4 * Copyright (C) 1995-99 Simon G. Vogl
5 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
6 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
7 * Michael Lawnick <michael.lawnick.ext@nsn.com>
9 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
16 * This program is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
21 #define pr_fmt(fmt) "i2c-core: " fmt
23 #include <dt-bindings/i2c/i2c.h>
24 #include <linux/acpi.h>
25 #include <linux/clk/clk-conf.h>
26 #include <linux/completion.h>
27 #include <linux/delay.h>
28 #include <linux/err.h>
29 #include <linux/errno.h>
30 #include <linux/gpio.h>
31 #include <linux/i2c.h>
32 #include <linux/idr.h>
33 #include <linux/init.h>
34 #include <linux/irqflags.h>
35 #include <linux/jump_label.h>
36 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/mutex.h>
39 #include <linux/of_device.h>
41 #include <linux/of_irq.h>
42 #include <linux/pm_domain.h>
43 #include <linux/pm_runtime.h>
44 #include <linux/pm_wakeirq.h>
45 #include <linux/property.h>
46 #include <linux/rwsem.h>
47 #include <linux/slab.h>
51 #define CREATE_TRACE_POINTS
52 #include <trace/events/i2c.h>
54 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
55 #define I2C_ADDR_OFFSET_SLAVE 0x1000
57 #define I2C_ADDR_7BITS_MAX 0x77
58 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
61 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
62 * deletion of detected devices, and attach_adapter calls are serialized
64 static DEFINE_MUTEX(core_lock
);
65 static DEFINE_IDR(i2c_adapter_idr
);
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
;
70 static bool is_registered
;
72 int i2c_transfer_trace_reg(void)
74 static_key_slow_inc(&i2c_trace_msg
);
78 void i2c_transfer_trace_unreg(void)
80 static_key_slow_dec(&i2c_trace_msg
);
83 const struct i2c_device_id
*i2c_match_id(const struct i2c_device_id
*id
,
84 const struct i2c_client
*client
)
90 if (strcmp(client
->name
, id
->name
) == 0)
96 EXPORT_SYMBOL_GPL(i2c_match_id
);
98 static int i2c_device_match(struct device
*dev
, struct device_driver
*drv
)
100 struct i2c_client
*client
= i2c_verify_client(dev
);
101 struct i2c_driver
*driver
;
104 /* Attempt an OF style match */
105 if (i2c_of_match_device(drv
->of_match_table
, client
))
108 /* Then ACPI style match */
109 if (acpi_driver_match_device(dev
, drv
))
112 driver
= to_i2c_driver(drv
);
114 /* Finally an I2C match */
115 if (i2c_match_id(driver
->id_table
, client
))
121 static int i2c_device_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
123 struct i2c_client
*client
= to_i2c_client(dev
);
126 rc
= acpi_device_uevent_modalias(dev
, env
);
130 return add_uevent_var(env
, "MODALIAS=%s%s", I2C_MODULE_PREFIX
, client
->name
);
133 /* i2c bus recovery routines */
134 static int get_scl_gpio_value(struct i2c_adapter
*adap
)
136 return gpio_get_value(adap
->bus_recovery_info
->scl_gpio
);
139 static void set_scl_gpio_value(struct i2c_adapter
*adap
, int val
)
141 gpio_set_value(adap
->bus_recovery_info
->scl_gpio
, val
);
144 static int get_sda_gpio_value(struct i2c_adapter
*adap
)
146 return gpio_get_value(adap
->bus_recovery_info
->sda_gpio
);
149 static int i2c_get_gpios_for_recovery(struct i2c_adapter
*adap
)
151 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
152 struct device
*dev
= &adap
->dev
;
155 ret
= gpio_request_one(bri
->scl_gpio
, GPIOF_OPEN_DRAIN
|
156 GPIOF_OUT_INIT_HIGH
, "i2c-scl");
158 dev_warn(dev
, "Can't get SCL gpio: %d\n", bri
->scl_gpio
);
163 if (gpio_request_one(bri
->sda_gpio
, GPIOF_IN
, "i2c-sda")) {
164 /* work without SDA polling */
165 dev_warn(dev
, "Can't get SDA gpio: %d. Not using SDA polling\n",
174 static void i2c_put_gpios_for_recovery(struct i2c_adapter
*adap
)
176 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
179 gpio_free(bri
->sda_gpio
);
181 gpio_free(bri
->scl_gpio
);
185 * We are generating clock pulses. ndelay() determines durating of clk pulses.
