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 <dt-bindings/i2c/i2c.h>
31 #include <linux/module.h>
32 #include <linux/kernel.h>
33 #include <linux/delay.h>
34 #include <linux/errno.h>
35 #include <linux/gpio.h>
36 #include <linux/slab.h>
37 #include <linux/i2c.h>
38 #include <linux/init.h>
39 #include <linux/idr.h>
40 #include <linux/mutex.h>
42 #include <linux/of_device.h>
43 #include <linux/of_irq.h>
44 #include <linux/clk/clk-conf.h>
45 #include <linux/completion.h>
46 #include <linux/hardirq.h>
47 #include <linux/irqflags.h>
48 #include <linux/rwsem.h>
49 #include <linux/pm_runtime.h>
50 #include <linux/pm_domain.h>
51 #include <linux/pm_wakeirq.h>
52 #include <linux/acpi.h>
53 #include <linux/jump_label.h>
54 #include <asm/uaccess.h>
55 #include <linux/err.h>
56 #include <linux/property.h>
60 #define CREATE_TRACE_POINTS
61 #include <trace/events/i2c.h>
63 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
64 #define I2C_ADDR_OFFSET_SLAVE 0x1000
66 /* core_lock protects i2c_adapter_idr, and guarantees
67 that device detection, deletion of detected devices, and attach_adapter
68 calls are serialized */
69 static DEFINE_MUTEX(core_lock
);
70 static DEFINE_IDR(i2c_adapter_idr
);
72 static struct device_type i2c_client_type
;
73 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
);
75 static struct static_key i2c_trace_msg
= STATIC_KEY_INIT_FALSE
;
77 void i2c_transfer_trace_reg(void)
79 static_key_slow_inc(&i2c_trace_msg
);
82 void i2c_transfer_trace_unreg(void)
84 static_key_slow_dec(&i2c_trace_msg
);
87 #if defined(CONFIG_ACPI)
88 struct acpi_i2c_handler_data
{
89 struct acpi_connection_info info
;
90 struct i2c_adapter
*adapter
;
103 struct acpi_i2c_lookup
{
104 struct i2c_board_info
*info
;
105 acpi_handle adapter_handle
;
106 acpi_handle device_handle
;
109 static int acpi_i2c_find_address(struct acpi_resource
*ares
, void *data
)
111 struct acpi_i2c_lookup
*lookup
= data
;
112 struct i2c_board_info
*info
= lookup
->info
;
113 struct acpi_resource_i2c_serialbus
*sb
;
114 acpi_handle adapter_handle
;
117 if (info
->addr
|| ares
->type
!= ACPI_RESOURCE_TYPE_SERIAL_BUS
)
120 sb
= &ares
->data
.i2c_serial_bus
;
121 if (sb
->type
!= ACPI_RESOURCE_SERIAL_TYPE_I2C
)
125 * Extract the ResourceSource and make sure that the handle matches
126 * with the I2C adapter handle.
128 status
= acpi_get_handle(lookup
->device_handle
,
129 sb
->resource_source
.string_ptr
,
131 if (ACPI_SUCCESS(status
) && adapter_handle
== lookup
->adapter_handle
) {
132 info
->addr
= sb
->slave_address
;
133 if (sb
->access_mode
== ACPI_I2C_10BIT_MODE
)
134 info
->flags
|= I2C_CLIENT_TEN
;
140 static acpi_status
acpi_i2c_add_device(acpi_handle handle
, u32 level
,
141 void *data
, void **return_value
)
143 struct i2c_adapter
*adapter
= data
;
144 struct list_head resource_list
;
145 struct acpi_i2c_lookup lookup
;
146 struct resource_entry
*entry
;
147 struct i2c_board_info info
;
148 struct acpi_device
*adev
;
151 if (acpi_bus_get_device(handle
, &adev
))
153 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
156 memset(&info
, 0, sizeof(info
));
157 info
.fwnode
= acpi_fwnode_handle(adev
);
159 memset(&lookup
, 0, sizeof(lookup
));
160 lookup
.adapter_handle
= ACPI_HANDLE(&adapter
->dev
);
161 lookup
.device_handle
= handle
;
165 * Look up for I2cSerialBus resource with ResourceSource that
166 * matches with this adapter.
168 INIT_LIST_HEAD(&resource_list
);
169 ret
= acpi_dev_get_resources(adev
, &resource_list
,
170 acpi_i2c_find_address
, &lookup
);
171 acpi_dev_free_resource_list(&resource_list
);
173 if (ret
< 0 || !info
.addr
)
176 /* Then fill IRQ number if any */
177 ret
= acpi_dev_get_resources(adev
, &resource_list
, NULL
, NULL
);
181 resource_list_for_each_entry(entry
, &resource_list
) {
182 if (resource_type(entry
->res
) == IORESOURCE_IRQ
) {
183 info
.irq
= entry
->res
->start
;
188 acpi_dev_free_resource_list(&resource_list
);
190 adev
->power
.flags
.ignore_parent
= true;
191 strlcpy(info
.type
, dev_name(&adev
->dev
), sizeof(info
.type
));
192 if (!i2c_new_device(adapter
, &info
)) {
193 adev
->power
.flags
.ignore_parent
= false;
194 dev_err(&adapter
->dev
,
195 "failed to add I2C device %s from ACPI\n",
196 dev_name(&adev
->dev
));
202 #define ACPI_I2C_MAX_SCAN_DEPTH 32
205 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
206 * @adap: pointer to adapter
208 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
209 * namespace. When a device is found it will be added to the Linux device
210 * model and bound to the corresponding ACPI handle.
212 static void acpi_i2c_register_devices(struct i2c_adapter
*adap
)
216 if (!has_acpi_companion(&adap
->dev
))
219 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, ACPI_ROOT_OBJECT
,
220 ACPI_I2C_MAX_SCAN_DEPTH
,
221 acpi_i2c_add_device
, NULL
,
223 if (ACPI_FAILURE(status
))
224 dev_warn(&adap
->dev
, "failed to enumerate I2C slaves\n");
227 #else /* CONFIG_ACPI */
228 static inline void acpi_i2c_register_devices(struct i2c_adapter
*adap
) { }
229 #endif /* CONFIG_ACPI */
231 #ifdef CONFIG_ACPI_I2C_OPREGION
232 static int acpi_gsb_i2c_read_bytes(struct i2c_client
*client
,
233 u8 cmd
, u8
*data
, u8 data_len
)
236 struct i2c_msg msgs
[2];
240 buffer
= kzalloc(data_len
, GFP_KERNEL
);
244 msgs
[0].addr
= client
->addr
;
245 msgs
[0].flags
= client
->flags
;
249 msgs
[1].addr
= client
->addr
;
250 msgs
[1].flags
= client
->flags
| I2C_M_RD
;
251 msgs
[1].len
= data_len
;
252 msgs
[1].buf
= buffer
;
254 ret
= i2c_transfer(client
->adapter
, msgs
, ARRAY_SIZE(msgs
));
256 dev_err(&client
->adapter
->dev
, "i2c read failed\n");
258 memcpy(data
, buffer
, data_len
);
264 static int acpi_gsb_i2c_write_bytes(struct i2c_client
*client
,
265 u8 cmd
, u8
*data
, u8 data_len
)
268 struct i2c_msg msgs
[1];
272 buffer
= kzalloc(data_len
+ 1, GFP_KERNEL
);
277 memcpy(buffer
+ 1, data
, data_len
);
279 msgs
[0].addr
= client
->addr
;
280 msgs
[0].flags
= client
->flags
;
281 msgs
[0].len
= data_len
+ 1;
282 msgs
[0].buf
= buffer
;
284 ret
= i2c_transfer(client
->adapter
, msgs
, ARRAY_SIZE(msgs
));
286 dev_err(&client
->adapter
->dev
, "i2c write failed\n");
293 acpi_i2c_space_handler(u32 function
, acpi_physical_address command
,
294 u32 bits
, u64
*value64
,
295 void *handler_context
, void *region_context
)
297 struct gsb_buffer
*gsb
= (struct gsb_buffer
*)value64
;
298 struct acpi_i2c_handler_data
*data
= handler_context
;
299 struct acpi_connection_info
*info
= &data
->info
;
300 struct acpi_resource_i2c_serialbus
*sb
;
301 struct i2c_adapter
*adapter
= data
->adapter
;
302 struct i2c_client
*client
;
303 struct acpi_resource
*ares
;
304 u32 accessor_type
= function
>> 16;
305 u8 action
= function
& ACPI_IO_MASK
;
309 ret
= acpi_buffer_to_resource(info
->connection
, info
->length
, &ares
);
310 if (ACPI_FAILURE(ret
))
313 client
= kzalloc(sizeof(*client
), GFP_KERNEL
);
319 if (!value64
|| ares
->type
!= ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
320 ret
= AE_BAD_PARAMETER
;
324 sb
= &ares
->data
.i2c_serial_bus
;
325 if (sb
->type
!= ACPI_RESOURCE_SERIAL_TYPE_I2C
) {
326 ret
= AE_BAD_PARAMETER
;
330 client
->adapter
= adapter
;
331 client
->addr
= sb
->slave_address
;
333 if (sb
->access_mode
== ACPI_I2C_10BIT_MODE
)
334 client
->flags
|= I2C_CLIENT_TEN
;
336 switch (accessor_type
) {
337 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV
:
338 if (action
== ACPI_READ
) {
339 status
= i2c_smbus_read_byte(client
);
345 status
= i2c_smbus_write_byte(client
, gsb
->bdata
);
349 case ACPI_GSB_ACCESS_ATTRIB_BYTE
:
350 if (action
== ACPI_READ
) {
351 status
= i2c_smbus_read_byte_data(client
, command
);
357 status
= i2c_smbus_write_byte_data(client
, command
,
362 case ACPI_GSB_ACCESS_ATTRIB_WORD
:
363 if (action
== ACPI_READ
) {
364 status
= i2c_smbus_read_word_data(client
, command
);
370 status
= i2c_smbus_write_word_data(client
, command
,
375 case ACPI_GSB_ACCESS_ATTRIB_BLOCK
:
376 if (action
== ACPI_READ
) {
377 status
= i2c_smbus_read_block_data(client
, command
,
384 status
= i2c_smbus_write_block_data(client
, command
,
385 gsb
->len
, gsb
->data
);
389 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE
:
390 if (action
== ACPI_READ
) {
391 status
= acpi_gsb_i2c_read_bytes(client
, command
,
392 gsb
->data
, info
->access_length
);
396 status
= acpi_gsb_i2c_write_bytes(client
, command
,
397 gsb
->data
, info
->access_length
);
402 pr_info("protocol(0x%02x) is not supported.\n", accessor_type
);
403 ret
= AE_BAD_PARAMETER
;
407 gsb
->status
= status
;
416 static int acpi_i2c_install_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 data
= kzalloc(sizeof(struct acpi_i2c_handler_data
),
435 data
->adapter
= adapter
;
436 status
= acpi_bus_attach_private_data(handle
, (void *)data
);
437 if (ACPI_FAILURE(status
)) {
442 status
= acpi_install_address_space_handler(handle
,
443 ACPI_ADR_SPACE_GSBUS
,
444 &acpi_i2c_space_handler
,
447 if (ACPI_FAILURE(status
)) {
448 dev_err(&adapter
->dev
, "Error installing i2c space handler\n");
449 acpi_bus_detach_private_data(handle
);
454 acpi_walk_dep_device_list(handle
);
458 static void acpi_i2c_remove_space_handler(struct i2c_adapter
*adapter
)
461 struct acpi_i2c_handler_data
*data
;
464 if (!adapter
->dev
.parent
)
467 handle
= ACPI_HANDLE(adapter
->dev
.parent
);
472 acpi_remove_address_space_handler(handle
,
473 ACPI_ADR_SPACE_GSBUS
,
474 &acpi_i2c_space_handler
);
476 status
= acpi_bus_get_private_data(handle
, (void **)&data
);
477 if (ACPI_SUCCESS(status
))
480 acpi_bus_detach_private_data(handle
);
482 #else /* CONFIG_ACPI_I2C_OPREGION */
483 static inline void acpi_i2c_remove_space_handler(struct i2c_adapter
*adapter
)
486 static inline int acpi_i2c_install_space_handler(struct i2c_adapter
*adapter
)
488 #endif /* CONFIG_ACPI_I2C_OPREGION */
490 /* ------------------------------------------------------------------------- */
492 static const struct i2c_device_id
*i2c_match_id(const struct i2c_device_id
*id
,
493 const struct i2c_client
*client
)
495 while (id
->name
[0]) {
496 if (strcmp(client
->name
, id
->name
) == 0)
503 static int i2c_device_match(struct device
*dev
, struct device_driver
*drv
)
505 struct i2c_client
*client
= i2c_verify_client(dev
);
506 struct i2c_driver
*driver
;
511 /* Attempt an OF style match */
512 if (of_driver_match_device(dev
, drv
))
515 /* Then ACPI style match */
516 if (acpi_driver_match_device(dev
, drv
))
519 driver
= to_i2c_driver(drv
);
520 /* match on an id table if there is one */
521 if (driver
->id_table
)
522 return i2c_match_id(driver
->id_table
, client
) != NULL
;
528 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
529 static int i2c_device_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
531 struct i2c_client
*client
= to_i2c_client(dev
);
534 rc
= acpi_device_uevent_modalias(dev
, env
);
538 if (add_uevent_var(env
, "MODALIAS=%s%s",
539 I2C_MODULE_PREFIX
, client
->name
))
541 dev_dbg(dev
, "uevent\n");
545 /* i2c bus recovery routines */
546 static int get_scl_gpio_value(struct i2c_adapter
*adap
)
548 return gpio_get_value(adap
->bus_recovery_info
->scl_gpio
);
551 static void set_scl_gpio_value(struct i2c_adapter
*adap
, int val
)
553 gpio_set_value(adap
->bus_recovery_info
->scl_gpio
, val
);
556 static int get_sda_gpio_value(struct i2c_adapter
*adap
)
558 return gpio_get_value(adap
->bus_recovery_info
->sda_gpio
);
561 static int i2c_get_gpios_for_recovery(struct i2c_adapter
*adap
)
563 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
564 struct device
*dev
= &adap
->dev
;
567 ret
= gpio_request_one(bri
->scl_gpio
, GPIOF_OPEN_DRAIN
|
568 GPIOF_OUT_INIT_HIGH
, "i2c-scl");
570 dev_warn(dev
, "Can't get SCL gpio: %d\n", bri
->scl_gpio
);
575 if (gpio_request_one(bri
->sda_gpio
, GPIOF_IN
, "i2c-sda")) {
576 /* work without SDA polling */
577 dev_warn(dev
, "Can't get SDA gpio: %d. Not using SDA polling\n",
586 static void i2c_put_gpios_for_recovery(struct i2c_adapter
*adap
)
588 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
591 gpio_free(bri
->sda_gpio
);
593 gpio_free(bri
->scl_gpio
);
597 * We are generating clock pulses. ndelay() determines durating of clk pulses.
