4 * Copyright (C) 1995-99 Simon G. Vogl
5 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
6 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
7 * Michael Lawnick <michael.lawnick.ext@nsn.com>
9 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
16 * This program is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
21 #define pr_fmt(fmt) "i2c-core: " fmt
23 #include <dt-bindings/i2c/i2c.h>
24 #include <linux/acpi.h>
25 #include <linux/clk/clk-conf.h>
26 #include <linux/completion.h>
27 #include <linux/delay.h>
28 #include <linux/err.h>
29 #include <linux/errno.h>
30 #include <linux/gpio/consumer.h>
31 #include <linux/i2c.h>
32 #include <linux/i2c-smbus.h>
33 #include <linux/idr.h>
34 #include <linux/init.h>
35 #include <linux/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)
61 #define I2C_ADDR_DEVICE_ID 0x7c
64 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
65 * deletion of detected devices, and attach_adapter calls are serialized
67 static DEFINE_MUTEX(core_lock);
68 static DEFINE_IDR(i2c_adapter_idr);
70 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
72 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
73 static bool is_registered;
75 int i2c_transfer_trace_reg(void)
77 static_branch_inc(&i2c_trace_msg_key);
81 void i2c_transfer_trace_unreg(void)
83 static_branch_dec(&i2c_trace_msg_key);
86 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
87 const struct i2c_client *client)
93 if (strcmp(client->name, id->name) == 0)
99 EXPORT_SYMBOL_GPL(i2c_match_id);
101 static int i2c_device_match(struct device *dev, struct device_driver *drv)
103 struct i2c_client *client = i2c_verify_client(dev);
104 struct i2c_driver *driver;
107 /* Attempt an OF style match */
108 if (i2c_of_match_device(drv->of_match_table, client))
111 /* Then ACPI style match */
112 if (acpi_driver_match_device(dev, drv))
115 driver = to_i2c_driver(drv);
117 /* Finally an I2C match */
118 if (i2c_match_id(driver->id_table, client))
124 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
126 struct i2c_client *client = to_i2c_client(dev);
129 rc = of_device_uevent_modalias(dev, env);
133 rc = acpi_device_uevent_modalias(dev, env);
137 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
140 /* i2c bus recovery routines */
141 static int get_scl_gpio_value(struct i2c_adapter *adap)
143 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
146 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
148 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
151 static int get_sda_gpio_value(struct i2c_adapter *adap)
153 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
156 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
158 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
162 * We are generating clock pulses. ndelay() determines durating of clk pulses.
163 * We will generate clock with rate 100 KHz and so duration of both clock levels
164 * is: delay in ns = (10^6 / 100) / 2
166 #define RECOVERY_NDELAY 5000
167 #define RECOVERY_CLK_CNT 9
169 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
171 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
172 int i = 0, val = 1, ret = 0;
174 if (bri->prepare_recovery)
175 bri->prepare_recovery(adap);
177 bri->set_scl(adap, val);
179 bri->set_sda(adap, 1);
180 ndelay(RECOVERY_NDELAY);
183 * By this time SCL is high, as we need to give 9 falling-rising edges
185 while (i++ < RECOVERY_CLK_CNT * 2) {
187 /* SCL shouldn't be low here */
188 if (!bri->get_scl(adap)) {
190 "SCL is stuck low, exit recovery\n");
194 /* Break if SDA is high */
195 if (bri->get_sda && bri->get_sda(adap))
200 bri->set_scl(adap, val);
203 * If we can set SDA, we will always create STOP here to ensure
204 * the additional pulses will do no harm. This is achieved by
205 * letting SDA follow SCL half a cycle later.
207 ndelay(RECOVERY_NDELAY / 2);
209 bri->set_sda(adap, val);
210 ndelay(RECOVERY_NDELAY / 2);
213 /* check if recovery actually succeeded */
214 if (bri->get_sda && !bri->get_sda(adap))
217 /* If all went well, send STOP for a sane bus state. */
218 if (ret == 0 && bri->set_sda) {
219 bri->set_scl(adap, 0);
220 ndelay(RECOVERY_NDELAY / 2);
221 bri->set_sda(adap, 0);
222 ndelay(RECOVERY_NDELAY / 2);
223 bri->set_scl(adap, 1);
224 ndelay(RECOVERY_NDELAY / 2);
225 bri->set_sda(adap, 1);
226 ndelay(RECOVERY_NDELAY / 2);
229 if (bri->unprepare_recovery)
230 bri->unprepare_recovery(adap);
234 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
236 int i2c_recover_bus(struct i2c_adapter *adap)
238 if (!adap->bus_recovery_info)
241 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
242 return adap->bus_recovery_info->recover_bus(adap);
244 EXPORT_SYMBOL_GPL(i2c_recover_bus);
246 static void i2c_init_recovery(struct i2c_adapter *adap)
248 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
254 if (!bri->recover_bus) {
255 err_str = "no recover_bus() found";
259 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
260 bri->get_scl = get_scl_gpio_value;
261 bri->set_scl = set_scl_gpio_value;
262 if (bri->sda_gpiod) {
263 bri->get_sda = get_sda_gpio_value;
264 /* FIXME: add proper flag instead of '0' once available */
265 if (gpiod_get_direction(bri->sda_gpiod) == 0)
266 bri->set_sda = set_sda_gpio_value;
271 if (bri->recover_bus == i2c_generic_scl_recovery) {
272 /* Generic SCL recovery */
273 if (!bri->set_scl || !bri->get_scl) {
274 err_str = "no {get|set}_scl() found";
281 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
282 adap->bus_recovery_info = NULL;
285 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
287 struct i2c_adapter *adap = client->adapter;
290 if (!adap->host_notify_domain)
293 if (client->flags & I2C_CLIENT_TEN)
296 irq = irq_find_mapping(adap->host_notify_domain, client->addr);
298 irq = irq_create_mapping(adap->host_notify_domain,
301 return irq > 0 ? irq : -ENXIO;
304 static int i2c_device_probe(struct device *dev)
306 struct i2c_client *client = i2c_verify_client(dev);
307 struct i2c_driver *driver;
313 driver = to_i2c_driver(dev->driver);
315 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
318 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
319 dev_dbg(dev, "Using Host Notify IRQ\n");
320 irq = i2c_smbus_host_notify_to_irq(client);
321 } else if (dev->of_node) {
322 irq = of_irq_get_byname(dev->of_node, "irq");
323 if (irq == -EINVAL || irq == -ENODATA)
324 irq = of_irq_get(dev->of_node, 0);
325 } else if (ACPI_COMPANION(dev)) {
326 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
328 if (irq == -EPROBE_DEFER)
338 * An I2C ID table is not mandatory, if and only if, a suitable OF
339 * or ACPI ID table is supplied for the probing device.
