify_irq_domain(adap);
1248 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1253 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1254 adap->dev.bus = &i2c_bus_type;
1255 adap->dev.type = &i2c_adapter_type;
1256 res = device_register(&adap->dev);
1258 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1262 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1264 pm_runtime_no_callbacks(&adap->dev);
1265 pm_suspend_ignore_children(&adap->dev, true);
1266 pm_runtime_enable(&adap->dev);
1268 #ifdef CONFIG_I2C_COMPAT
1269 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1272 dev_warn(&adap->dev,
1273 "Failed to create compatibility class link\n");
1276 i2c_init_recovery(adap);
1278 /* create pre-declared device nodes */
1279 of_i2c_register_devices(adap);
1280 i2c_acpi_register_devices(adap);
1281 i2c_acpi_install_space_handler(adap);
1283 if (adap->nr < __i2c_first_dynamic_bus_num)
1284 i2c_scan_static_board_info(adap);
1286 /* Notify drivers */
1287 mutex_lock(&core_lock);
1288 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1289 mutex_unlock(&core_lock);
1294 mutex_lock(&core_lock);
1295 idr_remove(&i2c_adapter_idr, adap->nr);
1296 mutex_unlock(&core_lock);
1301 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1302 * @adap: the adapter to register (with adap->nr initialized)
1303 * Context: can sleep
1305 * See i2c_add_numbered_adapter() for details.
1307 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1311 mutex_lock(&core_lock);
1312 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1313 mutex_unlock(&core_lock);
1314 if (WARN(id < 0, "couldn't get idr"))
1315 return id == -ENOSPC ? -EBUSY : id;
1317 return i2c_register_adapter(adap);
1321 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1322 * @adapter: the adapter to add
1323 * Context: can sleep
1325 * This routine is used to declare an I2C adapter when its bus number
1326 * doesn't matter or when its bus number is specified by an dt alias.
1327 * Examples of bases when the bus number doesn't matter: I2C adapters
1328 * dynamically added by USB links or PCI plugin cards.
1330 * When this returns zero, a new bus number was allocated and stored
1331 * in adap->nr, and the specified adapter became available for clients.
1332 * Otherwise, a negative errno value is returned.
1334 int i2c_add_adapter(struct i2c_adapter *adapter)
1336 struct device *dev = &adapter->dev;
1340 id = of_alias_get_id(dev->of_node, "i2c");
1343 return __i2c_add_numbered_adapter(adapter);
1347 mutex_lock(&core_lock);
1348 id = idr_alloc(&i2c_adapter_idr, adapter,
1349 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1350 mutex_unlock(&core_lock);
1351 if (WARN(id < 0, "couldn't get idr"))
1356 return i2c_register_adapter(adapter);
1358 EXPORT_SYMBOL(i2c_add_adapter);
1361 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1362 * @adap: the adapter to register (with adap->nr initialized)
1363 * Context: can sleep
1365 * This routine is used to declare an I2C adapter when its bus number
1366 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1367 * or otherwise built in to the system's mainboard, and where i2c_board_info
1368 * is used to properly configure I2C devices.
1370 * If the requested bus number is set to -1, then this function will behave
1371 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1373 * If no devices have pre-been declared for this bus, then be sure to
1374 * register the adapter before any dynamically allocated ones. Otherwise
1375 * the required bus ID may not be available.
1377 * When this returns zero, the specified adapter became available for
1378 * clients using the bus number provided in adap->nr. Also, the table
1379 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1380 * and the appropriate driver model device nodes are created. Otherwise, a
1381 * negative errno value is returned.