598 * We will generate clock with rate 100 KHz and so duration of both clock levels
599 * is: delay in ns = (10^6 / 100) / 2
601 #define RECOVERY_NDELAY 5000
602 #define RECOVERY_CLK_CNT 9
604 static int i2c_generic_recovery(struct i2c_adapter
*adap
)
606 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
607 int i
= 0, val
= 1, ret
= 0;
609 if (bri
->prepare_recovery
)
610 bri
->prepare_recovery(adap
);
612 bri
->set_scl(adap
, val
);
613 ndelay(RECOVERY_NDELAY
);
616 * By this time SCL is high, as we need to give 9 falling-rising edges
618 while (i
++ < RECOVERY_CLK_CNT
* 2) {
620 /* Break if SDA is high */
621 if (bri
->get_sda
&& bri
->get_sda(adap
))
623 /* SCL shouldn't be low here */
624 if (!bri
->get_scl(adap
)) {
626 "SCL is stuck low, exit recovery\n");
633 bri
->set_scl(adap
, val
);
634 ndelay(RECOVERY_NDELAY
);
637 if (bri
->unprepare_recovery
)
638 bri
->unprepare_recovery(adap
);
643 int i2c_generic_scl_recovery(struct i2c_adapter
*adap
)
645 return i2c_generic_recovery(adap
);
647 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery
);
649 int i2c_generic_gpio_recovery(struct i2c_adapter
*adap
)
653 ret
= i2c_get_gpios_for_recovery(adap
);
657 ret
= i2c_generic_recovery(adap
);
658 i2c_put_gpios_for_recovery(adap
);
662 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery
);
664 int i2c_recover_bus(struct i2c_adapter
*adap
)
666 if (!adap
->bus_recovery_info
)
669 dev_dbg(&adap
->dev
, "Trying i2c bus recovery\n");
670 return adap
->bus_recovery_info
->recover_bus(adap
);
672 EXPORT_SYMBOL_GPL(i2c_recover_bus
);
674 static int i2c_device_probe(struct device
*dev
)
676 struct i2c_client
*client
= i2c_verify_client(dev
);
677 struct i2c_driver
*driver
;
687 irq
= of_irq_get_byname(dev
->of_node
, "irq");
688 if (irq
== -EINVAL
|| irq
== -ENODATA
)
689 irq
= of_irq_get(dev
->of_node
, 0);
690 } else if (ACPI_COMPANION(dev
)) {
691 irq
= acpi_dev_gpio_irq_get(ACPI_COMPANION(dev
), 0);
693 if (irq
== -EPROBE_DEFER
)
701 driver
= to_i2c_driver(dev
->driver
);
702 if (!driver
->probe
|| !driver
->id_table
)
705 if (client
->flags
& I2C_CLIENT_WAKE
) {
706 int wakeirq
= -ENOENT
;
709 wakeirq
= of_irq_get_byname(dev
->of_node
, "wakeup");
710 if (wakeirq
== -EPROBE_DEFER
)
714 device_init_wakeup(&client
->dev
, true);
716 if (wakeirq
> 0 && wakeirq
!= client
->irq
)
717 status
= dev_pm_set_dedicated_wake_irq(dev
, wakeirq
);
718 else if (client
->irq
> 0)
719 status
= dev_pm_set_wake_irq(dev
, client
->irq
);
724 dev_warn(&client
->dev
, "failed to set up wakeup irq");
727 dev_dbg(dev
, "probe\n");
729 status
= of_clk_set_defaults(dev
->of_node
, false);
731 goto err_clear_wakeup_irq
;
733 status
= dev_pm_domain_attach(&client
->dev
, true);
734 if (status
== -EPROBE_DEFER
)
735 goto err_clear_wakeup_irq
;
737 status
= driver
->probe(client
, i2c_match_id(driver
->id_table
, client
));
739 goto err_detach_pm_domain
;
743 err_detach_pm_domain
:
744 dev_pm_domain_detach(&client
->dev
, true);
745 err_clear_wakeup_irq
:
746 dev_pm_clear_wake_irq(&client
->dev
);
747 device_init_wakeup(&client
->dev
, false);
751 static int i2c_device_remove(struct device
*dev
)
753 struct i2c_client
*client
= i2c_verify_client(dev
);
754 struct i2c_driver
*driver
;
757 if (!client
|| !dev
->driver
)
760 driver
= to_i2c_driver(dev
->driver
);
761 if (driver
->remove
) {
762 dev_dbg(dev
, "remove\n");
763 status
= driver
->remove(client
);
766 dev_pm_domain_detach(&client
->dev
, true);
768 dev_pm_clear_wake_irq(&client
->dev
);
769 device_init_wakeup(&client
->dev
, false);
774 static void i2c_device_shutdown(struct device
*dev
)
776 struct i2c_client
*client
= i2c_verify_client(dev
);
777 struct i2c_driver
*driver
;
779 if (!client
|| !dev
->driver
)
781 driver
= to_i2c_driver(dev
->driver
);
782 if (driver
->shutdown
)
783 driver
->shutdown(client
);
786 static void i2c_client_dev_release(struct device
*dev
)
788 kfree(to_i2c_client(dev
));
792 show_name(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
794 return sprintf(buf
, "%s\n", dev
->type
== &i2c_client_type
?
795 to_i2c_client(dev
)->name
: to_i2c_adapter(dev
)->name
);
797 static DEVICE_ATTR(name
, S_IRUGO
, show_name
, NULL
);
800 show_modalias(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
802 struct i2c_client
*client
= to_i2c_client(dev
);
805 len
= acpi_device_modalias(dev
, buf
, PAGE_SIZE
-1);
809 return sprintf(buf
, "%s%s\n", I2C_MODULE_PREFIX
, client
->name
);
811 static DEVICE_ATTR(modalias
, S_IRUGO
, show_modalias
, NULL
);
813 static struct attribute
*i2c_dev_attrs
[] = {
815 /* modalias helps coldplug: modprobe $(cat .../modalias) */
816 &dev_attr_modalias
.attr
,
819 ATTRIBUTE_GROUPS(i2c_dev
);
821 struct bus_type i2c_bus_type
= {
823 .match
= i2c_device_match
,
824 .probe
= i2c_device_probe
,
825 .remove
= i2c_device_remove
,
826 .shutdown
= i2c_device_shutdown
,
828 EXPORT_SYMBOL_GPL(i2c_bus_type
);
830 static struct device_type i2c_client_type
= {
831 .groups
= i2c_dev_groups
,
832 .uevent
= i2c_device_uevent
,
833 .release
= i2c_client_dev_release
,
838 * i2c_verify_client - return parameter as i2c_client, or NULL
839 * @dev: device, probably from some driver model iterator
841 * When traversing the driver model tree, perhaps using driver model
842 * iterators like @device_for_each_child(), you can't assume very much
843 * about the nodes you find. Use this function to avoid oopses caused
844 * by wrongly treating some non-I2C device as an i2c_client.
