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 if (client
->dev
.of_node
)
1016 of_node_clear_flag(client
->dev
.of_node
, OF_POPULATED
);
1017 device_unregister(&client
->dev
);
1019 EXPORT_SYMBOL_GPL(i2c_unregister_device
);
1022 static const struct i2c_device_id dummy_id
[] = {
1027 static int dummy_probe(struct i2c_client
*client
,
1028 const struct i2c_device_id
*id
)
1033 static int dummy_remove(struct i2c_client
*client
)
1038 static struct i2c_driver dummy_driver
= {
1039 .driver
.name
= "dummy",
1040 .probe
= dummy_probe
,
1041 .remove
= dummy_remove
,
1042 .id_table
= dummy_id
,
1046 * i2c_new_dummy - return a new i2c device bound to a dummy driver
1047 * @adapter: the adapter managing the device
1048 * @address: seven bit address to be used
1049 * Context: can sleep
1051 * This returns an I2C client bound to the "dummy" driver, intended for use
1052 * with devices that consume multiple addresses. Examples of such chips
1053 * include various EEPROMS (like 24c04 and 24c08 models).
1055 * These dummy devices have two main uses. First, most I2C and SMBus calls
1056 * except i2c_transfer() need a client handle; the dummy will be that handle.
1057 * And second, this prevents the specified address from being bound to a
1060 * This returns the new i2c client, which should be saved for later use with
1061 * i2c_unregister_device(); or NULL to indicate an error.
1063 struct i2c_client
*i2c_new_dummy(struct i2c_adapter
*adapter
, u16 address
)
1065 struct i2c_board_info info
= {
1066 I2C_BOARD_INFO("dummy", address
),
1069 return i2c_new_device(adapter
, &info
);
1071 EXPORT_SYMBOL_GPL(i2c_new_dummy
);
1073 /* ------------------------------------------------------------------------- */
1075 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1077 static void i2c_adapter_dev_release(struct device
*dev
)
1079 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1080 complete(&adap
->dev_released
);
1084 * This function is only needed for mutex_lock_nested, so it is never
1085 * called unless locking correctness checking is enabled. Thus we
1086 * make it inline to avoid a compiler warning. That's what gcc ends up
1089 static inline unsigned int i2c_adapter_depth(struct i2c_adapter
*adapter
)
1091 unsigned int depth
= 0;
1093 while ((adapter
= i2c_parent_is_i2c_adapter(adapter
)))
1100 * Let users instantiate I2C devices through sysfs. This can be used when
1101 * platform initialization code doesn't contain the proper data for
1102 * whatever reason. Also useful for drivers that do device detection and
1103 * detection fails, either because the device uses an unexpected address,
1104 * or this is a compatible device with different ID register values.
1106 * Parameter checking may look overzealous, but we really don't want
1107 * the user to provide incorrect parameters.
1110 i2c_sysfs_new_device(struct device
*dev
, struct device_attribute
*attr
,
1111 const char *buf
, size_t count
)
1113 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1114 struct i2c_board_info info
;
1115 struct i2c_client
*client
;
1119 memset(&info
, 0, sizeof(struct i2c_board_info
));
1121 blank
= strchr(buf
, ' ');
1123 dev_err(dev
, "%s: Missing parameters\n", "new_device");
1126 if (blank
- buf
> I2C_NAME_SIZE
- 1) {
1127 dev_err(dev
, "%s: Invalid device name\n", "new_device");
1130 memcpy(info
.type
, buf
, blank
- buf
);
1132 /* Parse remaining parameters, reject extra parameters */
1133 res
= sscanf(++blank
, "%hi%c", &info
.addr
, &end
);
1135 dev_err(dev
, "%s: Can't parse I2C address\n", "new_device");
1138 if (res
> 1 && end
!= '\n') {
1139 dev_err(dev
, "%s: Extra parameters\n", "new_device");
1143 client
= i2c_new_device(adap
, &info
);
1147 /* Keep track of the added device */
1148 mutex_lock(&adap
->userspace_clients_lock
);
1149 list_add_tail(&client
->detected
, &adap
->userspace_clients
);
1150 mutex_unlock(&adap
->userspace_clients_lock
);
1151 dev_info(dev
, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1152 info
.type
, info
.addr
);
1156 static DEVICE_ATTR(new_device
, S_IWUSR
, NULL
, i2c_sysfs_new_device
);
1159 * And of course let the users delete the devices they instantiated, if
1160 * they got it wrong. This interface can only be used to delete devices
1161 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1162 * don't delete devices to which some kernel code still has references.
1164 * Parameter checking may look overzealous, but we really don't want
1165 * the user to delete the wrong device.
1168 i2c_sysfs_delete_device(struct device
*dev
, struct device_attribute
*attr
,
1169 const char *buf
, size_t count
)
1171 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1172 struct i2c_client
*client
, *next
;
1173 unsigned short addr
;
1177 /* Parse parameters, reject extra parameters */
1178 res
= sscanf(buf
, "%hi%c", &addr
, &end
);
1180 dev_err(dev
, "%s: Can't parse I2C address\n", "delete_device");
1183 if (res
> 1 && end
!= '\n') {
1184 dev_err(dev
, "%s: Extra parameters\n", "delete_device");
1188 /* Make sure the device was added through sysfs */
1190 mutex_lock_nested(&adap
->userspace_clients_lock
,
1191 i2c_adapter_depth(adap
));
1192 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1194 if (client
->addr
== addr
) {
1195 dev_info(dev
, "%s: Deleting device %s at 0x%02hx\n",
1196 "delete_device", client
->name
, client
->addr
);
1198 list_del(&client
->detected
);
1199 i2c_unregister_device(client
);
1204 mutex_unlock(&adap
->userspace_clients_lock
);
1207 dev_err(dev
, "%s: Can't find device in list\n",
1211 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device
, S_IWUSR
, NULL
,
1212 i2c_sysfs_delete_device
);
1214 static struct attribute
*i2c_adapter_attrs
[] = {
1215 &dev_attr_name
.attr
,
1216 &dev_attr_new_device
.attr
,
1217 &dev_attr_delete_device
.attr
,
1220 ATTRIBUTE_GROUPS(i2c_adapter
);
1222 struct device_type i2c_adapter_type
= {
1223 .groups
= i2c_adapter_groups
,
1224 .release
= i2c_adapter_dev_release
,
1226 EXPORT_SYMBOL_GPL(i2c_adapter_type
);
1229 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1230 * @dev: device, probably from some driver model iterator
1232 * When traversing the driver model tree, perhaps using driver model
1233 * iterators like @device_for_each_child(), you can't assume very much
1234 * about the nodes you find. Use this function to avoid oopses caused
1235 * by wrongly treating some non-I2C device as an i2c_adapter.
