1 /* i2c-core.c - a device driver for the iic-bus interface */
2 /* ------------------------------------------------------------------------- */
3 /* Copyright (C) 1995-99 Simon G. Vogl
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details. */
14 /* ------------------------------------------------------------------------- */
16 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
17 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
18 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
19 Jean Delvare <jdelvare@suse.de>
20 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
21 Michael Lawnick <michael.lawnick.ext@nsn.com>
22 OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
23 (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
24 (c) 2013 Wolfram Sang <wsa@the-dreams.de>
25 I2C ACPI code Copyright (C) 2014 Intel Corp
26 Author: Lan Tianyu <tianyu.lan@intel.com>
27 I2C slave support (c) 2014 by Wolfram Sang <wsa@sang-engineering.com>
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32 #include <linux/delay.h>
33 #include <linux/errno.h>
34 #include <linux/gpio.h>
35 #include <linux/slab.h>
36 #include <linux/i2c.h>
37 #include <linux/init.h>
38 #include <linux/idr.h>
39 #include <linux/mutex.h>
41 #include <linux/of_device.h>
42 #include <linux/of_irq.h>
43 #include <linux/clk/clk-conf.h>
44 #include <linux/completion.h>
45 #include <linux/hardirq.h>
46 #include <linux/irqflags.h>
47 #include <linux/rwsem.h>
48 #include <linux/pm_runtime.h>
49 #include <linux/pm_domain.h>
50 #include <linux/acpi.h>
51 #include <linux/jump_label.h>
52 #include <asm/uaccess.h>
53 #include <linux/err.h>
57 #define CREATE_TRACE_POINTS
58 #include <trace/events/i2c.h>
60 /* core_lock protects i2c_adapter_idr, and guarantees
61 that device detection, deletion of detected devices, and attach_adapter
62 calls are serialized */
63 static DEFINE_MUTEX(core_lock);
64 static DEFINE_IDR(i2c_adapter_idr);
66 static struct device_type i2c_client_type;
67 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
69 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
71 void i2c_transfer_trace_reg(void)
73 static_key_slow_inc(&i2c_trace_msg);
76 void i2c_transfer_trace_unreg(void)
78 static_key_slow_dec(&i2c_trace_msg);
81 #if defined(CONFIG_ACPI)
82 struct acpi_i2c_handler_data {
83 struct acpi_connection_info info;
84 struct i2c_adapter *adapter;
97 static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
99 struct i2c_board_info *info = data;
101 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
102 struct acpi_resource_i2c_serialbus *sb;
104 sb = &ares->data.i2c_serial_bus;
105 if (!info->addr && sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
106 info->addr = sb->slave_address;
107 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
108 info->flags |= I2C_CLIENT_TEN;
110 } else if (!info->irq) {
113 if (acpi_dev_resource_interrupt(ares, 0, &r))
117 /* Tell the ACPI core to skip this resource */
121 static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
122 void *data, void **return_value)
124 struct i2c_adapter *adapter = data;
125 struct list_head resource_list;
126 struct i2c_board_info info;
127 struct acpi_device *adev;
130 if (acpi_bus_get_device(handle, &adev))
132 if (acpi_bus_get_status(adev) || !adev->status.present)
135 memset(&info, 0, sizeof(info));
136 info.fwnode = acpi_fwnode_handle(adev);
138 INIT_LIST_HEAD(&resource_list);
139 ret = acpi_dev_get_resources(adev, &resource_list,
140 acpi_i2c_add_resource, &info);
141 acpi_dev_free_resource_list(&resource_list);
143 if (ret < 0 || !info.addr)
146 adev->power.flags.ignore_parent = true;
147 strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
148 if (!i2c_new_device(adapter, &info)) {
149 adev->power.flags.ignore_parent = false;
150 dev_err(&adapter->dev,
151 "failed to add I2C device %s from ACPI\n",
152 dev_name(&adev->dev));
159 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
160 * @adap: pointer to adapter
162 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
163 * namespace. When a device is found it will be added to the Linux device
164 * model and bound to the corresponding ACPI handle.
166 static void acpi_i2c_register_devices(struct i2c_adapter *adap)
171 if (!adap->dev.parent)
174 handle = ACPI_HANDLE(adap->dev.parent);
178 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
179 acpi_i2c_add_device, NULL,
181 if (ACPI_FAILURE(status))
182 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
185 #else /* CONFIG_ACPI */
186 static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) { }
187 #endif /* CONFIG_ACPI */
189 #ifdef CONFIG_ACPI_I2C_OPREGION
190 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
191 u8 cmd, u8 *data, u8 data_len)
194 struct i2c_msg msgs[2];
198 buffer = kzalloc(data_len, GFP_KERNEL);
202 msgs[0].addr = client->addr;
203 msgs[0].flags = client->flags;
207 msgs[1].addr = client->addr;
208 msgs[1].flags = client->flags | I2C_M_RD;
209 msgs[1].len = data_len;
210 msgs[1].buf = buffer;
212 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
214 dev_err(&client->adapter->dev, "i2c read failed\n");
216 memcpy(data, buffer, data_len);
222 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
223 u8 cmd, u8 *data, u8 data_len)
226 struct i2c_msg msgs[1];
230 buffer = kzalloc(data_len + 1, GFP_KERNEL);
235 memcpy(buffer + 1, data, data_len);
237 msgs[0].addr = client->addr;
238 msgs[0].flags = client->flags;
239 msgs[0].len = data_len + 1;
240 msgs[0].buf = buffer;
242 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
244 dev_err(&client->adapter->dev, "i2c write failed\n");
251 acpi_i2c_space_handler(u32 function, acpi_physical_address command,
252 u32 bits, u64 *value64,
253 void *handler_context, void *region_context)
255 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
256 struct acpi_i2c_handler_data *data = handler_context;
257 struct acpi_connection_info *info = &data->info;
258 struct acpi_resource_i2c_serialbus *sb;
259 struct i2c_adapter *adapter = data->adapter;
260 struct i2c_client *client;
261 struct acpi_resource *ares;
262 u32 accessor_type = function >> 16;
263 u8 action = function & ACPI_IO_MASK;
267 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
268 if (ACPI_FAILURE(ret))
271 client = kzalloc(sizeof(*client), GFP_KERNEL);
277 if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
278 ret = AE_BAD_PARAMETER;
282 sb = &ares->data.i2c_serial_bus;
283 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
284 ret = AE_BAD_PARAMETER;
288 client->adapter = adapter;
289 client->addr = sb->slave_address;
291 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
292 client->flags |= I2C_CLIENT_TEN;
294 switch (accessor_type) {
295 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
296 if (action == ACPI_READ) {
297 status = i2c_smbus_read_byte(client);
303 status = i2c_smbus_write_byte(client, gsb->bdata);
307 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
308 if (action == ACPI_READ) {
309 status = i2c_smbus_read_byte_data(client, command);
315 status = i2c_smbus_write_byte_data(client, command,
320 case ACPI_GSB_ACCESS_ATTRIB_WORD:
321 if (action == ACPI_READ) {
322 status = i2c_smbus_read_word_data(client, command);
328 status = i2c_smbus_write_word_data(client, command,
333 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
334 if (action == ACPI_READ) {
335 status = i2c_smbus_read_block_data(client, command,
342 status = i2c_smbus_write_block_data(client, command,
343 gsb->len, gsb->data);
347 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
348 if (action == ACPI_READ) {
349 status = acpi_gsb_i2c_read_bytes(client, command,
350 gsb->data, info->access_length);
354 status = acpi_gsb_i2c_write_bytes(client, command,
355 gsb->data, info->access_length);
360 pr_info("protocol(0x%02x) is not supported.\n", accessor_type);
361 ret = AE_BAD_PARAMETER;
365 gsb->status = status;
374 static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
377 struct acpi_i2c_handler_data *data;
380 if (!adapter->dev.parent)
383 handle = ACPI_HANDLE(adapter->dev.parent);
388 data = kzalloc(sizeof(struct acpi_i2c_handler_data),
393 data->adapter = adapter;
394 status = acpi_bus_attach_private_data(handle, (void *)data);
395 if (ACPI_FAILURE(status)) {
400 status = acpi_install_address_space_handler(handle,
401 ACPI_ADR_SPACE_GSBUS,
402 &acpi_i2c_space_handler,
405 if (ACPI_FAILURE(status)) {
406 dev_err(&adapter->dev, "Error installing i2c space handler\n");
407 acpi_bus_detach_private_data(handle);
412 acpi_walk_dep_device_list(handle);
416 static void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
419 struct acpi_i2c_handler_data *data;
422 if (!adapter->dev.parent)
425 handle = ACPI_HANDLE(adapter->dev.parent);
430 acpi_remove_address_space_handler(handle,
431 ACPI_ADR_SPACE_GSBUS,
432 &acpi_i2c_space_handler);
434 status = acpi_bus_get_private_data(handle, (void **)&data);
435 if (ACPI_SUCCESS(status))
438 acpi_bus_detach_private_data(handle);
440 #else /* CONFIG_ACPI_I2C_OPREGION */
441 static inline void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
444 static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
446 #endif /* CONFIG_ACPI_I2C_OPREGION */
448 /* ------------------------------------------------------------------------- */
450 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
451 const struct i2c_client *client)
453 while (id->name[0]) {
454 if (strcmp(client->name, id->name) == 0)
461 static int i2c_device_match(struct device *dev, struct device_driver *drv)
463 struct i2c_client *client = i2c_verify_client(dev);
464 struct i2c_driver *driver;
469 /* Attempt an OF style match */
470 if (of_driver_match_device(dev, drv))
473 /* Then ACPI style match */
474 if (acpi_driver_match_device(dev, drv))
477 driver = to_i2c_driver(drv);
478 /* match on an id table if there is one */
479 if (driver->id_table)
480 return i2c_match_id(driver->id_table, client) != NULL;
486 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
487 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
489 struct i2c_client *client = to_i2c_client(dev);
492 rc = acpi_device_uevent_modalias(dev, env);
496 if (add_uevent_var(env, "MODALIAS=%s%s",
497 I2C_MODULE_PREFIX, client->name))
499 dev_dbg(dev, "uevent\n");
503 /* i2c bus recovery routines */
504 static int get_scl_gpio_value(struct i2c_adapter *adap)
506 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
509 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
511 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
514 static int get_sda_gpio_value(struct i2c_adapter *adap)
516 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
519 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
521 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
522 struct device *dev = &adap->dev;
525 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
526 GPIOF_OUT_INIT_HIGH, "i2c-scl");
528 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
533 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
534 /* work without SDA polling */
535 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
544 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
546 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
549 gpio_free(bri->sda_gpio);
551 gpio_free(bri->scl_gpio);
555 * We are generating clock pulses. ndelay() determines durating of clk pulses.