186 * We will generate clock with rate 100 KHz and so duration of both clock levels
187 * is: delay in ns = (10^6 / 100) / 2
189 #define RECOVERY_NDELAY 5000
190 #define RECOVERY_CLK_CNT 9
192 static int i2c_generic_recovery(struct i2c_adapter
*adap
)
194 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
195 int i
= 0, val
= 1, ret
= 0;
197 if (bri
->prepare_recovery
)
198 bri
->prepare_recovery(adap
);
200 bri
->set_scl(adap
, val
);
201 ndelay(RECOVERY_NDELAY
);
204 * By this time SCL is high, as we need to give 9 falling-rising edges
206 while (i
++ < RECOVERY_CLK_CNT
* 2) {
208 /* Break if SDA is high */
209 if (bri
->get_sda
&& bri
->get_sda(adap
))
211 /* SCL shouldn't be low here */
212 if (!bri
->get_scl(adap
)) {
214 "SCL is stuck low, exit recovery\n");
221 bri
->set_scl(adap
, val
);
222 ndelay(RECOVERY_NDELAY
);
225 if (bri
->unprepare_recovery
)
226 bri
->unprepare_recovery(adap
);
231 int i2c_generic_scl_recovery(struct i2c_adapter
*adap
)
233 return i2c_generic_recovery(adap
);
235 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery
);
237 int i2c_generic_gpio_recovery(struct i2c_adapter
*adap
)
241 ret
= i2c_get_gpios_for_recovery(adap
);
245 ret
= i2c_generic_recovery(adap
);
246 i2c_put_gpios_for_recovery(adap
);
250 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery
);
252 int i2c_recover_bus(struct i2c_adapter
*adap
)
254 if (!adap
->bus_recovery_info
)
257 dev_dbg(&adap
->dev
, "Trying i2c bus recovery\n");
258 return adap
->bus_recovery_info
->recover_bus(adap
);
260 EXPORT_SYMBOL_GPL(i2c_recover_bus
);
262 static void i2c_init_recovery(struct i2c_adapter
*adap
)
264 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
270 if (!bri
->recover_bus
) {
271 err_str
= "no recover_bus() found";
275 /* Generic GPIO recovery */
276 if (bri
->recover_bus
== i2c_generic_gpio_recovery
) {
277 if (!gpio_is_valid(bri
->scl_gpio
)) {
278 err_str
= "invalid SCL gpio";
282 if (gpio_is_valid(bri
->sda_gpio
))
283 bri
->get_sda
= get_sda_gpio_value
;
287 bri
->get_scl
= get_scl_gpio_value
;
288 bri
->set_scl
= set_scl_gpio_value
;
289 } else if (bri
->recover_bus
== i2c_generic_scl_recovery
) {
290 /* Generic SCL recovery */
291 if (!bri
->set_scl
|| !bri
->get_scl
) {
292 err_str
= "no {get|set}_scl() found";
299 dev_err(&adap
->dev
, "Not using recovery: %s\n", err_str
);
300 adap
->bus_recovery_info
= NULL
;
303 static int i2c_smbus_host_notify_to_irq(const struct i2c_client
*client
)
305 struct i2c_adapter
*adap
= client
->adapter
;
308 if (!adap
->host_notify_domain
)
311 if (client
->flags
& I2C_CLIENT_TEN
)
314 irq
= irq_find_mapping(adap
->host_notify_domain
, client
->addr
);
316 irq
= irq_create_mapping(adap
->host_notify_domain
,
319 return irq
> 0 ? irq
: -ENXIO
;
322 static int i2c_device_probe(struct device
*dev
)
324 struct i2c_client
*client
= i2c_verify_client(dev
);
325 struct i2c_driver
*driver
;
331 driver
= to_i2c_driver(dev
->driver
);
333 if (!client
->irq
&& !driver
->disable_i2c_core_irq_mapping
) {
336 if (client
->flags
& I2C_CLIENT_HOST_NOTIFY
) {
337 dev_dbg(dev
, "Using Host Notify IRQ\n");
338 irq
= i2c_smbus_host_notify_to_irq(client
);
339 } else if (dev
->of_node
) {
340 irq
= of_irq_get_byname(dev
->of_node
, "irq");
341 if (irq
== -EINVAL
|| irq
== -ENODATA
)
342 irq
= of_irq_get(dev
->of_node
, 0);
343 } else if (ACPI_COMPANION(dev
)) {
344 irq
= acpi_dev_gpio_irq_get(ACPI_COMPANION(dev
), 0);
346 if (irq
== -EPROBE_DEFER
)
356 * An I2C ID table is not mandatory, if and only if, a suitable OF
357 * or ACPI ID table is supplied for the probing device.
