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)
62 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
63 * deletion of detected devices, and attach_adapter calls are serialized
65 static DEFINE_MUTEX(core_lock);
66 static DEFINE_IDR(i2c_adapter_idr);
68 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
70 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
71 static bool is_registered;
73 int i2c_transfer_trace_reg(void)
75 static_key_slow_inc(&i2c_trace_msg);
79 void i2c_transfer_trace_unreg(void)
81 static_key_slow_dec(&i2c_trace_msg);
84 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
85 const struct i2c_client *client)
91 if (strcmp(client->name, id->name) == 0)
97 EXPORT_SYMBOL_GPL(i2c_match_id);
99 static int i2c_device_match(struct device *dev, struct device_driver *drv)
101 struct i2c_client *client = i2c_verify_client(dev);
102 struct i2c_driver *driver;
105 /* Attempt an OF style match */
106 if (i2c_of_match_device(drv->of_match_table, client))
109 /* Then ACPI style match */
110 if (acpi_driver_match_device(dev, drv))
113 driver = to_i2c_driver(drv);
115 /* Finally an I2C match */
116 if (i2c_match_id(driver->id_table, client))
122 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
124 struct i2c_client *client = to_i2c_client(dev);
127 rc = acpi_device_uevent_modalias(dev, env);
131 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
134 /* i2c bus recovery routines */
135 static int get_scl_gpio_value(struct i2c_adapter *adap)
137 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
140 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
142 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
145 static int get_sda_gpio_value(struct i2c_adapter *adap)
147 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
150 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
152 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
156 * We are generating clock pulses. ndelay() determines durating of clk pulses.
157 * We will generate clock with rate 100 KHz and so duration of both clock levels
158 * is: delay in ns = (10^6 / 100) / 2
160 #define RECOVERY_NDELAY 5000
161 #define RECOVERY_CLK_CNT 9
163 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
165 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
166 int i = 0, val = 1, ret = 0;
168 if (bri->prepare_recovery)
169 bri->prepare_recovery(adap);
171 bri->set_scl(adap, val);
173 bri->set_sda(adap, 1);
174 ndelay(RECOVERY_NDELAY);
177 * By this time SCL is high, as we need to give 9 falling-rising edges
179 while (i++ < RECOVERY_CLK_CNT * 2) {
181 /* SCL shouldn't be low here */
182 if (!bri->get_scl(adap)) {
184 "SCL is stuck low, exit recovery\n");
188 /* Break if SDA is high */
189 if (bri->get_sda && bri->get_sda(adap))
194 bri->set_scl(adap, val);
195 ndelay(RECOVERY_NDELAY);
198 /* check if recovery actually succeeded */
199 if (bri->get_sda && !bri->get_sda(adap))
202 /* If all went well, send STOP for a sane bus state. */
203 if (ret == 0 && bri->set_sda) {
204 bri->set_scl(adap, 0);
205 ndelay(RECOVERY_NDELAY / 2);
206 bri->set_sda(adap, 0);
207 ndelay(RECOVERY_NDELAY / 2);
208 bri->set_scl(adap, 1);
209 ndelay(RECOVERY_NDELAY / 2);
210 bri->set_sda(adap, 1);
211 ndelay(RECOVERY_NDELAY / 2);
214 if (bri->unprepare_recovery)
215 bri->unprepare_recovery(adap);
219 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
221 int i2c_recover_bus(struct i2c_adapter *adap)
223 if (!adap->bus_recovery_info)
226 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
227 return adap->bus_recovery_info->recover_bus(adap);
229 EXPORT_SYMBOL_GPL(i2c_recover_bus);
231 static void i2c_init_recovery(struct i2c_adapter *adap)
233 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
239 if (!bri->recover_bus) {
240 err_str = "no recover_bus() found";
244 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
245 bri->get_scl = get_scl_gpio_value;
246 bri->set_scl = set_scl_gpio_value;
247 if (bri->sda_gpiod) {
248 bri->get_sda = get_sda_gpio_value;
249 /* FIXME: add proper flag instead of '0' once available */
250 if (gpiod_get_direction(bri->sda_gpiod) == 0)
251 bri->set_sda = set_sda_gpio_value;
256 if (bri->recover_bus == i2c_generic_scl_recovery) {
257 /* Generic SCL recovery */
258 if (!bri->set_scl || !bri->get_scl) {
259 err_str = "no {get|set}_scl() found";
266 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
267 adap->bus_recovery_info = NULL;
270 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
272 struct i2c_adapter *adap = client->adapter;
275 if (!adap->host_notify_domain)
278 if (client->flags & I2C_CLIENT_TEN)
281 irq = irq_find_mapping(adap->host_notify_domain, client->addr);
283 irq = irq_create_mapping(adap->host_notify_domain,
286 return irq > 0 ? irq : -ENXIO;
289 static int i2c_device_probe(struct device *dev)
291 struct i2c_client *client = i2c_verify_client(dev);
292 struct i2c_driver *driver;
298 driver = to_i2c_driver(dev->driver);
300 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
303 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
304 dev_dbg(dev, "Using Host Notify IRQ\n");
305 irq = i2c_smbus_host_notify_to_irq(client);
306 } else if (dev->of_node) {
307 irq = of_irq_get_byname(dev->of_node, "irq");
308 if (irq == -EINVAL || irq == -ENODATA)
309 irq = of_irq_get(dev->of_node, 0);
310 } else if (ACPI_COMPANION(dev)) {
311 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
313 if (irq == -EPROBE_DEFER)
323 * An I2C ID table is not mandatory, if and only if, a suitable OF
324 * or ACPI ID table is supplied for the probing device.
326 if (!driver->id_table &&
327 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
328 !i2c_of_match_device(dev->driver->of_match_table, client))
331 if (client->flags & I2C_CLIENT_WAKE) {
332 int wakeirq = -ENOENT;
335 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
336 if (wakeirq == -EPROBE_DEFER)
340 device_init_wakeup(&client->dev, true);
342 if (wakeirq > 0 && wakeirq != client->irq)
343 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
344 else if (client->irq > 0)
345 status = dev_pm_set_wake_irq(dev, client->irq);
350 dev_warn(&client->dev, "failed to set up wakeup irq\n");
353 dev_dbg(dev, "probe\n");
355 status = of_clk_set_defaults(dev->of_node, false);
357 goto err_clear_wakeup_irq;
359 status = dev_pm_domain_attach(&client->dev, true);
360 if (status == -EPROBE_DEFER)
361 goto err_clear_wakeup_irq;
364 * When there are no more users of probe(),
365 * rename probe_new to probe.