846 struct i2c_client
*i2c_verify_client(struct device
*dev
)
848 return (dev
->type
== &i2c_client_type
)
852 EXPORT_SYMBOL(i2c_verify_client
);
855 /* Return a unique address which takes the flags of the client into account */
856 static unsigned short i2c_encode_flags_to_addr(struct i2c_client
*client
)
858 unsigned short addr
= client
->addr
;
860 /* For some client flags, add an arbitrary offset to avoid collisions */
861 if (client
->flags
& I2C_CLIENT_TEN
)
862 addr
|= I2C_ADDR_OFFSET_TEN_BIT
;
864 if (client
->flags
& I2C_CLIENT_SLAVE
)
865 addr
|= I2C_ADDR_OFFSET_SLAVE
;
870 /* This is a permissive address validity check, I2C address map constraints
871 * are purposely not enforced, except for the general call address. */
872 static int i2c_check_addr_validity(unsigned addr
, unsigned short flags
)
874 if (flags
& I2C_CLIENT_TEN
) {
875 /* 10-bit address, all values are valid */
879 /* 7-bit address, reject the general call address */
880 if (addr
== 0x00 || addr
> 0x7f)
886 /* And this is a strict address validity check, used when probing. If a
887 * device uses a reserved address, then it shouldn't be probed. 7-bit
888 * addressing is assumed, 10-bit address devices are rare and should be
889 * explicitly enumerated. */
890 static int i2c_check_7bit_addr_validity_strict(unsigned short addr
)
893 * Reserved addresses per I2C specification:
894 * 0x00 General call address / START byte
896 * 0x02 Reserved for different bus format
897 * 0x03 Reserved for future purposes
898 * 0x04-0x07 Hs-mode master code
899 * 0x78-0x7b 10-bit slave addressing
900 * 0x7c-0x7f Reserved for future purposes
902 if (addr
< 0x08 || addr
> 0x77)
907 static int __i2c_check_addr_busy(struct device
*dev
, void *addrp
)
909 struct i2c_client
*client
= i2c_verify_client(dev
);
910 int addr
= *(int *)addrp
;
912 if (client
&& i2c_encode_flags_to_addr(client
) == addr
)
917 /* walk up mux tree */
918 static int i2c_check_mux_parents(struct i2c_adapter
*adapter
, int addr
)
920 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
923 result
= device_for_each_child(&adapter
->dev
, &addr
,
924 __i2c_check_addr_busy
);
926 if (!result
&& parent
)
927 result
= i2c_check_mux_parents(parent
, addr
);
932 /* recurse down mux tree */
933 static int i2c_check_mux_children(struct device
*dev
, void *addrp
)
937 if (dev
->type
== &i2c_adapter_type
)
938 result
= device_for_each_child(dev
, addrp
,
939 i2c_check_mux_children
);
941 result
= __i2c_check_addr_busy(dev
, addrp
);
946 static int i2c_check_addr_busy(struct i2c_adapter
*adapter
, int addr
)
948 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
952 result
= i2c_check_mux_parents(parent
, addr
);
955 result
= device_for_each_child(&adapter
->dev
, &addr
,
956 i2c_check_mux_children
);
962 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
963 * @adapter: Target I2C bus segment
965 void i2c_lock_adapter(struct i2c_adapter
*adapter
)
967 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
970 i2c_lock_adapter(parent
);
972 rt_mutex_lock(&adapter
->bus_lock
);
974 EXPORT_SYMBOL_GPL(i2c_lock_adapter
);
977 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
978 * @adapter: Target I2C bus segment
980 static int i2c_trylock_adapter(struct i2c_adapter
*adapter
)
982 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
985 return i2c_trylock_adapter(parent
);
987 return rt_mutex_trylock(&adapter
->bus_lock
);
991 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
992 * @adapter: Target I2C bus segment
994 void i2c_unlock_adapter(struct i2c_adapter
*adapter
)
996 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
999 i2c_unlock_adapter(parent
);
1001 rt_mutex_unlock(&adapter
->bus_lock
);
1003 EXPORT_SYMBOL_GPL(i2c_unlock_adapter
);
1005 static void i2c_dev_set_name(struct i2c_adapter
*adap
,
1006 struct i2c_client
*client
)
1008 struct acpi_device
*adev
= ACPI_COMPANION(&client
->dev
);
1011 dev_set_name(&client
->dev
, "i2c-%s", acpi_dev_name(adev
));
1015 dev_set_name(&client
->dev
, "%d-%04x", i2c_adapter_id(adap
),
1016 i2c_encode_flags_to_addr(client
));
1020 * i2c_new_device - instantiate an i2c device
1021 * @adap: the adapter managing the device
1022 * @info: describes one I2C device; bus_num is ignored
1023 * Context: can sleep
1025 * Create an i2c device. Binding is handled through driver model
1026 * probe()/remove() methods. A driver may be bound to this device when we
1027 * return from this function, or any later moment (e.g. maybe hotplugging will
1028 * load the driver module). This call is not appropriate for use by mainboard
1029 * initialization logic, which usually runs during an arch_initcall() long
1030 * before any i2c_adapter could exist.
1032 * This returns the new i2c client, which may be saved for later use with
1033 * i2c_unregister_device(); or NULL to indicate an error.
1036 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
)
1038 struct i2c_client
*client
;
1041 client
= kzalloc(sizeof *client
, GFP_KERNEL
);
1045 client
->adapter
= adap
;
1047 client
->dev
.platform_data
= info
->platform_data
;
1050 client
->dev
.archdata
= *info
->archdata
;
1052 client
->flags
= info
->flags
;
1053 client
->addr
= info
->addr
;
1054 client
->irq
= info
->irq
;
1056 strlcpy(client
->name
, info
->type
, sizeof(client
->name
));
1058 status
= i2c_check_addr_validity(client
->addr
, client
->flags
);
1060 dev_err(&adap
->dev
, "Invalid %d-bit I2C address 0x%02hx\n",
1061 client
->flags
& I2C_CLIENT_TEN
? 10 : 7, client
->addr
);
1062 goto out_err_silent
;
1065 /* Check for address business */
1066 status
= i2c_check_addr_busy(adap
, i2c_encode_flags_to_addr(client
));
1070 client
->dev
.parent
= &client
->adapter
->dev
;
1071 client
->dev
.bus
= &i2c_bus_type
;
1072 client
->dev
.type
= &i2c_client_type
;
1073 client
->dev
.of_node
= info
->of_node
;
1074 client
->dev
.fwnode
= info
->fwnode
;
1076 i2c_dev_set_name(adap
, client
);
1077 status
= device_register(&client
->dev
);
1081 dev_dbg(&adap
->dev
, "client [%s] registered with bus id %s\n",
1082 client
->name
, dev_name(&client
->dev
));
1087 dev_err(&adap
->dev
, "Failed to register i2c client %s at 0x%02x "
1088 "(%d)\n", client
->name
, client
->addr
, status
);
1093 EXPORT_SYMBOL_GPL(i2c_new_device
);
1097 * i2c_unregister_device - reverse effect of i2c_new_device()
1098 * @client: value returned from i2c_new_device()
1099 * Context: can sleep
1101 void i2c_unregister_device(struct i2c_client
*client
)
1103 if (client
->dev
.of_node
)
1104 of_node_clear_flag(client
->dev
.of_node
, OF_POPULATED
);
1105 device_unregister(&client
->dev
);
1107 EXPORT_SYMBOL_GPL(i2c_unregister_device
);
1110 static const struct i2c_device_id dummy_id
[] = {
1115 static int dummy_probe(struct i2c_client
*client
,
1116 const struct i2c_device_id
*id
)
1121 static int dummy_remove(struct i2c_client
*client
)
1126 static struct i2c_driver dummy_driver
= {
1127 .driver
.name
= "dummy",
1128 .probe
= dummy_probe
,
1129 .remove
= dummy_remove
,
1130 .id_table
= dummy_id
,
1134 * i2c_new_dummy - return a new i2c device bound to a dummy driver
1135 * @adapter: the adapter managing the device
1136 * @address: seven bit address to be used
1137 * Context: can sleep
1139 * This returns an I2C client bound to the "dummy" driver, intended for use
1140 * with devices that consume multiple addresses. Examples of such chips
1141 * include various EEPROMS (like 24c04 and 24c08 models).
1143 * These dummy devices have two main uses. First, most I2C and SMBus calls
1144 * except i2c_transfer() need a client handle; the dummy will be that handle.
1145 * And second, this prevents the specified address from being bound to a
1148 * This returns the new i2c client, which should be saved for later use with
1149 * i2c_unregister_device(); or NULL to indicate an error.
1151 struct i2c_client
*i2c_new_dummy(struct i2c_adapter
*adapter
, u16 address
)
1153 struct i2c_board_info info
= {
1154 I2C_BOARD_INFO("dummy", address
),
1157 return i2c_new_device(adapter
, &info
);
1159 EXPORT_SYMBOL_GPL(i2c_new_dummy
);
1161 /* ------------------------------------------------------------------------- */
1163 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1165 static void i2c_adapter_dev_release(struct device
*dev
)
1167 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1168 complete(&adap
->dev_released
);
1172 * This function is only needed for mutex_lock_nested, so it is never
1173 * called unless locking correctness checking is enabled. Thus we
1174 * make it inline to avoid a compiler warning. That's what gcc ends up
1177 static inline unsigned int i2c_adapter_depth(struct i2c_adapter
*adapter
)
1179 unsigned int depth
= 0;
1181 while ((adapter
= i2c_parent_is_i2c_adapter(adapter
)))
1188 * Let users instantiate I2C devices through sysfs. This can be used when
1189 * platform initialization code doesn't contain the proper data for
1190 * whatever reason. Also useful for drivers that do device detection and
1191 * detection fails, either because the device uses an unexpected address,
1192 * or this is a compatible device with different ID register values.
1194 * Parameter checking may look overzealous, but we really don't want
1195 * the user to provide incorrect parameters.
1198 i2c_sysfs_new_device(struct device
*dev
, struct device_attribute
*attr
,
1199 const char *buf
, size_t count
)
1201 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1202 struct i2c_board_info info
;
1203 struct i2c_client
*client
;
1207 memset(&info
, 0, sizeof(struct i2c_board_info
));
1209 blank
= strchr(buf
, ' ');
1211 dev_err(dev
, "%s: Missing parameters\n", "new_device");
1214 if (blank
- buf
> I2C_NAME_SIZE
- 1) {
1215 dev_err(dev
, "%s: Invalid device name\n", "new_device");
1218 memcpy(info
.type
, buf
, blank
- buf
);
1220 /* Parse remaining parameters, reject extra parameters */
1221 res
= sscanf(++blank
, "%hi%c", &info
.addr
, &end
);
1223 dev_err(dev
, "%s: Can't parse I2C address\n", "new_device");
1226 if (res
> 1 && end
!= '\n') {
1227 dev_err(dev
, "%s: Extra parameters\n", "new_device");
1231 if ((info
.addr
& I2C_ADDR_OFFSET_TEN_BIT
) == I2C_ADDR_OFFSET_TEN_BIT
) {
1232 info
.addr
&= ~I2C_ADDR_OFFSET_TEN_BIT
;
1233 info
.flags
|= I2C_CLIENT_TEN
;
1236 if (info
.addr
& I2C_ADDR_OFFSET_SLAVE
) {
1237 info
.addr
&= ~I2C_ADDR_OFFSET_SLAVE
;
1238 info
.flags
|= I2C_CLIENT_SLAVE
;
1241 client
= i2c_new_device(adap
, &info
);
1245 /* Keep track of the added device */
1246 mutex_lock(&adap
->userspace_clients_lock
);
1247 list_add_tail(&client
->detected
, &adap
->userspace_clients
);
1248 mutex_unlock(&adap
->userspace_clients_lock
);
1249 dev_info(dev
, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1250 info
.type
, info
.addr
);
1254 static DEVICE_ATTR(new_device
, S_IWUSR
, NULL
, i2c_sysfs_new_device
);
1257 * And of course let the users delete the devices they instantiated, if
1258 * they got it wrong. This interface can only be used to delete devices
1259 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1260 * don't delete devices to which some kernel code still has references.
1262 * Parameter checking may look overzealous, but we really don't want
1263 * the user to delete the wrong device.
1266 i2c_sysfs_delete_device(struct device
*dev
, struct device_attribute
*attr
,
1267 const char *buf
, size_t count
)
1269 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1270 struct i2c_client
*client
, *next
;
1271 unsigned short addr
;
1275 /* Parse parameters, reject extra parameters */
1276 res
= sscanf(buf
, "%hi%c", &addr
, &end
);
1278 dev_err(dev
, "%s: Can't parse I2C address\n", "delete_device");
1281 if (res
> 1 && end
!= '\n') {
1282 dev_err(dev
, "%s: Extra parameters\n", "delete_device");
1286 /* Make sure the device was added through sysfs */
1288 mutex_lock_nested(&adap
->userspace_clients_lock
,
1289 i2c_adapter_depth(adap
));
1290 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1292 if (i2c_encode_flags_to_addr(client
) == addr
) {
1293 dev_info(dev
, "%s: Deleting device %s at 0x%02hx\n",
1294 "delete_device", client
->name
, client
->addr
);
1296 list_del(&client
->detected
);
1297 i2c_unregister_device(client
);
1302 mutex_unlock(&adap
->userspace_clients_lock
);
1305 dev_err(dev
, "%s: Can't find device in list\n",
1309 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device
, S_IWUSR
, NULL
,
1310 i2c_sysfs_delete_device
);
1312 static struct attribute
*i2c_adapter_attrs
[] = {
1313 &dev_attr_name
.attr
,
1314 &dev_attr_new_device
.attr
,
1315 &dev_attr_delete_device
.attr
,
1318 ATTRIBUTE_GROUPS(i2c_adapter
);
1320 struct device_type i2c_adapter_type
= {
1321 .groups
= i2c_adapter_groups
,
1322 .release
= i2c_adapter_dev_release
,
1324 EXPORT_SYMBOL_GPL(i2c_adapter_type
);
1327 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1328 * @dev: device, probably from some driver model iterator
1330 * When traversing the driver model tree, perhaps using driver model
1331 * iterators like @device_for_each_child(), you can't assume very much
1332 * about the nodes you find. Use this function to avoid oopses caused
1333 * by wrongly treating some non-I2C device as an i2c_adapter.