341 if (!driver->id_table &&
342 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
343 !i2c_of_match_device(dev->driver->of_match_table, client))
346 if (client->flags & I2C_CLIENT_WAKE) {
347 int wakeirq = -ENOENT;
350 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
351 if (wakeirq == -EPROBE_DEFER)
355 device_init_wakeup(&client->dev, true);
357 if (wakeirq > 0 && wakeirq != client->irq)
358 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
359 else if (client->irq > 0)
360 status = dev_pm_set_wake_irq(dev, client->irq);
365 dev_warn(&client->dev, "failed to set up wakeup irq\n");
368 dev_dbg(dev, "probe\n");
370 status = of_clk_set_defaults(dev->of_node, false);
372 goto err_clear_wakeup_irq;
374 status = dev_pm_domain_attach(&client->dev, true);
376 goto err_clear_wakeup_irq;
379 * When there are no more users of probe(),
380 * rename probe_new to probe.
382 if (driver->probe_new)
383 status = driver->probe_new(client);
384 else if (driver->probe)
385 status = driver->probe(client,
386 i2c_match_id(driver->id_table, client));
391 goto err_detach_pm_domain;
395 err_detach_pm_domain:
396 dev_pm_domain_detach(&client->dev, true);
397 err_clear_wakeup_irq:
398 dev_pm_clear_wake_irq(&client->dev);
399 device_init_wakeup(&client->dev, false);
403 static int i2c_device_remove(struct device *dev)
405 struct i2c_client *client = i2c_verify_client(dev);
406 struct i2c_driver *driver;
409 if (!client || !dev->driver)
412 driver = to_i2c_driver(dev->driver);
413 if (driver->remove) {
414 dev_dbg(dev, "remove\n");
415 status = driver->remove(client);
418 dev_pm_domain_detach(&client->dev, true);
420 dev_pm_clear_wake_irq(&client->dev);
421 device_init_wakeup(&client->dev, false);
426 static void i2c_device_shutdown(struct device *dev)
428 struct i2c_client *client = i2c_verify_client(dev);
429 struct i2c_driver *driver;
431 if (!client || !dev->driver)
433 driver = to_i2c_driver(dev->driver);
434 if (driver->shutdown)
435 driver->shutdown(client);
438 static void i2c_client_dev_release(struct device *dev)
440 kfree(to_i2c_client(dev));
444 show_name(struct device *dev, struct device_attribute *attr, char *buf)
446 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
447 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
449 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
452 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
454 struct i2c_client *client = to_i2c_client(dev);
457 len = of_device_modalias(dev, buf, PAGE_SIZE);
461 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
465 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
467 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
469 static struct attribute *i2c_dev_attrs[] = {
471 /* modalias helps coldplug: modprobe $(cat .../modalias) */
472 &dev_attr_modalias.attr,
475 ATTRIBUTE_GROUPS(i2c_dev);
477 struct bus_type i2c_bus_type = {
479 .match = i2c_device_match,
480 .probe = i2c_device_probe,
481 .remove = i2c_device_remove,
482 .shutdown = i2c_device_shutdown,
484 EXPORT_SYMBOL_GPL(i2c_bus_type);
486 struct device_type i2c_client_type = {
487 .groups = i2c_dev_groups,
488 .uevent = i2c_device_uevent,
489 .release = i2c_client_dev_release,
491 EXPORT_SYMBOL_GPL(i2c_client_type);
495 * i2c_verify_client - return parameter as i2c_client, or NULL
496 * @dev: device, probably from some driver model iterator
498 * When traversing the driver model tree, perhaps using driver model
499 * iterators like @device_for_each_child(), you can't assume very much
500 * about the nodes you find. Use this function to avoid oopses caused
501 * by wrongly treating some non-I2C device as an i2c_client.