367 if (driver->probe_new)
368 status = driver->probe_new(client);
369 else if (driver->probe)
370 status = driver->probe(client,
371 i2c_match_id(driver->id_table, client));
376 goto err_detach_pm_domain;
380 err_detach_pm_domain:
381 dev_pm_domain_detach(&client->dev, true);
382 err_clear_wakeup_irq:
383 dev_pm_clear_wake_irq(&client->dev);
384 device_init_wakeup(&client->dev, false);
388 static int i2c_device_remove(struct device *dev)
390 struct i2c_client *client = i2c_verify_client(dev);
391 struct i2c_driver *driver;
394 if (!client || !dev->driver)
397 driver = to_i2c_driver(dev->driver);
398 if (driver->remove) {
399 dev_dbg(dev, "remove\n");
400 status = driver->remove(client);
403 dev_pm_domain_detach(&client->dev, true);
405 dev_pm_clear_wake_irq(&client->dev);
406 device_init_wakeup(&client->dev, false);
411 static void i2c_device_shutdown(struct device *dev)
413 struct i2c_client *client = i2c_verify_client(dev);
414 struct i2c_driver *driver;
416 if (!client || !dev->driver)
418 driver = to_i2c_driver(dev->driver);
419 if (driver->shutdown)
420 driver->shutdown(client);
423 static void i2c_client_dev_release(struct device *dev)
425 kfree(to_i2c_client(dev));
429 show_name(struct device *dev, struct device_attribute *attr, char *buf)
431 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
432 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
434 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
437 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
439 struct i2c_client *client = to_i2c_client(dev);
442 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
446 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
448 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
450 static struct attribute *i2c_dev_attrs[] = {
452 /* modalias helps coldplug: modprobe $(cat .../modalias) */
453 &dev_attr_modalias.attr,
456 ATTRIBUTE_GROUPS(i2c_dev);
458 struct bus_type i2c_bus_type = {
460 .match = i2c_device_match,
461 .probe = i2c_device_probe,
462 .remove = i2c_device_remove,
463 .shutdown = i2c_device_shutdown,
465 EXPORT_SYMBOL_GPL(i2c_bus_type);
467 struct device_type i2c_client_type = {
468 .groups = i2c_dev_groups,
469 .uevent = i2c_device_uevent,
470 .release = i2c_client_dev_release,
472 EXPORT_SYMBOL_GPL(i2c_client_type);
476 * i2c_verify_client - return parameter as i2c_client, or NULL
477 * @dev: device, probably from some driver model iterator
479 * When traversing the driver model tree, perhaps using driver model
480 * iterators like @device_for_each_child(), you can't assume very much
481 * about the nodes you find. Use this function to avoid oopses caused
482 * by wrongly treating some non-I2C device as an i2c_client.
484 struct i2c_client *i2c_verify_client(struct device *dev)
486 return (dev->type == &i2c_client_type)
490 EXPORT_SYMBOL(i2c_verify_client);
493 /* Return a unique address which takes the flags of the client into account */
494 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
496 unsigned short addr = client->addr;
498 /* For some client flags, add an arbitrary offset to avoid collisions */
499 if (client->flags & I2C_CLIENT_TEN)
500 addr |= I2C_ADDR_OFFSET_TEN_BIT;
502 if (client->flags & I2C_CLIENT_SLAVE)
503 addr |= I2C_ADDR_OFFSET_SLAVE;
508 /* This is a permissive address validity check, I2C address map constraints
509 * are purposely not enforced, except for the general call address. */
510 int i2c_check_addr_validity(unsigned addr, unsigned short flags)
512 if (flags & I2C_CLIENT_TEN) {
513 /* 10-bit address, all values are valid */
517 /* 7-bit address, reject the general call address */
518 if (addr == 0x00 || addr > 0x7f)
524 /* And this is a strict address validity check, used when probing. If a
525 * device uses a reserved address, then it shouldn't be probed. 7-bit
526 * addressing is assumed, 10-bit address devices are rare and should be
527 * explicitly enumerated. */
528 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
531 * Reserved addresses per I2C specification:
532 * 0x00 General call address / START byte
534 * 0x02 Reserved for different bus format
535 * 0x03 Reserved for future purposes
536 * 0x04-0x07 Hs-mode master code
537 * 0x78-0x7b 10-bit slave addressing
538 * 0x7c-0x7f Reserved for future purposes
540 if (addr < 0x08 || addr > 0x77)
545 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
547 struct i2c_client *client = i2c_verify_client(dev);
548 int addr = *(int *)addrp;
550 if (client && i2c_encode_flags_to_addr(client) == addr)
555 /* walk up mux tree */
556 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
558 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
561 result = device_for_each_child(&adapter->dev, &addr,
562 __i2c_check_addr_busy);
564 if (!result && parent)
565 result = i2c_check_mux_parents(parent, addr);
570 /* recurse down mux tree */
571 static int i2c_check_mux_children(struct device *dev, void *addrp)
575 if (dev->type == &i2c_adapter_type)
576 result = device_for_each_child(dev, addrp,
577 i2c_check_mux_children);
579 result = __i2c_check_addr_busy(dev, addrp);
584 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
586 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
590 result = i2c_check_mux_parents(parent, addr);
593 result = device_for_each_child(&adapter->dev, &addr,
594 i2c_check_mux_children);
600 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
601 * @adapter: Target I2C bus segment
602 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
603 * locks only this branch in the adapter tree
605 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
608 rt_mutex_lock(&adapter->bus_lock);
612 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
613 * @adapter: Target I2C bus segment
614 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
615 * trylocks only this branch in the adapter tree
617 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
620 return rt_mutex_trylock(&adapter->bus_lock);
624 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
625 * @adapter: Target I2C bus segment
626 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
627 * unlocks only this branch in the adapter tree
629 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
632 rt_mutex_unlock(&adapter->bus_lock);
635 static void i2c_dev_set_name(struct i2c_adapter *adap,
636 struct i2c_client *client,
637 struct i2c_board_info const *info)
639 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
641 if (info && info->dev_name) {
642 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
647 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
651 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
652 i2c_encode_flags_to_addr(client));
655 static int i2c_dev_irq_from_resources(const struct resource *resources,
656 unsigned int num_resources)
658 struct irq_data *irqd;
661 for (i = 0; i < num_resources; i++) {
662 const struct resource *r = &resources[i];
664 if (resource_type(r) != IORESOURCE_IRQ)
667 if (r->flags & IORESOURCE_BITS) {
668 irqd = irq_get_irq_data(r->start);
672 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
682 * i2c_new_device - instantiate an i2c device
683 * @adap: the adapter managing the device
684 * @info: describes one I2C device; bus_num is ignored
687 * Create an i2c device. Binding is handled through driver model
688 * probe()/remove() methods. A driver may be bound to this device when we
689 * return from this function, or any later moment (e.g. maybe hotplugging will
690 * load the driver module). This call is not appropriate for use by mainboard
691 * initialization logic, which usually runs during an arch_initcall() long
692 * before any i2c_adapter could exist.