1237 struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
)
1239 return (dev
->type
== &i2c_adapter_type
)
1240 ? to_i2c_adapter(dev
)
1243 EXPORT_SYMBOL(i2c_verify_adapter
);
1245 #ifdef CONFIG_I2C_COMPAT
1246 static struct class_compat
*i2c_adapter_compat_class
;
1249 static void i2c_scan_static_board_info(struct i2c_adapter
*adapter
)
1251 struct i2c_devinfo
*devinfo
;
1253 down_read(&__i2c_board_lock
);
1254 list_for_each_entry(devinfo
, &__i2c_board_list
, list
) {
1255 if (devinfo
->busnum
== adapter
->nr
1256 && !i2c_new_device(adapter
,
1257 &devinfo
->board_info
))
1258 dev_err(&adapter
->dev
,
1259 "Can't create device at 0x%02x\n",
1260 devinfo
->board_info
.addr
);
1262 up_read(&__i2c_board_lock
);
1265 /* OF support code */
1267 #if IS_ENABLED(CONFIG_OF)
1268 static struct i2c_client
*of_i2c_register_device(struct i2c_adapter
*adap
,
1269 struct device_node
*node
)
1271 struct i2c_client
*result
;
1272 struct i2c_board_info info
= {};
1273 struct dev_archdata dev_ad
= {};
1277 dev_dbg(&adap
->dev
, "of_i2c: register %s\n", node
->full_name
);
1279 if (of_modalias_node(node
, info
.type
, sizeof(info
.type
)) < 0) {
1280 dev_err(&adap
->dev
, "of_i2c: modalias failure on %s\n",
1282 return ERR_PTR(-EINVAL
);
1285 addr
= of_get_property(node
, "reg", &len
);
1286 if (!addr
|| (len
< sizeof(*addr
))) {
1287 dev_err(&adap
->dev
, "of_i2c: invalid reg on %s\n",
1289 return ERR_PTR(-EINVAL
);
1292 info
.addr
= be32_to_cpup(addr
);
1293 if (info
.addr
> (1 << 10) - 1) {
1294 dev_err(&adap
->dev
, "of_i2c: invalid addr=%x on %s\n",
1295 info
.addr
, node
->full_name
);
1296 return ERR_PTR(-EINVAL
);
1299 info
.of_node
= of_node_get(node
);
1300 info
.archdata
= &dev_ad
;
1302 if (of_get_property(node
, "wakeup-source", NULL
))
1303 info
.flags
|= I2C_CLIENT_WAKE
;
1305 result
= i2c_new_device(adap
, &info
);
1306 if (result
== NULL
) {
1307 dev_err(&adap
->dev
, "of_i2c: Failure registering %s\n",
1310 return ERR_PTR(-EINVAL
);
1315 static void of_i2c_register_devices(struct i2c_adapter
*adap
)
1317 struct device_node
*node
;
1319 /* Only register child devices if the adapter has a node pointer set */
1320 if (!adap
->dev
.of_node
)
1323 dev_dbg(&adap
->dev
, "of_i2c: walking child nodes\n");
1325 for_each_available_child_of_node(adap
->dev
.of_node
, node
) {
1326 if (of_node_test_and_set_flag(node
, OF_POPULATED
))
1328 of_i2c_register_device(adap
, node
);
1332 static int of_dev_node_match(struct device
*dev
, void *data
)
1334 return dev
->of_node
== data
;
1337 /* must call put_device() when done with returned i2c_client device */
1338 struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
)
1342 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
,
1347 return i2c_verify_client(dev
);
1349 EXPORT_SYMBOL(of_find_i2c_device_by_node
);
1351 /* must call put_device() when done with returned i2c_adapter device */
1352 struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
)
1356 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
,
1361 return i2c_verify_adapter(dev
);
1363 EXPORT_SYMBOL(of_find_i2c_adapter_by_node
);
1365 static void of_i2c_register_devices(struct i2c_adapter
*adap
) { }
1366 #endif /* CONFIG_OF */
1368 static int i2c_do_add_adapter(struct i2c_driver
*driver
,
1369 struct i2c_adapter
*adap
)
1371 /* Detect supported devices on that bus, and instantiate them */
1372 i2c_detect(adap
, driver
);
1374 /* Let legacy drivers scan this bus for matching devices */
1375 if (driver
->attach_adapter
) {
1376 dev_warn(&adap
->dev
, "%s: attach_adapter method is deprecated\n",
1377 driver
->driver
.name
);
1378 dev_warn(&adap
->dev
, "Please use another way to instantiate "
1379 "your i2c_client\n");
1380 /* We ignore the return code; if it fails, too bad */
1381 driver
->attach_adapter(adap
);
1386 static int __process_new_adapter(struct device_driver
*d
, void *data
)
1388 return i2c_do_add_adapter(to_i2c_driver(d
), data
);
1391 static int i2c_register_adapter(struct i2c_adapter
*adap
)
1395 /* Can't register until after driver model init */
1396 if (unlikely(WARN_ON(!i2c_bus_type
.p
))) {
1402 if (unlikely(adap
->name
[0] == '\0')) {
1403 pr_err("i2c-core: Attempt to register an adapter with "
1407 if (unlikely(!adap
->algo
)) {
1408 pr_err("i2c-core: Attempt to register adapter '%s' with "
1409 "no algo!\n", adap
->name
);
1413 rt_mutex_init(&adap
->bus_lock
);
1414 mutex_init(&adap
->userspace_clients_lock
);
1415 INIT_LIST_HEAD(&adap
->userspace_clients
);
1417 /* Set default timeout to 1 second if not already set */
1418 if (adap
->timeout
== 0)
1421 dev_set_name(&adap
->dev
, "i2c-%d", adap
->nr
);
1422 adap
->dev
.bus
= &i2c_bus_type
;
1423 adap
->dev
.type
= &i2c_adapter_type
;
1424 res
= device_register(&adap
->dev
);
1428 dev_dbg(&adap
->dev
, "adapter [%s] registered\n", adap
->name
);
1430 pm_runtime_no_callbacks(&adap
->dev
);
1432 #ifdef CONFIG_I2C_COMPAT
1433 res
= class_compat_create_link(i2c_adapter_compat_class
, &adap
->dev
,
1436 dev_warn(&adap
->dev
,
1437 "Failed to create compatibility class link\n");
1440 /* bus recovery specific initialization */
1441 if (adap
->bus_recovery_info
) {
1442 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
1444 if (!bri
->recover_bus
) {
1445 dev_err(&adap
->dev
, "No recover_bus() found, not using recovery\n");
1446 adap
->bus_recovery_info
= NULL
;
1450 /* Generic GPIO recovery */
1451 if (bri
->recover_bus
== i2c_generic_gpio_recovery
) {
1452 if (!gpio_is_valid(bri
->scl_gpio
)) {
1453 dev_err(&adap
->dev
, "Invalid SCL gpio, not using recovery\n");
1454 adap
->bus_recovery_info
= NULL
;
1458 if (gpio_is_valid(bri
->sda_gpio
))
1459 bri
->get_sda
= get_sda_gpio_value
;
1461 bri
->get_sda
= NULL
;
1463 bri
->get_scl
= get_scl_gpio_value
;
1464 bri
->set_scl
= set_scl_gpio_value
;
1465 } else if (!bri
->set_scl
|| !bri
->get_scl
) {
1466 /* Generic SCL recovery */
1467 dev_err(&adap
->dev
, "No {get|set}_gpio() found, not using recovery\n");
1468 adap
->bus_recovery_info
= NULL
;
1473 /* create pre-declared device nodes */
1474 of_i2c_register_devices(adap
);
1475 acpi_i2c_register_devices(adap
);
1476 acpi_i2c_install_space_handler(adap
);
1478 if (adap
->nr
< __i2c_first_dynamic_bus_num
)
1479 i2c_scan_static_board_info(adap
);
1481 /* Notify drivers */
1482 mutex_lock(&core_lock
);
1483 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
, __process_new_adapter
);
1484 mutex_unlock(&core_lock
);
1489 mutex_lock(&core_lock
);
1490 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1491 mutex_unlock(&core_lock
);
1496 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1497 * @adap: the adapter to register (with adap->nr initialized)
1498 * Context: can sleep
1500 * See i2c_add_numbered_adapter() for details.
1502 static int __i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1506 mutex_lock(&core_lock
);
1507 id
= idr_alloc(&i2c_adapter_idr
, adap
, adap
->nr
, adap
->nr
+ 1,
1509 mutex_unlock(&core_lock
);
1511 return id
== -ENOSPC
? -EBUSY
: id
;
1513 return i2c_register_adapter(adap
);
1517 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1518 * @adapter: the adapter to add
1519 * Context: can sleep
1521 * This routine is used to declare an I2C adapter when its bus number
1522 * doesn't matter or when its bus number is specified by an dt alias.