359 if (!driver
->id_table
&&
360 !i2c_acpi_match_device(dev
->driver
->acpi_match_table
, client
) &&
361 !i2c_of_match_device(dev
->driver
->of_match_table
, client
))
364 if (client
->flags
& I2C_CLIENT_WAKE
) {
365 int wakeirq
= -ENOENT
;
368 wakeirq
= of_irq_get_byname(dev
->of_node
, "wakeup");
369 if (wakeirq
== -EPROBE_DEFER
)
373 device_init_wakeup(&client
->dev
, true);
375 if (wakeirq
> 0 && wakeirq
!= client
->irq
)
376 status
= dev_pm_set_dedicated_wake_irq(dev
, wakeirq
);
377 else if (client
->irq
> 0)
378 status
= dev_pm_set_wake_irq(dev
, client
->irq
);
383 dev_warn(&client
->dev
, "failed to set up wakeup irq\n");
386 dev_dbg(dev
, "probe\n");
388 status
= of_clk_set_defaults(dev
->of_node
, false);
390 goto err_clear_wakeup_irq
;
392 status
= dev_pm_domain_attach(&client
->dev
, true);
393 if (status
== -EPROBE_DEFER
)
394 goto err_clear_wakeup_irq
;
397 * When there are no more users of probe(),
398 * rename probe_new to probe.
400 if (driver
->probe_new
)
401 status
= driver
->probe_new(client
);
402 else if (driver
->probe
)
403 status
= driver
->probe(client
,
404 i2c_match_id(driver
->id_table
, client
));
409 goto err_detach_pm_domain
;
413 err_detach_pm_domain
:
414 dev_pm_domain_detach(&client
->dev
, true);
415 err_clear_wakeup_irq
:
416 dev_pm_clear_wake_irq(&client
->dev
);
417 device_init_wakeup(&client
->dev
, false);
421 static int i2c_device_remove(struct device
*dev
)
423 struct i2c_client
*client
= i2c_verify_client(dev
);
424 struct i2c_driver
*driver
;
427 if (!client
|| !dev
->driver
)
430 driver
= to_i2c_driver(dev
->driver
);
431 if (driver
->remove
) {
432 dev_dbg(dev
, "remove\n");
433 status
= driver
->remove(client
);
436 dev_pm_domain_detach(&client
->dev
, true);
438 dev_pm_clear_wake_irq(&client
->dev
);
439 device_init_wakeup(&client
->dev
, false);
444 static void i2c_device_shutdown(struct device
*dev
)
446 struct i2c_client
*client
= i2c_verify_client(dev
);
447 struct i2c_driver
*driver
;
449 if (!client
|| !dev
->driver
)
451 driver
= to_i2c_driver(dev
->driver
);
452 if (driver
->shutdown
)
453 driver
->shutdown(client
);
456 static void i2c_client_dev_release(struct device
*dev
)
458 kfree(to_i2c_client(dev
));
462 show_name(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
464 return sprintf(buf
, "%s\n", dev
->type
== &i2c_client_type
?