556 * We will generate clock with rate 100 KHz and so duration of both clock levels
557 * is: delay in ns = (10^6 / 100) / 2
559 #define RECOVERY_NDELAY 5000
560 #define RECOVERY_CLK_CNT 9
562 static int i2c_generic_recovery(struct i2c_adapter *adap)
564 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
565 int i = 0, val = 1, ret = 0;
567 if (bri->prepare_recovery)
568 bri->prepare_recovery(adap);
571 * By this time SCL is high, as we need to give 9 falling-rising edges
573 while (i++ < RECOVERY_CLK_CNT * 2) {
575 /* Break if SDA is high */
576 if (bri->get_sda && bri->get_sda(adap))
578 /* SCL shouldn't be low here */
579 if (!bri->get_scl(adap)) {
581 "SCL is stuck low, exit recovery\n");
588 bri->set_scl(adap, val);
589 ndelay(RECOVERY_NDELAY);
592 if (bri->unprepare_recovery)
593 bri->unprepare_recovery(adap);
598 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
600 adap->bus_recovery_info->set_scl(adap, 1);
601 return i2c_generic_recovery(adap);
603 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
605 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
609 ret = i2c_get_gpios_for_recovery(adap);
613 ret = i2c_generic_recovery(adap);
614 i2c_put_gpios_for_recovery(adap);
618 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
620 int i2c_recover_bus(struct i2c_adapter *adap)
622 if (!adap->bus_recovery_info)
625 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
626 return adap->bus_recovery_info->recover_bus(adap);
628 EXPORT_SYMBOL_GPL(i2c_recover_bus);
630 static int i2c_device_probe(struct device *dev)
632 struct i2c_client *client = i2c_verify_client(dev);
633 struct i2c_driver *driver;
643 irq = of_irq_get(dev->of_node, 0);
644 else if (ACPI_COMPANION(dev))
645 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
647 if (irq == -EPROBE_DEFER)
655 driver = to_i2c_driver(dev->driver);
656 if (!driver->probe || !driver->id_table)
659 if (!device_can_wakeup(&client->dev))
660 device_init_wakeup(&client->dev,
661 client->flags & I2C_CLIENT_WAKE);
662 dev_dbg(dev, "probe\n");
664 status = of_clk_set_defaults(dev->of_node, false);
668 status = dev_pm_domain_attach(&client->dev, true);
669 if (status != -EPROBE_DEFER) {
670 status = driver->probe(client, i2c_match_id(driver->id_table,
673 dev_pm_domain_detach(&client->dev, true);
679 static int i2c_device_remove(struct device *dev)
681 struct i2c_client *client = i2c_verify_client(dev);
682 struct i2c_driver *driver;
685 if (!client || !dev->driver)
688 driver = to_i2c_driver(dev->driver);
689 if (driver->remove) {
690 dev_dbg(dev, "remove\n");
691 status = driver->remove(client);
694 dev_pm_domain_detach(&client->dev, true);
698 static void i2c_device_shutdown(struct device *dev)
700 struct i2c_client *client = i2c_verify_client(dev);
701 struct i2c_driver *driver;
703 if (!client || !dev->driver)
705 driver = to_i2c_driver(dev->driver);
706 if (driver->shutdown)
707 driver->shutdown(client);
710 static void i2c_client_dev_release(struct device *dev)
712 kfree(to_i2c_client(dev));
716 show_name(struct device *dev, struct device_attribute *attr, char *buf)
718 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
719 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
721 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
724 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
726 struct i2c_client *client = to_i2c_client(dev);
729 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
733 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
735 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
737 static struct attribute *i2c_dev_attrs[] = {
739 /* modalias helps coldplug: modprobe $(cat .../modalias) */
740 &dev_attr_modalias.attr,
743 ATTRIBUTE_GROUPS(i2c_dev);
745 struct bus_type i2c_bus_type = {
747 .match = i2c_device_match,
748 .probe = i2c_device_probe,
749 .remove = i2c_device_remove,
750 .shutdown = i2c_device_shutdown,
752 EXPORT_SYMBOL_GPL(i2c_bus_type);
754 static struct device_type i2c_client_type = {
755 .groups = i2c_dev_groups,
756 .uevent = i2c_device_uevent,
757 .release = i2c_client_dev_release,
762 * i2c_verify_client - return parameter as i2c_client, or NULL
763 * @dev: device, probably from some driver model iterator
765 * When traversing the driver model tree, perhaps using driver model
766 * iterators like @device_for_each_child(), you can't assume very much
767 * about the nodes you find. Use this function to avoid oopses caused
768 * by wrongly treating some non-I2C device as an i2c_client.