1335 struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
)
1337 return (dev
->type
== &i2c_adapter_type
)
1338 ? to_i2c_adapter(dev
)
1341 EXPORT_SYMBOL(i2c_verify_adapter
);
1343 #ifdef CONFIG_I2C_COMPAT
1344 static struct class_compat
*i2c_adapter_compat_class
;
1347 static void i2c_scan_static_board_info(struct i2c_adapter
*adapter
)
1349 struct i2c_devinfo
*devinfo
;
1351 down_read(&__i2c_board_lock
);
1352 list_for_each_entry(devinfo
, &__i2c_board_list
, list
) {
1353 if (devinfo
->busnum
== adapter
->nr
1354 && !i2c_new_device(adapter
,
1355 &devinfo
->board_info
))
1356 dev_err(&adapter
->dev
,
1357 "Can't create device at 0x%02x\n",
1358 devinfo
->board_info
.addr
);
1360 up_read(&__i2c_board_lock
);
1363 /* OF support code */
1365 #if IS_ENABLED(CONFIG_OF)
1366 static struct i2c_client
*of_i2c_register_device(struct i2c_adapter
*adap
,
1367 struct device_node
*node
)
1369 struct i2c_client
*result
;
1370 struct i2c_board_info info
= {};
1371 struct dev_archdata dev_ad
= {};
1372 const __be32
*addr_be
;
1376 dev_dbg(&adap
->dev
, "of_i2c: register %s\n", node
->full_name
);
1378 if (of_modalias_node(node
, info
.type
, sizeof(info
.type
)) < 0) {
1379 dev_err(&adap
->dev
, "of_i2c: modalias failure on %s\n",
1381 return ERR_PTR(-EINVAL
);
1384 addr_be
= of_get_property(node
, "reg", &len
);
1385 if (!addr_be
|| (len
< sizeof(*addr_be
))) {
1386 dev_err(&adap
->dev
, "of_i2c: invalid reg on %s\n",
1388 return ERR_PTR(-EINVAL
);
1391 addr
= be32_to_cpup(addr_be
);
1392 if (addr
& I2C_TEN_BIT_ADDRESS
) {
1393 addr
&= ~I2C_TEN_BIT_ADDRESS
;
1394 info
.flags
|= I2C_CLIENT_TEN
;
1397 if (addr
& I2C_OWN_SLAVE_ADDRESS
) {
1398 addr
&= ~I2C_OWN_SLAVE_ADDRESS
;
1399 info
.flags
|= I2C_CLIENT_SLAVE
;
1402 if (i2c_check_addr_validity(addr
, info
.flags
)) {
1403 dev_err(&adap
->dev
, "of_i2c: invalid addr=%x on %s\n",
1404 info
.addr
, node
->full_name
);
1405 return ERR_PTR(-EINVAL
);
1409 info
.of_node
= of_node_get(node
);
1410 info
.archdata
= &dev_ad
;
1412 if (of_get_property(node
, "wakeup-source", NULL
))
1413 info
.flags
|= I2C_CLIENT_WAKE
;
1415 result
= i2c_new_device(adap
, &info
);
1416 if (result
== NULL
) {
1417 dev_err(&adap
->dev
, "of_i2c: Failure registering %s\n",
1420 return ERR_PTR(-EINVAL
);
1425 static void of_i2c_register_devices(struct i2c_adapter
*adap
)
1427 struct device_node
*node
;
1429 /* Only register child devices if the adapter has a node pointer set */
1430 if (!adap
->dev
.of_node
)
1433 dev_dbg(&adap
->dev
, "of_i2c: walking child nodes\n");
1435 for_each_available_child_of_node(adap
->dev
.of_node
, node
) {
1436 if (of_node_test_and_set_flag(node
, OF_POPULATED
))
1438 of_i2c_register_device(adap
, node
);
1442 static int of_dev_node_match(struct device
*dev
, void *data
)
1444 return dev
->of_node
== data
;
1447 /* must call put_device() when done with returned i2c_client device */
1448 struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
)
1451 struct i2c_client
*client
;
1453 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
, of_dev_node_match
);
1457 client
= i2c_verify_client(dev
);
1463 EXPORT_SYMBOL(of_find_i2c_device_by_node
);
1465 /* must call put_device() when done with returned i2c_adapter device */
1466 struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
)
1469 struct i2c_adapter
*adapter
;
1471 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
, of_dev_node_match
);
1475 adapter
= i2c_verify_adapter(dev
);
1481 EXPORT_SYMBOL(of_find_i2c_adapter_by_node
);
1483 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
1484 struct i2c_adapter
*of_get_i2c_adapter_by_node(struct device_node
*node
)
1486 struct i2c_adapter
*adapter
;
1488 adapter
= of_find_i2c_adapter_by_node(node
);
1492 if (!try_module_get(adapter
->owner
)) {
1493 put_device(&adapter
->dev
);
1499 EXPORT_SYMBOL(of_get_i2c_adapter_by_node
);
1501 static void of_i2c_register_devices(struct i2c_adapter
*adap
) { }
1502 #endif /* CONFIG_OF */
1504 static int i2c_do_add_adapter(struct i2c_driver
*driver
,
1505 struct i2c_adapter
*adap
)
1507 /* Detect supported devices on that bus, and instantiate them */
1508 i2c_detect(adap
, driver
);
1510 /* Let legacy drivers scan this bus for matching devices */
1511 if (driver
->attach_adapter
) {
1512 dev_warn(&adap
->dev
, "%s: attach_adapter method is deprecated\n",
1513 driver
->driver
.name
);
1514 dev_warn(&adap
->dev
, "Please use another way to instantiate "
1515 "your i2c_client\n");
1516 /* We ignore the return code; if it fails, too bad */
1517 driver
->attach_adapter(adap
);
1522 static int __process_new_adapter(struct device_driver
*d
, void *data
)
1524 return i2c_do_add_adapter(to_i2c_driver(d
), data
);
1527 static int i2c_register_adapter(struct i2c_adapter
*adap
)
1531 /* Can't register until after driver model init */
1532 if (unlikely(WARN_ON(!i2c_bus_type
.p
))) {
1538 if (unlikely(adap
->name
[0] == '\0')) {
1539 pr_err("i2c-core: Attempt to register an adapter with "
1543 if (unlikely(!adap
->algo
)) {
1544 pr_err("i2c-core: Attempt to register adapter '%s' with "
1545 "no algo!\n", adap
->name
);
1549 rt_mutex_init(&adap
->bus_lock
);
1550 mutex_init(&adap
->userspace_clients_lock
);
1551 INIT_LIST_HEAD(&adap
->userspace_clients
);
1553 /* Set default timeout to 1 second if not already set */
1554 if (adap
->timeout
== 0)
1557 dev_set_name(&adap
->dev
, "i2c-%d", adap
->nr
);
1558 adap
->dev
.bus
= &i2c_bus_type
;
1559 adap
->dev
.type
= &i2c_adapter_type
;
1560 res
= device_register(&adap
->dev
);
1564 dev_dbg(&adap
->dev
, "adapter [%s] registered\n", adap
->name
);
1566 pm_runtime_no_callbacks(&adap
->dev
);
1567 pm_runtime_enable(&adap
->dev
);
1569 #ifdef CONFIG_I2C_COMPAT
1570 res
= class_compat_create_link(i2c_adapter_compat_class
, &adap
->dev
,
1573 dev_warn(&adap
->dev
,
1574 "Failed to create compatibility class link\n");
1577 /* bus recovery specific initialization */
1578 if (adap
->bus_recovery_info
) {
1579 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
1581 if (!bri
->recover_bus
) {
1582 dev_err(&adap
->dev
, "No recover_bus() found, not using recovery\n");
1583 adap
->bus_recovery_info
= NULL
;
1587 /* Generic GPIO recovery */
1588 if (bri
->recover_bus
== i2c_generic_gpio_recovery
) {
1589 if (!gpio_is_valid(bri
->scl_gpio
)) {
1590 dev_err(&adap
->dev
, "Invalid SCL gpio, not using recovery\n");
1591 adap
->bus_recovery_info
= NULL
;
1595 if (gpio_is_valid(bri
->sda_gpio
))
1596 bri
->get_sda
= get_sda_gpio_value
;
1598 bri
->get_sda
= NULL
;
1600 bri
->get_scl
= get_scl_gpio_value
;
1601 bri
->set_scl
= set_scl_gpio_value
;
1602 } else if (!bri
->set_scl
|| !bri
->get_scl
) {
1603 /* Generic SCL recovery */
1604 dev_err(&adap
->dev
, "No {get|set}_gpio() found, not using recovery\n");
1605 adap
->bus_recovery_info
= NULL
;
1610 /* create pre-declared device nodes */
1611 of_i2c_register_devices(adap
);
1612 acpi_i2c_register_devices(adap
);
1613 acpi_i2c_install_space_handler(adap
);
1615 if (adap
->nr
< __i2c_first_dynamic_bus_num
)
1616 i2c_scan_static_board_info(adap
);
1618 /* Notify drivers */
1619 mutex_lock(&core_lock
);
1620 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
, __process_new_adapter
);
1621 mutex_unlock(&core_lock
);
1626 mutex_lock(&core_lock
);
1627 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1628 mutex_unlock(&core_lock
);
1633 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1634 * @adap: the adapter to register (with adap->nr initialized)
1635 * Context: can sleep
1637 * See i2c_add_numbered_adapter() for details.
1639 static int __i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1643 mutex_lock(&core_lock
);
1644 id
= idr_alloc(&i2c_adapter_idr
, adap
, adap
->nr
, adap
->nr
+ 1,
1646 mutex_unlock(&core_lock
);
1648 return id
== -ENOSPC
? -EBUSY
: id
;
1650 return i2c_register_adapter(adap
);
1654 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1655 * @adapter: the adapter to add
1656 * Context: can sleep
1658 * This routine is used to declare an I2C adapter when its bus number
1659 * doesn't matter or when its bus number is specified by an dt alias.
1660 * Examples of bases when the bus number doesn't matter: I2C adapters
1661 * dynamically added by USB links or PCI plugin cards.
1663 * When this returns zero, a new bus number was allocated and stored
1664 * in adap->nr, and the specified adapter became available for clients.
1665 * Otherwise, a negative errno value is returned.
1667 int i2c_add_adapter(struct i2c_adapter
*adapter
)
1669 struct device
*dev
= &adapter
->dev
;
1673 id
= of_alias_get_id(dev
->of_node
, "i2c");
1676 return __i2c_add_numbered_adapter(adapter
);
1680 mutex_lock(&core_lock
);
1681 id
= idr_alloc(&i2c_adapter_idr
, adapter
,
1682 __i2c_first_dynamic_bus_num
, 0, GFP_KERNEL
);
1683 mutex_unlock(&core_lock
);
1689 return i2c_register_adapter(adapter
);
1691 EXPORT_SYMBOL(i2c_add_adapter
);
1694 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1695 * @adap: the adapter to register (with adap->nr initialized)
1696 * Context: can sleep
1698 * This routine is used to declare an I2C adapter when its bus number
1699 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1700 * or otherwise built in to the system's mainboard, and where i2c_board_info
1701 * is used to properly configure I2C devices.
1703 * If the requested bus number is set to -1, then this function will behave
1704 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1706 * If no devices have pre-been declared for this bus, then be sure to
1707 * register the adapter before any dynamically allocated ones. Otherwise
1708 * the required bus ID may not be available.
1710 * When this returns zero, the specified adapter became available for
1711 * clients using the bus number provided in adap->nr. Also, the table
1712 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1713 * and the appropriate driver model device nodes are created. Otherwise, a
1714 * negative errno value is returned.