694 * This returns the new i2c client, which may be saved for later use with
695 * i2c_unregister_device(); or NULL to indicate an error.
698 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
700 struct i2c_client *client;
703 client = kzalloc(sizeof *client, GFP_KERNEL);
707 client->adapter = adap;
709 client->dev.platform_data = info->platform_data;
712 client->dev.archdata = *info->archdata;
714 client->flags = info->flags;
715 client->addr = info->addr;
717 client->irq = info->irq;
719 client->irq = i2c_dev_irq_from_resources(info->resources,
720 info->num_resources);
722 strlcpy(client->name, info->type, sizeof(client->name));
724 status = i2c_check_addr_validity(client->addr, client->flags);
726 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
727 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
731 /* Check for address business */
732 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
736 client->dev.parent = &client->adapter->dev;
737 client->dev.bus = &i2c_bus_type;
738 client->dev.type = &i2c_client_type;
739 client->dev.of_node = info->of_node;
740 client->dev.fwnode = info->fwnode;
742 i2c_dev_set_name(adap, client, info);
744 if (info->properties) {
745 status = device_add_properties(&client->dev, info->properties);
748 "Failed to add properties to client %s: %d\n",
749 client->name, status);
754 status = device_register(&client->dev);
758 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
759 client->name, dev_name(&client->dev));
764 if (info->properties)
765 device_remove_properties(&client->dev);
768 "Failed to register i2c client %s at 0x%02x (%d)\n",
769 client->name, client->addr, status);
774 EXPORT_SYMBOL_GPL(i2c_new_device);
778 * i2c_unregister_device - reverse effect of i2c_new_device()
779 * @client: value returned from i2c_new_device()
782 void i2c_unregister_device(struct i2c_client *client)
787 if (client->dev.of_node) {
788 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
789 of_node_put(client->dev.of_node);
792 if (ACPI_COMPANION(&client->dev))
793 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
794 device_unregister(&client->dev);
796 EXPORT_SYMBOL_GPL(i2c_unregister_device);
799 static const struct i2c_device_id dummy_id[] = {
804 static int dummy_probe(struct i2c_client *client,
805 const struct i2c_device_id *id)
810 static int dummy_remove(struct i2c_client *client)
815 static struct i2c_driver dummy_driver = {
816 .driver.name = "dummy",
817 .probe = dummy_probe,
818 .remove = dummy_remove,
819 .id_table = dummy_id,
823 * i2c_new_dummy - return a new i2c device bound to a dummy driver
824 * @adapter: the adapter managing the device
825 * @address: seven bit address to be used
828 * This returns an I2C client bound to the "dummy" driver, intended for use
829 * with devices that consume multiple addresses. Examples of such chips
830 * include various EEPROMS (like 24c04 and 24c08 models).
832 * These dummy devices have two main uses. First, most I2C and SMBus calls
833 * except i2c_transfer() need a client handle; the dummy will be that handle.
834 * And second, this prevents the specified address from being bound to a
837 * This returns the new i2c client, which should be saved for later use with
838 * i2c_unregister_device(); or NULL to indicate an error.
840 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
842 struct i2c_board_info info = {
843 I2C_BOARD_INFO("dummy", address),
846 return i2c_new_device(adapter, &info);
848 EXPORT_SYMBOL_GPL(i2c_new_dummy);
851 * i2c_new_secondary_device - Helper to get the instantiated secondary address
852 * and create the associated device
853 * @client: Handle to the primary client
854 * @name: Handle to specify which secondary address to get
855 * @default_addr: Used as a fallback if no secondary address was specified
858 * I2C clients can be composed of multiple I2C slaves bound together in a single
859 * component. The I2C client driver then binds to the master I2C slave and needs
860 * to create I2C dummy clients to communicate with all the other slaves.
862 * This function creates and returns an I2C dummy client whose I2C address is
863 * retrieved from the platform firmware based on the given slave name. If no
864 * address is specified by the firmware default_addr is used.
866 * On DT-based platforms the address is retrieved from the "reg" property entry
867 * cell whose "reg-names" value matches the slave name.
869 * This returns the new i2c client, which should be saved for later use with
870 * i2c_unregister_device(); or NULL to indicate an error.
872 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
876 struct device_node *np = client->dev.of_node;
877 u32 addr = default_addr;
881 i = of_property_match_string(np, "reg-names", name);
883 of_property_read_u32_index(np, "reg", i, &addr);
886 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
887 return i2c_new_dummy(client->adapter, addr);
889 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
891 /* ------------------------------------------------------------------------- */
893 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
895 static void i2c_adapter_dev_release(struct device *dev)
897 struct i2c_adapter *adap = to_i2c_adapter(dev);
898 complete(&adap->dev_released);
901 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
903 unsigned int depth = 0;
905 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
908 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
909 "adapter depth exceeds lockdep subclass limit\n");
913 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
916 * Let users instantiate I2C devices through sysfs. This can be used when
917 * platform initialization code doesn't contain the proper data for
918 * whatever reason. Also useful for drivers that do device detection and
919 * detection fails, either because the device uses an unexpected address,
920 * or this is a compatible device with different ID register values.