503 struct i2c_client *i2c_verify_client(struct device *dev)
505 return (dev->type == &i2c_client_type)
509 EXPORT_SYMBOL(i2c_verify_client);
512 /* Return a unique address which takes the flags of the client into account */
513 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
515 unsigned short addr = client->addr;
517 /* For some client flags, add an arbitrary offset to avoid collisions */
518 if (client->flags & I2C_CLIENT_TEN)
519 addr |= I2C_ADDR_OFFSET_TEN_BIT;
521 if (client->flags & I2C_CLIENT_SLAVE)
522 addr |= I2C_ADDR_OFFSET_SLAVE;
527 /* This is a permissive address validity check, I2C address map constraints
528 * are purposely not enforced, except for the general call address. */
529 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
531 if (flags & I2C_CLIENT_TEN) {
532 /* 10-bit address, all values are valid */
536 /* 7-bit address, reject the general call address */
537 if (addr == 0x00 || addr > 0x7f)
543 /* And this is a strict address validity check, used when probing. If a
544 * device uses a reserved address, then it shouldn't be probed. 7-bit
545 * addressing is assumed, 10-bit address devices are rare and should be
546 * explicitly enumerated. */
547 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
550 * Reserved addresses per I2C specification:
551 * 0x00 General call address / START byte
553 * 0x02 Reserved for different bus format
554 * 0x03 Reserved for future purposes
555 * 0x04-0x07 Hs-mode master code
556 * 0x78-0x7b 10-bit slave addressing
557 * 0x7c-0x7f Reserved for future purposes
559 if (addr < 0x08 || addr > 0x77)
564 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
566 struct i2c_client *client = i2c_verify_client(dev);
567 int addr = *(int *)addrp;
569 if (client && i2c_encode_flags_to_addr(client) == addr)
574 /* walk up mux tree */
575 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
577 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
580 result = device_for_each_child(&adapter->dev, &addr,
581 __i2c_check_addr_busy);
583 if (!result && parent)
584 result = i2c_check_mux_parents(parent, addr);
589 /* recurse down mux tree */
590 static int i2c_check_mux_children(struct device *dev, void *addrp)
594 if (dev->type == &i2c_adapter_type)
595 result = device_for_each_child(dev, addrp,
596 i2c_check_mux_children);
598 result = __i2c_check_addr_busy(dev, addrp);
603 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
605 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
609 result = i2c_check_mux_parents(parent, addr);
612 result = device_for_each_child(&adapter->dev, &addr,
613 i2c_check_mux_children);
619 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
620 * @adapter: Target I2C bus segment
621 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
622 * locks only this branch in the adapter tree
624 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
627 rt_mutex_lock(&adapter->bus_lock);
631 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
632 * @adapter: Target I2C bus segment
633 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
634 * trylocks only this branch in the adapter tree
636 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
639 return rt_mutex_trylock(&adapter->bus_lock);
643 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
644 * @adapter: Target I2C bus segment
645 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
646 * unlocks only this branch in the adapter tree
648 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
651 rt_mutex_unlock(&adapter->bus_lock);
654 static void i2c_dev_set_name(struct i2c_adapter *adap,
655 struct i2c_client *client,
656 struct i2c_board_info const *info)
658 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
660 if (info && info->dev_name) {
661 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
666 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
670 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
671 i2c_encode_flags_to_addr(client));
674 static int i2c_dev_irq_from_resources(const struct resource *resources,
675 unsigned int num_resources)
677 struct irq_data *irqd;
680 for (i = 0; i < num_resources; i++) {
681 const struct resource *r = &resources[i];
683 if (resource_type(r) != IORESOURCE_IRQ)
686 if (r->flags & IORESOURCE_BITS) {
687 irqd = irq_get_irq_data(r->start);
691 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
701 * i2c_new_device - instantiate an i2c device
702 * @adap: the adapter managing the device
703 * @info: describes one I2C device; bus_num is ignored
706 * Create an i2c device. Binding is handled through driver model
707 * probe()/remove() methods. A driver may be bound to this device when we
708 * return from this function, or any later moment (e.g. maybe hotplugging will
709 * load the driver module). This call is not appropriate for use by mainboard
710 * initialization logic, which usually runs during an arch_initcall() long
711 * before any i2c_adapter could exist.
713 * This returns the new i2c client, which may be saved for later use with
714 * i2c_unregister_device(); or NULL to indicate an error.
717 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
719 struct i2c_client *client;
722 client = kzalloc(sizeof *client, GFP_KERNEL);
726 client->adapter = adap;
728 client->dev.platform_data = info->platform_data;
729 client->flags = info->flags;
730 client->addr = info->addr;
732 client->irq = info->irq;
734 client->irq = i2c_dev_irq_from_resources(info->resources,
735 info->num_resources);
737 strlcpy(client->name, info->type, sizeof(client->name));
739 status = i2c_check_addr_validity(client->addr, client->flags);
741 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
742 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
746 /* Check for address business */
747 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
751 client->dev.parent = &client->adapter->dev;
752 client->dev.bus = &i2c_bus_type;
753 client->dev.type = &i2c_client_type;
754 client->dev.of_node = of_node_get(info->of_node);
755 client->dev.fwnode = info->fwnode;
757 i2c_dev_set_name(adap, client, info);
759 if (info->properties) {
760 status = device_add_properties(&client->dev, info->properties);
763 "Failed to add properties to client %s: %d\n",
764 client->name, status);
765 goto out_err_put_of_node;
769 status = device_register(&client->dev);
773 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
774 client->name, dev_name(&client->dev));
779 if (info->properties)
780 device_remove_properties(&client->dev);
782 of_node_put(info->of_node);
785 "Failed to register i2c client %s at 0x%02x (%d)\n",
786 client->name, client->addr, status);
791 EXPORT_SYMBOL_GPL(i2c_new_device);
795 * i2c_unregister_device - reverse effect of i2c_new_device()
796 * @client: value returned from i2c_new_device()
799 void i2c_unregister_device(struct i2c_client *client)
804 if (client->dev.of_node) {
805 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
806 of_node_put(client->dev.of_node);
809 if (ACPI_COMPANION(&client->dev))
810 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
811 device_unregister(&client->dev);
813 EXPORT_SYMBOL_GPL(i2c_unregister_device);
816 static const struct i2c_device_id dummy_id[] = {
821 static int dummy_probe(struct i2c_client *client,
822 const struct i2c_device_id *id)
827 static int dummy_remove(struct i2c_client *client)
832 static struct i2c_driver dummy_driver = {
833 .driver.name = "dummy",
834 .probe = dummy_probe,
835 .remove = dummy_remove,
836 .id_table = dummy_id,
840 * i2c_new_dummy - return a new i2c device bound to a dummy driver
841 * @adapter: the adapter managing the device
842 * @address: seven bit address to be used
845 * This returns an I2C client bound to the "dummy" driver, intended for use
846 * with devices that consume multiple addresses. Examples of such chips
847 * include various EEPROMS (like 24c04 and 24c08 models).
849 * These dummy devices have two main uses. First, most I2C and SMBus calls
850 * except i2c_transfer() need a client handle; the dummy will be that handle.
851 * And second, this prevents the specified address from being bound to a
854 * This returns the new i2c client, which should be saved for later use with
855 * i2c_unregister_device(); or NULL to indicate an error.
857 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
859 struct i2c_board_info info = {
860 I2C_BOARD_INFO("dummy", address),
863 return i2c_new_device(adapter, &info);
865 EXPORT_SYMBOL_GPL(i2c_new_dummy);
868 * i2c_new_secondary_device - Helper to get the instantiated secondary address
869 * and create the associated device
870 * @client: Handle to the primary client
871 * @name: Handle to specify which secondary address to get
872 * @default_addr: Used as a fallback if no secondary address was specified
875 * I2C clients can be composed of multiple I2C slaves bound together in a single
876 * component. The I2C client driver then binds to the master I2C slave and needs
877 * to create I2C dummy clients to communicate with all the other slaves.