1523 * Examples of bases when the bus number doesn't matter: I2C adapters
1524 * dynamically added by USB links or PCI plugin cards.
1526 * When this returns zero, a new bus number was allocated and stored
1527 * in adap->nr, and the specified adapter became available for clients.
1528 * Otherwise, a negative errno value is returned.
1530 int i2c_add_adapter(struct i2c_adapter
*adapter
)
1532 struct device
*dev
= &adapter
->dev
;
1536 id
= of_alias_get_id(dev
->of_node
, "i2c");
1539 return __i2c_add_numbered_adapter(adapter
);
1543 mutex_lock(&core_lock
);
1544 id
= idr_alloc(&i2c_adapter_idr
, adapter
,
1545 __i2c_first_dynamic_bus_num
, 0, GFP_KERNEL
);
1546 mutex_unlock(&core_lock
);
1552 return i2c_register_adapter(adapter
);
1554 EXPORT_SYMBOL(i2c_add_adapter
);
1557 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1558 * @adap: the adapter to register (with adap->nr initialized)
1559 * Context: can sleep
1561 * This routine is used to declare an I2C adapter when its bus number
1562 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1563 * or otherwise built in to the system's mainboard, and where i2c_board_info
1564 * is used to properly configure I2C devices.
1566 * If the requested bus number is set to -1, then this function will behave
1567 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1569 * If no devices have pre-been declared for this bus, then be sure to
1570 * register the adapter before any dynamically allocated ones. Otherwise
1571 * the required bus ID may not be available.
1573 * When this returns zero, the specified adapter became available for
1574 * clients using the bus number provided in adap->nr. Also, the table
1575 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1576 * and the appropriate driver model device nodes are created. Otherwise, a
1577 * negative errno value is returned.
1579 int i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1581 if (adap
->nr
== -1) /* -1 means dynamically assign bus id */
1582 return i2c_add_adapter(adap
);
1584 return __i2c_add_numbered_adapter(adap
);
1586 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter
);
1588 static void i2c_do_del_adapter(struct i2c_driver
*driver
,
1589 struct i2c_adapter
*adapter
)
1591 struct i2c_client
*client
, *_n
;
1593 /* Remove the devices we created ourselves as the result of hardware
1594 * probing (using a driver's detect method) */
1595 list_for_each_entry_safe(client
, _n
, &driver
->clients
, detected
) {
1596 if (client
->adapter
== adapter
) {
1597 dev_dbg(&adapter
->dev
, "Removing %s at 0x%x\n",
1598 client
->name
, client
->addr
);
1599 list_del(&client
->detected
);
1600 i2c_unregister_device(client
);
1605 static int __unregister_client(struct device
*dev
, void *dummy
)
1607 struct i2c_client
*client
= i2c_verify_client(dev
);
1608 if (client
&& strcmp(client
->name
, "dummy"))
1609 i2c_unregister_device(client
);
1613 static int __unregister_dummy(struct device
*dev
, void *dummy
)
1615 struct i2c_client
*client
= i2c_verify_client(dev
);
1617 i2c_unregister_device(client
);
1621 static int __process_removed_adapter(struct device_driver
*d
, void *data
)
1623 i2c_do_del_adapter(to_i2c_driver(d
), data
);
1628 * i2c_del_adapter - unregister I2C adapter
1629 * @adap: the adapter being unregistered
1630 * Context: can sleep
1632 * This unregisters an I2C adapter which was previously registered
1633 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1635 void i2c_del_adapter(struct i2c_adapter
*adap
)
1637 struct i2c_adapter
*found
;
1638 struct i2c_client
*client
, *next
;
1640 /* First make sure that this adapter was ever added */
1641 mutex_lock(&core_lock
);
1642 found
= idr_find(&i2c_adapter_idr
, adap
->nr
);
1643 mutex_unlock(&core_lock
);
1644 if (found
!= adap
) {
1645 pr_debug("i2c-core: attempting to delete unregistered "
1646 "adapter [%s]\n", adap
->name
);
1650 acpi_i2c_remove_space_handler(adap
);
1651 /* Tell drivers about this removal */
1652 mutex_lock(&core_lock
);
1653 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
1654 __process_removed_adapter
);
1655 mutex_unlock(&core_lock
);
1657 /* Remove devices instantiated from sysfs */
1658 mutex_lock_nested(&adap
->userspace_clients_lock
,
1659 i2c_adapter_depth(adap
));
1660 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1662 dev_dbg(&adap
->dev
, "Removing %s at 0x%x\n", client
->name
,
1664 list_del(&client
->detected
);
1665 i2c_unregister_device(client
);
1667 mutex_unlock(&adap
->userspace_clients_lock
);
1669 /* Detach any active clients. This can't fail, thus we do not
1670 * check the returned value. This is a two-pass process, because
1671 * we can't remove the dummy devices during the first pass: they
1672 * could have been instantiated by real devices wishing to clean
1673 * them up properly, so we give them a chance to do that first. */
1674 device_for_each_child(&adap
->dev
, NULL
, __unregister_client
);
1675 device_for_each_child(&adap
->dev
, NULL
, __unregister_dummy
);
1677 #ifdef CONFIG_I2C_COMPAT
1678 class_compat_remove_link(i2c_adapter_compat_class
, &adap
->dev
,
1682 /* device name is gone after device_unregister */
1683 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
1685 /* wait until all references to the device are gone
1687 * FIXME: This is old code and should ideally be replaced by an
1688 * alternative which results in decoupling the lifetime of the struct
1689 * device from the i2c_adapter, like spi or netdev do. Any solution
1690 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1692 init_completion(&adap
->dev_released
);
1693 device_unregister(&adap
->dev
);
1694 wait_for_completion(&adap
->dev_released
);
1697 mutex_lock(&core_lock
);
1698 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1699 mutex_unlock(&core_lock
);
1701 /* Clear the device structure in case this adapter is ever going to be
1703 memset(&adap
->dev
, 0, sizeof(adap
->dev
));
1705 EXPORT_SYMBOL(i2c_del_adapter
);
1707 /* ------------------------------------------------------------------------- */
1709 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *))
1713 mutex_lock(&core_lock
);
1714 res
= bus_for_each_dev(&i2c_bus_type
, NULL
, data
, fn
);
1715 mutex_unlock(&core_lock
);
1719 EXPORT_SYMBOL_GPL(i2c_for_each_dev
);
1721 static int __process_new_driver(struct device
*dev
, void *data
)
1723 if (dev
->type
!= &i2c_adapter_type
)
1725 return i2c_do_add_adapter(data
, to_i2c_adapter(dev
));
1729 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1730 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1733 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
1737 /* Can't register until after driver model init */
1738 if (unlikely(WARN_ON(!i2c_bus_type
.p
)))
1741 /* add the driver to the list of i2c drivers in the driver core */
1742 driver
->driver
.owner
= owner
;
1743 driver
->driver
.bus
= &i2c_bus_type
;
1745 /* When registration returns, the driver core
1746 * will have called probe() for all matching-but-unbound devices.