1716 int i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1718 if (adap
->nr
== -1) /* -1 means dynamically assign bus id */
1719 return i2c_add_adapter(adap
);
1721 return __i2c_add_numbered_adapter(adap
);
1723 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter
);
1725 static void i2c_do_del_adapter(struct i2c_driver
*driver
,
1726 struct i2c_adapter
*adapter
)
1728 struct i2c_client
*client
, *_n
;
1730 /* Remove the devices we created ourselves as the result of hardware
1731 * probing (using a driver's detect method) */
1732 list_for_each_entry_safe(client
, _n
, &driver
->clients
, detected
) {
1733 if (client
->adapter
== adapter
) {
1734 dev_dbg(&adapter
->dev
, "Removing %s at 0x%x\n",
1735 client
->name
, client
->addr
);
1736 list_del(&client
->detected
);
1737 i2c_unregister_device(client
);
1742 static int __unregister_client(struct device
*dev
, void *dummy
)
1744 struct i2c_client
*client
= i2c_verify_client(dev
);
1745 if (client
&& strcmp(client
->name
, "dummy"))
1746 i2c_unregister_device(client
);
1750 static int __unregister_dummy(struct device
*dev
, void *dummy
)
1752 struct i2c_client
*client
= i2c_verify_client(dev
);
1754 i2c_unregister_device(client
);
1758 static int __process_removed_adapter(struct device_driver
*d
, void *data
)
1760 i2c_do_del_adapter(to_i2c_driver(d
), data
);
1765 * i2c_del_adapter - unregister I2C adapter
1766 * @adap: the adapter being unregistered
1767 * Context: can sleep
1769 * This unregisters an I2C adapter which was previously registered
1770 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1772 void i2c_del_adapter(struct i2c_adapter
*adap
)
1774 struct i2c_adapter
*found
;
1775 struct i2c_client
*client
, *next
;
1777 /* First make sure that this adapter was ever added */
1778 mutex_lock(&core_lock
);
1779 found
= idr_find(&i2c_adapter_idr
, adap
->nr
);
1780 mutex_unlock(&core_lock
);
1781 if (found
!= adap
) {
1782 pr_debug("i2c-core: attempting to delete unregistered "
1783 "adapter [%s]\n", adap
->name
);
1787 acpi_i2c_remove_space_handler(adap
);
1788 /* Tell drivers about this removal */
1789 mutex_lock(&core_lock
);
1790 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
1791 __process_removed_adapter
);
1792 mutex_unlock(&core_lock
);
1794 /* Remove devices instantiated from sysfs */
1795 mutex_lock_nested(&adap
->userspace_clients_lock
,
1796 i2c_adapter_depth(adap
));
1797 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1799 dev_dbg(&adap
->dev
, "Removing %s at 0x%x\n", client
->name
,
1801 list_del(&client
->detected
);
1802 i2c_unregister_device(client
);
1804 mutex_unlock(&adap
->userspace_clients_lock
);
1806 /* Detach any active clients. This can't fail, thus we do not
1807 * check the returned value. This is a two-pass process, because
1808 * we can't remove the dummy devices during the first pass: they
1809 * could have been instantiated by real devices wishing to clean
1810 * them up properly, so we give them a chance to do that first. */
1811 device_for_each_child(&adap
->dev
, NULL
, __unregister_client
);
1812 device_for_each_child(&adap
->dev
, NULL
, __unregister_dummy
);
1814 #ifdef CONFIG_I2C_COMPAT
1815 class_compat_remove_link(i2c_adapter_compat_class
, &adap
->dev
,
1819 /* device name is gone after device_unregister */
1820 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
1822 pm_runtime_disable(&adap
->dev
);
1824 /* wait until all references to the device are gone
1826 * FIXME: This is old code and should ideally be replaced by an
1827 * alternative which results in decoupling the lifetime of the struct
1828 * device from the i2c_adapter, like spi or netdev do. Any solution
1829 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1831 init_completion(&adap
->dev_released
);
1832 device_unregister(&adap
->dev
);
1833 wait_for_completion(&adap
->dev_released
);
1836 mutex_lock(&core_lock
);
1837 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1838 mutex_unlock(&core_lock
);
1840 /* Clear the device structure in case this adapter is ever going to be
1842 memset(&adap
->dev
, 0, sizeof(adap
->dev
));
1844 EXPORT_SYMBOL(i2c_del_adapter
);
1847 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1848 * @dev: The device to scan for I2C timing properties
1849 * @t: the i2c_timings struct to be filled with values
1850 * @use_defaults: bool to use sane defaults derived from the I2C specification
1851 * when properties are not found, otherwise use 0
1853 * Scan the device for the generic I2C properties describing timing parameters
1854 * for the signal and fill the given struct with the results. If a property was
1855 * not found and use_defaults was true, then maximum timings are assumed which
1856 * are derived from the I2C specification. If use_defaults is not used, the
1857 * results will be 0, so drivers can apply their own defaults later. The latter
1858 * is mainly intended for avoiding regressions of existing drivers which want
1859 * to switch to this function. New drivers almost always should use the defaults.
1862 void i2c_parse_fw_timings(struct device
*dev
, struct i2c_timings
*t
, bool use_defaults
)
1866 memset(t
, 0, sizeof(*t
));
1868 ret
= device_property_read_u32(dev
, "clock-frequency", &t
->bus_freq_hz
);
1869 if (ret
&& use_defaults
)
1870 t
->bus_freq_hz
= 100000;
1872 ret
= device_property_read_u32(dev
, "i2c-scl-rising-time-ns", &t
->scl_rise_ns
);
1873 if (ret
&& use_defaults
) {
1874 if (t
->bus_freq_hz
<= 100000)
1875 t
->scl_rise_ns
= 1000;
1876 else if (t
->bus_freq_hz
<= 400000)
1877 t
->scl_rise_ns
= 300;
1879 t
->scl_rise_ns
= 120;
1882 ret
= device_property_read_u32(dev
, "i2c-scl-falling-time-ns", &t
->scl_fall_ns
);
1883 if (ret
&& use_defaults
) {
1884 if (t
->bus_freq_hz
<= 400000)
1885 t
->scl_fall_ns
= 300;
1887 t
->scl_fall_ns
= 120;
1890 device_property_read_u32(dev
, "i2c-scl-internal-delay-ns", &t
->scl_int_delay_ns
);
1892 ret
= device_property_read_u32(dev
, "i2c-sda-falling-time-ns", &t
->sda_fall_ns
);
1893 if (ret
&& use_defaults
)
1894 t
->sda_fall_ns
= t
->scl_fall_ns
;
1896 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings
);
1898 /* ------------------------------------------------------------------------- */
1900 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *))
1904 mutex_lock(&core_lock
);
1905 res
= bus_for_each_dev(&i2c_bus_type
, NULL
, data
, fn
);
1906 mutex_unlock(&core_lock
);
1910 EXPORT_SYMBOL_GPL(i2c_for_each_dev
);
1912 static int __process_new_driver(struct device
*dev
, void *data
)
1914 if (dev
->type
!= &i2c_adapter_type
)
1916 return i2c_do_add_adapter(data
, to_i2c_adapter(dev
));
1920 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1921 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1924 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
1928 /* Can't register until after driver model init */
1929 if (unlikely(WARN_ON(!i2c_bus_type
.p
)))
1932 /* add the driver to the list of i2c drivers in the driver core */
1933 driver
->driver
.owner
= owner
;
1934 driver
->driver
.bus
= &i2c_bus_type
;
1936 /* When registration returns, the driver core
1937 * will have called probe() for all matching-but-unbound devices.
1939 res
= driver_register(&driver
->driver
);
1943 pr_debug("i2c-core: driver [%s] registered\n", driver
->driver
.name
);
1945 INIT_LIST_HEAD(&driver
->clients
);
1946 /* Walk the adapters that are already present */
1947 i2c_for_each_dev(driver
, __process_new_driver
);
1951 EXPORT_SYMBOL(i2c_register_driver
);
1953 static int __process_removed_driver(struct device
*dev
, void *data
)
1955 if (dev
->type
== &i2c_adapter_type
)
1956 i2c_do_del_adapter(data
, to_i2c_adapter(dev
));
1961 * i2c_del_driver - unregister I2C driver
1962 * @driver: the driver being unregistered
1963 * Context: can sleep
1965 void i2c_del_driver(struct i2c_driver
*driver
)
1967 i2c_for_each_dev(driver
, __process_removed_driver
);
1969 driver_unregister(&driver
->driver
);
1970 pr_debug("i2c-core: driver [%s] unregistered\n", driver
->driver
.name
);
1972 EXPORT_SYMBOL(i2c_del_driver
);
1974 /* ------------------------------------------------------------------------- */
1977 * i2c_use_client - increments the reference count of the i2c client structure
1978 * @client: the client being referenced
1980 * Each live reference to a client should be refcounted. The driver model does
1981 * that automatically as part of driver binding, so that most drivers don't
1982 * need to do this explicitly: they hold a reference until they're unbound
1985 * A pointer to the client with the incremented reference counter is returned.
1987 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
1989 if (client
&& get_device(&client
->dev
))
1993 EXPORT_SYMBOL(i2c_use_client
);
1996 * i2c_release_client - release a use of the i2c client structure
1997 * @client: the client being no longer referenced
1999 * Must be called when a user of a client is finished with it.
2001 void i2c_release_client(struct i2c_client
*client
)
2004 put_device(&client
->dev
);
2006 EXPORT_SYMBOL(i2c_release_client
);
2008 struct i2c_cmd_arg
{
2013 static int i2c_cmd(struct device
*dev
, void *_arg
)
2015 struct i2c_client
*client
= i2c_verify_client(dev
);
2016 struct i2c_cmd_arg
*arg
= _arg
;
2017 struct i2c_driver
*driver
;
2019 if (!client
|| !client
->dev
.driver
)
2022 driver
= to_i2c_driver(client
->dev
.driver
);
2023 if (driver
->command
)
2024 driver
->command(client
, arg
->cmd
, arg
->arg
);
2028 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
2030 struct i2c_cmd_arg cmd_arg
;
2034 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
2036 EXPORT_SYMBOL(i2c_clients_command
);
2038 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2039 static int of_i2c_notify(struct notifier_block
*nb
, unsigned long action
,
2042 struct of_reconfig_data
*rd
= arg
;
2043 struct i2c_adapter
*adap
;
2044 struct i2c_client
*client
;
2046 switch (of_reconfig_get_state_change(action
, rd
)) {
2047 case OF_RECONFIG_CHANGE_ADD
:
2048 adap
= of_find_i2c_adapter_by_node(rd
->dn
->parent
);
2050 return NOTIFY_OK
; /* not for us */
2052 if (of_node_test_and_set_flag(rd
->dn
, OF_POPULATED
)) {
2053 put_device(&adap
->dev
);
2057 client
= of_i2c_register_device(adap
, rd
->dn
);
2058 put_device(&adap
->dev
);
2060 if (IS_ERR(client
)) {
2061 pr_err("%s: failed to create for '%s'\n",
2062 __func__
, rd
->dn
->full_name
);
2063 return notifier_from_errno(PTR_ERR(client
));
2066 case OF_RECONFIG_CHANGE_REMOVE
:
2067 /* already depopulated? */
2068 if (!of_node_check_flag(rd
->dn
, OF_POPULATED
))
2071 /* find our device by node */
2072 client
= of_find_i2c_device_by_node(rd
->dn
);
2074 return NOTIFY_OK
; /* no? not meant for us */
2076 /* unregister takes one ref away */
2077 i2c_unregister_device(client
);
2079 /* and put the reference of the find */
2080 put_device(&client
->dev
);
2086 static struct notifier_block i2c_of_notifier
= {
2087 .notifier_call
= of_i2c_notify
,
2090 extern struct notifier_block i2c_of_notifier
;
2091 #endif /* CONFIG_OF_DYNAMIC */
2093 static int __init
i2c_init(void)
2097 retval
= of_alias_get_highest_id("i2c");
2099 down_write(&__i2c_board_lock
);
2100 if (retval
>= __i2c_first_dynamic_bus_num
)
2101 __i2c_first_dynamic_bus_num
= retval
+ 1;
2102 up_write(&__i2c_board_lock
);
2104 retval
= bus_register(&i2c_bus_type
);
2107 #ifdef CONFIG_I2C_COMPAT
2108 i2c_adapter_compat_class
= class_compat_register("i2c-adapter");
2109 if (!i2c_adapter_compat_class
) {
2114 retval
= i2c_add_driver(&dummy_driver
);
2118 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
2119 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier
));
2124 #ifdef CONFIG_I2C_COMPAT
2125 class_compat_unregister(i2c_adapter_compat_class
);
2128 bus_unregister(&i2c_bus_type
);
2132 static void __exit
i2c_exit(void)
2134 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
2135 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier
));
2136 i2c_del_driver(&dummy_driver
);
2137 #ifdef CONFIG_I2C_COMPAT
2138 class_compat_unregister(i2c_adapter_compat_class
);
2140 bus_unregister(&i2c_bus_type
);
2141 tracepoint_synchronize_unregister();
2144 /* We must initialize early, because some subsystems register i2c drivers
2145 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2147 postcore_initcall(i2c_init
);
2148 module_exit(i2c_exit
);
2150 /* ----------------------------------------------------
2151 * the functional interface to the i2c busses.