1383 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1385 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1386 return i2c_add_adapter(adap);
1388 return __i2c_add_numbered_adapter(adap);
1390 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1392 static void i2c_do_del_adapter(struct i2c_driver *driver,
1393 struct i2c_adapter *adapter)
1395 struct i2c_client *client, *_n;
1397 /* Remove the devices we created ourselves as the result of hardware
1398 * probing (using a driver's detect method) */
1399 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1400 if (client->adapter == adapter) {
1401 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1402 client->name, client->addr);
1403 list_del(&client->detected);
1404 i2c_unregister_device(client);
1409 static int __unregister_client(struct device *dev, void *dummy)
1411 struct i2c_client *client = i2c_verify_client(dev);
1412 if (client && strcmp(client->name, "dummy"))
1413 i2c_unregister_device(client);
1417 static int __unregister_dummy(struct device *dev, void *dummy)
1419 struct i2c_client *client = i2c_verify_client(dev);
1421 i2c_unregister_device(client);
1425 static int __process_removed_adapter(struct device_driver *d, void *data)
1427 i2c_do_del_adapter(to_i2c_driver(d), data);
1432 * i2c_del_adapter - unregister I2C adapter
1433 * @adap: the adapter being unregistered
1434 * Context: can sleep
1436 * This unregisters an I2C adapter which was previously registered
1437 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1439 void i2c_del_adapter(struct i2c_adapter *adap)
1441 struct i2c_adapter *found;
1442 struct i2c_client *client, *next;
1444 /* First make sure that this adapter was ever added */
1445 mutex_lock(&core_lock);
1446 found = idr_find(&i2c_adapter_idr, adap->nr);
1447 mutex_unlock(&core_lock);
1448 if (found != adap) {
1449 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1453 i2c_acpi_remove_space_handler(adap);
1454 /* Tell drivers about this removal */
1455 mutex_lock(&core_lock);
1456 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1457 __process_removed_adapter);
1458 mutex_unlock(&core_lock);
1460 /* Remove devices instantiated from sysfs */
1461 mutex_lock_nested(&adap->userspace_clients_lock,
1462 i2c_adapter_depth(adap));
1463 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1465 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1467 list_del(&client->detected);
1468 i2c_unregister_device(client);
1470 mutex_unlock(&adap->userspace_clients_lock);
1472 /* Detach any active clients. This can't fail, thus we do not
1473 * check the returned value. This is a two-pass process, because
1474 * we can't remove the dummy devices during the first pass: they
1475 * could have been instantiated by real devices wishing to clean
1476 * them up properly, so we give them a chance to do that first. */
1477 device_for_each_child(&adap->dev, NULL, __unregister_client);
1478 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1480 #ifdef CONFIG_I2C_COMPAT
1481 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1485 /* device name is gone after device_unregister */
1486 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1488 pm_runtime_disable(&adap->dev);
1490 i2c_host_notify_irq_teardown(adap);
1492 /* wait until all references to the device are gone
1494 * FIXME: This is old code and should ideally be replaced by an
1495 * alternative which results in decoupling the lifetime of the struct
1496 * device from the i2c_adapter, like spi or netdev do. Any solution
1497 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1499 init_completion(&adap->dev_released);
1500 device_unregister(&adap->dev);
1501 wait_for_completion(&adap->dev_released);
1504 mutex_lock(&core_lock);
1505 idr_remove(&i2c_adapter_idr, adap->nr);
1506 mutex_unlock(&core_lock);
1508 /* Clear the device structure in case this adapter is ever going to be
1510 memset(&adap->dev, 0, sizeof(adap->dev));
1512 EXPORT_SYMBOL(i2c_del_adapter);
1515 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1516 * @dev: The device to scan for I2C timing properties
1517 * @t: the i2c_timings struct to be filled with values
1518 * @use_defaults: bool to use sane defaults derived from the I2C specification
1519 * when properties are not found, otherwise use 0
1521 * Scan the device for the generic I2C properties describing timing parameters
1522 * for the signal and fill the given struct with the results. If a property was
1523 * not found and use_defaults was true, then maximum timings are assumed which
1524 * are derived from the I2C specification. If use_defaults is not used, the
1525 * results will be 0, so drivers can apply their own defaults later. The latter
1526 * is mainly intended for avoiding regressions of existing drivers which want
1527 * to switch to this function. New drivers almost always should use the defaults.