770 struct i2c_client *i2c_verify_client(struct device *dev)
772 return (dev->type == &i2c_client_type)
776 EXPORT_SYMBOL(i2c_verify_client);
779 /* This is a permissive address validity check, I2C address map constraints
780 * are purposely not enforced, except for the general call address. */
781 static int i2c_check_client_addr_validity(const struct i2c_client *client)
783 if (client->flags & I2C_CLIENT_TEN) {
784 /* 10-bit address, all values are valid */
785 if (client->addr > 0x3ff)
788 /* 7-bit address, reject the general call address */
789 if (client->addr == 0x00 || client->addr > 0x7f)
795 /* And this is a strict address validity check, used when probing. If a
796 * device uses a reserved address, then it shouldn't be probed. 7-bit
797 * addressing is assumed, 10-bit address devices are rare and should be
798 * explicitly enumerated. */
799 static int i2c_check_addr_validity(unsigned short addr)
802 * Reserved addresses per I2C specification:
803 * 0x00 General call address / START byte
805 * 0x02 Reserved for different bus format
806 * 0x03 Reserved for future purposes
807 * 0x04-0x07 Hs-mode master code
808 * 0x78-0x7b 10-bit slave addressing
809 * 0x7c-0x7f Reserved for future purposes
811 if (addr < 0x08 || addr > 0x77)
816 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
818 struct i2c_client *client = i2c_verify_client(dev);
819 int addr = *(int *)addrp;
821 if (client && client->addr == addr)
826 /* walk up mux tree */
827 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
829 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
832 result = device_for_each_child(&adapter->dev, &addr,
833 __i2c_check_addr_busy);
835 if (!result && parent)
836 result = i2c_check_mux_parents(parent, addr);
841 /* recurse down mux tree */
842 static int i2c_check_mux_children(struct device *dev, void *addrp)
846 if (dev->type == &i2c_adapter_type)
847 result = device_for_each_child(dev, addrp,
848 i2c_check_mux_children);
850 result = __i2c_check_addr_busy(dev, addrp);
855 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
857 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
861 result = i2c_check_mux_parents(parent, addr);
864 result = device_for_each_child(&adapter->dev, &addr,
865 i2c_check_mux_children);
871 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
872 * @adapter: Target I2C bus segment
874 void i2c_lock_adapter(struct i2c_adapter *adapter)
876 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
879 i2c_lock_adapter(parent);
881 rt_mutex_lock(&adapter->bus_lock);
883 EXPORT_SYMBOL_GPL(i2c_lock_adapter);
886 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
887 * @adapter: Target I2C bus segment
889 static int i2c_trylock_adapter(struct i2c_adapter *adapter)
891 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
894 return i2c_trylock_adapter(parent);
896 return rt_mutex_trylock(&adapter->bus_lock);
900 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
901 * @adapter: Target I2C bus segment
903 void i2c_unlock_adapter(struct i2c_adapter *adapter)
905 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
908 i2c_unlock_adapter(parent);
910 rt_mutex_unlock(&adapter->bus_lock);
912 EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
914 static void i2c_dev_set_name(struct i2c_adapter *adap,
915 struct i2c_client *client)
917 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
920 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
924 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
925 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
926 client->addr | ((client->flags & I2C_CLIENT_TEN)
931 * i2c_new_device - instantiate an i2c device
932 * @adap: the adapter managing the device
933 * @info: describes one I2C device; bus_num is ignored
936 * Create an i2c device. Binding is handled through driver model
937 * probe()/remove() methods. A driver may be bound to this device when we
938 * return from this function, or any later moment (e.g. maybe hotplugging will
939 * load the driver module). This call is not appropriate for use by mainboard
940 * initialization logic, which usually runs during an arch_initcall() long
941 * before any i2c_adapter could exist.
943 * This returns the new i2c client, which may be saved for later use with
944 * i2c_unregister_device(); or NULL to indicate an error.
947 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
949 struct i2c_client *client;
952 client = kzalloc(sizeof *client, GFP_KERNEL);
956 client->adapter = adap;
958 client->dev.platform_data = info->platform_data;
961 client->dev.archdata = *info->archdata;
963 client->flags = info->flags;
964 client->addr = info->addr;
965 client->irq = info->irq;
967 strlcpy(client->name, info->type, sizeof(client->name));
969 /* Check for address validity */
970 status = i2c_check_client_addr_validity(client);
972 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
973 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
977 /* Check for address business */
978 status = i2c_check_addr_busy(adap, client->addr);
982 client->dev.parent = &client->adapter->dev;
983 client->dev.bus = &i2c_bus_type;
984 client->dev.type = &i2c_client_type;
985 client->dev.of_node = info->of_node;
986 client->dev.fwnode = info->fwnode;
988 i2c_dev_set_name(adap, client);
989 status = device_register(&client->dev);
993 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
994 client->name, dev_name(&client->dev));
999 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
1000 "(%d)\n", client->name, client->addr, status);
1005 EXPORT_SYMBOL_GPL(i2c_new_device);
1009 * i2c_unregister_device - reverse effect of i2c_new_device()
1010 * @client: value returned from i2c_new_device()
1011 * Context: can sleep
1013 void i2c_unregister_device(struct i2c_client *client)
1015 device_unregister(&client->dev);
1017 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1020 static const struct i2c_device_id dummy_id[] = {
1025 static int dummy_probe(struct i2c_client *client,
1026 const struct i2c_device_id *id)
1031 static int dummy_remove(struct i2c_client *client)
1036 static struct i2c_driver dummy_driver = {
1037 .driver.name = "dummy",
1038 .probe = dummy_probe,
1039 .remove = dummy_remove,
1040 .id_table = dummy_id,
1044 * i2c_new_dummy - return a new i2c device bound to a dummy driver
1045 * @adapter: the adapter managing the device
1046 * @address: seven bit address to be used
1047 * Context: can sleep
1049 * This returns an I2C client bound to the "dummy" driver, intended for use
1050 * with devices that consume multiple addresses. Examples of such chips
1051 * include various EEPROMS (like 24c04 and 24c08 models).
1053 * These dummy devices have two main uses. First, most I2C and SMBus calls
1054 * except i2c_transfer() need a client handle; the dummy will be that handle.
1055 * And second, this prevents the specified address from being bound to a
1058 * This returns the new i2c client, which should be saved for later use with
1059 * i2c_unregister_device(); or NULL to indicate an error.
1061 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
1063 struct i2c_board_info info = {
1064 I2C_BOARD_INFO("dummy", address),
1067 return i2c_new_device(adapter, &info);
1069 EXPORT_SYMBOL_GPL(i2c_new_dummy);
1071 /* ------------------------------------------------------------------------- */
1073 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1075 static void i2c_adapter_dev_release(struct device *dev)
1077 struct i2c_adapter *adap = to_i2c_adapter(dev);
1078 complete(&adap->dev_released);
1082 * This function is only needed for mutex_lock_nested, so it is never
1083 * called unless locking correctness checking is enabled. Thus we
1084 * make it inline to avoid a compiler warning. That's what gcc ends up
1087 static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1089 unsigned int depth = 0;
1091 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1098 * Let users instantiate I2C devices through sysfs. This can be used when
1099 * platform initialization code doesn't contain the proper data for
1100 * whatever reason. Also useful for drivers that do device detection and
1101 * detection fails, either because the device uses an unexpected address,
1102 * or this is a compatible device with different ID register values.
1104 * Parameter checking may look overzealous, but we really don't want
1105 * the user to provide incorrect parameters.
1108 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
1109 const char *buf, size_t count)
1111 struct i2c_adapter *adap = to_i2c_adapter(dev);
1112 struct i2c_board_info info;
1113 struct i2c_client *client;
1117 memset(&info, 0, sizeof(struct i2c_board_info));
1119 blank = strchr(buf, ' ');
1121 dev_err(dev, "%s: Missing parameters\n", "new_device");
1124 if (blank - buf > I2C_NAME_SIZE - 1) {
1125 dev_err(dev, "%s: Invalid device name\n", "new_device");
1128 memcpy(info.type, buf, blank - buf);
1130 /* Parse remaining parameters, reject extra parameters */
1131 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1133 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1136 if (res > 1 && end != '\n') {
1137 dev_err(dev, "%s: Extra parameters\n", "new_device");
1141 client = i2c_new_device(adap, &info);
1145 /* Keep track of the added device */
1146 mutex_lock(&adap->userspace_clients_lock);
1147 list_add_tail(&client->detected, &adap->userspace_clients);
1148 mutex_unlock(&adap->userspace_clients_lock);
1149 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1150 info.type, info.addr);
1154 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1157 * And of course let the users delete the devices they instantiated, if
1158 * they got it wrong. This interface can only be used to delete devices
1159 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1160 * don't delete devices to which some kernel code still has references.
1162 * Parameter checking may look overzealous, but we really don't want
1163 * the user to delete the wrong device.
1166 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1167 const char *buf, size_t count)
1169 struct i2c_adapter *adap = to_i2c_adapter(dev);
1170 struct i2c_client *client, *next;
1171 unsigned short addr;
1175 /* Parse parameters, reject extra parameters */
1176 res = sscanf(buf, "%hi%c", &addr, &end);
1178 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1181 if (res > 1 && end != '\n') {
1182 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1186 /* Make sure the device was added through sysfs */
1188 mutex_lock_nested(&adap->userspace_clients_lock,
1189 i2c_adapter_depth(adap));
1190 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1192 if (client->addr == addr) {
1193 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1194 "delete_device", client->name, client->addr);
1196 list_del(&client->detected);
1197 i2c_unregister_device(client);
1202 mutex_unlock(&adap->userspace_clients_lock);
1205 dev_err(dev, "%s: Can't find device in list\n",
1209 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1210 i2c_sysfs_delete_device);
1212 static struct attribute *i2c_adapter_attrs[] = {
1213 &dev_attr_name.attr,
1214 &dev_attr_new_device.attr,
1215 &dev_attr_delete_device.attr,
1218 ATTRIBUTE_GROUPS(i2c_adapter);
1220 struct device_type i2c_adapter_type = {
1221 .groups = i2c_adapter_groups,
1222 .release = i2c_adapter_dev_release,
1224 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1227 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1228 * @dev: device, probably from some driver model iterator
1230 * When traversing the driver model tree, perhaps using driver model
1231 * iterators like @device_for_each_child(), you can't assume very much
1232 * about the nodes you find. Use this function to avoid oopses caused
1233 * by wrongly treating some non-I2C device as an i2c_adapter.