1748 res
= driver_register(&driver
->driver
);
1752 pr_debug("i2c-core: driver [%s] registered\n", driver
->driver
.name
);
1754 INIT_LIST_HEAD(&driver
->clients
);
1755 /* Walk the adapters that are already present */
1756 i2c_for_each_dev(driver
, __process_new_driver
);
1760 EXPORT_SYMBOL(i2c_register_driver
);
1762 static int __process_removed_driver(struct device
*dev
, void *data
)
1764 if (dev
->type
== &i2c_adapter_type
)
1765 i2c_do_del_adapter(data
, to_i2c_adapter(dev
));
1770 * i2c_del_driver - unregister I2C driver
1771 * @driver: the driver being unregistered
1772 * Context: can sleep
1774 void i2c_del_driver(struct i2c_driver
*driver
)
1776 i2c_for_each_dev(driver
, __process_removed_driver
);
1778 driver_unregister(&driver
->driver
);
1779 pr_debug("i2c-core: driver [%s] unregistered\n", driver
->driver
.name
);
1781 EXPORT_SYMBOL(i2c_del_driver
);
1783 /* ------------------------------------------------------------------------- */
1786 * i2c_use_client - increments the reference count of the i2c client structure
1787 * @client: the client being referenced
1789 * Each live reference to a client should be refcounted. The driver model does
1790 * that automatically as part of driver binding, so that most drivers don't
1791 * need to do this explicitly: they hold a reference until they're unbound
1794 * A pointer to the client with the incremented reference counter is returned.
1796 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
1798 if (client
&& get_device(&client
->dev
))
1802 EXPORT_SYMBOL(i2c_use_client
);
1805 * i2c_release_client - release a use of the i2c client structure
1806 * @client: the client being no longer referenced
1808 * Must be called when a user of a client is finished with it.
1810 void i2c_release_client(struct i2c_client
*client
)
1813 put_device(&client
->dev
);
1815 EXPORT_SYMBOL(i2c_release_client
);
1817 struct i2c_cmd_arg
{
1822 static int i2c_cmd(struct device
*dev
, void *_arg
)
1824 struct i2c_client
*client
= i2c_verify_client(dev
);
1825 struct i2c_cmd_arg
*arg
= _arg
;
1826 struct i2c_driver
*driver
;
1828 if (!client
|| !client
->dev
.driver
)
1831 driver
= to_i2c_driver(client
->dev
.driver
);
1832 if (driver
->command
)
1833 driver
->command(client
, arg
->cmd
, arg
->arg
);
1837 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
1839 struct i2c_cmd_arg cmd_arg
;
1843 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
1845 EXPORT_SYMBOL(i2c_clients_command
);
1847 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
1848 static int of_i2c_notify(struct notifier_block
*nb
, unsigned long action
,
1851 struct of_reconfig_data
*rd
= arg
;
1852 struct i2c_adapter
*adap
;
1853 struct i2c_client
*client
;
1855 switch (of_reconfig_get_state_change(action
, rd
)) {
1856 case OF_RECONFIG_CHANGE_ADD
:
1857 adap
= of_find_i2c_adapter_by_node(rd
->dn
->parent
);
1859 return NOTIFY_OK
; /* not for us */
1861 if (of_node_test_and_set_flag(rd
->dn
, OF_POPULATED
)) {
1862 put_device(&adap
->dev
);
1866 client
= of_i2c_register_device(adap
, rd
->dn
);
1867 put_device(&adap
->dev
);
1869 if (IS_ERR(client
)) {
1870 pr_err("%s: failed to create for '%s'\n",
1871 __func__
, rd
->dn
->full_name
);
1872 return notifier_from_errno(PTR_ERR(client
));
1875 case OF_RECONFIG_CHANGE_REMOVE
:
1876 /* already depopulated? */
1877 if (!of_node_check_flag(rd
->dn
, OF_POPULATED
))
1880 /* find our device by node */
1881 client
= of_find_i2c_device_by_node(rd
->dn
);
1883 return NOTIFY_OK
; /* no? not meant for us */
1885 /* unregister takes one ref away */
1886 i2c_unregister_device(client
);
1888 /* and put the reference of the find */
1889 put_device(&client
->dev
);
1895 static struct notifier_block i2c_of_notifier
= {
1896 .notifier_call
= of_i2c_notify
,
1899 extern struct notifier_block i2c_of_notifier
;
1900 #endif /* CONFIG_OF_DYNAMIC */
1902 static int __init
i2c_init(void)
1906 retval
= of_alias_get_highest_id("i2c");
1908 down_write(&__i2c_board_lock
);
1909 if (retval
>= __i2c_first_dynamic_bus_num
)
1910 __i2c_first_dynamic_bus_num
= retval
+ 1;
1911 up_write(&__i2c_board_lock
);
1913 retval
= bus_register(&i2c_bus_type
);
1916 #ifdef CONFIG_I2C_COMPAT
1917 i2c_adapter_compat_class
= class_compat_register("i2c-adapter");
1918 if (!i2c_adapter_compat_class
) {
1923 retval
= i2c_add_driver(&dummy_driver
);
1927 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
1928 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier
));
1933 #ifdef CONFIG_I2C_COMPAT
1934 class_compat_unregister(i2c_adapter_compat_class
);
1937 bus_unregister(&i2c_bus_type
);
1941 static void __exit
i2c_exit(void)
1943 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
1944 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier
));
1945 i2c_del_driver(&dummy_driver
);
1946 #ifdef CONFIG_I2C_COMPAT
1947 class_compat_unregister(i2c_adapter_compat_class
);
1949 bus_unregister(&i2c_bus_type
);
1950 tracepoint_synchronize_unregister();
1953 /* We must initialize early, because some subsystems register i2c drivers
1954 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1956 postcore_initcall(i2c_init
);
1957 module_exit(i2c_exit
);
1959 /* ----------------------------------------------------
1960 * the functional interface to the i2c busses.
1961 * ----------------------------------------------------
1964 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1965 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1967 static int i2c_quirk_error(struct i2c_adapter
*adap
, struct i2c_msg
*msg
, char *err_msg
)
1969 dev_err_ratelimited(&adap
->dev
, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1970 err_msg
, msg
->addr
, msg
->len
,
1971 msg
->flags
& I2C_M_RD
? "read" : "write");
1975 static int i2c_check_for_quirks(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
1977 const struct i2c_adapter_quirks
*q
= adap
->quirks
;
1978 int max_num
= q
->max_num_msgs
, i
;
1979 bool do_len_check
= true;
1981 if (q
->flags
& I2C_AQ_COMB
) {
1984 /* special checks for combined messages */
1986 if (q
->flags
& I2C_AQ_COMB_WRITE_FIRST
&& msgs
[0].flags
& I2C_M_RD
)
1987 return i2c_quirk_error(adap
, &msgs
[0], "1st comb msg must be write");
1989 if (q
->flags
& I2C_AQ_COMB_READ_SECOND
&& !(msgs
[1].flags
& I2C_M_RD
))
1990 return i2c_quirk_error(adap
, &msgs
[1], "2nd comb msg must be read");
1992 if (q
->flags
& I2C_AQ_COMB_SAME_ADDR
&& msgs
[0].addr
!= msgs
[1].addr
)
1993 return i2c_quirk_error(adap
, &msgs
[0], "comb msg only to same addr");
1995 if (i2c_quirk_exceeded(msgs
[0].len
, q
->max_comb_1st_msg_len
))
1996 return i2c_quirk_error(adap
, &msgs
[0], "msg too long");
1998 if (i2c_quirk_exceeded(msgs
[1].len
, q
->max_comb_2nd_msg_len
))
1999 return i2c_quirk_error(adap
, &msgs
[1], "msg too long");
2001 do_len_check
= false;
2005 if (i2c_quirk_exceeded(num
, max_num
))
2006 return i2c_quirk_error(adap
, &msgs
[0], "too many messages");
2008 for (i
= 0; i
< num
; i
++) {
2009 u16 len
= msgs
[i
].len
;
2011 if (msgs
[i
].flags
& I2C_M_RD
) {
2012 if (do_len_check
&& i2c_quirk_exceeded(len
, q
->max_read_len
))
2013 return i2c_quirk_error(adap
, &msgs
[i
], "msg too long");
2015 if (do_len_check
&& i2c_quirk_exceeded(len
, q
->max_write_len
))
2016 return i2c_quirk_error(adap
, &msgs
[i
], "msg too long");
2024 * __i2c_transfer - unlocked flavor of i2c_transfer
2025 * @adap: Handle to I2C bus
2026 * @msgs: One or more messages to execute before STOP is issued to
2027 * terminate the operation; each message begins with a START.