465 to_i2c_client(dev
)->name
: to_i2c_adapter(dev
)->name
);
467 static DEVICE_ATTR(name
, S_IRUGO
, show_name
, NULL
);
470 show_modalias(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
472 struct i2c_client
*client
= to_i2c_client(dev
);
475 len
= acpi_device_modalias(dev
, buf
, PAGE_SIZE
-1);
479 return sprintf(buf
, "%s%s\n", I2C_MODULE_PREFIX
, client
->name
);
481 static DEVICE_ATTR(modalias
, S_IRUGO
, show_modalias
, NULL
);
483 static struct attribute
*i2c_dev_attrs
[] = {
485 /* modalias helps coldplug: modprobe $(cat .../modalias) */
486 &dev_attr_modalias
.attr
,
489 ATTRIBUTE_GROUPS(i2c_dev
);
491 struct bus_type i2c_bus_type
= {
493 .match
= i2c_device_match
,
494 .probe
= i2c_device_probe
,
495 .remove
= i2c_device_remove
,
496 .shutdown
= i2c_device_shutdown
,
498 EXPORT_SYMBOL_GPL(i2c_bus_type
);
500 struct device_type i2c_client_type
= {
501 .groups
= i2c_dev_groups
,
502 .uevent
= i2c_device_uevent
,
503 .release
= i2c_client_dev_release
,
505 EXPORT_SYMBOL_GPL(i2c_client_type
);
509 * i2c_verify_client - return parameter as i2c_client, or NULL
510 * @dev: device, probably from some driver model iterator
512 * When traversing the driver model tree, perhaps using driver model
513 * iterators like @device_for_each_child(), you can't assume very much
514 * about the nodes you find. Use this function to avoid oopses caused
515 * by wrongly treating some non-I2C device as an i2c_client.
517 struct i2c_client
*i2c_verify_client(struct device
*dev
)
519 return (dev
->type
== &i2c_client_type
)
523 EXPORT_SYMBOL(i2c_verify_client
);
526 /* Return a unique address which takes the flags of the client into account */
527 static unsigned short i2c_encode_flags_to_addr(struct i2c_client
*client
)
529 unsigned short addr
= client
->addr
;
531 /* For some client flags, add an arbitrary offset to avoid collisions */
532 if (client
->flags
& I2C_CLIENT_TEN
)
533 addr
|= I2C_ADDR_OFFSET_TEN_BIT
;
535 if (client
->flags
& I2C_CLIENT_SLAVE
)
536 addr
|= I2C_ADDR_OFFSET_SLAVE
;
541 /* This is a permissive address validity check, I2C address map constraints
542 * are purposely not enforced, except for the general call address. */
543 int i2c_check_addr_validity(unsigned addr
, unsigned short flags
)
545 if (flags
& I2C_CLIENT_TEN
) {
546 /* 10-bit address, all values are valid */
550 /* 7-bit address, reject the general call address */
551 if (addr
== 0x00 || addr
> 0x7f)
557 /* And this is a strict address validity check, used when probing. If a
558 * device uses a reserved address, then it shouldn't be probed. 7-bit
559 * addressing is assumed, 10-bit address devices are rare and should be
560 * explicitly enumerated. */
561 int i2c_check_7bit_addr_validity_strict(unsigned short addr
)
564 * Reserved addresses per I2C specification:
565 * 0x00 General call address / START byte
567 * 0x02 Reserved for different bus format
568 * 0x03 Reserved for future purposes
569 * 0x04-0x07 Hs-mode master code
570 * 0x78-0x7b 10-bit slave addressing
571 * 0x7c-0x7f Reserved for future purposes
573 if (addr
< 0x08 || addr
> 0x77)
578 static int __i2c_check_addr_busy(struct device
*dev
, void *addrp
)
580 struct i2c_client
*client
= i2c_verify_client(dev
);
581 int addr
= *(int *)addrp
;
583 if (client
&& i2c_encode_flags_to_addr(client
) == addr
)