1235 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1237 return (dev->type == &i2c_adapter_type)
1238 ? to_i2c_adapter(dev)
1241 EXPORT_SYMBOL(i2c_verify_adapter);
1243 #ifdef CONFIG_I2C_COMPAT
1244 static struct class_compat *i2c_adapter_compat_class;
1247 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1249 struct i2c_devinfo *devinfo;
1251 down_read(&__i2c_board_lock);
1252 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1253 if (devinfo->busnum == adapter->nr
1254 && !i2c_new_device(adapter,
1255 &devinfo->board_info))
1256 dev_err(&adapter->dev,
1257 "Can't create device at 0x%02x\n",
1258 devinfo->board_info.addr);
1260 up_read(&__i2c_board_lock);
1263 /* OF support code */
1265 #if IS_ENABLED(CONFIG_OF)
1266 static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
1267 struct device_node *node)
1269 struct i2c_client *result;
1270 struct i2c_board_info info = {};
1271 struct dev_archdata dev_ad = {};
1275 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1277 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
1278 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
1280 return ERR_PTR(-EINVAL);
1283 addr = of_get_property(node, "reg", &len);
1284 if (!addr || (len < sizeof(*addr))) {
1285 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
1287 return ERR_PTR(-EINVAL);
1290 info.addr = be32_to_cpup(addr);
1291 if (info.addr > (1 << 10) - 1) {
1292 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1293 info.addr, node->full_name);
1294 return ERR_PTR(-EINVAL);
1297 info.of_node = of_node_get(node);
1298 info.archdata = &dev_ad;
1300 if (of_get_property(node, "wakeup-source", NULL))
1301 info.flags |= I2C_CLIENT_WAKE;
1303 result = i2c_new_device(adap, &info);
1304 if (result == NULL) {
1305 dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
1308 return ERR_PTR(-EINVAL);
1313 static void of_i2c_register_devices(struct i2c_adapter *adap)
1315 struct device_node *node;
1317 /* Only register child devices if the adapter has a node pointer set */
1318 if (!adap->dev.of_node)
1321 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
1323 for_each_available_child_of_node(adap->dev.of_node, node)
1324 of_i2c_register_device(adap, node);
1327 static int of_dev_node_match(struct device *dev, void *data)
1329 return dev->of_node == data;
1332 /* must call put_device() when done with returned i2c_client device */
1333 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1337 dev = bus_find_device(&i2c_bus_type, NULL, node,
1342 return i2c_verify_client(dev);
1344 EXPORT_SYMBOL(of_find_i2c_device_by_node);
1346 /* must call put_device() when done with returned i2c_adapter device */
1347 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1351 dev = bus_find_device(&i2c_bus_type, NULL, node,
1356 return i2c_verify_adapter(dev);
1358 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1360 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
1361 #endif /* CONFIG_OF */
1363 static int i2c_do_add_adapter(struct i2c_driver *driver,
1364 struct i2c_adapter *adap)
1366 /* Detect supported devices on that bus, and instantiate them */
1367 i2c_detect(adap, driver);
1369 /* Let legacy drivers scan this bus for matching devices */
1370 if (driver->attach_adapter) {
1371 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1372 driver->driver.name);
1373 dev_warn(&adap->dev, "Please use another way to instantiate "
1374 "your i2c_client\n");
1375 /* We ignore the return code; if it fails, too bad */
1376 driver->attach_adapter(adap);
1381 static int __process_new_adapter(struct device_driver *d, void *data)
1383 return i2c_do_add_adapter(to_i2c_driver(d), data);
1386 static int i2c_register_adapter(struct i2c_adapter *adap)
1390 /* Can't register until after driver model init */
1391 if (unlikely(WARN_ON(!i2c_bus_type.p))) {
1397 if (unlikely(adap->name[0] == '\0')) {
1398 pr_err("i2c-core: Attempt to register an adapter with "
1402 if (unlikely(!adap->algo)) {
1403 pr_err("i2c-core: Attempt to register adapter '%s' with "
1404 "no algo!\n", adap->name);
1408 rt_mutex_init(&adap->bus_lock);
1409 mutex_init(&adap->userspace_clients_lock);
1410 INIT_LIST_HEAD(&adap->userspace_clients);
1412 /* Set default timeout to 1 second if not already set */
1413 if (adap->timeout == 0)
1416 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1417 adap->dev.bus = &i2c_bus_type;
1418 adap->dev.type = &i2c_adapter_type;
1419 res = device_register(&adap->dev);
1423 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1425 pm_runtime_no_callbacks(&adap->dev);
1427 #ifdef CONFIG_I2C_COMPAT
1428 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1431 dev_warn(&adap->dev,
1432 "Failed to create compatibility class link\n");
1435 /* bus recovery specific initialization */
1436 if (adap->bus_recovery_info) {
1437 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
1439 if (!bri->recover_bus) {
1440 dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
1441 adap->bus_recovery_info = NULL;
1445 /* Generic GPIO recovery */
1446 if (bri->recover_bus == i2c_generic_gpio_recovery) {
1447 if (!gpio_is_valid(bri->scl_gpio)) {
1448 dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
1449 adap->bus_recovery_info = NULL;
1453 if (gpio_is_valid(bri->sda_gpio))
1454 bri->get_sda = get_sda_gpio_value;
1456 bri->get_sda = NULL;
1458 bri->get_scl = get_scl_gpio_value;
1459 bri->set_scl = set_scl_gpio_value;
1460 } else if (!bri->set_scl || !bri->get_scl) {
1461 /* Generic SCL recovery */
1462 dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
1463 adap->bus_recovery_info = NULL;
1468 /* create pre-declared device nodes */
1469 of_i2c_register_devices(adap);
1470 acpi_i2c_register_devices(adap);
1471 acpi_i2c_install_space_handler(adap);
1473 if (adap->nr < __i2c_first_dynamic_bus_num)
1474 i2c_scan_static_board_info(adap);
1476 /* Notify drivers */
1477 mutex_lock(&core_lock);
1478 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1479 mutex_unlock(&core_lock);
1484 mutex_lock(&core_lock);
1485 idr_remove(&i2c_adapter_idr, adap->nr);
1486 mutex_unlock(&core_lock);
1491 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1492 * @adap: the adapter to register (with adap->nr initialized)
1493 * Context: can sleep
1495 * See i2c_add_numbered_adapter() for details.
1497 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1501 mutex_lock(&core_lock);
1502 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
1504 mutex_unlock(&core_lock);
1506 return id == -ENOSPC ? -EBUSY : id;
1508 return i2c_register_adapter(adap);
1512 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1513 * @adapter: the adapter to add
1514 * Context: can sleep
1516 * This routine is used to declare an I2C adapter when its bus number
1517 * doesn't matter or when its bus number is specified by an dt alias.
1518 * Examples of bases when the bus number doesn't matter: I2C adapters
1519 * dynamically added by USB links or PCI plugin cards.
1521 * When this returns zero, a new bus number was allocated and stored
1522 * in adap->nr, and the specified adapter became available for clients.
1523 * Otherwise, a negative errno value is returned.
1525 int i2c_add_adapter(struct i2c_adapter *adapter)
1527 struct device *dev = &adapter->dev;
1531 id = of_alias_get_id(dev->of_node, "i2c");
1534 return __i2c_add_numbered_adapter(adapter);
1538 mutex_lock(&core_lock);
1539 id = idr_alloc(&i2c_adapter_idr, adapter,
1540 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1541 mutex_unlock(&core_lock);
1547 return i2c_register_adapter(adapter);
1549 EXPORT_SYMBOL(i2c_add_adapter);
1552 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1553 * @adap: the adapter to register (with adap->nr initialized)
1554 * Context: can sleep
1556 * This routine is used to declare an I2C adapter when its bus number
1557 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1558 * or otherwise built in to the system's mainboard, and where i2c_board_info
1559 * is used to properly configure I2C devices.
1561 * If the requested bus number is set to -1, then this function will behave
1562 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1564 * If no devices have pre-been declared for this bus, then be sure to
1565 * register the adapter before any dynamically allocated ones. Otherwise
1566 * the required bus ID may not be available.
1568 * When this returns zero, the specified adapter became available for
1569 * clients using the bus number provided in adap->nr. Also, the table
1570 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1571 * and the appropriate driver model device nodes are created. Otherwise, a
1572 * negative errno value is returned.