2028 * @num: Number of messages to be executed.
2030 * Returns negative errno, else the number of messages executed.
2032 * Adapter lock must be held when calling this function. No debug logging
2033 * takes place. adap->algo->master_xfer existence isn't checked.
2035 int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2037 unsigned long orig_jiffies
;
2040 if (adap
->quirks
&& i2c_check_for_quirks(adap
, msgs
, num
))
2043 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
2044 * enabled. This is an efficient way of keeping the for-loop from
2045 * being executed when not needed.
2047 if (static_key_false(&i2c_trace_msg
)) {
2049 for (i
= 0; i
< num
; i
++)
2050 if (msgs
[i
].flags
& I2C_M_RD
)
2051 trace_i2c_read(adap
, &msgs
[i
], i
);
2053 trace_i2c_write(adap
, &msgs
[i
], i
);
2056 /* Retry automatically on arbitration loss */
2057 orig_jiffies
= jiffies
;
2058 for (ret
= 0, try = 0; try <= adap
->retries
; try++) {
2059 ret
= adap
->algo
->master_xfer(adap
, msgs
, num
);
2062 if (time_after(jiffies
, orig_jiffies
+ adap
->timeout
))
2066 if (static_key_false(&i2c_trace_msg
)) {
2068 for (i
= 0; i
< ret
; i
++)
2069 if (msgs
[i
].flags
& I2C_M_RD
)
2070 trace_i2c_reply(adap
, &msgs
[i
], i
);
2071 trace_i2c_result(adap
, i
, ret
);
2076 EXPORT_SYMBOL(__i2c_transfer
);
2079 * i2c_transfer - execute a single or combined I2C message
2080 * @adap: Handle to I2C bus
2081 * @msgs: One or more messages to execute before STOP is issued to
2082 * terminate the operation; each message begins with a START.
2083 * @num: Number of messages to be executed.
2085 * Returns negative errno, else the number of messages executed.
2087 * Note that there is no requirement that each message be sent to
2088 * the same slave address, although that is the most common model.
2090 int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2094 /* REVISIT the fault reporting model here is weak:
2096 * - When we get an error after receiving N bytes from a slave,
2097 * there is no way to report "N".
2099 * - When we get a NAK after transmitting N bytes to a slave,
2100 * there is no way to report "N" ... or to let the master
2101 * continue executing the rest of this combined message, if
2102 * that's the appropriate response.
2104 * - When for example "num" is two and we successfully complete
2105 * the first message but get an error part way through the
2106 * second, it's unclear whether that should be reported as
2107 * one (discarding status on the second message) or errno
2108 * (discarding status on the first one).
2111 if (adap
->algo
->master_xfer
) {
2113 for (ret
= 0; ret
< num
; ret
++) {
2114 dev_dbg(&adap
->dev
, "master_xfer[%d] %c, addr=0x%02x, "
2115 "len=%d%s\n", ret
, (msgs
[ret
].flags
& I2C_M_RD
)
2116 ? 'R' : 'W', msgs
[ret
].addr
, msgs
[ret
].len
,
2117 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
2121 if (in_atomic() || irqs_disabled()) {
2122 ret
= i2c_trylock_adapter(adap
);
2124 /* I2C activity is ongoing. */
2127 i2c_lock_adapter(adap
);
2130 ret
= __i2c_transfer(adap
, msgs
, num
);
2131 i2c_unlock_adapter(adap
);
2135 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
2139 EXPORT_SYMBOL(i2c_transfer
);
2142 * i2c_master_send - issue a single I2C message in master transmit mode
2143 * @client: Handle to slave device
2144 * @buf: Data that will be written to the slave
2145 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2147 * Returns negative errno, or else the number of bytes written.
2149 int i2c_master_send(const struct i2c_client
*client
, const char *buf
, int count
)
2152 struct i2c_adapter
*adap
= client
->adapter
;
2155 msg
.addr
= client
->addr
;
2156 msg
.flags
= client
->flags
& I2C_M_TEN
;
2158 msg
.buf
= (char *)buf
;
2160 ret
= i2c_transfer(adap
, &msg
, 1);
2163 * If everything went ok (i.e. 1 msg transmitted), return #bytes
2164 * transmitted, else error code.
2166 return (ret
== 1) ? count
: ret
;
2168 EXPORT_SYMBOL(i2c_master_send
);
2171 * i2c_master_recv - issue a single I2C message in master receive mode
2172 * @client: Handle to slave device
2173 * @buf: Where to store data read from slave
2174 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2176 * Returns negative errno, or else the number of bytes read.
2178 int i2c_master_recv(const struct i2c_client
*client
, char *buf
, int count
)
2180 struct i2c_adapter
*adap
= client
->adapter
;
2184 msg
.addr
= client
->addr
;
2185 msg
.flags
= client
->flags
& I2C_M_TEN
;
2186 msg
.flags
|= I2C_M_RD
;
2190 ret
= i2c_transfer(adap
, &msg
, 1);
2193 * If everything went ok (i.e. 1 msg received), return #bytes received,
2196 return (ret
== 1) ? count
: ret
;
2198 EXPORT_SYMBOL(i2c_master_recv
);
2200 /* ----------------------------------------------------
2201 * the i2c address scanning function
2202 * Will not work for 10-bit addresses!
2203 * ----------------------------------------------------
2207 * Legacy default probe function, mostly relevant for SMBus. The default
2208 * probe method is a quick write, but it is known to corrupt the 24RF08
2209 * EEPROMs due to a state machine bug, and could also irreversibly
2210 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2211 * we use a short byte read instead. Also, some bus drivers don't implement
2212 * quick write, so we fallback to a byte read in that case too.
2213 * On x86, there is another special case for FSC hardware monitoring chips,
2214 * which want regular byte reads (address 0x73.) Fortunately, these are the
2215 * only known chips using this I2C address on PC hardware.
2216 * Returns 1 if probe succeeded, 0 if not.