879 * This function creates and returns an I2C dummy client whose I2C address is
880 * retrieved from the platform firmware based on the given slave name. If no
881 * address is specified by the firmware default_addr is used.
883 * On DT-based platforms the address is retrieved from the "reg" property entry
884 * cell whose "reg-names" value matches the slave name.
886 * This returns the new i2c client, which should be saved for later use with
887 * i2c_unregister_device(); or NULL to indicate an error.
889 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
893 struct device_node *np = client->dev.of_node;
894 u32 addr = default_addr;
898 i = of_property_match_string(np, "reg-names", name);
900 of_property_read_u32_index(np, "reg", i, &addr);
903 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
904 return i2c_new_dummy(client->adapter, addr);
906 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
908 /* ------------------------------------------------------------------------- */
910 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
912 static void i2c_adapter_dev_release(struct device *dev)
914 struct i2c_adapter *adap = to_i2c_adapter(dev);
915 complete(&adap->dev_released);
918 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
920 unsigned int depth = 0;
922 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
925 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
926 "adapter depth exceeds lockdep subclass limit\n");
930 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
933 * Let users instantiate I2C devices through sysfs. This can be used when
934 * platform initialization code doesn't contain the proper data for
935 * whatever reason. Also useful for drivers that do device detection and
936 * detection fails, either because the device uses an unexpected address,
937 * or this is a compatible device with different ID register values.
939 * Parameter checking may look overzealous, but we really don't want
940 * the user to provide incorrect parameters.
943 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
944 const char *buf, size_t count)
946 struct i2c_adapter *adap = to_i2c_adapter(dev);
947 struct i2c_board_info info;
948 struct i2c_client *client;
952 memset(&info, 0, sizeof(struct i2c_board_info));
954 blank = strchr(buf, ' ');
956 dev_err(dev, "%s: Missing parameters\n", "new_device");
959 if (blank - buf > I2C_NAME_SIZE - 1) {
960 dev_err(dev, "%s: Invalid device name\n", "new_device");
963 memcpy(info.type, buf, blank - buf);
965 /* Parse remaining parameters, reject extra parameters */
966 res = sscanf(++blank, "%hi%c", &info.addr, &end);
968 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
971 if (res > 1 && end != '\n') {
972 dev_err(dev, "%s: Extra parameters\n", "new_device");
976 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
977 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
978 info.flags |= I2C_CLIENT_TEN;
981 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
982 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
983 info.flags |= I2C_CLIENT_SLAVE;
986 client = i2c_new_device(adap, &info);
990 /* Keep track of the added device */
991 mutex_lock(&adap->userspace_clients_lock);
992 list_add_tail(&client->detected, &adap->userspace_clients);
993 mutex_unlock(&adap->userspace_clients_lock);
994 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
995 info.type, info.addr);
999 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1002 * And of course let the users delete the devices they instantiated, if
1003 * they got it wrong. This interface can only be used to delete devices
1004 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1005 * don't delete devices to which some kernel code still has references.
1007 * Parameter checking may look overzealous, but we really don't want
1008 * the user to delete the wrong device.
1011 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1012 const char *buf, size_t count)
1014 struct i2c_adapter *adap = to_i2c_adapter(dev);
1015 struct i2c_client *client, *next;
1016 unsigned short addr;
1020 /* Parse parameters, reject extra parameters */
1021 res = sscanf(buf, "%hi%c", &addr, &end);
1023 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1026 if (res > 1 && end != '\n') {
1027 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1031 /* Make sure the device was added through sysfs */
1033 mutex_lock_nested(&adap->userspace_clients_lock,
1034 i2c_adapter_depth(adap));
1035 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1037 if (i2c_encode_flags_to_addr(client) == addr) {
1038 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1039 "delete_device", client->name, client->addr);
1041 list_del(&client->detected);
1042 i2c_unregister_device(client);
1047 mutex_unlock(&adap->userspace_clients_lock);
1050 dev_err(dev, "%s: Can't find device in list\n",
1054 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1055 i2c_sysfs_delete_device);
1057 static struct attribute *i2c_adapter_attrs[] = {
1058 &dev_attr_name.attr,
1059 &dev_attr_new_device.attr,
1060 &dev_attr_delete_device.attr,
1063 ATTRIBUTE_GROUPS(i2c_adapter);
1065 struct device_type i2c_adapter_type = {
1066 .groups = i2c_adapter_groups,
1067 .release = i2c_adapter_dev_release,
1069 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1072 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1073 * @dev: device, probably from some driver model iterator
1075 * When traversing the driver model tree, perhaps using driver model
1076 * iterators like @device_for_each_child(), you can't assume very much
1077 * about the nodes you find. Use this function to avoid oopses caused
1078 * by wrongly treating some non-I2C device as an i2c_adapter.