1574 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1576 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1577 return i2c_add_adapter(adap);
1579 return __i2c_add_numbered_adapter(adap);
1581 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1583 static void i2c_do_del_adapter(struct i2c_driver *driver,
1584 struct i2c_adapter *adapter)
1586 struct i2c_client *client, *_n;
1588 /* Remove the devices we created ourselves as the result of hardware
1589 * probing (using a driver's detect method) */
1590 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1591 if (client->adapter == adapter) {
1592 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1593 client->name, client->addr);
1594 list_del(&client->detected);
1595 i2c_unregister_device(client);
1600 static int __unregister_client(struct device *dev, void *dummy)
1602 struct i2c_client *client = i2c_verify_client(dev);
1603 if (client && strcmp(client->name, "dummy"))
1604 i2c_unregister_device(client);
1608 static int __unregister_dummy(struct device *dev, void *dummy)
1610 struct i2c_client *client = i2c_verify_client(dev);
1612 i2c_unregister_device(client);
1616 static int __process_removed_adapter(struct device_driver *d, void *data)
1618 i2c_do_del_adapter(to_i2c_driver(d), data);
1623 * i2c_del_adapter - unregister I2C adapter
1624 * @adap: the adapter being unregistered
1625 * Context: can sleep
1627 * This unregisters an I2C adapter which was previously registered
1628 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1630 void i2c_del_adapter(struct i2c_adapter *adap)
1632 struct i2c_adapter *found;
1633 struct i2c_client *client, *next;
1635 /* First make sure that this adapter was ever added */
1636 mutex_lock(&core_lock);
1637 found = idr_find(&i2c_adapter_idr, adap->nr);
1638 mutex_unlock(&core_lock);
1639 if (found != adap) {
1640 pr_debug("i2c-core: attempting to delete unregistered "
1641 "adapter [%s]\n", adap->name);
1645 acpi_i2c_remove_space_handler(adap);
1646 /* Tell drivers about this removal */
1647 mutex_lock(&core_lock);
1648 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1649 __process_removed_adapter);
1650 mutex_unlock(&core_lock);
1652 /* Remove devices instantiated from sysfs */
1653 mutex_lock_nested(&adap->userspace_clients_lock,
1654 i2c_adapter_depth(adap));
1655 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1657 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1659 list_del(&client->detected);
1660 i2c_unregister_device(client);
1662 mutex_unlock(&adap->userspace_clients_lock);
1664 /* Detach any active clients. This can't fail, thus we do not
1665 * check the returned value. This is a two-pass process, because
1666 * we can't remove the dummy devices during the first pass: they
1667 * could have been instantiated by real devices wishing to clean
1668 * them up properly, so we give them a chance to do that first. */
1669 device_for_each_child(&adap->dev, NULL, __unregister_client);
1670 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1672 #ifdef CONFIG_I2C_COMPAT
1673 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1677 /* device name is gone after device_unregister */
1678 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1680 /* wait until all references to the device are gone
1682 * FIXME: This is old code and should ideally be replaced by an
1683 * alternative which results in decoupling the lifetime of the struct
1684 * device from the i2c_adapter, like spi or netdev do. Any solution
1685 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1687 init_completion(&adap->dev_released);
1688 device_unregister(&adap->dev);
1689 wait_for_completion(&adap->dev_released);
1692 mutex_lock(&core_lock);
1693 idr_remove(&i2c_adapter_idr, adap->nr);
1694 mutex_unlock(&core_lock);
1696 /* Clear the device structure in case this adapter is ever going to be
1698 memset(&adap->dev, 0, sizeof(adap->dev));
1700 EXPORT_SYMBOL(i2c_del_adapter);
1702 /* ------------------------------------------------------------------------- */
1704 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1708 mutex_lock(&core_lock);
1709 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1710 mutex_unlock(&core_lock);
1714 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1716 static int __process_new_driver(struct device *dev, void *data)
1718 if (dev->type != &i2c_adapter_type)
1720 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1724 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1725 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1728 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1732 /* Can't register until after driver model init */
1733 if (unlikely(WARN_ON(!i2c_bus_type.p)))
1736 /* add the driver to the list of i2c drivers in the driver core */
1737 driver->driver.owner = owner;
1738 driver->driver.bus = &i2c_bus_type;
1740 /* When registration returns, the driver core
1741 * will have called probe() for all matching-but-unbound devices.
1743 res = driver_register(&driver->driver);
1747 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
1749 INIT_LIST_HEAD(&driver->clients);
1750 /* Walk the adapters that are already present */
1751 i2c_for_each_dev(driver, __process_new_driver);
1755 EXPORT_SYMBOL(i2c_register_driver);
1757 static int __process_removed_driver(struct device *dev, void *data)
1759 if (dev->type == &i2c_adapter_type)
1760 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1765 * i2c_del_driver - unregister I2C driver
1766 * @driver: the driver being unregistered
1767 * Context: can sleep
1769 void i2c_del_driver(struct i2c_driver *driver)
1771 i2c_for_each_dev(driver, __process_removed_driver);
1773 driver_unregister(&driver->driver);
1774 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
1776 EXPORT_SYMBOL(i2c_del_driver);
1778 /* ------------------------------------------------------------------------- */
1781 * i2c_use_client - increments the reference count of the i2c client structure
1782 * @client: the client being referenced
1784 * Each live reference to a client should be refcounted. The driver model does
1785 * that automatically as part of driver binding, so that most drivers don't
1786 * need to do this explicitly: they hold a reference until they're unbound
1789 * A pointer to the client with the incremented reference counter is returned.
1791 struct i2c_client *i2c_use_client(struct i2c_client *client)
1793 if (client && get_device(&client->dev))
1797 EXPORT_SYMBOL(i2c_use_client);
1800 * i2c_release_client - release a use of the i2c client structure
1801 * @client: the client being no longer referenced
1803 * Must be called when a user of a client is finished with it.
1805 void i2c_release_client(struct i2c_client *client)
1808 put_device(&client->dev);
1810 EXPORT_SYMBOL(i2c_release_client);
1812 struct i2c_cmd_arg {
1817 static int i2c_cmd(struct device *dev, void *_arg)
1819 struct i2c_client *client = i2c_verify_client(dev);
1820 struct i2c_cmd_arg *arg = _arg;
1821 struct i2c_driver *driver;
1823 if (!client || !client->dev.driver)
1826 driver = to_i2c_driver(client->dev.driver);
1827 if (driver->command)
1828 driver->command(client, arg->cmd, arg->arg);
1832 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1834 struct i2c_cmd_arg cmd_arg;
1838 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1840 EXPORT_SYMBOL(i2c_clients_command);
1842 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
1843 static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
1846 struct of_reconfig_data *rd = arg;
1847 struct i2c_adapter *adap;
1848 struct i2c_client *client;
1850 switch (of_reconfig_get_state_change(action, rd)) {
1851 case OF_RECONFIG_CHANGE_ADD:
1852 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
1854 return NOTIFY_OK; /* not for us */
1856 client = of_i2c_register_device(adap, rd->dn);
1857 put_device(&adap->dev);
1859 if (IS_ERR(client)) {
1860 pr_err("%s: failed to create for '%s'\n",
1861 __func__, rd->dn->full_name);
1862 return notifier_from_errno(PTR_ERR(client));
1865 case OF_RECONFIG_CHANGE_REMOVE:
1866 /* find our device by node */
1867 client = of_find_i2c_device_by_node(rd->dn);
1869 return NOTIFY_OK; /* no? not meant for us */
1871 /* unregister takes one ref away */
1872 i2c_unregister_device(client);
1874 /* and put the reference of the find */
1875 put_device(&client->dev);
1881 static struct notifier_block i2c_of_notifier = {
1882 .notifier_call = of_i2c_notify,
1885 extern struct notifier_block i2c_of_notifier;
1886 #endif /* CONFIG_OF_DYNAMIC */
1888 static int __init i2c_init(void)
1892 retval = of_alias_get_highest_id("i2c");
1894 down_write(&__i2c_board_lock);
1895 if (retval >= __i2c_first_dynamic_bus_num)
1896 __i2c_first_dynamic_bus_num = retval + 1;
1897 up_write(&__i2c_board_lock);
1899 retval = bus_register(&i2c_bus_type);
1902 #ifdef CONFIG_I2C_COMPAT
1903 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1904 if (!i2c_adapter_compat_class) {
1909 retval = i2c_add_driver(&dummy_driver);
1913 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1914 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1919 #ifdef CONFIG_I2C_COMPAT
1920 class_compat_unregister(i2c_adapter_compat_class);
1923 bus_unregister(&i2c_bus_type);
1927 static void __exit i2c_exit(void)
1929 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1930 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1931 i2c_del_driver(&dummy_driver);
1932 #ifdef CONFIG_I2C_COMPAT
1933 class_compat_unregister(i2c_adapter_compat_class);
1935 bus_unregister(&i2c_bus_type);
1936 tracepoint_synchronize_unregister();
1939 /* We must initialize early, because some subsystems register i2c drivers
1940 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1942 postcore_initcall(i2c_init);
1943 module_exit(i2c_exit);
1945 /* ----------------------------------------------------
1946 * the functional interface to the i2c busses.