2218 static int i2c_default_probe(struct i2c_adapter
*adap
, unsigned short addr
)
2221 union i2c_smbus_data dummy
;
2224 if (addr
== 0x73 && (adap
->class & I2C_CLASS_HWMON
)
2225 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE_DATA
))
2226 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2227 I2C_SMBUS_BYTE_DATA
, &dummy
);
2230 if (!((addr
& ~0x07) == 0x30 || (addr
& ~0x0f) == 0x50)
2231 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
))
2232 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_WRITE
, 0,
2233 I2C_SMBUS_QUICK
, NULL
);
2234 else if (i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
))
2235 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2236 I2C_SMBUS_BYTE
, &dummy
);
2238 dev_warn(&adap
->dev
, "No suitable probing method supported for address 0x%02X\n",
2246 static int i2c_detect_address(struct i2c_client
*temp_client
,
2247 struct i2c_driver
*driver
)
2249 struct i2c_board_info info
;
2250 struct i2c_adapter
*adapter
= temp_client
->adapter
;
2251 int addr
= temp_client
->addr
;
2254 /* Make sure the address is valid */
2255 err
= i2c_check_addr_validity(addr
);
2257 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
2262 /* Skip if already in use */
2263 if (i2c_check_addr_busy(adapter
, addr
))
2266 /* Make sure there is something at this address */
2267 if (!i2c_default_probe(adapter
, addr
))
2270 /* Finally call the custom detection function */
2271 memset(&info
, 0, sizeof(struct i2c_board_info
));
2273 err
= driver
->detect(temp_client
, &info
);
2275 /* -ENODEV is returned if the detection fails. We catch it
2276 here as this isn't an error. */
2277 return err
== -ENODEV
? 0 : err
;
2280 /* Consistency check */
2281 if (info
.type
[0] == '\0') {
2282 dev_err(&adapter
->dev
, "%s detection function provided "
2283 "no name for 0x%x\n", driver
->driver
.name
,
2286 struct i2c_client
*client
;
2288 /* Detection succeeded, instantiate the device */
2289 if (adapter
->class & I2C_CLASS_DEPRECATED
)
2290 dev_warn(&adapter
->dev
,
2291 "This adapter will soon drop class based instantiation of devices. "
2292 "Please make sure client 0x%02x gets instantiated by other means. "
2293 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2296 dev_dbg(&adapter
->dev
, "Creating %s at 0x%02x\n",
2297 info
.type
, info
.addr
);
2298 client
= i2c_new_device(adapter
, &info
);
2300 list_add_tail(&client
->detected
, &driver
->clients
);
2302 dev_err(&adapter
->dev
, "Failed creating %s at 0x%02x\n",
2303 info
.type
, info
.addr
);
2308 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
)
2310 const unsigned short *address_list
;
2311 struct i2c_client
*temp_client
;
2313 int adap_id
= i2c_adapter_id(adapter
);
2315 address_list
= driver
->address_list
;
2316 if (!driver
->detect
|| !address_list
)
2319 /* Warn that the adapter lost class based instantiation */
2320 if (adapter
->class == I2C_CLASS_DEPRECATED
) {
2321 dev_dbg(&adapter
->dev
,
2322 "This adapter dropped support for I2C classes and "
2323 "won't auto-detect %s devices anymore. If you need it, check "
2324 "'Documentation/i2c/instantiating-devices' for alternatives.\n",
2325 driver
->driver
.name
);
2329 /* Stop here if the classes do not match */
2330 if (!(adapter
->class & driver
->class))
2333 /* Set up a temporary client to help detect callback */
2334 temp_client
= kzalloc(sizeof(struct i2c_client
), GFP_KERNEL
);
2337 temp_client
->adapter
= adapter
;
2339 for (i
= 0; address_list
[i
] != I2C_CLIENT_END
; i
+= 1) {
2340 dev_dbg(&adapter
->dev
, "found normal entry for adapter %d, "
2341 "addr 0x%02x\n", adap_id
, address_list
[i
]);
2342 temp_client
->addr
= address_list
[i
];
2343 err
= i2c_detect_address(temp_client
, driver
);
2352 int i2c_probe_func_quick_read(struct i2c_adapter
*adap
, unsigned short addr
)
2354 return i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2355 I2C_SMBUS_QUICK
, NULL
) >= 0;
2357 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read
);
2360 i2c_new_probed_device(struct i2c_adapter
*adap
,
2361 struct i2c_board_info
*info
,
2362 unsigned short const *addr_list
,
2363 int (*probe
)(struct i2c_adapter
*, unsigned short addr
))
2368 probe
= i2c_default_probe
;
2370 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
2371 /* Check address validity */
2372 if (i2c_check_addr_validity(addr_list
[i
]) < 0) {
2373 dev_warn(&adap
->dev
, "Invalid 7-bit address "
2374 "0x%02x\n", addr_list
[i
]);
2378 /* Check address availability */
2379 if (i2c_check_addr_busy(adap
, addr_list
[i
])) {
2380 dev_dbg(&adap
->dev
, "Address 0x%02x already in "
2381 "use, not probing\n", addr_list
[i
]);
2385 /* Test address responsiveness */
2386 if (probe(adap
, addr_list
[i
]))
2390 if (addr_list
[i
] == I2C_CLIENT_END
) {
2391 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
2395 info
->addr
= addr_list
[i
];
2396 return i2c_new_device(adap
, info
);
2398 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
2400 struct i2c_adapter
*i2c_get_adapter(int nr
)
2402 struct i2c_adapter
*adapter
;
2404 mutex_lock(&core_lock
);
2405 adapter
= idr_find(&i2c_adapter_idr
, nr
);
2406 if (adapter
&& !try_module_get(adapter
->owner
))
2409 mutex_unlock(&core_lock
);
2412 EXPORT_SYMBOL(i2c_get_adapter
);
2414 void i2c_put_adapter(struct i2c_adapter
*adap
)
2417 module_put(adap
->owner
);
2419 EXPORT_SYMBOL(i2c_put_adapter
);
2421 /* The SMBus parts */
2423 #define POLY (0x1070U << 3)
2424 static u8
crc8(u16 data
)
2428 for (i
= 0; i
< 8; i
++) {
2433 return (u8
)(data
>> 8);
2436 /* Incremental CRC8 over count bytes in the array pointed to by p */
2437 static u8
i2c_smbus_pec(u8 crc
, u8
*p
, size_t count
)
2441 for (i
= 0; i
< count
; i
++)
2442 crc
= crc8((crc
^ p
[i
]) << 8);
2446 /* Assume a 7-bit address, which is reasonable for SMBus */
2447 static u8
i2c_smbus_msg_pec(u8 pec
, struct i2c_msg
*msg
)
2449 /* The address will be sent first */
2450 u8 addr
= (msg
->addr
<< 1) | !!(msg
->flags
& I2C_M_RD
);
2451 pec
= i2c_smbus_pec(pec
, &addr
, 1);
2453 /* The data buffer follows */
2454 return i2c_smbus_pec(pec
, msg
->buf
, msg
->len
);
2457 /* Used for write only transactions */
2458 static inline void i2c_smbus_add_pec(struct i2c_msg
*msg
)
2460 msg
->buf
[msg
->len
] = i2c_smbus_msg_pec(0, msg
);
2464 /* Return <0 on CRC error
2465 If there was a write before this read (most cases) we need to take the
2466 partial CRC from the write part into account.
2467 Note that this function does modify the message (we need to decrease the
2468 message length to hide the CRC byte from the caller). */
2469 static int i2c_smbus_check_pec(u8 cpec
, struct i2c_msg
*msg
)
2471 u8 rpec
= msg
->buf
[--msg
->len
];
2472 cpec
= i2c_smbus_msg_pec(cpec
, msg
);
2475 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2483 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2484 * @client: Handle to slave device
2486 * This executes the SMBus "receive byte" protocol, returning negative errno
2487 * else the byte received from the device.
2489 s32
i2c_smbus_read_byte(const struct i2c_client
*client
)
2491 union i2c_smbus_data data
;
2494 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2496 I2C_SMBUS_BYTE
, &data
);
2497 return (status
< 0) ? status
: data
.byte
;
2499 EXPORT_SYMBOL(i2c_smbus_read_byte
);
2502 * i2c_smbus_write_byte - SMBus "send byte" protocol
2503 * @client: Handle to slave device
2504 * @value: Byte to be sent
2506 * This executes the SMBus "send byte" protocol, returning negative errno
2507 * else zero on success.
2509 s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
)
2511 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2512 I2C_SMBUS_WRITE
, value
, I2C_SMBUS_BYTE
, NULL
);
2514 EXPORT_SYMBOL(i2c_smbus_write_byte
);
2517 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2518 * @client: Handle to slave device
2519 * @command: Byte interpreted by slave
2521 * This executes the SMBus "read byte" protocol, returning negative errno
2522 * else a data byte received from the device.