588 /* walk up mux tree */
589 static int i2c_check_mux_parents(struct i2c_adapter
*adapter
, int addr
)
591 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
594 result
= device_for_each_child(&adapter
->dev
, &addr
,
595 __i2c_check_addr_busy
);
597 if (!result
&& parent
)
598 result
= i2c_check_mux_parents(parent
, addr
);
603 /* recurse down mux tree */
604 static int i2c_check_mux_children(struct device
*dev
, void *addrp
)
608 if (dev
->type
== &i2c_adapter_type
)
609 result
= device_for_each_child(dev
, addrp
,
610 i2c_check_mux_children
);
612 result
= __i2c_check_addr_busy(dev
, addrp
);
617 static int i2c_check_addr_busy(struct i2c_adapter
*adapter
, int addr
)
619 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
623 result
= i2c_check_mux_parents(parent
, addr
);
626 result
= device_for_each_child(&adapter
->dev
, &addr
,
627 i2c_check_mux_children
);
633 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
634 * @adapter: Target I2C bus segment
635 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
636 * locks only this branch in the adapter tree
638 static void i2c_adapter_lock_bus(struct i2c_adapter
*adapter
,
641 rt_mutex_lock(&adapter
->bus_lock
);
645 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
646 * @adapter: Target I2C bus segment
647 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
648 * trylocks only this branch in the adapter tree
650 static int i2c_adapter_trylock_bus(struct i2c_adapter
*adapter
,
653 return rt_mutex_trylock(&adapter
->bus_lock
);
657 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
658 * @adapter: Target I2C bus segment
659 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
660 * unlocks only this branch in the adapter tree
662 static void i2c_adapter_unlock_bus(struct i2c_adapter
*adapter
,
665 rt_mutex_unlock(&adapter
->bus_lock
);
668 static void i2c_dev_set_name(struct i2c_adapter
*adap
,
669 struct i2c_client
*client
)
671 struct acpi_device
*adev
= ACPI_COMPANION(&client
->dev
);
674 dev_set_name(&client
->dev
, "i2c-%s", acpi_dev_name(adev
));
678 dev_set_name(&client
->dev
, "%d-%04x", i2c_adapter_id(adap
),
679 i2c_encode_flags_to_addr(client
));
682 static int i2c_dev_irq_from_resources(const struct resource
*resources
,
683 unsigned int num_resources
)
685 struct irq_data
*irqd
;
688 for (i
= 0; i
< num_resources
; i
++) {
689 const struct resource
*r
= &resources
[i
];
691 if (resource_type(r
) != IORESOURCE_IRQ
)
694 if (r
->flags
& IORESOURCE_BITS
) {
695 irqd
= irq_get_irq_data(r
->start
);
699 irqd_set_trigger_type(irqd
, r
->flags
& IORESOURCE_BITS
);
709 * i2c_new_device - instantiate an i2c device
710 * @adap: the adapter managing the device
711 * @info: describes one I2C device; bus_num is ignored
714 * Create an i2c device. Binding is handled through driver model
715 * probe()/remove() methods. A driver may be bound to this device when we
716 * return from this function, or any later moment (e.g. maybe hotplugging will
717 * load the driver module). This call is not appropriate for use by mainboard
718 * initialization logic, which usually runs during an arch_initcall() long
719 * before any i2c_adapter could exist.
721 * This returns the new i2c client, which may be saved for later use with
722 * i2c_unregister_device(); or NULL to indicate an error.