922 * Parameter checking may look overzealous, but we really don't want
923 * the user to provide incorrect parameters.
926 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
927 const char *buf, size_t count)
929 struct i2c_adapter *adap = to_i2c_adapter(dev);
930 struct i2c_board_info info;
931 struct i2c_client *client;
935 memset(&info, 0, sizeof(struct i2c_board_info));
937 blank = strchr(buf, ' ');
939 dev_err(dev, "%s: Missing parameters\n", "new_device");
942 if (blank - buf > I2C_NAME_SIZE - 1) {
943 dev_err(dev, "%s: Invalid device name\n", "new_device");
946 memcpy(info.type, buf, blank - buf);
948 /* Parse remaining parameters, reject extra parameters */
949 res = sscanf(++blank, "%hi%c", &info.addr, &end);
951 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
954 if (res > 1 && end != '\n') {
955 dev_err(dev, "%s: Extra parameters\n", "new_device");
959 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
960 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
961 info.flags |= I2C_CLIENT_TEN;
964 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
965 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
966 info.flags |= I2C_CLIENT_SLAVE;
969 client = i2c_new_device(adap, &info);
973 /* Keep track of the added device */
974 mutex_lock(&adap->userspace_clients_lock);
975 list_add_tail(&client->detected, &adap->userspace_clients);
976 mutex_unlock(&adap->userspace_clients_lock);
977 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
978 info.type, info.addr);
982 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
985 * And of course let the users delete the devices they instantiated, if
986 * they got it wrong. This interface can only be used to delete devices
987 * instantiated by i2c_sysfs_new_device above. This guarantees that we
988 * don't delete devices to which some kernel code still has references.
990 * Parameter checking may look overzealous, but we really don't want
991 * the user to delete the wrong device.
994 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
995 const char *buf, size_t count)
997 struct i2c_adapter *adap = to_i2c_adapter(dev);
998 struct i2c_client *client, *next;
1003 /* Parse parameters, reject extra parameters */
1004 res = sscanf(buf, "%hi%c", &addr, &end);
1006 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1009 if (res > 1 && end != '\n') {
1010 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1014 /* Make sure the device was added through sysfs */
1016 mutex_lock_nested(&adap->userspace_clients_lock,
1017 i2c_adapter_depth(adap));
1018 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1020 if (i2c_encode_flags_to_addr(client) == addr) {
1021 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1022 "delete_device", client->name, client->addr);
1024 list_del(&client->detected);
1025 i2c_unregister_device(client);
1030 mutex_unlock(&adap->userspace_clients_lock);
1033 dev_err(dev, "%s: Can't find device in list\n",
1037 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1038 i2c_sysfs_delete_device);
1040 static struct attribute *i2c_adapter_attrs[] = {
1041 &dev_attr_name.attr,
1042 &dev_attr_new_device.attr,
1043 &dev_attr_delete_device.attr,
1046 ATTRIBUTE_GROUPS(i2c_adapter);
1048 struct device_type i2c_adapter_type = {
1049 .groups = i2c_adapter_groups,
1050 .release = i2c_adapter_dev_release,
1052 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1055 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1056 * @dev: device, probably from some driver model iterator
1058 * When traversing the driver model tree, perhaps using driver model
1059 * iterators like @device_for_each_child(), you can't assume very much
1060 * about the nodes you find. Use this function to avoid oopses caused
1061 * by wrongly treating some non-I2C device as an i2c_adapter.
1063 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1065 return (dev->type == &i2c_adapter_type)
1066 ? to_i2c_adapter(dev)
1069 EXPORT_SYMBOL(i2c_verify_adapter);
1071 #ifdef CONFIG_I2C_COMPAT
1072 static struct class_compat *i2c_adapter_compat_class;
1075 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1077 struct i2c_devinfo *devinfo;
1079 down_read(&__i2c_board_lock);
1080 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1081 if (devinfo->busnum == adapter->nr
1082 && !i2c_new_device(adapter,
1083 &devinfo->board_info))
1084 dev_err(&adapter->dev,
1085 "Can't create device at 0x%02x\n",
1086 devinfo->board_info.addr);
1088 up_read(&__i2c_board_lock);
1091 static int i2c_do_add_adapter(struct i2c_driver *driver,
1092 struct i2c_adapter *adap)
1094 /* Detect supported devices on that bus, and instantiate them */
1095 i2c_detect(adap, driver);
1097 /* Let legacy drivers scan this bus for matching devices */
1098 if (driver->attach_adapter) {
1099 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1100 driver->driver.name);
1101 dev_warn(&adap->dev,
1102 "Please use another way to instantiate your i2c_client\n");
1103 /* We ignore the return code; if it fails, too bad */
1104 driver->attach_adapter(adap);
1109 static int __process_new_adapter(struct device_driver *d, void *data)
1111 return i2c_do_add_adapter(to_i2c_driver(d), data);
1114 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1115 .lock_bus = i2c_adapter_lock_bus,
1116 .trylock_bus = i2c_adapter_trylock_bus,
1117 .unlock_bus = i2c_adapter_unlock_bus,
1120 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1122 struct irq_domain *domain = adap->host_notify_domain;
1123 irq_hw_number_t hwirq;
1128 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1129 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1131 irq_domain_remove(domain);
1132 adap->host_notify_domain = NULL;
1135 static int i2c_host_notify_irq_map(struct irq_domain *h,
1137 irq_hw_number_t hw_irq_num)
1139 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1144 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1145 .map = i2c_host_notify_irq_map,
1148 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1150 struct irq_domain *domain;
1152 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1155 domain = irq_domain_create_linear(adap->dev.fwnode,
1156 I2C_ADDR_7BITS_COUNT,
1157 &i2c_host_notify_irq_ops, adap);
1161 adap->host_notify_domain = domain;
1167 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1169 * @adap: the adapter
1170 * @addr: the I2C address of the notifying device
1171 * Context: can't sleep
1173 * Helper function to be called from an I2C bus driver's interrupt
1174 * handler. It will schedule the Host Notify IRQ.