1530 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1534 memset(t, 0, sizeof(*t));
1536 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1537 if (ret && use_defaults)
1538 t->bus_freq_hz = 100000;
1540 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1541 if (ret && use_defaults) {
1542 if (t->bus_freq_hz <= 100000)
1543 t->scl_rise_ns = 1000;
1544 else if (t->bus_freq_hz <= 400000)
1545 t->scl_rise_ns = 300;
1547 t->scl_rise_ns = 120;
1550 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1551 if (ret && use_defaults) {
1552 if (t->bus_freq_hz <= 400000)
1553 t->scl_fall_ns = 300;
1555 t->scl_fall_ns = 120;
1558 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1560 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1561 if (ret && use_defaults)
1562 t->sda_fall_ns = t->scl_fall_ns;
1564 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1566 /* ------------------------------------------------------------------------- */
1568 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1572 mutex_lock(&core_lock);
1573 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1574 mutex_unlock(&core_lock);
1578 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1580 static int __process_new_driver(struct device *dev, void *data)
1582 if (dev->type != &i2c_adapter_type)
1584 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1588 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1589 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1592 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1596 /* Can't register until after driver model init */
1597 if (WARN_ON(!is_registered))
1600 /* add the driver to the list of i2c drivers in the driver core */
1601 driver->driver.owner = owner;
1602 driver->driver.bus = &i2c_bus_type;
1603 INIT_LIST_HEAD(&driver->clients);
1605 /* When registration returns, the driver core
1606 * will have called probe() for all matching-but-unbound devices.
1608 res = driver_register(&driver->driver);
1612 pr_debug("driver [%s] registered\n", driver->driver.name);
1614 /* Walk the adapters that are already present */
1615 i2c_for_each_dev(driver, __process_new_driver);
1619 EXPORT_SYMBOL(i2c_register_driver);
1621 static int __process_removed_driver(struct device *dev, void *data)
1623 if (dev->type == &i2c_adapter_type)
1624 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1629 * i2c_del_driver - unregister I2C driver
1630 * @driver: the driver being unregistered
1631 * Context: can sleep
1633 void i2c_del_driver(struct i2c_driver *driver)
1635 i2c_for_each_dev(driver, __process_removed_driver);
1637 driver_unregister(&driver->driver);
1638 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1640 EXPORT_SYMBOL(i2c_del_driver);
1642 /* ------------------------------------------------------------------------- */
1645 * i2c_use_client - increments the reference count of the i2c client structure
1646 * @client: the client being referenced
1648 * Each live reference to a client should be refcounted. The driver model does
1649 * that automatically as part of driver binding, so that most drivers don't
1650 * need to do this explicitly: they hold a reference until they're unbound
1653 * A pointer to the client with the incremented reference counter is returned.
1655 struct i2c_client *i2c_use_client(struct i2c_client *client)
1657 if (client && get_device(&client->dev))
1661 EXPORT_SYMBOL(i2c_use_client);
1664 * i2c_release_client - release a use of the i2c client structure
1665 * @client: the client being no longer referenced
1667 * Must be called when a user of a client is finished with it.