1080 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1082 return (dev->type == &i2c_adapter_type)
1083 ? to_i2c_adapter(dev)
1086 EXPORT_SYMBOL(i2c_verify_adapter);
1088 #ifdef CONFIG_I2C_COMPAT
1089 static struct class_compat *i2c_adapter_compat_class;
1092 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1094 struct i2c_devinfo *devinfo;
1096 down_read(&__i2c_board_lock);
1097 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1098 if (devinfo->busnum == adapter->nr
1099 && !i2c_new_device(adapter,
1100 &devinfo->board_info))
1101 dev_err(&adapter->dev,
1102 "Can't create device at 0x%02x\n",
1103 devinfo->board_info.addr);
1105 up_read(&__i2c_board_lock);
1108 static int i2c_do_add_adapter(struct i2c_driver *driver,
1109 struct i2c_adapter *adap)
1111 /* Detect supported devices on that bus, and instantiate them */
1112 i2c_detect(adap, driver);
1114 /* Let legacy drivers scan this bus for matching devices */
1115 if (driver->attach_adapter) {
1116 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1117 driver->driver.name);
1118 dev_warn(&adap->dev,
1119 "Please use another way to instantiate your i2c_client\n");
1120 /* We ignore the return code; if it fails, too bad */
1121 driver->attach_adapter(adap);
1126 static int __process_new_adapter(struct device_driver *d, void *data)
1128 return i2c_do_add_adapter(to_i2c_driver(d), data);
1131 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1132 .lock_bus = i2c_adapter_lock_bus,
1133 .trylock_bus = i2c_adapter_trylock_bus,
1134 .unlock_bus = i2c_adapter_unlock_bus,
1137 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1139 struct irq_domain *domain = adap->host_notify_domain;
1140 irq_hw_number_t hwirq;
1145 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1146 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1148 irq_domain_remove(domain);
1149 adap->host_notify_domain = NULL;
1152 static int i2c_host_notify_irq_map(struct irq_domain *h,
1154 irq_hw_number_t hw_irq_num)
1156 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1161 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1162 .map = i2c_host_notify_irq_map,
1165 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1167 struct irq_domain *domain;
1169 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1172 domain = irq_domain_create_linear(adap->dev.fwnode,
1173 I2C_ADDR_7BITS_COUNT,
1174 &i2c_host_notify_irq_ops, adap);
1178 adap->host_notify_domain = domain;
1184 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1186 * @adap: the adapter
1187 * @addr: the I2C address of the notifying device
1188 * Context: can't sleep
1190 * Helper function to be called from an I2C bus driver's interrupt
1191 * handler. It will schedule the Host Notify IRQ.
1193 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1200 irq = irq_find_mapping(adap->host_notify_domain, addr);
1204 generic_handle_irq(irq);
1208 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1210 static int i2c_register_adapter(struct i2c_adapter *adap)
1214 /* Can't register until after driver model init */
1215 if (WARN_ON(!is_registered)) {
1221 if (WARN(!adap->name[0], "i2c adapter has no name"))
1225 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1229 if (!adap->lock_ops)
1230 adap->lock_ops = &i2c_adapter_lock_ops;
1232 rt_mutex_init(&adap->bus_lock);
1233 rt_mutex_init(&adap->mux_lock);
1234 mutex_init(&adap->userspace_clients_lock);
1235 INIT_LIST_HEAD(&adap->userspace_clients);
1237 /* Set default timeout to 1 second if not already set */
1238 if (adap->timeout == 0)
1241 /* register soft irqs for Host Notify */
1242 res = i2c_setup_host_notify_irq_domain(adap);
1244 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1249 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1250 adap->dev.bus = &i2c_bus_type;
1251 adap->dev.type = &i2c_adapter_type;
1252 res = device_register(&adap->dev);
1254 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1258 res = of_i2c_setup_smbus_alert(adap);
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 init_completion(&adap->dev_released);
1295 device_unregister(&adap->dev);
1296 wait_for_completion(&adap->dev_released);
1298 mutex_lock(&core_lock);
1299 idr_remove(&i2c_adapter_idr, adap->nr);
1300 mutex_unlock(&core_lock);
1305 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1306 * @adap: the adapter to register (with adap->nr initialized)
1307 * Context: can sleep
1309 * See i2c_add_numbered_adapter() for details.
1311 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1315 mutex_lock(&core_lock);
1316 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1317 mutex_unlock(&core_lock);
1318 if (WARN(id < 0, "couldn't get idr"))
1319 return id == -ENOSPC ? -EBUSY : id;
1321 return i2c_register_adapter(adap);
1325 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1326 * @adapter: the adapter to add
1327 * Context: can sleep
1329 * This routine is used to declare an I2C adapter when its bus number
1330 * doesn't matter or when its bus number is specified by an dt alias.
1331 * Examples of bases when the bus number doesn't matter: I2C adapters
1332 * dynamically added by USB links or PCI plugin cards.
1334 * When this returns zero, a new bus number was allocated and stored
1335 * in adap->nr, and the specified adapter became available for clients.
1336 * Otherwise, a negative errno value is returned.
1338 int i2c_add_adapter(struct i2c_adapter *adapter)
1340 struct device *dev = &adapter->dev;
1344 id = of_alias_get_id(dev->of_node, "i2c");
1347 return __i2c_add_numbered_adapter(adapter);
1351 mutex_lock(&core_lock);
1352 id = idr_alloc(&i2c_adapter_idr, adapter,
1353 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1354 mutex_unlock(&core_lock);
1355 if (WARN(id < 0, "couldn't get idr"))
1360 return i2c_register_adapter(adapter);
1362 EXPORT_SYMBOL(i2c_add_adapter);
1365 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1366 * @adap: the adapter to register (with adap->nr initialized)
1367 * Context: can sleep
1369 * This routine is used to declare an I2C adapter when its bus number
1370 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1371 * or otherwise built in to the system's mainboard, and where i2c_board_info
1372 * is used to properly configure I2C devices.
1374 * If the requested bus number is set to -1, then this function will behave
1375 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1377 * If no devices have pre-been declared for this bus, then be sure to
1378 * register the adapter before any dynamically allocated ones. Otherwise
1379 * the required bus ID may not be available.
1381 * When this returns zero, the specified adapter became available for
1382 * clients using the bus number provided in adap->nr. Also, the table
1383 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1384 * and the appropriate driver model device nodes are created. Otherwise, a
1385 * negative errno value is returned.