1176 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1183 irq = irq_find_mapping(adap->host_notify_domain, addr);
1187 generic_handle_irq(irq);
1191 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1193 static int i2c_register_adapter(struct i2c_adapter *adap)
1197 /* Can't register until after driver model init */
1198 if (WARN_ON(!is_registered)) {
1204 if (WARN(!adap->name[0], "i2c adapter has no name"))
1208 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1212 if (!adap->lock_ops)
1213 adap->lock_ops = &i2c_adapter_lock_ops;
1215 rt_mutex_init(&adap->bus_lock);
1216 rt_mutex_init(&adap->mux_lock);
1217 mutex_init(&adap->userspace_clients_lock);
1218 INIT_LIST_HEAD(&adap->userspace_clients);
1220 /* Set default timeout to 1 second if not already set */
1221 if (adap->timeout == 0)
1224 /* register soft irqs for Host Notify */
1225 res = i2c_setup_host_notify_irq_domain(adap);
1227 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1232 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1233 adap->dev.bus = &i2c_bus_type;
1234 adap->dev.type = &i2c_adapter_type;
1235 res = device_register(&adap->dev);
1237 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1241 res = of_i2c_setup_smbus_alert(adap);
1245 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1247 pm_runtime_no_callbacks(&adap->dev);
1248 pm_suspend_ignore_children(&adap->dev, true);
1249 pm_runtime_enable(&adap->dev);
1251 #ifdef CONFIG_I2C_COMPAT
1252 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1255 dev_warn(&adap->dev,
1256 "Failed to create compatibility class link\n");
1259 i2c_init_recovery(adap);
1261 /* create pre-declared device nodes */
1262 of_i2c_register_devices(adap);
1263 i2c_acpi_register_devices(adap);
1264 i2c_acpi_install_space_handler(adap);
1266 if (adap->nr < __i2c_first_dynamic_bus_num)
1267 i2c_scan_static_board_info(adap);
1269 /* Notify drivers */
1270 mutex_lock(&core_lock);
1271 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1272 mutex_unlock(&core_lock);
1277 init_completion(&adap->dev_released);
1278 device_unregister(&adap->dev);
1279 wait_for_completion(&adap->dev_released);
1281 mutex_lock(&core_lock);
1282 idr_remove(&i2c_adapter_idr, adap->nr);
1283 mutex_unlock(&core_lock);
1288 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1289 * @adap: the adapter to register (with adap->nr initialized)
1290 * Context: can sleep
1292 * See i2c_add_numbered_adapter() for details.
1294 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1298 mutex_lock(&core_lock);
1299 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1300 mutex_unlock(&core_lock);
1301 if (WARN(id < 0, "couldn't get idr"))
1302 return id == -ENOSPC ? -EBUSY : id;
1304 return i2c_register_adapter(adap);
1308 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1309 * @adapter: the adapter to add
1310 * Context: can sleep
1312 * This routine is used to declare an I2C adapter when its bus number
1313 * doesn't matter or when its bus number is specified by an dt alias.
1314 * Examples of bases when the bus number doesn't matter: I2C adapters
1315 * dynamically added by USB links or PCI plugin cards.
1317 * When this returns zero, a new bus number was allocated and stored
1318 * in adap->nr, and the specified adapter became available for clients.
1319 * Otherwise, a negative errno value is returned.
1321 int i2c_add_adapter(struct i2c_adapter *adapter)
1323 struct device *dev = &adapter->dev;
1327 id = of_alias_get_id(dev->of_node, "i2c");
1330 return __i2c_add_numbered_adapter(adapter);
1334 mutex_lock(&core_lock);
1335 id = idr_alloc(&i2c_adapter_idr, adapter,
1336 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1337 mutex_unlock(&core_lock);
1338 if (WARN(id < 0, "couldn't get idr"))
1343 return i2c_register_adapter(adapter);
1345 EXPORT_SYMBOL(i2c_add_adapter);
1348 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1349 * @adap: the adapter to register (with adap->nr initialized)
1350 * Context: can sleep
1352 * This routine is used to declare an I2C adapter when its bus number
1353 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1354 * or otherwise built in to the system's mainboard, and where i2c_board_info
1355 * is used to properly configure I2C devices.
1357 * If the requested bus number is set to -1, then this function will behave
1358 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1360 * If no devices have pre-been declared for this bus, then be sure to
1361 * register the adapter before any dynamically allocated ones. Otherwise
1362 * the required bus ID may not be available.
1364 * When this returns zero, the specified adapter became available for
1365 * clients using the bus number provided in adap->nr. Also, the table
1366 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1367 * and the appropriate driver model device nodes are created. Otherwise, a
1368 * negative errno value is returned.