725 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
)
727 struct i2c_client
*client
;
730 client
= kzalloc(sizeof *client
, GFP_KERNEL
);
734 client
->adapter
= adap
;
736 client
->dev
.platform_data
= info
->platform_data
;
739 client
->dev
.archdata
= *info
->archdata
;
741 client
->flags
= info
->flags
;
742 client
->addr
= info
->addr
;
744 client
->irq
= info
->irq
;
746 client
->irq
= i2c_dev_irq_from_resources(info
->resources
,
747 info
->num_resources
);
749 strlcpy(client
->name
, info
->type
, sizeof(client
->name
));
751 status
= i2c_check_addr_validity(client
->addr
, client
->flags
);
753 dev_err(&adap
->dev
, "Invalid %d-bit I2C address 0x%02hx\n",
754 client
->flags
& I2C_CLIENT_TEN
? 10 : 7, client
->addr
);
758 /* Check for address business */
759 status
= i2c_check_addr_busy(adap
, i2c_encode_flags_to_addr(client
));
763 client
->dev
.parent
= &client
->adapter
->dev
;
764 client
->dev
.bus
= &i2c_bus_type
;
765 client
->dev
.type
= &i2c_client_type
;
766 client
->dev
.of_node
= info
->of_node
;
767 client
->dev
.fwnode
= info
->fwnode
;
769 i2c_dev_set_name(adap
, client
);
771 if (info
->properties
) {
772 status
= device_add_properties(&client
->dev
, info
->properties
);
775 "Failed to add properties to client %s: %d\n",
776 client
->name
, status
);
781 status
= device_register(&client
->dev
);
785 dev_dbg(&adap
->dev
, "client [%s] registered with bus id %s\n",
786 client
->name
, dev_name(&client
->dev
));
791 if (info
->properties
)
792 device_remove_properties(&client
->dev
);
795 "Failed to register i2c client %s at 0x%02x (%d)\n",
796 client
->name
, client
->addr
, status
);
801 EXPORT_SYMBOL_GPL(i2c_new_device
);
805 * i2c_unregister_device - reverse effect of i2c_new_device()
806 * @client: value returned from i2c_new_device()
809 void i2c_unregister_device(struct i2c_client
*client
)
811 if (client
->dev
.of_node
)
812 of_node_clear_flag(client
->dev
.of_node
, OF_POPULATED
);
813 if (ACPI_COMPANION(&client
->dev
))
814 acpi_device_clear_enumerated(ACPI_COMPANION(&client
->dev
));
815 device_unregister(&client
->dev
);
817 EXPORT_SYMBOL_GPL(i2c_unregister_device
);
820 static const struct i2c_device_id dummy_id
[] = {
825 static int dummy_probe(struct i2c_client
*client
,
826 const struct i2c_device_id
*id
)
831 static int dummy_remove(struct i2c_client
*client
)
836 static struct i2c_driver dummy_driver
= {
837 .driver
.name
= "dummy",
838 .probe
= dummy_probe
,
839 .remove
= dummy_remove
,
840 .id_table
= dummy_id
,
844 * i2c_new_dummy - return a new i2c device bound to a dummy driver
845 * @adapter: the adapter managing the device
846 * @address: seven bit address to be used
849 * This returns an I2C client bound to the "dummy" driver, intended for use
850 * with devices that consume multiple addresses. Examples of such chips
851 * include various EEPROMS (like 24c04 and 24c08 models).
853 * These dummy devices have two main uses. First, most I2C and SMBus calls
854 * except i2c_transfer() need a client handle; the dummy will be that handle.
855 * And second, this prevents the specified address from being bound to a
858 * This returns the new i2c client, which should be saved for later use with
859 * i2c_unregister_device(); or NULL to indicate an error.
861 struct i2c_client
*i2c_new_dummy(struct i2c_adapter
*adapter
, u16 address
)
863 struct i2c_board_info info
= {
864 I2C_BOARD_INFO("dummy", address
),
867 return i2c_new_device(adapter
, &info
);
869 EXPORT_SYMBOL_GPL(i2c_new_dummy
);
872 * i2c_new_secondary_device - Helper to get the instantiated secondary address
873 * and create the associated device
874 * @client: Handle to the primary client
875 * @name: Handle to specify which secondary address to get
876 * @default_addr: Used as a fallback if no secondary address was specified
879 * I2C clients can be composed of multiple I2C slaves bound together in a single
880 * component. The I2C client driver then binds to the master I2C slave and needs
881 * to create I2C dummy clients to communicate with all the other slaves.
883 * This function creates and returns an I2C dummy client whose I2C address is
884 * retrieved from the platform firmware based on the given slave name. If no
885 * address is specified by the firmware default_addr is used.
887 * On DT-based platforms the address is retrieved from the "reg" property entry
888 * cell whose "reg-names" value matches the slave name.