2524 s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
, u8 command
)
2526 union i2c_smbus_data data
;
2529 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2530 I2C_SMBUS_READ
, command
,
2531 I2C_SMBUS_BYTE_DATA
, &data
);
2532 return (status
< 0) ? status
: data
.byte
;
2534 EXPORT_SYMBOL(i2c_smbus_read_byte_data
);
2537 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2538 * @client: Handle to slave device
2539 * @command: Byte interpreted by slave
2540 * @value: Byte being written
2542 * This executes the SMBus "write byte" protocol, returning negative errno
2543 * else zero on success.
2545 s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
, u8 command
,
2548 union i2c_smbus_data data
;
2550 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2551 I2C_SMBUS_WRITE
, command
,
2552 I2C_SMBUS_BYTE_DATA
, &data
);
2554 EXPORT_SYMBOL(i2c_smbus_write_byte_data
);
2557 * i2c_smbus_read_word_data - SMBus "read word" protocol
2558 * @client: Handle to slave device
2559 * @command: Byte interpreted by slave
2561 * This executes the SMBus "read word" protocol, returning negative errno
2562 * else a 16-bit unsigned "word" received from the device.
2564 s32
i2c_smbus_read_word_data(const struct i2c_client
*client
, u8 command
)
2566 union i2c_smbus_data data
;
2569 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2570 I2C_SMBUS_READ
, command
,
2571 I2C_SMBUS_WORD_DATA
, &data
);
2572 return (status
< 0) ? status
: data
.word
;
2574 EXPORT_SYMBOL(i2c_smbus_read_word_data
);
2577 * i2c_smbus_write_word_data - SMBus "write word" protocol
2578 * @client: Handle to slave device
2579 * @command: Byte interpreted by slave
2580 * @value: 16-bit "word" being written
2582 * This executes the SMBus "write word" protocol, returning negative errno
2583 * else zero on success.
2585 s32
i2c_smbus_write_word_data(const struct i2c_client
*client
, u8 command
,
2588 union i2c_smbus_data data
;
2590 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2591 I2C_SMBUS_WRITE
, command
,
2592 I2C_SMBUS_WORD_DATA
, &data
);
2594 EXPORT_SYMBOL(i2c_smbus_write_word_data
);
2597 * i2c_smbus_read_block_data - SMBus "block read" protocol
2598 * @client: Handle to slave device
2599 * @command: Byte interpreted by slave
2600 * @values: Byte array into which data will be read; big enough to hold
2601 * the data returned by the slave. SMBus allows at most 32 bytes.
2603 * This executes the SMBus "block read" protocol, returning negative errno
2604 * else the number of data bytes in the slave's response.
2606 * Note that using this function requires that the client's adapter support
2607 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2608 * support this; its emulation through I2C messaging relies on a specific
2609 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2611 s32
i2c_smbus_read_block_data(const struct i2c_client
*client
, u8 command
,
2614 union i2c_smbus_data data
;
2617 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2618 I2C_SMBUS_READ
, command
,
2619 I2C_SMBUS_BLOCK_DATA
, &data
);
2623 memcpy(values
, &data
.block
[1], data
.block
[0]);
2624 return data
.block
[0];
2626 EXPORT_SYMBOL(i2c_smbus_read_block_data
);
2629 * i2c_smbus_write_block_data - SMBus "block write" protocol
2630 * @client: Handle to slave device
2631 * @command: Byte interpreted by slave
2632 * @length: Size of data block; SMBus allows at most 32 bytes
2633 * @values: Byte array which will be written.
2635 * This executes the SMBus "block write" protocol, returning negative errno
2636 * else zero on success.
2638 s32
i2c_smbus_write_block_data(const struct i2c_client
*client
, u8 command
,
2639 u8 length
, const u8
*values
)
2641 union i2c_smbus_data data
;
2643 if (length
> I2C_SMBUS_BLOCK_MAX
)
2644 length
= I2C_SMBUS_BLOCK_MAX
;
2645 data
.block
[0] = length
;
2646 memcpy(&data
.block
[1], values
, length
);
2647 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2648 I2C_SMBUS_WRITE
, command
,
2649 I2C_SMBUS_BLOCK_DATA
, &data
);
2651 EXPORT_SYMBOL(i2c_smbus_write_block_data
);
2653 /* Returns the number of read bytes */
2654 s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2655 u8 length
, u8
*values
)
2657 union i2c_smbus_data data
;
2660 if (length
> I2C_SMBUS_BLOCK_MAX
)
2661 length
= I2C_SMBUS_BLOCK_MAX
;
2662 data
.block
[0] = length
;
2663 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2664 I2C_SMBUS_READ
, command
,
2665 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2669 memcpy(values
, &data
.block
[1], data
.block
[0]);
2670 return data
.block
[0];
2672 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data
);
2674 s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2675 u8 length
, const u8
*values
)
2677 union i2c_smbus_data data
;
2679 if (length
> I2C_SMBUS_BLOCK_MAX
)
2680 length
= I2C_SMBUS_BLOCK_MAX
;
2681 data
.block
[0] = length
;
2682 memcpy(data
.block
+ 1, values
, length
);
2683 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2684 I2C_SMBUS_WRITE
, command
,
2685 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2687 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data
);
2689 /* Simulate a SMBus command using the i2c protocol
2690 No checking of parameters is done! */
2691 static s32
i2c_smbus_xfer_emulated(struct i2c_adapter
*adapter
, u16 addr
,
2692 unsigned short flags
,
2693 char read_write
, u8 command
, int size
,
2694 union i2c_smbus_data
*data
)
2696 /* So we need to generate a series of msgs. In the case of writing, we
2697 need to use only one message; when reading, we need two. We initialize
2698 most things with sane defaults, to keep the code below somewhat
2700 unsigned char msgbuf0
[I2C_SMBUS_BLOCK_MAX
+3];
2701 unsigned char msgbuf1
[I2C_SMBUS_BLOCK_MAX
+2];
2702 int num
= read_write
== I2C_SMBUS_READ
? 2 : 1;
2706 struct i2c_msg msg
[2] = {
2714 .flags
= flags
| I2C_M_RD
,
2720 msgbuf0
[0] = command
;
2722 case I2C_SMBUS_QUICK
:
2724 /* Special case: The read/write field is used as data */
2725 msg
[0].flags
= flags
| (read_write
== I2C_SMBUS_READ
?