1669 void i2c_release_client(struct i2c_client *client)
1672 put_device(&client->dev);
1674 EXPORT_SYMBOL(i2c_release_client);
1676 struct i2c_cmd_arg {
1681 static int i2c_cmd(struct device *dev, void *_arg)
1683 struct i2c_client *client = i2c_verify_client(dev);
1684 struct i2c_cmd_arg *arg = _arg;
1685 struct i2c_driver *driver;
1687 if (!client || !client->dev.driver)
1690 driver = to_i2c_driver(client->dev.driver);
1691 if (driver->command)
1692 driver->command(client, arg->cmd, arg->arg);
1696 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1698 struct i2c_cmd_arg cmd_arg;
1702 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1704 EXPORT_SYMBOL(i2c_clients_command);
1706 static int __init i2c_init(void)
1710 retval = of_alias_get_highest_id("i2c");
1712 down_write(&__i2c_board_lock);
1713 if (retval >= __i2c_first_dynamic_bus_num)
1714 __i2c_first_dynamic_bus_num = retval + 1;
1715 up_write(&__i2c_board_lock);
1717 retval = bus_register(&i2c_bus_type);
1721 is_registered = true;
1723 #ifdef CONFIG_I2C_COMPAT
1724 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1725 if (!i2c_adapter_compat_class) {
1730 retval = i2c_add_driver(&dummy_driver);
1734 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1735 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1736 if (IS_ENABLED(CONFIG_ACPI))
1737 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1742 #ifdef CONFIG_I2C_COMPAT
1743 class_compat_unregister(i2c_adapter_compat_class);
1746 is_registered = false;
1747 bus_unregister(&i2c_bus_type);
1751 static void __exit i2c_exit(void)
1753 if (IS_ENABLED(CONFIG_ACPI))
1754 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1755 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1756 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1757 i2c_del_driver(&dummy_driver);
1758 #ifdef CONFIG_I2C_COMPAT
1759 class_compat_unregister(i2c_adapter_compat_class);
1761 bus_unregister(&i2c_bus_type);
1762 tracepoint_synchronize_unregister();
1765 /* We must initialize early, because some subsystems register i2c drivers
1766 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1768 postcore_initcall(i2c_init);
1769 module_exit(i2c_exit);
1771 /* ----------------------------------------------------
1772 * the functional interface to the i2c busses.
1773 * ----------------------------------------------------
1776 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1777 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1779 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1781 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1782 err_msg, msg->addr, msg->len,
1783 msg->flags & I2C_M_RD ? "read" : "write");
1787 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1789 const struct i2c_adapter_quirks *q = adap->quirks;
1790 int max_num = q->max_num_msgs, i;
1791 bool do_len_check = true;
1793 if (q->flags & I2C_AQ_COMB) {
1796 /* special checks for combined messages */
1798 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1799 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1801 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1802 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1804 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1805 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1807 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1808 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1810 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1811 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1813 do_len_check = false;
1817 if (i2c_quirk_exceeded(num, max_num))
1818 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1820 for (i = 0; i < num; i++) {
1821 u16 len = msgs[i].len;
1823 if (msgs[i].flags & I2C_M_RD) {
1824 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1825 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1827 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1828 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1836 * __i2c_transfer - unlocked flavor of i2c_transfer
1837 * @adap: Handle to I2C bus
1838 * @msgs: One or more messages to execute before STOP is issued to
1839 * terminate the operation; each message begins with a START.
1840 * @num: Number of messages to be executed.
1842 * Returns negative errno, else the number of messages executed.
1844 * Adapter lock must be held when calling this function. No debug logging
1845 * takes place. adap->algo->master_xfer existence isn't checked.
1847 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1849 unsigned long orig_jiffies;
1852 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1855 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1856 * enabled. This is an efficient way of keeping the for-loop from
1857 * being executed when not needed.
1859 if (static_key_false(&i2c_trace_msg)) {
1861 for (i = 0; i < num; i++)
1862 if (msgs[i].flags & I2C_M_RD)
1863 trace_i2c_read(adap, &msgs[i], i);
1865 trace_i2c_write(adap, &msgs[i], i);
1868 /* Retry automatically on arbitration loss */
1869 orig_jiffies = jiffies;
1870 for (ret = 0, try = 0; try <= adap->retries; try++) {
1871 ret = adap->algo->master_xfer(adap, msgs, num);
1874 if (time_after(jiffies, orig_jiffies + adap->timeout))
1878 if (static_key_false(&i2c_trace_msg)) {
1880 for (i = 0; i < ret; i++)
1881 if (msgs[i].flags & I2C_M_RD)
1882 trace_i2c_reply(adap, &msgs[i], i);
1883 trace_i2c_result(adap, i, ret);
1888 EXPORT_SYMBOL(__i2c_transfer);
1891 * i2c_transfer - execute a single or combined I2C message
1892 * @adap: Handle to I2C bus
1893 * @msgs: One or more messages to execute before STOP is issued to
1894 * terminate the operation; each message begins with a START.