1947 * ----------------------------------------------------
1950 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1951 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1953 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1955 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1956 err_msg, msg->addr, msg->len,
1957 msg->flags & I2C_M_RD ? "read" : "write");
1961 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1963 const struct i2c_adapter_quirks *q = adap->quirks;
1964 int max_num = q->max_num_msgs, i;
1965 bool do_len_check = true;
1967 if (q->flags & I2C_AQ_COMB) {
1970 /* special checks for combined messages */
1972 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1973 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1975 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1976 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1978 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1979 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1981 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1982 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1984 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1985 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1987 do_len_check = false;
1991 if (i2c_quirk_exceeded(num, max_num))
1992 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1994 for (i = 0; i < num; i++) {
1995 u16 len = msgs[i].len;
1997 if (msgs[i].flags & I2C_M_RD) {
1998 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1999 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2001 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2002 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2010 * __i2c_transfer - unlocked flavor of i2c_transfer
2011 * @adap: Handle to I2C bus
2012 * @msgs: One or more messages to execute before STOP is issued to
2013 * terminate the operation; each message begins with a START.
2014 * @num: Number of messages to be executed.
2016 * Returns negative errno, else the number of messages executed.
2018 * Adapter lock must be held when calling this function. No debug logging
2019 * takes place. adap->algo->master_xfer existence isn't checked.
2021 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2023 unsigned long orig_jiffies;
2026 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2029 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
2030 * enabled. This is an efficient way of keeping the for-loop from
2031 * being executed when not needed.
2033 if (static_key_false(&i2c_trace_msg)) {
2035 for (i = 0; i < num; i++)
2036 if (msgs[i].flags & I2C_M_RD)
2037 trace_i2c_read(adap, &msgs[i], i);
2039 trace_i2c_write(adap, &msgs[i], i);
2042 /* Retry automatically on arbitration loss */
2043 orig_jiffies = jiffies;
2044 for (ret = 0, try = 0; try <= adap->retries; try++) {
2045 ret = adap->algo->master_xfer(adap, msgs, num);
2048 if (time_after(jiffies, orig_jiffies + adap->timeout))
2052 if (static_key_false(&i2c_trace_msg)) {
2054 for (i = 0; i < ret; i++)
2055 if (msgs[i].flags & I2C_M_RD)
2056 trace_i2c_reply(adap, &msgs[i], i);
2057 trace_i2c_result(adap, i, ret);
2062 EXPORT_SYMBOL(__i2c_transfer);
2065 * i2c_transfer - execute a single or combined I2C message
2066 * @adap: Handle to I2C bus
2067 * @msgs: One or more messages to execute before STOP is issued to
2068 * terminate the operation; each message begins with a START.
2069 * @num: Number of messages to be executed.
2071 * Returns negative errno, else the number of messages executed.
2073 * Note that there is no requirement that each message be sent to
2074 * the same slave address, although that is the most common model.
2076 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2080 /* REVISIT the fault reporting model here is weak:
2082 * - When we get an error after receiving N bytes from a slave,
2083 * there is no way to report "N".
2085 * - When we get a NAK after transmitting N bytes to a slave,
2086 * there is no way to report "N" ... or to let the master
2087 * continue executing the rest of this combined message, if
2088 * that's the appropriate response.
2090 * - When for example "num" is two and we successfully complete
2091 * the first message but get an error part way through the
2092 * second, it's unclear whether that should be reported as
2093 * one (discarding status on the second message) or errno
2094 * (discarding status on the first one).
2097 if (adap->algo->master_xfer) {
2099 for (ret = 0; ret < num; ret++) {
2100 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
2101 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
2102 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
2103 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
2107 if (in_atomic() || irqs_disabled()) {
2108 ret = i2c_trylock_adapter(adap);
2110 /* I2C activity is ongoing. */
2113 i2c_lock_adapter(adap);
2116 ret = __i2c_transfer(adap, msgs, num);
2117 i2c_unlock_adapter(adap);
2121 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2125 EXPORT_SYMBOL(i2c_transfer);
2128 * i2c_master_send - issue a single I2C message in master transmit mode
2129 * @client: Handle to slave device
2130 * @buf: Data that will be written to the slave
2131 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2133 * Returns negative errno, or else the number of bytes written.
2135 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
2138 struct i2c_adapter *adap = client->adapter;
2141 msg.addr = client->addr;
2142 msg.flags = client->flags & I2C_M_TEN;
2144 msg.buf = (char *)buf;
2146 ret = i2c_transfer(adap, &msg, 1);
2149 * If everything went ok (i.e. 1 msg transmitted), return #bytes
2150 * transmitted, else error code.
2152 return (ret == 1) ? count : ret;
2154 EXPORT_SYMBOL(i2c_master_send);
2157 * i2c_master_recv - issue a single I2C message in master receive mode
2158 * @client: Handle to slave device
2159 * @buf: Where to store data read from slave
2160 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2162 * Returns negative errno, or else the number of bytes read.
2164 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
2166 struct i2c_adapter *adap = client->adapter;
2170 msg.addr = client->addr;
2171 msg.flags = client->flags & I2C_M_TEN;
2172 msg.flags |= I2C_M_RD;
2176 ret = i2c_transfer(adap, &msg, 1);
2179 * If everything went ok (i.e. 1 msg received), return #bytes received,
2182 return (ret == 1) ? count : ret;
2184 EXPORT_SYMBOL(i2c_master_recv);
2186 /* ----------------------------------------------------
2187 * the i2c address scanning function
2188 * Will not work for 10-bit addresses!
2189 * ----------------------------------------------------
2193 * Legacy default probe function, mostly relevant for SMBus. The default
2194 * probe method is a quick write, but it is known to corrupt the 24RF08
2195 * EEPROMs due to a state machine bug, and could also irreversibly
2196 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2197 * we use a short byte read instead. Also, some bus drivers don't implement
2198 * quick write, so we fallback to a byte read in that case too.
2199 * On x86, there is another special case for FSC hardware monitoring chips,
2200 * which want regular byte reads (address 0x73.) Fortunately, these are the
2201 * only known chips using this I2C address on PC hardware.
2202 * Returns 1 if probe succeeded, 0 if not.