1370 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1372 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1373 return i2c_add_adapter(adap);
1375 return __i2c_add_numbered_adapter(adap);
1377 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1379 static void i2c_do_del_adapter(struct i2c_driver *driver,
1380 struct i2c_adapter *adapter)
1382 struct i2c_client *client, *_n;
1384 /* Remove the devices we created ourselves as the result of hardware
1385 * probing (using a driver's detect method) */
1386 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1387 if (client->adapter == adapter) {
1388 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1389 client->name, client->addr);
1390 list_del(&client->detected);
1391 i2c_unregister_device(client);
1396 static int __unregister_client(struct device *dev, void *dummy)
1398 struct i2c_client *client = i2c_verify_client(dev);
1399 if (client && strcmp(client->name, "dummy"))
1400 i2c_unregister_device(client);
1404 static int __unregister_dummy(struct device *dev, void *dummy)
1406 struct i2c_client *client = i2c_verify_client(dev);
1407 i2c_unregister_device(client);
1411 static int __process_removed_adapter(struct device_driver *d, void *data)
1413 i2c_do_del_adapter(to_i2c_driver(d), data);
1418 * i2c_del_adapter - unregister I2C adapter
1419 * @adap: the adapter being unregistered
1420 * Context: can sleep
1422 * This unregisters an I2C adapter which was previously registered
1423 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1425 void i2c_del_adapter(struct i2c_adapter *adap)
1427 struct i2c_adapter *found;
1428 struct i2c_client *client, *next;
1430 /* First make sure that this adapter was ever added */
1431 mutex_lock(&core_lock);
1432 found = idr_find(&i2c_adapter_idr, adap->nr);
1433 mutex_unlock(&core_lock);
1434 if (found != adap) {
1435 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1439 i2c_acpi_remove_space_handler(adap);
1440 /* Tell drivers about this removal */
1441 mutex_lock(&core_lock);
1442 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1443 __process_removed_adapter);
1444 mutex_unlock(&core_lock);
1446 /* Remove devices instantiated from sysfs */
1447 mutex_lock_nested(&adap->userspace_clients_lock,
1448 i2c_adapter_depth(adap));
1449 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1451 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1453 list_del(&client->detected);
1454 i2c_unregister_device(client);
1456 mutex_unlock(&adap->userspace_clients_lock);
1458 /* Detach any active clients. This can't fail, thus we do not
1459 * check the returned value. This is a two-pass process, because
1460 * we can't remove the dummy devices during the first pass: they
1461 * could have been instantiated by real devices wishing to clean
1462 * them up properly, so we give them a chance to do that first. */
1463 device_for_each_child(&adap->dev, NULL, __unregister_client);
1464 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1466 #ifdef CONFIG_I2C_COMPAT
1467 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1471 /* device name is gone after device_unregister */
1472 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1474 pm_runtime_disable(&adap->dev);
1476 i2c_host_notify_irq_teardown(adap);
1478 /* wait until all references to the device are gone
1480 * FIXME: This is old code and should ideally be replaced by an
1481 * alternative which results in decoupling the lifetime of the struct
1482 * device from the i2c_adapter, like spi or netdev do. Any solution
1483 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1485 init_completion(&adap->dev_released);
1486 device_unregister(&adap->dev);
1487 wait_for_completion(&adap->dev_released);
1490 mutex_lock(&core_lock);
1491 idr_remove(&i2c_adapter_idr, adap->nr);
1492 mutex_unlock(&core_lock);
1494 /* Clear the device structure in case this adapter is ever going to be
1496 memset(&adap->dev, 0, sizeof(adap->dev));
1498 EXPORT_SYMBOL(i2c_del_adapter);
1501 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1502 * @dev: The device to scan for I2C timing properties
1503 * @t: the i2c_timings struct to be filled with values
1504 * @use_defaults: bool to use sane defaults derived from the I2C specification
1505 * when properties are not found, otherwise use 0
1507 * Scan the device for the generic I2C properties describing timing parameters
1508 * for the signal and fill the given struct with the results. If a property was
1509 * not found and use_defaults was true, then maximum timings are assumed which
1510 * are derived from the I2C specification. If use_defaults is not used, the
1511 * results will be 0, so drivers can apply their own defaults later. The latter
1512 * is mainly intended for avoiding regressions of existing drivers which want
1513 * to switch to this function. New drivers almost always should use the defaults.
1516 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1520 memset(t, 0, sizeof(*t));
1522 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1523 if (ret && use_defaults)
1524 t->bus_freq_hz = 100000;
1526 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1527 if (ret && use_defaults) {
1528 if (t->bus_freq_hz <= 100000)
1529 t->scl_rise_ns = 1000;
1530 else if (t->bus_freq_hz <= 400000)
1531 t->scl_rise_ns = 300;
1533 t->scl_rise_ns = 120;
1536 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1537 if (ret && use_defaults) {
1538 if (t->bus_freq_hz <= 400000)
1539 t->scl_fall_ns = 300;
1541 t->scl_fall_ns = 120;
1544 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1546 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1547 if (ret && use_defaults)
1548 t->sda_fall_ns = t->scl_fall_ns;
1550 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1552 /* ------------------------------------------------------------------------- */
1554 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1558 mutex_lock(&core_lock);
1559 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1560 mutex_unlock(&core_lock);
1564 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1566 static int __process_new_driver(struct device *dev, void *data)
1568 if (dev->type != &i2c_adapter_type)
1570 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1574 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1575 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1578 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1582 /* Can't register until after driver model init */
1583 if (WARN_ON(!is_registered))
1586 /* add the driver to the list of i2c drivers in the driver core */
1587 driver->driver.owner = owner;
1588 driver->driver.bus = &i2c_bus_type;
1589 INIT_LIST_HEAD(&driver->clients);
1591 /* When registration returns, the driver core
1592 * will have called probe() for all matching-but-unbound devices.
1594 res = driver_register(&driver->driver);
1598 pr_debug("driver [%s] registered\n", driver->driver.name);
1600 /* Walk the adapters that are already present */
1601 i2c_for_each_dev(driver, __process_new_driver);
1605 EXPORT_SYMBOL(i2c_register_driver);
1607 static int __process_removed_driver(struct device *dev, void *data)
1609 if (dev->type == &i2c_adapter_type)
1610 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1615 * i2c_del_driver - unregister I2C driver
1616 * @driver: the driver being unregistered
1617 * Context: can sleep
1619 void i2c_del_driver(struct i2c_driver *driver)
1621 i2c_for_each_dev(driver, __process_removed_driver);
1623 driver_unregister(&driver->driver);
1624 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1626 EXPORT_SYMBOL(i2c_del_driver);
1628 /* ------------------------------------------------------------------------- */
1631 * i2c_use_client - increments the reference count of the i2c client structure
1632 * @client: the client being referenced
1634 * Each live reference to a client should be refcounted. The driver model does
1635 * that automatically as part of driver binding, so that most drivers don't
1636 * need to do this explicitly: they hold a reference until they're unbound
1639 * A pointer to the client with the incremented reference counter is returned.
1641 struct i2c_client *i2c_use_client(struct i2c_client *client)
1643 if (client && get_device(&client->dev))
1647 EXPORT_SYMBOL(i2c_use_client);
1650 * i2c_release_client - release a use of the i2c client structure
1651 * @client: the client being no longer referenced
1653 * Must be called when a user of a client is finished with it.