1387 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1389 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1390 return i2c_add_adapter(adap);
1392 return __i2c_add_numbered_adapter(adap);
1394 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1396 static void i2c_do_del_adapter(struct i2c_driver *driver,
1397 struct i2c_adapter *adapter)
1399 struct i2c_client *client, *_n;
1401 /* Remove the devices we created ourselves as the result of hardware
1402 * probing (using a driver's detect method) */
1403 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1404 if (client->adapter == adapter) {
1405 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1406 client->name, client->addr);
1407 list_del(&client->detected);
1408 i2c_unregister_device(client);
1413 static int __unregister_client(struct device *dev, void *dummy)
1415 struct i2c_client *client = i2c_verify_client(dev);
1416 if (client && strcmp(client->name, "dummy"))
1417 i2c_unregister_device(client);
1421 static int __unregister_dummy(struct device *dev, void *dummy)
1423 struct i2c_client *client = i2c_verify_client(dev);
1424 i2c_unregister_device(client);
1428 static int __process_removed_adapter(struct device_driver *d, void *data)
1430 i2c_do_del_adapter(to_i2c_driver(d), data);
1435 * i2c_del_adapter - unregister I2C adapter
1436 * @adap: the adapter being unregistered
1437 * Context: can sleep
1439 * This unregisters an I2C adapter which was previously registered
1440 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1442 void i2c_del_adapter(struct i2c_adapter *adap)
1444 struct i2c_adapter *found;
1445 struct i2c_client *client, *next;
1447 /* First make sure that this adapter was ever added */
1448 mutex_lock(&core_lock);
1449 found = idr_find(&i2c_adapter_idr, adap->nr);
1450 mutex_unlock(&core_lock);
1451 if (found != adap) {
1452 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1456 i2c_acpi_remove_space_handler(adap);
1457 /* Tell drivers about this removal */
1458 mutex_lock(&core_lock);
1459 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1460 __process_removed_adapter);
1461 mutex_unlock(&core_lock);
1463 /* Remove devices instantiated from sysfs */
1464 mutex_lock_nested(&adap->userspace_clients_lock,
1465 i2c_adapter_depth(adap));
1466 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1468 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1470 list_del(&client->detected);
1471 i2c_unregister_device(client);
1473 mutex_unlock(&adap->userspace_clients_lock);
1475 /* Detach any active clients. This can't fail, thus we do not
1476 * check the returned value. This is a two-pass process, because
1477 * we can't remove the dummy devices during the first pass: they
1478 * could have been instantiated by real devices wishing to clean
1479 * them up properly, so we give them a chance to do that first. */
1480 device_for_each_child(&adap->dev, NULL, __unregister_client);
1481 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1483 #ifdef CONFIG_I2C_COMPAT
1484 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1488 /* device name is gone after device_unregister */
1489 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1491 pm_runtime_disable(&adap->dev);
1493 i2c_host_notify_irq_teardown(adap);
1495 /* wait until all references to the device are gone
1497 * FIXME: This is old code and should ideally be replaced by an
1498 * alternative which results in decoupling the lifetime of the struct
1499 * device from the i2c_adapter, like spi or netdev do. Any solution
1500 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1502 init_completion(&adap->dev_released);
1503 device_unregister(&adap->dev);
1504 wait_for_completion(&adap->dev_released);
1507 mutex_lock(&core_lock);
1508 idr_remove(&i2c_adapter_idr, adap->nr);
1509 mutex_unlock(&core_lock);
1511 /* Clear the device structure in case this adapter is ever going to be
1513 memset(&adap->dev, 0, sizeof(adap->dev));
1515 EXPORT_SYMBOL(i2c_del_adapter);
1518 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1519 * @dev: The device to scan for I2C timing properties
1520 * @t: the i2c_timings struct to be filled with values
1521 * @use_defaults: bool to use sane defaults derived from the I2C specification
1522 * when properties are not found, otherwise use 0
1524 * Scan the device for the generic I2C properties describing timing parameters
1525 * for the signal and fill the given struct with the results. If a property was
1526 * not found and use_defaults was true, then maximum timings are assumed which
1527 * are derived from the I2C specification. If use_defaults is not used, the
1528 * results will be 0, so drivers can apply their own defaults later. The latter
1529 * is mainly intended for avoiding regressions of existing drivers which want
1530 * to switch to this function. New drivers almost always should use the defaults.
1533 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1537 memset(t, 0, sizeof(*t));
1539 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1540 if (ret && use_defaults)
1541 t->bus_freq_hz = 100000;
1543 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1544 if (ret && use_defaults) {
1545 if (t->bus_freq_hz <= 100000)
1546 t->scl_rise_ns = 1000;
1547 else if (t->bus_freq_hz <= 400000)
1548 t->scl_rise_ns = 300;
1550 t->scl_rise_ns = 120;
1553 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1554 if (ret && use_defaults) {
1555 if (t->bus_freq_hz <= 400000)
1556 t->scl_fall_ns = 300;
1558 t->scl_fall_ns = 120;
1561 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1563 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1564 if (ret && use_defaults)
1565 t->sda_fall_ns = t->scl_fall_ns;
1567 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1569 /* ------------------------------------------------------------------------- */
1571 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1575 mutex_lock(&core_lock);
1576 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1577 mutex_unlock(&core_lock);
1581 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1583 static int __process_new_driver(struct device *dev, void *data)
1585 if (dev->type != &i2c_adapter_type)
1587 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1591 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1592 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1595 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1599 /* Can't register until after driver model init */
1600 if (WARN_ON(!is_registered))
1603 /* add the driver to the list of i2c drivers in the driver core */
1604 driver->driver.owner = owner;
1605 driver->driver.bus = &i2c_bus_type;
1606 INIT_LIST_HEAD(&driver->clients);
1608 /* When registration returns, the driver core
1609 * will have called probe() for all matching-but-unbound devices.
1611 res = driver_register(&driver->driver);
1615 pr_debug("driver [%s] registered\n", driver->driver.name);
1617 /* Walk the adapters that are already present */
1618 i2c_for_each_dev(driver, __process_new_driver);
1622 EXPORT_SYMBOL(i2c_register_driver);
1624 static int __process_removed_driver(struct device *dev, void *data)
1626 if (dev->type == &i2c_adapter_type)
1627 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1632 * i2c_del_driver - unregister I2C driver
1633 * @driver: the driver being unregistered
1634 * Context: can sleep
1636 void i2c_del_driver(struct i2c_driver *driver)
1638 i2c_for_each_dev(driver, __process_removed_driver);
1640 driver_unregister(&driver->driver);
1641 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1643 EXPORT_SYMBOL(i2c_del_driver);
1645 /* ------------------------------------------------------------------------- */
1648 * i2c_use_client - increments the reference count of the i2c client structure
1649 * @client: the client being referenced
1651 * Each live reference to a client should be refcounted. The driver model does
1652 * that automatically as part of driver binding, so that most drivers don't
1653 * need to do this explicitly: they hold a reference until they're unbound
1656 * A pointer to the client with the incremented reference counter is returned.