2204 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2207 union i2c_smbus_data dummy;
2210 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2211 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2212 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2213 I2C_SMBUS_BYTE_DATA, &dummy);
2216 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2217 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2218 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2219 I2C_SMBUS_QUICK, NULL);
2220 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2221 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2222 I2C_SMBUS_BYTE, &dummy);
2224 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2232 static int i2c_detect_address(struct i2c_client *temp_client,
2233 struct i2c_driver *driver)
2235 struct i2c_board_info info;
2236 struct i2c_adapter *adapter = temp_client->adapter;
2237 int addr = temp_client->addr;
2240 /* Make sure the address is valid */
2241 err = i2c_check_addr_validity(addr);
2243 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2248 /* Skip if already in use */
2249 if (i2c_check_addr_busy(adapter, addr))
2252 /* Make sure there is something at this address */
2253 if (!i2c_default_probe(adapter, addr))
2256 /* Finally call the custom detection function */
2257 memset(&info, 0, sizeof(struct i2c_board_info));
2259 err = driver->detect(temp_client, &info);
2261 /* -ENODEV is returned if the detection fails. We catch it
2262 here as this isn't an error. */
2263 return err == -ENODEV ? 0 : err;
2266 /* Consistency check */
2267 if (info.type[0] == '\0') {
2268 dev_err(&adapter->dev, "%s detection function provided "
2269 "no name for 0x%x\n", driver->driver.name,
2272 struct i2c_client *client;
2274 /* Detection succeeded, instantiate the device */
2275 if (adapter->class & I2C_CLASS_DEPRECATED)
2276 dev_warn(&adapter->dev,
2277 "This adapter will soon drop class based instantiation of devices. "
2278 "Please make sure client 0x%02x gets instantiated by other means. "
2279 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2282 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2283 info.type, info.addr);
2284 client = i2c_new_device(adapter, &info);
2286 list_add_tail(&client->detected, &driver->clients);
2288 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2289 info.type, info.addr);
2294 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2296 const unsigned short *address_list;
2297 struct i2c_client *temp_client;
2299 int adap_id = i2c_adapter_id(adapter);
2301 address_list = driver->address_list;
2302 if (!driver->detect || !address_list)
2305 /* Warn that the adapter lost class based instantiation */
2306 if (adapter->class == I2C_CLASS_DEPRECATED) {
2307 dev_dbg(&adapter->dev,
2308 "This adapter dropped support for I2C classes and "
2309 "won't auto-detect %s devices anymore. If you need it, check "
2310 "'Documentation/i2c/instantiating-devices' for alternatives.\n",
2311 driver->driver.name);
2315 /* Stop here if the classes do not match */
2316 if (!(adapter->class & driver->class))
2319 /* Set up a temporary client to help detect callback */
2320 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2323 temp_client->adapter = adapter;
2325 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2326 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
2327 "addr 0x%02x\n", adap_id, address_list[i]);
2328 temp_client->addr = address_list[i];
2329 err = i2c_detect_address(temp_client, driver);
2338 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2340 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2341 I2C_SMBUS_QUICK, NULL) >= 0;
2343 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2346 i2c_new_probed_device(struct i2c_adapter *adap,
2347 struct i2c_board_info *info,
2348 unsigned short const *addr_list,
2349 int (*probe)(struct i2c_adapter *, unsigned short addr))
2354 probe = i2c_default_probe;
2356 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2357 /* Check address validity */
2358 if (i2c_check_addr_validity(addr_list[i]) < 0) {
2359 dev_warn(&adap->dev, "Invalid 7-bit address "
2360 "0x%02x\n", addr_list[i]);
2364 /* Check address availability */
2365 if (i2c_check_addr_busy(adap, addr_list[i])) {
2366 dev_dbg(&adap->dev, "Address 0x%02x already in "
2367 "use, not probing\n", addr_list[i]);
2371 /* Test address responsiveness */
2372 if (probe(adap, addr_list[i]))
2376 if (addr_list[i] == I2C_CLIENT_END) {
2377 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2381 info->addr = addr_list[i];
2382 return i2c_new_device(adap, info);
2384 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2386 struct i2c_adapter *i2c_get_adapter(int nr)
2388 struct i2c_adapter *adapter;
2390 mutex_lock(&core_lock);
2391 adapter = idr_find(&i2c_adapter_idr, nr);
2392 if (adapter && !try_module_get(adapter->owner))
2395 mutex_unlock(&core_lock);
2398 EXPORT_SYMBOL(i2c_get_adapter);
2400 void i2c_put_adapter(struct i2c_adapter *adap)
2403 module_put(adap->owner);
2405 EXPORT_SYMBOL(i2c_put_adapter);
2407 /* The SMBus parts */
2409 #define POLY (0x1070U << 3)
2410 static u8 crc8(u16 data)
2414 for (i = 0; i < 8; i++) {
2419 return (u8)(data >> 8);
2422 /* Incremental CRC8 over count bytes in the array pointed to by p */
2423 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
2427 for (i = 0; i < count; i++)
2428 crc = crc8((crc ^ p[i]) << 8);
2432 /* Assume a 7-bit address, which is reasonable for SMBus */
2433 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
2435 /* The address will be sent first */
2436 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
2437 pec = i2c_smbus_pec(pec, &addr, 1);
2439 /* The data buffer follows */
2440 return i2c_smbus_pec(pec, msg->buf, msg->len);
2443 /* Used for write only transactions */
2444 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
2446 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
2450 /* Return <0 on CRC error
2451 If there was a write before this read (most cases) we need to take the
2452 partial CRC from the write part into account.
2453 Note that this function does modify the message (we need to decrease the
2454 message length to hide the CRC byte from the caller). */
2455 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
2457 u8 rpec = msg->buf[--msg->len];
2458 cpec = i2c_smbus_msg_pec(cpec, msg);
2461 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2469 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2470 * @client: Handle to slave device
2472 * This executes the SMBus "receive byte" protocol, returning negative errno
2473 * else the byte received from the device.
2475 s32 i2c_smbus_read_byte(const struct i2c_client *client)
2477 union i2c_smbus_data data;
2480 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2482 I2C_SMBUS_BYTE, &data);
2483 return (status < 0) ? status : data.byte;
2485 EXPORT_SYMBOL(i2c_smbus_read_byte);
2488 * i2c_smbus_write_byte - SMBus "send byte" protocol
2489 * @client: Handle to slave device
2490 * @value: Byte to be sent
2492 * This executes the SMBus "send byte" protocol, returning negative errno
2493 * else zero on success.
2495 s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
2497 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2498 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
2500 EXPORT_SYMBOL(i2c_smbus_write_byte);
2503 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2504 * @client: Handle to slave device
2505 * @command: Byte interpreted by slave
2507 * This executes the SMBus "read byte" protocol, returning negative errno
2508 * else a data byte received from the device.
2510 s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
2512 union i2c_smbus_data data;
2515 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2516 I2C_SMBUS_READ, command,
2517 I2C_SMBUS_BYTE_DATA, &data);
2518 return (status < 0) ? status : data.byte;
2520 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
2523 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2524 * @client: Handle to slave device
2525 * @command: Byte interpreted by slave
2526 * @value: Byte being written
2528 * This executes the SMBus "write byte" protocol, returning negative errno
2529 * else zero on success.
2531 s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
2534 union i2c_smbus_data data;
2536 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2537 I2C_SMBUS_WRITE, command,
2538 I2C_SMBUS_BYTE_DATA, &data);
2540 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
2543 * i2c_smbus_read_word_data - SMBus "read word" protocol
2544 * @client: Handle to slave device
2545 * @command: Byte interpreted by slave
2547 * This executes the SMBus "read word" protocol, returning negative errno
2548 * else a 16-bit unsigned "word" received from the device.
2550 s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
2552 union i2c_smbus_data data;
2555 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2556 I2C_SMBUS_READ, command,
2557 I2C_SMBUS_WORD_DATA, &data);
2558 return (status < 0) ? status : data.word;
2560 EXPORT_SYMBOL(i2c_smbus_read_word_data);
2563 * i2c_smbus_write_word_data - SMBus "write word" protocol
2564 * @client: Handle to slave device
2565 * @command: Byte interpreted by slave
2566 * @value: 16-bit "word" being written
2568 * This executes the SMBus "write word" protocol, returning negative errno
2569 * else zero on success.
2571 s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
2574 union i2c_smbus_data data;
2576 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2577 I2C_SMBUS_WRITE, command,
2578 I2C_SMBUS_WORD_DATA, &data);
2580 EXPORT_SYMBOL(i2c_smbus_write_word_data);
2583 * i2c_smbus_read_block_data - SMBus "block read" protocol
2584 * @client: Handle to slave device
2585 * @command: Byte interpreted by slave
2586 * @values: Byte array into which data will be read; big enough to hold
2587 * the data returned by the slave. SMBus allows at most 32 bytes.
2589 * This executes the SMBus "block read" protocol, returning negative errno
2590 * else the number of data bytes in the slave's response.
2592 * Note that using this function requires that the client's adapter support
2593 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2594 * support this; its emulation through I2C messaging relies on a specific
2595 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2597 s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2600 union i2c_smbus_data data;
2603 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2604 I2C_SMBUS_READ, command,
2605 I2C_SMBUS_BLOCK_DATA, &data);
2609 memcpy(values, &data.block[1], data.block[0]);
2610 return data.block[0];
2612 EXPORT_SYMBOL(i2c_smbus_read_block_data);
2615 * i2c_smbus_write_block_data - SMBus "block write" protocol
2616 * @client: Handle to slave device
2617 * @command: Byte interpreted by slave
2618 * @length: Size of data block; SMBus allows at most 32 bytes
2619 * @values: Byte array which will be written.
2621 * This executes the SMBus "block write" protocol, returning negative errno
2622 * else zero on success.