1895 * @num: Number of messages to be executed.
1897 * Returns negative errno, else the number of messages executed.
1899 * Note that there is no requirement that each message be sent to
1900 * the same slave address, although that is the most common model.
1902 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1906 /* REVISIT the fault reporting model here is weak:
1908 * - When we get an error after receiving N bytes from a slave,
1909 * there is no way to report "N".
1911 * - When we get a NAK after transmitting N bytes to a slave,
1912 * there is no way to report "N" ... or to let the master
1913 * continue executing the rest of this combined message, if
1914 * that's the appropriate response.
1916 * - When for example "num" is two and we successfully complete
1917 * the first message but get an error part way through the
1918 * second, it's unclear whether that should be reported as
1919 * one (discarding status on the second message) or errno
1920 * (discarding status on the first one).
1923 if (adap->algo->master_xfer) {
1925 for (ret = 0; ret < num; ret++) {
1927 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1928 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1929 msgs[ret].addr, msgs[ret].len,
1930 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1934 if (in_atomic() || irqs_disabled()) {
1935 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1937 /* I2C activity is ongoing. */
1940 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1943 ret = __i2c_transfer(adap, msgs, num);
1944 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1948 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1952 EXPORT_SYMBOL(i2c_transfer);
1955 * i2c_master_send - issue a single I2C message in master transmit mode
1956 * @client: Handle to slave device
1957 * @buf: Data that will be written to the slave
1958 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1960 * Returns negative errno, or else the number of bytes written.
1962 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1965 struct i2c_adapter *adap = client->adapter;
1968 msg.addr = client->addr;
1969 msg.flags = client->flags & I2C_M_TEN;
1971 msg.buf = (char *)buf;
1973 ret = i2c_transfer(adap, &msg, 1);
1976 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1977 * transmitted, else error code.
1979 return (ret == 1) ? count : ret;
1981 EXPORT_SYMBOL(i2c_master_send);
1984 * i2c_master_recv - issue a single I2C message in master receive mode
1985 * @client: Handle to slave device
1986 * @buf: Where to store data read from slave
1987 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1989 * Returns negative errno, or else the number of bytes read.
1991 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
1993 struct i2c_adapter *adap = client->adapter;
1997 msg.addr = client->addr;
1998 msg.flags = client->flags & I2C_M_TEN;
1999 msg.flags |= I2C_M_RD;
2003 ret = i2c_transfer(adap, &msg, 1);
2006 * If everything went ok (i.e. 1 msg received), return #bytes received,
2009 return (ret == 1) ? count : ret;
2011 EXPORT_SYMBOL(i2c_master_recv);
2013 /* ----------------------------------------------------
2014 * the i2c address scanning function
2015 * Will not work for 10-bit addresses!
2016 * ----------------------------------------------------
2020 * Legacy default probe function, mostly relevant for SMBus. The default
2021 * probe method is a quick write, but it is known to corrupt the 24RF08
2022 * EEPROMs due to a state machine bug, and could also irreversibly
2023 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2024 * we use a short byte read instead. Also, some bus drivers don't implement
2025 * quick write, so we fallback to a byte read in that case too.
2026 * On x86, there is another special case for FSC hardware monitoring chips,
2027 * which want regular byte reads (address 0x73.) Fortunately, these are the
2028 * only known chips using this I2C address on PC hardware.
2029 * Returns 1 if probe succeeded, 0 if not.