2152 * ----------------------------------------------------
2155 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2156 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2158 static int i2c_quirk_error(struct i2c_adapter
*adap
, struct i2c_msg
*msg
, char *err_msg
)
2160 dev_err_ratelimited(&adap
->dev
, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2161 err_msg
, msg
->addr
, msg
->len
,
2162 msg
->flags
& I2C_M_RD
? "read" : "write");
2166 static int i2c_check_for_quirks(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2168 const struct i2c_adapter_quirks
*q
= adap
->quirks
;
2169 int max_num
= q
->max_num_msgs
, i
;
2170 bool do_len_check
= true;
2172 if (q
->flags
& I2C_AQ_COMB
) {
2175 /* special checks for combined messages */
2177 if (q
->flags
& I2C_AQ_COMB_WRITE_FIRST
&& msgs
[0].flags
& I2C_M_RD
)
2178 return i2c_quirk_error(adap
, &msgs
[0], "1st comb msg must be write");
2180 if (q
->flags
& I2C_AQ_COMB_READ_SECOND
&& !(msgs
[1].flags
& I2C_M_RD
))
2181 return i2c_quirk_error(adap
, &msgs
[1], "2nd comb msg must be read");
2183 if (q
->flags
& I2C_AQ_COMB_SAME_ADDR
&& msgs
[0].addr
!= msgs
[1].addr
)
2184 return i2c_quirk_error(adap
, &msgs
[0], "comb msg only to same addr");
2186 if (i2c_quirk_exceeded(msgs
[0].len
, q
->max_comb_1st_msg_len
))
2187 return i2c_quirk_error(adap
, &msgs
[0], "msg too long");
2189 if (i2c_quirk_exceeded(msgs
[1].len
, q
->max_comb_2nd_msg_len
))
2190 return i2c_quirk_error(adap
, &msgs
[1], "msg too long");
2192 do_len_check
= false;
2196 if (i2c_quirk_exceeded(num
, max_num
))
2197 return i2c_quirk_error(adap
, &msgs
[0], "too many messages");
2199 for (i
= 0; i
< num
; i
++) {
2200 u16 len
= msgs
[i
].len
;
2202 if (msgs
[i
].flags
& I2C_M_RD
) {
2203 if (do_len_check
&& i2c_quirk_exceeded(len
, q
->max_read_len
))
2204 return i2c_quirk_error(adap
, &msgs
[i
], "msg too long");
2206 if (do_len_check
&& i2c_quirk_exceeded(len
, q
->max_write_len
))
2207 return i2c_quirk_error(adap
, &msgs
[i
], "msg too long");
2215 * __i2c_transfer - unlocked flavor of i2c_transfer
2216 * @adap: Handle to I2C bus
2217 * @msgs: One or more messages to execute before STOP is issued to
2218 * terminate the operation; each message begins with a START.
2219 * @num: Number of messages to be executed.
2221 * Returns negative errno, else the number of messages executed.
2223 * Adapter lock must be held when calling this function. No debug logging
2224 * takes place. adap->algo->master_xfer existence isn't checked.
2226 int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2228 unsigned long orig_jiffies
;
2231 if (adap
->quirks
&& i2c_check_for_quirks(adap
, msgs
, num
))
2234 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
2235 * enabled. This is an efficient way of keeping the for-loop from
2236 * being executed when not needed.
2238 if (static_key_false(&i2c_trace_msg
)) {
2240 for (i
= 0; i
< num
; i
++)
2241 if (msgs
[i
].flags
& I2C_M_RD
)
2242 trace_i2c_read(adap
, &msgs
[i
], i
);
2244 trace_i2c_write(adap
, &msgs
[i
], i
);
2247 /* Retry automatically on arbitration loss */
2248 orig_jiffies
= jiffies
;
2249 for (ret
= 0, try = 0; try <= adap
->retries
; try++) {
2250 ret
= adap
->algo
->master_xfer(adap
, msgs
, num
);
2253 if (time_after(jiffies
, orig_jiffies
+ adap
->timeout
))
2257 if (static_key_false(&i2c_trace_msg
)) {
2259 for (i
= 0; i
< ret
; i
++)
2260 if (msgs
[i
].flags
& I2C_M_RD
)
2261 trace_i2c_reply(adap
, &msgs
[i
], i
);
2262 trace_i2c_result(adap
, i
, ret
);
2267 EXPORT_SYMBOL(__i2c_transfer
);
2270 * i2c_transfer - execute a single or combined I2C message
2271 * @adap: Handle to I2C bus
2272 * @msgs: One or more messages to execute before STOP is issued to
2273 * terminate the operation; each message begins with a START.
2274 * @num: Number of messages to be executed.
2276 * Returns negative errno, else the number of messages executed.
2278 * Note that there is no requirement that each message be sent to
2279 * the same slave address, although that is the most common model.
2281 int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2285 /* REVISIT the fault reporting model here is weak:
2287 * - When we get an error after receiving N bytes from a slave,
2288 * there is no way to report "N".
2290 * - When we get a NAK after transmitting N bytes to a slave,
2291 * there is no way to report "N" ... or to let the master
2292 * continue executing the rest of this combined message, if
2293 * that's the appropriate response.
2295 * - When for example "num" is two and we successfully complete
2296 * the first message but get an error part way through the
2297 * second, it's unclear whether that should be reported as
2298 * one (discarding status on the second message) or errno
2299 * (discarding status on the first one).
2302 if (adap
->algo
->master_xfer
) {
2304 for (ret
= 0; ret
< num
; ret
++) {
2305 dev_dbg(&adap
->dev
, "master_xfer[%d] %c, addr=0x%02x, "
2306 "len=%d%s\n", ret
, (msgs
[ret
].flags
& I2C_M_RD
)
2307 ? 'R' : 'W', msgs
[ret
].addr
, msgs
[ret
].len
,
2308 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
2312 if (in_atomic() || irqs_disabled()) {
2313 ret
= i2c_trylock_adapter(adap
);
2315 /* I2C activity is ongoing. */
2318 i2c_lock_adapter(adap
);
2321 ret
= __i2c_transfer(adap
, msgs
, num
);
2322 i2c_unlock_adapter(adap
);
2326 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
2330 EXPORT_SYMBOL(i2c_transfer
);
2333 * i2c_master_send - issue a single I2C message in master transmit mode
2334 * @client: Handle to slave device
2335 * @buf: Data that will be written to the slave
2336 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2338 * Returns negative errno, or else the number of bytes written.
2340 int i2c_master_send(const struct i2c_client
*client
, const char *buf
, int count
)
2343 struct i2c_adapter
*adap
= client
->adapter
;
2346 msg
.addr
= client
->addr
;
2347 msg
.flags
= client
->flags
& I2C_M_TEN
;
2349 msg
.buf
= (char *)buf
;
2351 ret
= i2c_transfer(adap
, &msg
, 1);
2354 * If everything went ok (i.e. 1 msg transmitted), return #bytes
2355 * transmitted, else error code.
2357 return (ret
== 1) ? count
: ret
;
2359 EXPORT_SYMBOL(i2c_master_send
);
2362 * i2c_master_recv - issue a single I2C message in master receive mode
2363 * @client: Handle to slave device
2364 * @buf: Where to store data read from slave
2365 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2367 * Returns negative errno, or else the number of bytes read.
2369 int i2c_master_recv(const struct i2c_client
*client
, char *buf
, int count
)
2371 struct i2c_adapter
*adap
= client
->adapter
;
2375 msg
.addr
= client
->addr
;
2376 msg
.flags
= client
->flags
& I2C_M_TEN
;
2377 msg
.flags
|= I2C_M_RD
;
2381 ret
= i2c_transfer(adap
, &msg
, 1);
2384 * If everything went ok (i.e. 1 msg received), return #bytes received,
2387 return (ret
== 1) ? count
: ret
;
2389 EXPORT_SYMBOL(i2c_master_recv
);
2391 /* ----------------------------------------------------
2392 * the i2c address scanning function
2393 * Will not work for 10-bit addresses!
2394 * ----------------------------------------------------
2398 * Legacy default probe function, mostly relevant for SMBus. The default
2399 * probe method is a quick write, but it is known to corrupt the 24RF08
2400 * EEPROMs due to a state machine bug, and could also irreversibly
2401 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2402 * we use a short byte read instead. Also, some bus drivers don't implement
2403 * quick write, so we fallback to a byte read in that case too.
2404 * On x86, there is another special case for FSC hardware monitoring chips,
2405 * which want regular byte reads (address 0x73.) Fortunately, these are the
2406 * only known chips using this I2C address on PC hardware.
2407 * Returns 1 if probe succeeded, 0 if not.