2624 s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2625 u8 length, const u8 *values)
2627 union i2c_smbus_data data;
2629 if (length > I2C_SMBUS_BLOCK_MAX)
2630 length = I2C_SMBUS_BLOCK_MAX;
2631 data.block[0] = length;
2632 memcpy(&data.block[1], values, length);
2633 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2634 I2C_SMBUS_WRITE, command,
2635 I2C_SMBUS_BLOCK_DATA, &data);
2637 EXPORT_SYMBOL(i2c_smbus_write_block_data);
2639 /* Returns the number of read bytes */
2640 s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2641 u8 length, u8 *values)
2643 union i2c_smbus_data data;
2646 if (length > I2C_SMBUS_BLOCK_MAX)
2647 length = I2C_SMBUS_BLOCK_MAX;
2648 data.block[0] = length;
2649 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2650 I2C_SMBUS_READ, command,
2651 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2655 memcpy(values, &data.block[1], data.block[0]);
2656 return data.block[0];
2658 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
2660 s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2661 u8 length, const u8 *values)
2663 union i2c_smbus_data data;
2665 if (length > I2C_SMBUS_BLOCK_MAX)
2666 length = I2C_SMBUS_BLOCK_MAX;
2667 data.block[0] = length;
2668 memcpy(data.block + 1, values, length);
2669 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2670 I2C_SMBUS_WRITE, command,
2671 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2673 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2675 /* Simulate a SMBus command using the i2c protocol
2676 No checking of parameters is done! */
2677 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
2678 unsigned short flags,
2679 char read_write, u8 command, int size,
2680 union i2c_smbus_data *data)
2682 /* So we need to generate a series of msgs. In the case of writing, we
2683 need to use only one message; when reading, we need two. We initialize
2684 most things with sane defaults, to keep the code below somewhat
2686 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
2687 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2688 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
2692 struct i2c_msg msg[2] = {
2700 .flags = flags | I2C_M_RD,
2706 msgbuf0[0] = command;
2708 case I2C_SMBUS_QUICK:
2710 /* Special case: The read/write field is used as data */
2711 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
2715 case I2C_SMBUS_BYTE:
2716 if (read_write == I2C_SMBUS_READ) {
2717 /* Special case: only a read! */
2718 msg[0].flags = I2C_M_RD | flags;
2722 case I2C_SMBUS_BYTE_DATA:
2723 if (read_write == I2C_SMBUS_READ)
2727 msgbuf0[1] = data->byte;
2730 case I2C_SMBUS_WORD_DATA:
2731 if (read_write == I2C_SMBUS_READ)
2735 msgbuf0[1] = data->word & 0xff;
2736 msgbuf0[2] = data->word >> 8;
2739 case I2C_SMBUS_PROC_CALL:
2740 num = 2; /* Special case */
2741 read_write = I2C_SMBUS_READ;
2744 msgbuf0[1] = data->word & 0xff;
2745 msgbuf0[2] = data->word >> 8;
2747 case I2C_SMBUS_BLOCK_DATA:
2748 if (read_write == I2C_SMBUS_READ) {
2749 msg[1].flags |= I2C_M_RECV_LEN;
2750 msg[1].len = 1; /* block length will be added by
2751 the underlying bus driver */
2753 msg[0].len = data->block[0] + 2;
2754 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
2755 dev_err(&adapter->dev,
2756 "Invalid block write size %d\n",
2760 for (i = 1; i < msg[0].len; i++)
2761 msgbuf0[i] = data->block[i-1];
2764 case I2C_SMBUS_BLOCK_PROC_CALL:
2765 num = 2; /* Another special case */
2766 read_write = I2C_SMBUS_READ;
2767 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
2768 dev_err(&adapter->dev,
2769 "Invalid block write size %d\n",
2773 msg[0].len = data->block[0] + 2;
2774 for (i = 1; i < msg[0].len; i++)
2775 msgbuf0[i] = data->block[i-1];
2776 msg[1].flags |= I2C_M_RECV_LEN;
2777 msg[1].len = 1; /* block length will be added by
2778 the underlying bus driver */
2780 case I2C_SMBUS_I2C_BLOCK_DATA:
2781 if (read_write == I2C_SMBUS_READ) {
2782 msg[1].len = data->block[0];
2784 msg[0].len = data->block[0] + 1;
2785 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
2786 dev_err(&adapter->dev,
2787 "Invalid block write size %d\n",
2791 for (i = 1; i <= data->block[0]; i++)
2792 msgbuf0[i] = data->block[i];
2796 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
2800 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
2801 && size != I2C_SMBUS_I2C_BLOCK_DATA);
2803 /* Compute PEC if first message is a write */
2804 if (!(msg[0].flags & I2C_M_RD)) {
2805 if (num == 1) /* Write only */
2806 i2c_smbus_add_pec(&msg[0]);
2807 else /* Write followed by read */
2808 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
2810 /* Ask for PEC if last message is a read */
2811 if (msg[num-1].flags & I2C_M_RD)
2815 status = i2c_transfer(adapter, msg, num);
2819 /* Check PEC if last message is a read */
2820 if (i && (msg[num-1].flags & I2C_M_RD)) {
2821 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
2826 if (read_write == I2C_SMBUS_READ)
2828 case I2C_SMBUS_BYTE:
2829 data->byte = msgbuf0[0];
2831 case I2C_SMBUS_BYTE_DATA:
2832 data->byte = msgbuf1[0];
2834 case I2C_SMBUS_WORD_DATA:
2835 case I2C_SMBUS_PROC_CALL:
2836 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
2838 case I2C_SMBUS_I2C_BLOCK_DATA:
2839 for (i = 0; i < data->block[0]; i++)
2840 data->block[i+1] = msgbuf1[i];
2842 case I2C_SMBUS_BLOCK_DATA:
2843 case I2C_SMBUS_BLOCK_PROC_CALL:
2844 for (i = 0; i < msgbuf1[0] + 1; i++)
2845 data->block[i] = msgbuf1[i];
2852 * i2c_smbus_xfer - execute SMBus protocol operations
2853 * @adapter: Handle to I2C bus
2854 * @addr: Address of SMBus slave on that bus
2855 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2856 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2857 * @command: Byte interpreted by slave, for protocols which use such bytes
2858 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2859 * @data: Data to be read or written
2861 * This executes an SMBus protocol operation, and returns a negative
2862 * errno code else zero on success.
2864 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
2865 char read_write, u8 command, int protocol,
2866 union i2c_smbus_data *data)
2868 unsigned long orig_jiffies;
2872 /* If enabled, the following two tracepoints are conditional on
2873 * read_write and protocol.
2875 trace_smbus_write(adapter, addr, flags, read_write,
2876 command, protocol, data);
2877 trace_smbus_read(adapter, addr, flags, read_write,
2880 flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
2882 if (adapter->algo->smbus_xfer) {
2883 i2c_lock_adapter(adapter);
2885 /* Retry automatically on arbitration loss */
2886 orig_jiffies = jiffies;
2887 for (res = 0, try = 0; try <= adapter->retries; try++) {
2888 res = adapter->algo->smbus_xfer(adapter, addr, flags,
2889 read_write, command,
2893 if (time_after(jiffies,
2894 orig_jiffies + adapter->timeout))
2897 i2c_unlock_adapter(adapter);
2899 if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
2902 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2903 * implement native support for the SMBus operation.
2907 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
2908 command, protocol, data);
2911 /* If enabled, the reply tracepoint is conditional on read_write. */
2912 trace_smbus_reply(adapter, addr, flags, read_write,
2913 command, protocol, data);
2914 trace_smbus_result(adapter, addr, flags, read_write,
2915 command, protocol, res);
2919 EXPORT_SYMBOL(i2c_smbus_xfer);
2921 #if IS_ENABLED(CONFIG_I2C_SLAVE)
2922 int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
2926 if (!client || !slave_cb) {
2927 WARN(1, "insufficent data\n");
2931 if (!(client->flags & I2C_CLIENT_TEN)) {
2932 /* Enforce stricter address checking */
2933 ret = i2c_check_addr_validity(client->addr);
2935 dev_err(&client->dev, "%s: invalid address\n", __func__);
2940 if (!client->adapter->algo->reg_slave) {
2941 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
2945 client->slave_cb = slave_cb;
2947 i2c_lock_adapter(client->adapter);
2948 ret = client->adapter->algo->reg_slave(client);
2949 i2c_unlock_adapter(client->adapter);
2952 client->slave_cb = NULL;
2953 dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
2958 EXPORT_SYMBOL_GPL(i2c_slave_register);
2960 int i2c_slave_unregister(struct i2c_client *client)
2964 if (!client->adapter->algo->unreg_slave) {
2965 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
2969 i2c_lock_adapter(client->adapter);
2970 ret = client->adapter->algo->unreg_slave(client);
2971 i2c_unlock_adapter(client->adapter);
2974 client->slave_cb = NULL;
2976 dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
2980 EXPORT_SYMBOL_GPL(i2c_slave_unregister);
2983 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2984 MODULE_DESCRIPTION("I2C-Bus main module");
2985 MODULE_LICENSE("GPL");