1655 void i2c_release_client(struct i2c_client *client)
1658 put_device(&client->dev);
1660 EXPORT_SYMBOL(i2c_release_client);
1662 struct i2c_cmd_arg {
1667 static int i2c_cmd(struct device *dev, void *_arg)
1669 struct i2c_client *client = i2c_verify_client(dev);
1670 struct i2c_cmd_arg *arg = _arg;
1671 struct i2c_driver *driver;
1673 if (!client || !client->dev.driver)
1676 driver = to_i2c_driver(client->dev.driver);
1677 if (driver->command)
1678 driver->command(client, arg->cmd, arg->arg);
1682 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1684 struct i2c_cmd_arg cmd_arg;
1688 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1690 EXPORT_SYMBOL(i2c_clients_command);
1692 static int __init i2c_init(void)
1696 retval = of_alias_get_highest_id("i2c");
1698 down_write(&__i2c_board_lock);
1699 if (retval >= __i2c_first_dynamic_bus_num)
1700 __i2c_first_dynamic_bus_num = retval + 1;
1701 up_write(&__i2c_board_lock);
1703 retval = bus_register(&i2c_bus_type);
1707 is_registered = true;
1709 #ifdef CONFIG_I2C_COMPAT
1710 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1711 if (!i2c_adapter_compat_class) {
1716 retval = i2c_add_driver(&dummy_driver);
1720 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1721 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1722 if (IS_ENABLED(CONFIG_ACPI))
1723 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1728 #ifdef CONFIG_I2C_COMPAT
1729 class_compat_unregister(i2c_adapter_compat_class);
1732 is_registered = false;
1733 bus_unregister(&i2c_bus_type);
1737 static void __exit i2c_exit(void)
1739 if (IS_ENABLED(CONFIG_ACPI))
1740 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1741 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1742 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1743 i2c_del_driver(&dummy_driver);
1744 #ifdef CONFIG_I2C_COMPAT
1745 class_compat_unregister(i2c_adapter_compat_class);
1747 bus_unregister(&i2c_bus_type);
1748 tracepoint_synchronize_unregister();
1751 /* We must initialize early, because some subsystems register i2c drivers
1752 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1754 postcore_initcall(i2c_init);
1755 module_exit(i2c_exit);
1757 /* ----------------------------------------------------
1758 * the functional interface to the i2c busses.
1759 * ----------------------------------------------------
1762 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1763 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1765 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1767 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1768 err_msg, msg->addr, msg->len,
1769 msg->flags & I2C_M_RD ? "read" : "write");
1773 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1775 const struct i2c_adapter_quirks *q = adap->quirks;
1776 int max_num = q->max_num_msgs, i;
1777 bool do_len_check = true;
1779 if (q->flags & I2C_AQ_COMB) {
1782 /* special checks for combined messages */
1784 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1785 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1787 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1788 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1790 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1791 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1793 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1794 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1796 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1797 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1799 do_len_check = false;
1803 if (i2c_quirk_exceeded(num, max_num))
1804 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1806 for (i = 0; i < num; i++) {
1807 u16 len = msgs[i].len;
1809 if (msgs[i].flags & I2C_M_RD) {
1810 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1811 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1813 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1814 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1822 * __i2c_transfer - unlocked flavor of i2c_transfer
1823 * @adap: Handle to I2C bus
1824 * @msgs: One or more messages to execute before STOP is issued to
1825 * terminate the operation; each message begins with a START.
1826 * @num: Number of messages to be executed.
1828 * Returns negative errno, else the number of messages executed.
1830 * Adapter lock must be held when calling this function. No debug logging
1831 * takes place. adap->algo->master_xfer existence isn't checked.
1833 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1835 unsigned long orig_jiffies;
1838 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1841 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1842 * enabled. This is an efficient way of keeping the for-loop from
1843 * being executed when not needed.
1845 if (static_key_false(&i2c_trace_msg)) {
1847 for (i = 0; i < num; i++)
1848 if (msgs[i].flags & I2C_M_RD)
1849 trace_i2c_read(adap, &msgs[i], i);
1851 trace_i2c_write(adap, &msgs[i], i);
1854 /* Retry automatically on arbitration loss */
1855 orig_jiffies = jiffies;
1856 for (ret = 0, try = 0; try <= adap->retries; try++) {
1857 ret = adap->algo->master_xfer(adap, msgs, num);
1860 if (time_after(jiffies, orig_jiffies + adap->timeout))
1864 if (static_key_false(&i2c_trace_msg)) {
1866 for (i = 0; i < ret; i++)
1867 if (msgs[i].flags & I2C_M_RD)
1868 trace_i2c_reply(adap, &msgs[i], i);
1869 trace_i2c_result(adap, i, ret);
1874 EXPORT_SYMBOL(__i2c_transfer);
1877 * i2c_transfer - execute a single or combined I2C message
1878 * @adap: Handle to I2C bus
1879 * @msgs: One or more messages to execute before STOP is issued to
1880 * terminate the operation; each message begins with a START.
1881 * @num: Number of messages to be executed.
1883 * Returns negative errno, else the number of messages executed.
1885 * Note that there is no requirement that each message be sent to
1886 * the same slave address, although that is the most common model.
1888 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1892 /* REVISIT the fault reporting model here is weak:
1894 * - When we get an error after receiving N bytes from a slave,
1895 * there is no way to report "N".
1897 * - When we get a NAK after transmitting N bytes to a slave,
1898 * there is no way to report "N" ... or to let the master
1899 * continue executing the rest of this combined message, if
1900 * that's the appropriate response.
1902 * - When for example "num" is two and we successfully complete
1903 * the first message but get an error part way through the
1904 * second, it's unclear whether that should be reported as
1905 * one (discarding status on the second message) or errno
1906 * (discarding status on the first one).
1909 if (adap->algo->master_xfer) {
1911 for (ret = 0; ret < num; ret++) {
1913 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1914 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1915 msgs[ret].addr, msgs[ret].len,
1916 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1920 if (in_atomic() || irqs_disabled()) {
1921 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1923 /* I2C activity is ongoing. */
1926 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1929 ret = __i2c_transfer(adap, msgs, num);
1930 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1934 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1938 EXPORT_SYMBOL(i2c_transfer);
1941 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1943 * @client: Handle to slave device
1944 * @buf: Where the data is stored
1945 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1946 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1948 * Returns negative errno, or else the number of bytes transferred.
1950 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1951 int count, u16 flags)
1954 struct i2c_msg msg = {
1955 .addr = client->addr,
1956 .flags = flags | (client->flags & I2C_M_TEN),
1961 ret = i2c_transfer(client->adapter, &msg, 1);
1964 * If everything went ok (i.e. 1 msg transferred), return #bytes
1965 * transferred, else error code.