1658 struct i2c_client *i2c_use_client(struct i2c_client *client)
1660 if (client && get_device(&client->dev))
1664 EXPORT_SYMBOL(i2c_use_client);
1667 * i2c_release_client - release a use of the i2c client structure
1668 * @client: the client being no longer referenced
1670 * Must be called when a user of a client is finished with it.
1672 void i2c_release_client(struct i2c_client *client)
1675 put_device(&client->dev);
1677 EXPORT_SYMBOL(i2c_release_client);
1679 struct i2c_cmd_arg {
1684 static int i2c_cmd(struct device *dev, void *_arg)
1686 struct i2c_client *client = i2c_verify_client(dev);
1687 struct i2c_cmd_arg *arg = _arg;
1688 struct i2c_driver *driver;
1690 if (!client || !client->dev.driver)
1693 driver = to_i2c_driver(client->dev.driver);
1694 if (driver->command)
1695 driver->command(client, arg->cmd, arg->arg);
1699 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1701 struct i2c_cmd_arg cmd_arg;
1705 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1707 EXPORT_SYMBOL(i2c_clients_command);
1709 static int __init i2c_init(void)
1713 retval = of_alias_get_highest_id("i2c");
1715 down_write(&__i2c_board_lock);
1716 if (retval >= __i2c_first_dynamic_bus_num)
1717 __i2c_first_dynamic_bus_num = retval + 1;
1718 up_write(&__i2c_board_lock);
1720 retval = bus_register(&i2c_bus_type);
1724 is_registered = true;
1726 #ifdef CONFIG_I2C_COMPAT
1727 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1728 if (!i2c_adapter_compat_class) {
1733 retval = i2c_add_driver(&dummy_driver);
1737 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1738 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1739 if (IS_ENABLED(CONFIG_ACPI))
1740 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1745 #ifdef CONFIG_I2C_COMPAT
1746 class_compat_unregister(i2c_adapter_compat_class);
1749 is_registered = false;
1750 bus_unregister(&i2c_bus_type);
1754 static void __exit i2c_exit(void)
1756 if (IS_ENABLED(CONFIG_ACPI))
1757 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1758 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1759 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1760 i2c_del_driver(&dummy_driver);
1761 #ifdef CONFIG_I2C_COMPAT
1762 class_compat_unregister(i2c_adapter_compat_class);
1764 bus_unregister(&i2c_bus_type);
1765 tracepoint_synchronize_unregister();
1768 /* We must initialize early, because some subsystems register i2c drivers
1769 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1771 postcore_initcall(i2c_init);
1772 module_exit(i2c_exit);
1774 /* ----------------------------------------------------
1775 * the functional interface to the i2c busses.
1776 * ----------------------------------------------------
1779 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1780 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1782 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1784 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1785 err_msg, msg->addr, msg->len,
1786 msg->flags & I2C_M_RD ? "read" : "write");
1790 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1792 const struct i2c_adapter_quirks *q = adap->quirks;
1793 int max_num = q->max_num_msgs, i;
1794 bool do_len_check = true;
1796 if (q->flags & I2C_AQ_COMB) {
1799 /* special checks for combined messages */
1801 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1802 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1804 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1805 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1807 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1808 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1810 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1811 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1813 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1814 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1816 do_len_check = false;
1820 if (i2c_quirk_exceeded(num, max_num))
1821 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1823 for (i = 0; i < num; i++) {
1824 u16 len = msgs[i].len;
1826 if (msgs[i].flags & I2C_M_RD) {
1827 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1828 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1830 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1831 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1839 * __i2c_transfer - unlocked flavor of i2c_transfer
1840 * @adap: Handle to I2C bus
1841 * @msgs: One or more messages to execute before STOP is issued to
1842 * terminate the operation; each message begins with a START.
1843 * @num: Number of messages to be executed.
1845 * Returns negative errno, else the number of messages executed.
1847 * Adapter lock must be held when calling this function. No debug logging
1848 * takes place. adap->algo->master_xfer existence isn't checked.
1850 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1852 unsigned long orig_jiffies;
1855 if (WARN_ON(!msgs || num < 1))
1858 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1862 * i2c_trace_msg_key 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_branch_unlikely(&i2c_trace_msg_key)) {
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_branch_unlikely(&i2c_trace_msg_key)) {
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, num, 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_transfer_buffer_flags - issue a single I2C message transferring data
1964 * @client: Handle to slave device
1965 * @buf: Where the data is stored
1966 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1967 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1969 * Returns negative errno, or else the number of bytes transferred.
1971 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1972 int count, u16 flags)
1975 struct i2c_msg msg = {
1976 .addr = client->addr,
1977 .flags = flags | (client->flags & I2C_M_TEN),
1982 ret = i2c_transfer(client->adapter, &msg, 1);
1985 * If everything went ok (i.e. 1 msg transferred), return #bytes
1986 * transferred, else error code.
1988 return (ret == 1) ? count : ret;
1990 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1993 * i2c_get_device_id - get manufacturer, part id and die revision of a device
1994 * @client: The device to query
1995 * @id: The queried information
1997 * Returns negative errno on error, zero on success.
1999 int i2c_get_device_id(const struct i2c_client *client,
2000 struct i2c_device_identity *id)
2002 struct i2c_adapter *adap = client->adapter;
2003 union i2c_smbus_data raw_id;
2006 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2009 raw_id.block[0] = 3;
2010 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2011 I2C_SMBUS_READ, client->addr << 1,
2012 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2016 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2017 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2018 id->die_revision = raw_id.block[3] & 0x7;
2021 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2023 /* ----------------------------------------------------
2024 * the i2c address scanning function
2025 * Will not work for 10-bit addresses!