2031 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2034 union i2c_smbus_data dummy;
2037 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2038 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2039 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2040 I2C_SMBUS_BYTE_DATA, &dummy);
2043 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2044 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2045 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2046 I2C_SMBUS_QUICK, NULL);
2047 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2048 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2049 I2C_SMBUS_BYTE, &dummy);
2051 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2059 static int i2c_detect_address(struct i2c_client *temp_client,
2060 struct i2c_driver *driver)
2062 struct i2c_board_info info;
2063 struct i2c_adapter *adapter = temp_client->adapter;
2064 int addr = temp_client->addr;
2067 /* Make sure the address is valid */
2068 err = i2c_check_7bit_addr_validity_strict(addr);
2070 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2075 /* Skip if already in use (7 bit, no need to encode flags) */
2076 if (i2c_check_addr_busy(adapter, addr))
2079 /* Make sure there is something at this address */
2080 if (!i2c_default_probe(adapter, addr))
2083 /* Finally call the custom detection function */
2084 memset(&info, 0, sizeof(struct i2c_board_info));
2086 err = driver->detect(temp_client, &info);
2088 /* -ENODEV is returned if the detection fails. We catch it
2089 here as this isn't an error. */
2090 return err == -ENODEV ? 0 : err;
2093 /* Consistency check */
2094 if (info.type[0] == '\0') {
2095 dev_err(&adapter->dev,
2096 "%s detection function provided no name for 0x%x\n",
2097 driver->driver.name, addr);
2099 struct i2c_client *client;
2101 /* Detection succeeded, instantiate the device */
2102 if (adapter->class & I2C_CLASS_DEPRECATED)
2103 dev_warn(&adapter->dev,
2104 "This adapter will soon drop class based instantiation of devices. "
2105 "Please make sure client 0x%02x gets instantiated by other means. "
2106 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2109 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2110 info.type, info.addr);
2111 client = i2c_new_device(adapter, &info);
2113 list_add_tail(&client->detected, &driver->clients);
2115 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2116 info.type, info.addr);
2121 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2123 const unsigned short *address_list;
2124 struct i2c_client *temp_client;
2126 int adap_id = i2c_adapter_id(adapter);
2128 address_list = driver->address_list;
2129 if (!driver->detect || !address_list)
2132 /* Warn that the adapter lost class based instantiation */
2133 if (adapter->class == I2C_CLASS_DEPRECATED) {
2134 dev_dbg(&adapter->dev,
2135 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2136 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2137 driver->driver.name);
2141 /* Stop here if the classes do not match */
2142 if (!(adapter->class & driver->class))
2145 /* Set up a temporary client to help detect callback */
2146 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2149 temp_client->adapter = adapter;
2151 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2152 dev_dbg(&adapter->dev,
2153 "found normal entry for adapter %d, addr 0x%02x\n",
2154 adap_id, address_list[i]);
2155 temp_client->addr = address_list[i];
2156 err = i2c_detect_address(temp_client, driver);
2165 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2167 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2168 I2C_SMBUS_QUICK, NULL) >= 0;
2170 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2173 i2c_new_probed_device(struct i2c_adapter *adap,
2174 struct i2c_board_info *info,
2175 unsigned short const *addr_list,
2176 int (*probe)(struct i2c_adapter *, unsigned short addr))
2181 probe = i2c_default_probe;
2183 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2184 /* Check address validity */
2185 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2186 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2191 /* Check address availability (7 bit, no need to encode flags) */
2192 if (i2c_check_addr_busy(adap, addr_list[i])) {
2194 "Address 0x%02x already in use, not probing\n",
2199 /* Test address responsiveness */
2200 if (probe(adap, addr_list[i]))
2204 if (addr_list[i] == I2C_CLIENT_END) {
2205 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2209 info->addr = addr_list[i];
2210 return i2c_new_device(adap, info);
2212 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2214 struct i2c_adapter *i2c_get_adapter(int nr)
2216 struct i2c_adapter *adapter;
2218 mutex_lock(&core_lock);
2219 adapter = idr_find(&i2c_adapter_idr, nr);
2223 if (try_module_get(adapter->owner))
2224 get_device(&adapter->dev);
2229 mutex_unlock(&core_lock);
2232 EXPORT_SYMBOL(i2c_get_adapter);
2234 void i2c_put_adapter(struct i2c_adapter *adap)
2239 put_device(&adap->dev);
2240 module_put(adap->owner);
2242 EXPORT_SYMBOL(i2c_put_adapter);
2244 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2245 MODULE_DESCRIPTION("I2C-Bus main module");
2246 MODULE_LICENSE("GPL");