2729 case I2C_SMBUS_BYTE
:
2730 if (read_write
== I2C_SMBUS_READ
) {
2731 /* Special case: only a read! */
2732 msg
[0].flags
= I2C_M_RD
| flags
;
2736 case I2C_SMBUS_BYTE_DATA
:
2737 if (read_write
== I2C_SMBUS_READ
)
2741 msgbuf0
[1] = data
->byte
;
2744 case I2C_SMBUS_WORD_DATA
:
2745 if (read_write
== I2C_SMBUS_READ
)
2749 msgbuf0
[1] = data
->word
& 0xff;
2750 msgbuf0
[2] = data
->word
>> 8;
2753 case I2C_SMBUS_PROC_CALL
:
2754 num
= 2; /* Special case */
2755 read_write
= I2C_SMBUS_READ
;
2758 msgbuf0
[1] = data
->word
& 0xff;
2759 msgbuf0
[2] = data
->word
>> 8;
2761 case I2C_SMBUS_BLOCK_DATA
:
2762 if (read_write
== I2C_SMBUS_READ
) {
2763 msg
[1].flags
|= I2C_M_RECV_LEN
;
2764 msg
[1].len
= 1; /* block length will be added by
2765 the underlying bus driver */
2767 msg
[0].len
= data
->block
[0] + 2;
2768 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 2) {
2769 dev_err(&adapter
->dev
,
2770 "Invalid block write size %d\n",
2774 for (i
= 1; i
< msg
[0].len
; i
++)
2775 msgbuf0
[i
] = data
->block
[i
-1];
2778 case I2C_SMBUS_BLOCK_PROC_CALL
:
2779 num
= 2; /* Another special case */
2780 read_write
= I2C_SMBUS_READ
;
2781 if (data
->block
[0] > I2C_SMBUS_BLOCK_MAX
) {
2782 dev_err(&adapter
->dev
,
2783 "Invalid block write size %d\n",
2787 msg
[0].len
= data
->block
[0] + 2;
2788 for (i
= 1; i
< msg
[0].len
; i
++)
2789 msgbuf0
[i
] = data
->block
[i
-1];
2790 msg
[1].flags
|= I2C_M_RECV_LEN
;
2791 msg
[1].len
= 1; /* block length will be added by
2792 the underlying bus driver */
2794 case I2C_SMBUS_I2C_BLOCK_DATA
:
2795 if (read_write
== I2C_SMBUS_READ
) {
2796 msg
[1].len
= data
->block
[0];
2798 msg
[0].len
= data
->block
[0] + 1;
2799 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 1) {
2800 dev_err(&adapter
->dev
,
2801 "Invalid block write size %d\n",
2805 for (i
= 1; i
<= data
->block
[0]; i
++)
2806 msgbuf0
[i
] = data
->block
[i
];
2810 dev_err(&adapter
->dev
, "Unsupported transaction %d\n", size
);
2814 i
= ((flags
& I2C_CLIENT_PEC
) && size
!= I2C_SMBUS_QUICK
2815 && size
!= I2C_SMBUS_I2C_BLOCK_DATA
);
2817 /* Compute PEC if first message is a write */
2818 if (!(msg
[0].flags
& I2C_M_RD
)) {
2819 if (num
== 1) /* Write only */
2820 i2c_smbus_add_pec(&msg
[0]);
2821 else /* Write followed by read */
2822 partial_pec
= i2c_smbus_msg_pec(0, &msg
[0]);
2824 /* Ask for PEC if last message is a read */
2825 if (msg
[num
-1].flags
& I2C_M_RD
)
2829 status
= i2c_transfer(adapter
, msg
, num
);
2833 /* Check PEC if last message is a read */
2834 if (i
&& (msg
[num
-1].flags
& I2C_M_RD
)) {
2835 status
= i2c_smbus_check_pec(partial_pec
, &msg
[num
-1]);
2840 if (read_write
== I2C_SMBUS_READ
)
2842 case I2C_SMBUS_BYTE
:
2843 data
->byte
= msgbuf0
[0];
2845 case I2C_SMBUS_BYTE_DATA
:
2846 data
->byte
= msgbuf1
[0];
2848 case I2C_SMBUS_WORD_DATA
:
2849 case I2C_SMBUS_PROC_CALL
:
2850 data
->word
= msgbuf1
[0] | (msgbuf1
[1] << 8);
2852 case I2C_SMBUS_I2C_BLOCK_DATA
:
2853 for (i
= 0; i
< data
->block
[0]; i
++)
2854 data
->block
[i
+1] = msgbuf1
[i
];
2856 case I2C_SMBUS_BLOCK_DATA
:
2857 case I2C_SMBUS_BLOCK_PROC_CALL
:
2858 for (i
= 0; i
< msgbuf1
[0] + 1; i
++)
2859 data
->block
[i
] = msgbuf1
[i
];
2866 * i2c_smbus_xfer - execute SMBus protocol operations
2867 * @adapter: Handle to I2C bus
2868 * @addr: Address of SMBus slave on that bus
2869 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2870 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2871 * @command: Byte interpreted by slave, for protocols which use such bytes
2872 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2873 * @data: Data to be read or written
2875 * This executes an SMBus protocol operation, and returns a negative
2876 * errno code else zero on success.
2878 s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
, unsigned short flags
,
2879 char read_write
, u8 command
, int protocol
,
2880 union i2c_smbus_data
*data
)
2882 unsigned long orig_jiffies
;
2886 /* If enabled, the following two tracepoints are conditional on
2887 * read_write and protocol.
2889 trace_smbus_write(adapter
, addr
, flags
, read_write
,
2890 command
, protocol
, data
);
2891 trace_smbus_read(adapter
, addr
, flags
, read_write
,
2894 flags
&= I2C_M_TEN
| I2C_CLIENT_PEC
| I2C_CLIENT_SCCB
;
2896 if (adapter
->algo
->smbus_xfer
) {
2897 i2c_lock_adapter(adapter
);
2899 /* Retry automatically on arbitration loss */
2900 orig_jiffies
= jiffies
;
2901 for (res
= 0, try = 0; try <= adapter
->retries
; try++) {
2902 res
= adapter
->algo
->smbus_xfer(adapter
, addr
, flags
,
2903 read_write
, command
,
2907 if (time_after(jiffies
,
2908 orig_jiffies
+ adapter
->timeout
))
2911 i2c_unlock_adapter(adapter
);
2913 if (res
!= -EOPNOTSUPP
|| !adapter
->algo
->master_xfer
)
2916 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2917 * implement native support for the SMBus operation.
2921 res
= i2c_smbus_xfer_emulated(adapter
, addr
, flags
, read_write
,
2922 command
, protocol
, data
);
2925 /* If enabled, the reply tracepoint is conditional on read_write. */
2926 trace_smbus_reply(adapter
, addr
, flags
, read_write
,
2927 command
, protocol
, data
);
2928 trace_smbus_result(adapter
, addr
, flags
, read_write
,
2929 command
, protocol
, res
);
2933 EXPORT_SYMBOL(i2c_smbus_xfer
);
2935 #if IS_ENABLED(CONFIG_I2C_SLAVE)
2936 int i2c_slave_register(struct i2c_client
*client
, i2c_slave_cb_t slave_cb
)
2940 if (!client
|| !slave_cb
) {
2941 WARN(1, "insufficent data\n");
2945 if (!(client
->flags
& I2C_CLIENT_TEN
)) {
2946 /* Enforce stricter address checking */
2947 ret
= i2c_check_addr_validity(client
->addr
);
2949 dev_err(&client
->dev
, "%s: invalid address\n", __func__
);
2954 if (!client
->adapter
->algo
->reg_slave
) {
2955 dev_err(&client
->dev
, "%s: not supported by adapter\n", __func__
);
2959 client
->slave_cb
= slave_cb
;
2961 i2c_lock_adapter(client
->adapter
);
2962 ret
= client
->adapter
->algo
->reg_slave(client
);
2963 i2c_unlock_adapter(client
->adapter
);
2966 client
->slave_cb
= NULL
;
2967 dev_err(&client
->dev
, "%s: adapter returned error %d\n", __func__
, ret
);
2972 EXPORT_SYMBOL_GPL(i2c_slave_register
);
2974 int i2c_slave_unregister(struct i2c_client
*client
)
2978 if (!client
->adapter
->algo
->unreg_slave
) {
2979 dev_err(&client
->dev
, "%s: not supported by adapter\n", __func__
);
2983 i2c_lock_adapter(client
->adapter
);
2984 ret
= client
->adapter
->algo
->unreg_slave(client
);
2985 i2c_unlock_adapter(client
->adapter
);
2988 client
->slave_cb
= NULL
;
2990 dev_err(&client
->dev
, "%s: adapter returned error %d\n", __func__
, ret
);
2994 EXPORT_SYMBOL_GPL(i2c_slave_unregister
);
2997 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2998 MODULE_DESCRIPTION("I2C-Bus main module");
2999 MODULE_LICENSE("GPL");