2026 * ----------------------------------------------------
2030 * Legacy default probe function, mostly relevant for SMBus. The default
2031 * probe method is a quick write, but it is known to corrupt the 24RF08
2032 * EEPROMs due to a state machine bug, and could also irreversibly
2033 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2034 * we use a short byte read instead. Also, some bus drivers don't implement
2035 * quick write, so we fallback to a byte read in that case too.
2036 * On x86, there is another special case for FSC hardware monitoring chips,
2037 * which want regular byte reads (address 0x73.) Fortunately, these are the
2038 * only known chips using this I2C address on PC hardware.
2039 * Returns 1 if probe succeeded, 0 if not.
2041 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2044 union i2c_smbus_data dummy;
2047 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2048 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2049 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2050 I2C_SMBUS_BYTE_DATA, &dummy);
2053 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2054 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2055 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2056 I2C_SMBUS_QUICK, NULL);
2057 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2058 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2059 I2C_SMBUS_BYTE, &dummy);
2061 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2069 static int i2c_detect_address(struct i2c_client *temp_client,
2070 struct i2c_driver *driver)
2072 struct i2c_board_info info;
2073 struct i2c_adapter *adapter = temp_client->adapter;
2074 int addr = temp_client->addr;
2077 /* Make sure the address is valid */
2078 err = i2c_check_7bit_addr_validity_strict(addr);
2080 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2085 /* Skip if already in use (7 bit, no need to encode flags) */
2086 if (i2c_check_addr_busy(adapter, addr))
2089 /* Make sure there is something at this address */
2090 if (!i2c_default_probe(adapter, addr))
2093 /* Finally call the custom detection function */
2094 memset(&info, 0, sizeof(struct i2c_board_info));
2096 err = driver->detect(temp_client, &info);
2098 /* -ENODEV is returned if the detection fails. We catch it
2099 here as this isn't an error. */
2100 return err == -ENODEV ? 0 : err;
2103 /* Consistency check */
2104 if (info.type[0] == '\0') {
2105 dev_err(&adapter->dev,
2106 "%s detection function provided no name for 0x%x\n",
2107 driver->driver.name, addr);
2109 struct i2c_client *client;
2111 /* Detection succeeded, instantiate the device */
2112 if (adapter->class & I2C_CLASS_DEPRECATED)
2113 dev_warn(&adapter->dev,
2114 "This adapter will soon drop class based instantiation of devices. "
2115 "Please make sure client 0x%02x gets instantiated by other means. "
2116 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2119 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2120 info.type, info.addr);
2121 client = i2c_new_device(adapter, &info);
2123 list_add_tail(&client->detected, &driver->clients);
2125 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2126 info.type, info.addr);
2131 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2133 const unsigned short *address_list;
2134 struct i2c_client *temp_client;
2136 int adap_id = i2c_adapter_id(adapter);
2138 address_list = driver->address_list;
2139 if (!driver->detect || !address_list)
2142 /* Warn that the adapter lost class based instantiation */
2143 if (adapter->class == I2C_CLASS_DEPRECATED) {
2144 dev_dbg(&adapter->dev,
2145 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2146 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2147 driver->driver.name);
2151 /* Stop here if the classes do not match */
2152 if (!(adapter->class & driver->class))
2155 /* Set up a temporary client to help detect callback */
2156 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2159 temp_client->adapter = adapter;
2161 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2162 dev_dbg(&adapter->dev,
2163 "found normal entry for adapter %d, addr 0x%02x\n",
2164 adap_id, address_list[i]);
2165 temp_client->addr = address_list[i];
2166 err = i2c_detect_address(temp_client, driver);
2175 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2177 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2178 I2C_SMBUS_QUICK, NULL) >= 0;
2180 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2183 i2c_new_probed_device(struct i2c_adapter *adap,
2184 struct i2c_board_info *info,
2185 unsigned short const *addr_list,
2186 int (*probe)(struct i2c_adapter *, unsigned short addr))
2191 probe = i2c_default_probe;
2193 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2194 /* Check address validity */
2195 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2196 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2201 /* Check address availability (7 bit, no need to encode flags) */
2202 if (i2c_check_addr_busy(adap, addr_list[i])) {
2204 "Address 0x%02x already in use, not probing\n",
2209 /* Test address responsiveness */
2210 if (probe(adap, addr_list[i]))
2214 if (addr_list[i] == I2C_CLIENT_END) {
2215 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2219 info->addr = addr_list[i];
2220 return i2c_new_device(adap, info);
2222 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2224 struct i2c_adapter *i2c_get_adapter(int nr)
2226 struct i2c_adapter *adapter;
2228 mutex_lock(&core_lock);
2229 adapter = idr_find(&i2c_adapter_idr, nr);
2233 if (try_module_get(adapter->owner))
2234 get_device(&adapter->dev);
2239 mutex_unlock(&core_lock);
2242 EXPORT_SYMBOL(i2c_get_adapter);
2244 void i2c_put_adapter(struct i2c_adapter *adap)
2249 put_device(&adap->dev);
2250 module_put(adap->owner);
2252 EXPORT_SYMBOL(i2c_put_adapter);
2255 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2256 * @msg: the message to be checked
2257 * @threshold: the minimum number of bytes for which using DMA makes sense
2259 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2260 * Or a valid pointer to be used with DMA. After use, release it by
2261 * calling i2c_release_dma_safe_msg_buf().
2263 * This function must only be called from process context!
2265 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2267 if (msg->len < threshold)
2270 if (msg->flags & I2C_M_DMA_SAFE)
2273 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2274 msg->addr, msg->len);
2276 if (msg->flags & I2C_M_RD)
2277 return kzalloc(msg->len, GFP_KERNEL);
2279 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2281 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2284 * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2285 * @msg: the message to be synced with
2286 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2288 void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
2290 if (!buf || buf == msg->buf)
2293 if (msg->flags & I2C_M_RD)
2294 memcpy(msg->buf, buf, msg->len);
2298 EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
2300 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2301 MODULE_DESCRIPTION("I2C-Bus main module");
2302 MODULE_LICENSE("GPL");