890 * This returns the new i2c client, which should be saved for later use with
891 * i2c_unregister_device(); or NULL to indicate an error.
893 struct i2c_client
*i2c_new_secondary_device(struct i2c_client
*client
,
897 struct device_node
*np
= client
->dev
.of_node
;
898 u32 addr
= default_addr
;
902 i
= of_property_match_string(np
, "reg-names", name
);
904 of_property_read_u32_index(np
, "reg", i
, &addr
);
907 dev_dbg(&client
->adapter
->dev
, "Address for %s : 0x%x\n", name
, addr
);
908 return i2c_new_dummy(client
->adapter
, addr
);
910 EXPORT_SYMBOL_GPL(i2c_new_secondary_device
);
912 /* ------------------------------------------------------------------------- */
914 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
916 static void i2c_adapter_dev_release(struct device
*dev
)
918 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
919 complete(&adap
->dev_released
);
922 unsigned int i2c_adapter_depth(struct i2c_adapter
*adapter
)
924 unsigned int depth
= 0;
926 while ((adapter
= i2c_parent_is_i2c_adapter(adapter
)))
929 WARN_ONCE(depth
>= MAX_LOCKDEP_SUBCLASSES
,
930 "adapter depth exceeds lockdep subclass limit\n");
934 EXPORT_SYMBOL_GPL(i2c_adapter_depth
);
937 * Let users instantiate I2C devices through sysfs. This can be used when
938 * platform initialization code doesn't contain the proper data for
939 * whatever reason. Also useful for drivers that do device detection and
940 * detection fails, either because the device uses an unexpected address,
941 * or this is a compatible device with different ID register values.
943 * Parameter checking may look overzealous, but we really don't want
944 * the user to provide incorrect parameters.
947 i2c_sysfs_new_device(struct device
*dev
, struct device_attribute
*attr
,
948 const char *buf
, size_t count
)
950 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
951 struct i2c_board_info info
;
952 struct i2c_client
*client
;
956 memset(&info
, 0, sizeof(struct i2c_board_info
));
958 blank
= strchr(buf
, ' ');
960 dev_err(dev
, "%s: Missing parameters\n", "new_device");
963 if (blank
- buf
> I2C_NAME_SIZE
- 1) {
964 dev_err(dev
, "%s: Invalid device name\n", "new_device");
967 memcpy(info
.type
, buf
, blank
- buf
);
969 /* Parse remaining parameters, reject extra parameters */
970 res
= sscanf(++blank
, "%hi%c", &info
.addr
, &end
);
972 dev_err(dev
, "%s: Can't parse I2C address\n", "new_device");
975 if (res
> 1 && end
!= '\n') {
976 dev_err(dev
, "%s: Extra parameters\n", "new_device");
980 if ((info
.addr
& I2C_ADDR_OFFSET_TEN_BIT
) == I2C_ADDR_OFFSET_TEN_BIT
) {
981 info
.addr
&= ~I2C_ADDR_OFFSET_TEN_BIT
;
982 info
.flags
|= I2C_CLIENT_TEN
;
985 if (info
.addr
& I2C_ADDR_OFFSET_SLAVE
) {
986 info
.addr
&= ~I2C_ADDR_OFFSET_SLAVE
;
987 info
.flags
|= I2C_CLIENT_SLAVE
;
990 client
= i2c_new_device(adap
, &info
);
994 /* Keep track of the added device */
995 mutex_lock(&adap
->userspace_clients_lock
);
996 list_add_tail(&client
->detected
, &adap
->userspace_clients
);
997 mutex_unlock(&adap
->userspace_clients_lock
);
998 dev_info(dev
, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
999 info
.type
, info
.addr
);
1003 static DEVICE_ATTR(new_device
, S_IWUSR
, NULL
, i2c_sysfs_new_device
);
1006 * And of course let the users delete the devices they instantiated, if
1007 * they got it wrong. This interface can only be used to delete devices
1008 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1009 * don't delete devices to which some kernel code still has references.