1967 return (ret == 1) ? count : ret;
1969 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1971 /* ----------------------------------------------------
1972 * the i2c address scanning function
1973 * Will not work for 10-bit addresses!
1974 * ----------------------------------------------------
1978 * Legacy default probe function, mostly relevant for SMBus. The default
1979 * probe method is a quick write, but it is known to corrupt the 24RF08
1980 * EEPROMs due to a state machine bug, and could also irreversibly
1981 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1982 * we use a short byte read instead. Also, some bus drivers don't implement
1983 * quick write, so we fallback to a byte read in that case too.
1984 * On x86, there is another special case for FSC hardware monitoring chips,
1985 * which want regular byte reads (address 0x73.) Fortunately, these are the
1986 * only known chips using this I2C address on PC hardware.
1987 * Returns 1 if probe succeeded, 0 if not.
1989 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
1992 union i2c_smbus_data dummy;
1995 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
1996 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
1997 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1998 I2C_SMBUS_BYTE_DATA, &dummy);
2001 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2002 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2003 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2004 I2C_SMBUS_QUICK, NULL);
2005 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2006 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2007 I2C_SMBUS_BYTE, &dummy);
2009 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2017 static int i2c_detect_address(struct i2c_client *temp_client,
2018 struct i2c_driver *driver)
2020 struct i2c_board_info info;
2021 struct i2c_adapter *adapter = temp_client->adapter;
2022 int addr = temp_client->addr;
2025 /* Make sure the address is valid */
2026 err = i2c_check_7bit_addr_validity_strict(addr);
2028 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2033 /* Skip if already in use (7 bit, no need to encode flags) */
2034 if (i2c_check_addr_busy(adapter, addr))
2037 /* Make sure there is something at this address */
2038 if (!i2c_default_probe(adapter, addr))
2041 /* Finally call the custom detection function */
2042 memset(&info, 0, sizeof(struct i2c_board_info));
2044 err = driver->detect(temp_client, &info);
2046 /* -ENODEV is returned if the detection fails. We catch it
2047 here as this isn't an error. */
2048 return err == -ENODEV ? 0 : err;
2051 /* Consistency check */
2052 if (info.type[0] == '\0') {
2053 dev_err(&adapter->dev,
2054 "%s detection function provided no name for 0x%x\n",
2055 driver->driver.name, addr);
2057 struct i2c_client *client;
2059 /* Detection succeeded, instantiate the device */
2060 if (adapter->class & I2C_CLASS_DEPRECATED)
2061 dev_warn(&adapter->dev,
2062 "This adapter will soon drop class based instantiation of devices. "
2063 "Please make sure client 0x%02x gets instantiated by other means. "
2064 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2067 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2068 info.type, info.addr);
2069 client = i2c_new_device(adapter, &info);
2071 list_add_tail(&client->detected, &driver->clients);
2073 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2074 info.type, info.addr);
2079 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2081 const unsigned short *address_list;
2082 struct i2c_client *temp_client;
2084 int adap_id = i2c_adapter_id(adapter);
2086 address_list = driver->address_list;
2087 if (!driver->detect || !address_list)
2090 /* Warn that the adapter lost class based instantiation */
2091 if (adapter->class == I2C_CLASS_DEPRECATED) {
2092 dev_dbg(&adapter->dev,
2093 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2094 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2095 driver->driver.name);
2099 /* Stop here if the classes do not match */
2100 if (!(adapter->class & driver->class))
2103 /* Set up a temporary client to help detect callback */
2104 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2107 temp_client->adapter = adapter;
2109 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2110 dev_dbg(&adapter->dev,
2111 "found normal entry for adapter %d, addr 0x%02x\n",
2112 adap_id, address_list[i]);
2113 temp_client->addr = address_list[i];
2114 err = i2c_detect_address(temp_client, driver);
2123 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2125 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2126 I2C_SMBUS_QUICK, NULL) >= 0;
2128 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2131 i2c_new_probed_device(struct i2c_adapter *adap,
2132 struct i2c_board_info *info,
2133 unsigned short const *addr_list,
2134 int (*probe)(struct i2c_adapter *, unsigned short addr))
2139 probe = i2c_default_probe;
2141 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2142 /* Check address validity */
2143 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2144 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2149 /* Check address availability (7 bit, no need to encode flags) */
2150 if (i2c_check_addr_busy(adap, addr_list[i])) {
2152 "Address 0x%02x already in use, not probing\n",
2157 /* Test address responsiveness */
2158 if (probe(adap, addr_list[i]))
2162 if (addr_list[i] == I2C_CLIENT_END) {
2163 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2167 info->addr = addr_list[i];
2168 return i2c_new_device(adap, info);
2170 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2172 struct i2c_adapter *i2c_get_adapter(int nr)
2174 struct i2c_adapter *adapter;
2176 mutex_lock(&core_lock);
2177 adapter = idr_find(&i2c_adapter_idr, nr);
2181 if (try_module_get(adapter->owner))
2182 get_device(&adapter->dev);
2187 mutex_unlock(&core_lock);
2190 EXPORT_SYMBOL(i2c_get_adapter);
2192 void i2c_put_adapter(struct i2c_adapter *adap)
2197 put_device(&adap->dev);
2198 module_put(adap->owner);
2200 EXPORT_SYMBOL(i2c_put_adapter);
2203 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2204 * @msg: the message to be checked
2205 * @threshold: the minimum number of bytes for which using DMA makes sense
2207 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2208 * Or a valid pointer to be used with DMA. After use, release it by
2209 * calling i2c_release_dma_safe_msg_buf().
2211 * This function must only be called from process context!
2213 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2215 if (msg->len < threshold)
2218 if (msg->flags & I2C_M_DMA_SAFE)
2221 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2222 msg->addr, msg->len);
2224 if (msg->flags & I2C_M_RD)
2225 return kzalloc(msg->len, GFP_KERNEL);
2227 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2229 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2232 * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2233 * @msg: the message to be synced with
2234 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2236 void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
2238 if (!buf || buf == msg->buf)
2241 if (msg->flags & I2C_M_RD)
2242 memcpy(msg->buf, buf, msg->len);
2246 EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
2248 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2249 MODULE_DESCRIPTION("I2C-Bus main module");
2250 MODULE_LICENSE("GPL");