2409 static int i2c_default_probe(struct i2c_adapter
*adap
, unsigned short addr
)
2412 union i2c_smbus_data dummy
;
2415 if (addr
== 0x73 && (adap
->class & I2C_CLASS_HWMON
)
2416 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE_DATA
))
2417 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2418 I2C_SMBUS_BYTE_DATA
, &dummy
);
2421 if (!((addr
& ~0x07) == 0x30 || (addr
& ~0x0f) == 0x50)
2422 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
))
2423 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_WRITE
, 0,
2424 I2C_SMBUS_QUICK
, NULL
);
2425 else if (i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
))
2426 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2427 I2C_SMBUS_BYTE
, &dummy
);
2429 dev_warn(&adap
->dev
, "No suitable probing method supported for address 0x%02X\n",
2437 static int i2c_detect_address(struct i2c_client
*temp_client
,
2438 struct i2c_driver
*driver
)
2440 struct i2c_board_info info
;
2441 struct i2c_adapter
*adapter
= temp_client
->adapter
;
2442 int addr
= temp_client
->addr
;
2445 /* Make sure the address is valid */
2446 err
= i2c_check_7bit_addr_validity_strict(addr
);
2448 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
2453 /* Skip if already in use (7 bit, no need to encode flags) */
2454 if (i2c_check_addr_busy(adapter
, addr
))
2457 /* Make sure there is something at this address */
2458 if (!i2c_default_probe(adapter
, addr
))
2461 /* Finally call the custom detection function */
2462 memset(&info
, 0, sizeof(struct i2c_board_info
));
2464 err
= driver
->detect(temp_client
, &info
);
2466 /* -ENODEV is returned if the detection fails. We catch it
2467 here as this isn't an error. */
2468 return err
== -ENODEV
? 0 : err
;
2471 /* Consistency check */
2472 if (info
.type
[0] == '\0') {
2473 dev_err(&adapter
->dev
, "%s detection function provided "
2474 "no name for 0x%x\n", driver
->driver
.name
,
2477 struct i2c_client
*client
;
2479 /* Detection succeeded, instantiate the device */
2480 if (adapter
->class & I2C_CLASS_DEPRECATED
)
2481 dev_warn(&adapter
->dev
,
2482 "This adapter will soon drop class based instantiation of devices. "
2483 "Please make sure client 0x%02x gets instantiated by other means. "
2484 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2487 dev_dbg(&adapter
->dev
, "Creating %s at 0x%02x\n",
2488 info
.type
, info
.addr
);
2489 client
= i2c_new_device(adapter
, &info
);
2491 list_add_tail(&client
->detected
, &driver
->clients
);
2493 dev_err(&adapter
->dev
, "Failed creating %s at 0x%02x\n",
2494 info
.type
, info
.addr
);
2499 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
)
2501 const unsigned short *address_list
;
2502 struct i2c_client
*temp_client
;
2504 int adap_id
= i2c_adapter_id(adapter
);
2506 address_list
= driver
->address_list
;
2507 if (!driver
->detect
|| !address_list
)
2510 /* Warn that the adapter lost class based instantiation */
2511 if (adapter
->class == I2C_CLASS_DEPRECATED
) {
2512 dev_dbg(&adapter
->dev
,
2513 "This adapter dropped support for I2C classes and "
2514 "won't auto-detect %s devices anymore. If you need it, check "
2515 "'Documentation/i2c/instantiating-devices' for alternatives.\n",
2516 driver
->driver
.name
);
2520 /* Stop here if the classes do not match */
2521 if (!(adapter
->class & driver
->class))
2524 /* Set up a temporary client to help detect callback */
2525 temp_client
= kzalloc(sizeof(struct i2c_client
), GFP_KERNEL
);
2528 temp_client
->adapter
= adapter
;
2530 for (i
= 0; address_list
[i
] != I2C_CLIENT_END
; i
+= 1) {
2531 dev_dbg(&adapter
->dev
, "found normal entry for adapter %d, "
2532 "addr 0x%02x\n", adap_id
, address_list
[i
]);
2533 temp_client
->addr
= address_list
[i
];
2534 err
= i2c_detect_address(temp_client
, driver
);
2543 int i2c_probe_func_quick_read(struct i2c_adapter
*adap
, unsigned short addr
)
2545 return i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2546 I2C_SMBUS_QUICK
, NULL
) >= 0;
2548 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read
);
2551 i2c_new_probed_device(struct i2c_adapter
*adap
,
2552 struct i2c_board_info
*info
,
2553 unsigned short const *addr_list
,
2554 int (*probe
)(struct i2c_adapter
*, unsigned short addr
))
2559 probe
= i2c_default_probe
;
2561 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
2562 /* Check address validity */
2563 if (i2c_check_7bit_addr_validity_strict(addr_list
[i
]) < 0) {
2564 dev_warn(&adap
->dev
, "Invalid 7-bit address "
2565 "0x%02x\n", addr_list
[i
]);
2569 /* Check address availability (7 bit, no need to encode flags) */
2570 if (i2c_check_addr_busy(adap
, addr_list
[i
])) {
2571 dev_dbg(&adap
->dev
, "Address 0x%02x already in "
2572 "use, not probing\n", addr_list
[i
]);
2576 /* Test address responsiveness */
2577 if (probe(adap
, addr_list
[i
]))
2581 if (addr_list
[i
] == I2C_CLIENT_END
) {
2582 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
2586 info
->addr
= addr_list
[i
];
2587 return i2c_new_device(adap
, info
);
2589 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
2591 struct i2c_adapter
*i2c_get_adapter(int nr
)
2593 struct i2c_adapter
*adapter
;
2595 mutex_lock(&core_lock
);
2596 adapter
= idr_find(&i2c_adapter_idr
, nr
);
2600 if (try_module_get(adapter
->owner
))
2601 get_device(&adapter
->dev
);
2606 mutex_unlock(&core_lock
);
2609 EXPORT_SYMBOL(i2c_get_adapter
);
2611 void i2c_put_adapter(struct i2c_adapter
*adap
)
2616 put_device(&adap
->dev
);
2617 module_put(adap
->owner
);
2619 EXPORT_SYMBOL(i2c_put_adapter
);
2621 /* The SMBus parts */
2623 #define POLY (0x1070U << 3)
2624 static u8
crc8(u16 data
)
2628 for (i
= 0; i
< 8; i
++) {
2633 return (u8
)(data
>> 8);
2636 /* Incremental CRC8 over count bytes in the array pointed to by p */
2637 static u8
i2c_smbus_pec(u8 crc
, u8
*p
, size_t count
)
2641 for (i
= 0; i
< count
; i
++)
2642 crc
= crc8((crc
^ p
[i
]) << 8);
2646 /* Assume a 7-bit address, which is reasonable for SMBus */
2647 static u8
i2c_smbus_msg_pec(u8 pec
, struct i2c_msg
*msg
)
2649 /* The address will be sent first */
2650 u8 addr
= (msg
->addr
<< 1) | !!(msg
->flags
& I2C_M_RD
);
2651 pec
= i2c_smbus_pec(pec
, &addr
, 1);
2653 /* The data buffer follows */
2654 return i2c_smbus_pec(pec
, msg
->buf
, msg
->len
);
2657 /* Used for write only transactions */
2658 static inline void i2c_smbus_add_pec(struct i2c_msg
*msg
)
2660 msg
->buf
[msg
->len
] = i2c_smbus_msg_pec(0, msg
);
2664 /* Return <0 on CRC error
2665 If there was a write before this read (most cases) we need to take the
2666 partial CRC from the write part into account.
2667 Note that this function does modify the message (we need to decrease the
2668 message length to hide the CRC byte from the caller). */
2669 static int i2c_smbus_check_pec(u8 cpec
, struct i2c_msg
*msg
)
2671 u8 rpec
= msg
->buf
[--msg
->len
];
2672 cpec
= i2c_smbus_msg_pec(cpec
, msg
);
2675 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2683 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2684 * @client: Handle to slave device
2686 * This executes the SMBus "receive byte" protocol, returning negative errno
2687 * else the byte received from the device.
2689 s32
i2c_smbus_read_byte(const struct i2c_client
*client
)
2691 union i2c_smbus_data data
;
2694 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2696 I2C_SMBUS_BYTE
, &data
);
2697 return (status
< 0) ? status
: data
.byte
;
2699 EXPORT_SYMBOL(i2c_smbus_read_byte
);
2702 * i2c_smbus_write_byte - SMBus "send byte" protocol
2703 * @client: Handle to slave device
2704 * @value: Byte to be sent
2706 * This executes the SMBus "send byte" protocol, returning negative errno
2707 * else zero on success.
2709 s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
)
2711 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2712 I2C_SMBUS_WRITE
, value
, I2C_SMBUS_BYTE
, NULL
);
2714 EXPORT_SYMBOL(i2c_smbus_write_byte
);
2717 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2718 * @client: Handle to slave device
2719 * @command: Byte interpreted by slave
2721 * This executes the SMBus "read byte" protocol, returning negative errno
2722 * else a data byte received from the device.
2724 s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
, u8 command
)
2726 union i2c_smbus_data data
;
2729 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2730 I2C_SMBUS_READ
, command
,
2731 I2C_SMBUS_BYTE_DATA
, &data
);
2732 return (status
< 0) ? status
: data
.byte
;
2734 EXPORT_SYMBOL(i2c_smbus_read_byte_data
);
2737 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2738 * @client: Handle to slave device
2739 * @command: Byte interpreted by slave
2740 * @value: Byte being written
2742 * This executes the SMBus "write byte" protocol, returning negative errno
2743 * else zero on success.
2745 s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
, u8 command
,
2748 union i2c_smbus_data data
;
2750 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2751 I2C_SMBUS_WRITE
, command
,
2752 I2C_SMBUS_BYTE_DATA
, &data
);
2754 EXPORT_SYMBOL(i2c_smbus_write_byte_data
);
2757 * i2c_smbus_read_word_data - SMBus "read word" protocol
2758 * @client: Handle to slave device
2759 * @command: Byte interpreted by slave
2761 * This executes the SMBus "read word" protocol, returning negative errno
2762 * else a 16-bit unsigned "word" received from the device.
2764 s32
i2c_smbus_read_word_data(const struct i2c_client
*client
, u8 command
)
2766 union i2c_smbus_data data
;
2769 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2770 I2C_SMBUS_READ
, command
,
2771 I2C_SMBUS_WORD_DATA
, &data
);
2772 return (status
< 0) ? status
: data
.word
;
2774 EXPORT_SYMBOL(i2c_smbus_read_word_data
);
2777 * i2c_smbus_write_word_data - SMBus "write word" protocol
2778 * @client: Handle to slave device
2779 * @command: Byte interpreted by slave
2780 * @value: 16-bit "word" being written
2782 * This executes the SMBus "write word" protocol, returning negative errno
2783 * else zero on success.
2785 s32
i2c_smbus_write_word_data(const struct i2c_client
*client
, u8 command
,
2788 union i2c_smbus_data data
;
2790 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2791 I2C_SMBUS_WRITE
, command
,
2792 I2C_SMBUS_WORD_DATA
, &data
);
2794 EXPORT_SYMBOL(i2c_smbus_write_word_data
);
2797 * i2c_smbus_read_block_data - SMBus "block read" protocol
2798 * @client: Handle to slave device
2799 * @command: Byte interpreted by slave
2800 * @values: Byte array into which data will be read; big enough to hold
2801 * the data returned by the slave. SMBus allows at most 32 bytes.
2803 * This executes the SMBus "block read" protocol, returning negative errno
2804 * else the number of data bytes in the slave's response.
2806 * Note that using this function requires that the client's adapter support
2807 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2808 * support this; its emulation through I2C messaging relies on a specific
2809 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2811 s32
i2c_smbus_read_block_data(const struct i2c_client
*client
, u8 command
,
2814 union i2c_smbus_data data
;
2817 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2818 I2C_SMBUS_READ
, command
,
2819 I2C_SMBUS_BLOCK_DATA
, &data
);
2823 memcpy(values
, &data
.block
[1], data
.block
[0]);
2824 return data
.block
[0];
2826 EXPORT_SYMBOL(i2c_smbus_read_block_data
);
2829 * i2c_smbus_write_block_data - SMBus "block write" protocol
2830 * @client: Handle to slave device
2831 * @command: Byte interpreted by slave
2832 * @length: Size of data block; SMBus allows at most 32 bytes
2833 * @values: Byte array which will be written.
2835 * This executes the SMBus "block write" protocol, returning negative errno
2836 * else zero on success.
2838 s32
i2c_smbus_write_block_data(const struct i2c_client
*client
, u8 command
,
2839 u8 length
, const u8
*values
)
2841 union i2c_smbus_data data
;
2843 if (length
> I2C_SMBUS_BLOCK_MAX
)
2844 length
= I2C_SMBUS_BLOCK_MAX
;
2845 data
.block
[0] = length
;
2846 memcpy(&data
.block
[1], values
, length
);
2847 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2848 I2C_SMBUS_WRITE
, command
,
2849 I2C_SMBUS_BLOCK_DATA
, &data
);
2851 EXPORT_SYMBOL(i2c_smbus_write_block_data
);
2853 /* Returns the number of read bytes */
2854 s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2855 u8 length
, u8
*values
)
2857 union i2c_smbus_data data
;
2860 if (length
> I2C_SMBUS_BLOCK_MAX
)
2861 length
= I2C_SMBUS_BLOCK_MAX
;
2862 data
.block
[0] = length
;
2863 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2864 I2C_SMBUS_READ
, command
,
2865 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2869 memcpy(values
, &data
.block
[1], data
.block
[0]);
2870 return data
.block
[0];
2872 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data
);
2874 s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2875 u8 length
, const u8
*values
)
2877 union i2c_smbus_data data
;
2879 if (length
> I2C_SMBUS_BLOCK_MAX
)
2880 length
= I2C_SMBUS_BLOCK_MAX
;
2881 data
.block
[0] = length
;
2882 memcpy(data
.block
+ 1, values
, length
);
2883 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2884 I2C_SMBUS_WRITE
, command
,
2885 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2887 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data
);
2889 /* Simulate a SMBus command using the i2c protocol
2890 No checking of parameters is done! */
2891 static s32
i2c_smbus_xfer_emulated(struct i2c_adapter
*adapter
, u16 addr
,
2892 unsigned short flags
,
2893 char read_write
, u8 command
, int size
,
2894 union i2c_smbus_data
*data
)
2896 /* So we need to generate a series of msgs. In the case of writing, we
2897 need to use only one message; when reading, we need two. We initialize
2898 most things with sane defaults, to keep the code below somewhat
2900 unsigned char msgbuf0
[I2C_SMBUS_BLOCK_MAX
+3];
2901 unsigned char msgbuf1
[I2C_SMBUS_BLOCK_MAX
+2];
2902 int num
= read_write
== I2C_SMBUS_READ
? 2 : 1;
2906 struct i2c_msg msg
[2] = {
2914 .flags
= flags
| I2C_M_RD
,
2920 msgbuf0
[0] = command
;
2922 case I2C_SMBUS_QUICK
:
2924 /* Special case: The read/write field is used as data */
2925 msg
[0].flags
= flags
| (read_write
== I2C_SMBUS_READ
?
2929 case I2C_SMBUS_BYTE
:
2930 if (read_write
== I2C_SMBUS_READ
) {
2931 /* Special case: only a read! */
2932 msg
[0].flags
= I2C_M_RD
| flags
;
2936 case I2C_SMBUS_BYTE_DATA
:
2937 if (read_write
== I2C_SMBUS_READ
)
2941 msgbuf0
[1] = data
->byte
;
2944 case I2C_SMBUS_WORD_DATA
:
2945 if (read_write
== I2C_SMBUS_READ
)
2949 msgbuf0
[1] = data
->word
& 0xff;
2950 msgbuf0
[2] = data
->word
>> 8;
2953 case I2C_SMBUS_PROC_CALL
:
2954 num
= 2; /* Special case */
2955 read_write
= I2C_SMBUS_READ
;
2958 msgbuf0
[1] = data
->word
& 0xff;
2959 msgbuf0
[2] = data
->word
>> 8;
2961 case I2C_SMBUS_BLOCK_DATA
:
2962 if (read_write
== I2C_SMBUS_READ
) {
2963 msg
[1].flags
|= I2C_M_RECV_LEN
;
2964 msg
[1].len
= 1; /* block length will be added by
2965 the underlying bus driver */
2967 msg
[0].len
= data
->block
[0] + 2;
2968 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 2) {
2969 dev_err(&adapter
->dev
,
2970 "Invalid block write size %d\n",
2974 for (i
= 1; i
< msg
[0].len
; i
++)
2975 msgbuf0
[i
] = data
->block
[i
-1];
2978 case I2C_SMBUS_BLOCK_PROC_CALL
:
2979 num
= 2; /* Another special case */
2980 read_write
= I2C_SMBUS_READ
;
2981 if (data
->block
[0] > I2C_SMBUS_BLOCK_MAX
) {
2982 dev_err(&adapter
->dev
,
2983 "Invalid block write size %d\n",
2987 msg
[0].len
= data
->block
[0] + 2;
2988 for (i
= 1; i
< msg
[0].len
; i
++)
2989 msgbuf0
[i
] = data
->block
[i
-1];
2990 msg
[1].flags
|= I2C_M_RECV_LEN
;
2991 msg
[1].len
= 1; /* block length will be added by
2992 the underlying bus driver */
2994 case I2C_SMBUS_I2C_BLOCK_DATA
:
2995 if (read_write
== I2C_SMBUS_READ
) {
2996 msg
[1].len
= data
->block
[0];
2998 msg
[0].len
= data
->block
[0] + 1;
2999 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 1) {
3000 dev_err(&adapter
->dev
,
3001 "Invalid block write size %d\n",
3005 for (i
= 1; i
<= data
->block
[0]; i
++)
3006 msgbuf0
[i
] = data
->block
[i
];
3010 dev_err(&adapter
->dev
, "Unsupported transaction %d\n", size
);
3014 i
= ((flags
& I2C_CLIENT_PEC
) && size
!= I2C_SMBUS_QUICK
3015 && size
!= I2C_SMBUS_I2C_BLOCK_DATA
);
3017 /* Compute PEC if first message is a write */
3018 if (!(msg
[0].flags
& I2C_M_RD
)) {
3019 if (num
== 1) /* Write only */
3020 i2c_smbus_add_pec(&msg
[0]);
3021 else /* Write followed by read */
3022 partial_pec
= i2c_smbus_msg_pec(0, &msg
[0]);
3024 /* Ask for PEC if last message is a read */
3025 if (msg
[num
-1].flags
& I2C_M_RD
)
3029 status
= i2c_transfer(adapter
, msg
, num
);
3033 /* Check PEC if last message is a read */
3034 if (i
&& (msg
[num
-1].flags
& I2C_M_RD
)) {
3035 status
= i2c_smbus_check_pec(partial_pec
, &msg
[num
-1]);
3040 if (read_write
== I2C_SMBUS_READ
)
3042 case I2C_SMBUS_BYTE
:
3043 data
->byte
= msgbuf0
[0];
3045 case I2C_SMBUS_BYTE_DATA
:
3046 data
->byte
= msgbuf1
[0];
3048 case I2C_SMBUS_WORD_DATA
:
3049 case I2C_SMBUS_PROC_CALL
:
3050 data
->word
= msgbuf1
[0] | (msgbuf1
[1] << 8);
3052 case I2C_SMBUS_I2C_BLOCK_DATA
:
3053 for (i
= 0; i
< data
->block
[0]; i
++)
3054 data
->block
[i
+1] = msgbuf1
[i
];
3056 case I2C_SMBUS_BLOCK_DATA
:
3057 case I2C_SMBUS_BLOCK_PROC_CALL
:
3058 for (i
= 0; i
< msgbuf1
[0] + 1; i
++)
3059 data
->block
[i
] = msgbuf1
[i
];
3066 * i2c_smbus_xfer - execute SMBus protocol operations
3067 * @adapter: Handle to I2C bus
3068 * @addr: Address of SMBus slave on that bus
3069 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
3070 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
3071 * @command: Byte interpreted by slave, for protocols which use such bytes
3072 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
3073 * @data: Data to be read or written
3075 * This executes an SMBus protocol operation, and returns a negative
3076 * errno code else zero on success.
3078 s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
, unsigned short flags
,
3079 char read_write
, u8 command
, int protocol
,
3080 union i2c_smbus_data
*data
)
3082 unsigned long orig_jiffies
;
3086 /* If enabled, the following two tracepoints are conditional on
3087 * read_write and protocol.
3089 trace_smbus_write(adapter
, addr
, flags
, read_write
,
3090 command
, protocol
, data
);
3091 trace_smbus_read(adapter
, addr
, flags
, read_write
,
3094 flags
&= I2C_M_TEN
| I2C_CLIENT_PEC
| I2C_CLIENT_SCCB
;
3096 if (adapter
->algo
->smbus_xfer
) {
3097 i2c_lock_adapter(adapter
);
3099 /* Retry automatically on arbitration loss */
3100 orig_jiffies
= jiffies
;
3101 for (res
= 0, try = 0; try <= adapter
->retries
; try++) {
3102 res
= adapter
->algo
->smbus_xfer(adapter
, addr
, flags
,
3103 read_write
, command
,
3107 if (time_after(jiffies
,
3108 orig_jiffies
+ adapter
->timeout
))
3111 i2c_unlock_adapter(adapter
);
3113 if (res
!= -EOPNOTSUPP
|| !adapter
->algo
->master_xfer
)
3116 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
3117 * implement native support for the SMBus operation.
3121 res
= i2c_smbus_xfer_emulated(adapter
, addr
, flags
, read_write
,
3122 command
, protocol
, data
);
3125 /* If enabled, the reply tracepoint is conditional on read_write. */
3126 trace_smbus_reply(adapter
, addr
, flags
, read_write
,
3127 command
, protocol
, data
);
3128 trace_smbus_result(adapter
, addr
, flags
, read_write
,
3129 command
, protocol
, res
);
3133 EXPORT_SYMBOL(i2c_smbus_xfer
);
3136 * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
3137 * @client: Handle to slave device
3138 * @command: Byte interpreted by slave
3139 * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes
3140 * @values: Byte array into which data will be read; big enough to hold
3141 * the data returned by the slave. SMBus allows at most
3142 * I2C_SMBUS_BLOCK_MAX bytes.
3144 * This executes the SMBus "block read" protocol if supported by the adapter.
3145 * If block read is not supported, it emulates it using either word or byte
3146 * read protocols depending on availability.
3148 * The addresses of the I2C slave device that are accessed with this function
3149 * must be mapped to a linear region, so that a block read will have the same
3150 * effect as a byte read. Before using this function you must double-check
3151 * if the I2C slave does support exchanging a block transfer with a byte
3154 s32
i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client
*client
,
3155 u8 command
, u8 length
, u8
*values
)
3160 if (length
> I2C_SMBUS_BLOCK_MAX
)
3161 length
= I2C_SMBUS_BLOCK_MAX
;
3163 if (i2c_check_functionality(client
->adapter
, I2C_FUNC_SMBUS_READ_I2C_BLOCK
))
3164 return i2c_smbus_read_i2c_block_data(client
, command
, length
, values
);
3166 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_SMBUS_READ_BYTE_DATA
))
3169 if (i2c_check_functionality(client
->adapter
, I2C_FUNC_SMBUS_READ_WORD_DATA
)) {
3170 while ((i
+ 2) <= length
) {
3171 status
= i2c_smbus_read_word_data(client
, command
+ i
);
3174 values
[i
] = status
& 0xff;
3175 values
[i
+ 1] = status
>> 8;
3180 while (i
< length
) {
3181 status
= i2c_smbus_read_byte_data(client
, command
+ i
);
3190 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated
);
3192 #if IS_ENABLED(CONFIG_I2C_SLAVE)
3193 int i2c_slave_register(struct i2c_client
*client
, i2c_slave_cb_t slave_cb
)
3197 if (!client
|| !slave_cb
) {
3198 WARN(1, "insufficent data\n");
3202 if (!(client
->flags
& I2C_CLIENT_SLAVE
))
3203 dev_warn(&client
->dev
, "%s: client slave flag not set. You might see address collisions\n",
3206 if (!(client
->flags
& I2C_CLIENT_TEN
)) {
3207 /* Enforce stricter address checking */
3208 ret
= i2c_check_7bit_addr_validity_strict(client
->addr
);
3210 dev_err(&client
->dev
, "%s: invalid address\n", __func__
);
3215 if (!client
->adapter
->algo
->reg_slave
) {
3216 dev_err(&client
->dev
, "%s: not supported by adapter\n", __func__
);
3220 client
->slave_cb
= slave_cb
;
3222 i2c_lock_adapter(client
->adapter
);
3223 ret
= client
->adapter
->algo
->reg_slave(client
);
3224 i2c_unlock_adapter(client
->adapter
);
3227 client
->slave_cb
= NULL
;
3228 dev_err(&client
->dev
, "%s: adapter returned error %d\n", __func__
, ret
);
3233 EXPORT_SYMBOL_GPL(i2c_slave_register
);
3235 int i2c_slave_unregister(struct i2c_client
*client
)
3239 if (!client
->adapter
->algo
->unreg_slave
) {
3240 dev_err(&client
->dev
, "%s: not supported by adapter\n", __func__
);
3244 i2c_lock_adapter(client
->adapter
);
3245 ret
= client
->adapter
->algo
->unreg_slave(client
);
3246 i2c_unlock_adapter(client
->adapter
);
3249 client
->slave_cb
= NULL
;
3251 dev_err(&client
->dev
, "%s: adapter returned error %d\n", __func__
, ret
);
3255 EXPORT_SYMBOL_GPL(i2c_slave_unregister
);
3258 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
3259 MODULE_DESCRIPTION("I2C-Bus main module");
3260 MODULE_LICENSE("GPL");