1011 * Parameter checking may look overzealous, but we really don't want
1012 * the user to delete the wrong device.
1015 i2c_sysfs_delete_device(struct device
*dev
, struct device_attribute
*attr
,
1016 const char *buf
, size_t count
)
1018 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1019 struct i2c_client
*client
, *next
;
1020 unsigned short addr
;
1024 /* Parse parameters, reject extra parameters */
1025 res
= sscanf(buf
, "%hi%c", &addr
, &end
);
1027 dev_err(dev
, "%s: Can't parse I2C address\n", "delete_device");
1030 if (res
> 1 && end
!= '\n') {
1031 dev_err(dev
, "%s: Extra parameters\n", "delete_device");
1035 /* Make sure the device was added through sysfs */
1037 mutex_lock_nested(&adap
->userspace_clients_lock
,
1038 i2c_adapter_depth(adap
));
1039 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1041 if (i2c_encode_flags_to_addr(client
) == addr
) {
1042 dev_info(dev
, "%s: Deleting device %s at 0x%02hx\n",
1043 "delete_device", client
->name
, client
->addr
);
1045 list_del(&client
->detected
);
1046 i2c_unregister_device(client
);
1051 mutex_unlock(&adap
->userspace_clients_lock
);
1054 dev_err(dev
, "%s: Can't find device in list\n",
1058 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device
, S_IWUSR
, NULL
,
1059 i2c_sysfs_delete_device
);
1061 static struct attribute
*i2c_adapter_attrs
[] = {
1062 &dev_attr_name
.attr
,
1063 &dev_attr_new_device
.attr
,
1064 &dev_attr_delete_device
.attr
,
1067 ATTRIBUTE_GROUPS(i2c_adapter
);
1069 struct device_type i2c_adapter_type
= {
1070 .groups
= i2c_adapter_groups
,
1071 .release
= i2c_adapter_dev_release
,
1073 EXPORT_SYMBOL_GPL(i2c_adapter_type
);
1076 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1077 * @dev: device, probably from some driver model iterator
1079 * When traversing the driver model tree, perhaps using driver model
1080 * iterators like @device_for_each_child(), you can't assume very much
1081 * about the nodes you find. Use this function to avoid oopses caused
1082 * by wrongly treating some non-I2C device as an i2c_adapter.
1084 struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
)
1086 return (dev
->type
== &i2c_adapter_type
)
1087 ? to_i2c_adapter(dev
)
1090 EXPORT_SYMBOL(i2c_verify_adapter
);
1092 #ifdef CONFIG_I2C_COMPAT
1093 static struct class_compat
*i2c_adapter_compat_class
;
1096 static void i2c_scan_static_board_info(struct i2c_adapter
*adapter
)
1098 struct i2c_devinfo
*devinfo
;
1100 down_read(&__i2c_board_lock
);
1101 list_for_each_entry(devinfo
, &__i2c_board_list
, list
) {
1102 if (devinfo
->busnum
== adapter
->nr
1103 && !i2c_new_device(adapter
,
1104 &devinfo
->board_info
))
1105 dev_err(&adapter
->dev
,
1106 "Can't create device at 0x%02x\n",
1107 devinfo
->board_info
.addr
);
1109 up_read(&__i2c_board_lock
);
1112 static int i2c_do_add_adapter(struct i2c_driver
*driver
,
1113 struct i2c_adapter
*adap
)
1115 /* Detect supported devices on that bus, and instantiate them */
1116 i2c_detect(adap
, driver
);
1118 /* Let legacy drivers scan this bus for matching devices */
1119 if (driver
->attach_adapter
) {
1120 dev_warn(&adap
->dev
, "%s: attach_adapter method is deprecated\n",
1121 driver
->driver
.name
);
1122 dev_warn(&adap
->dev
,
1123 "Please use another way to instantiate your i2c_client\n");
1124 /* We ignore the return code; if it fails, too bad */
1125 driver
->attach_adapter(adap
);
1130 static int __process_new_adapter(struct device_driver
*d
, void *data
)
1132 return i2c_do_add_adapter(to_i2c_driver(d
), data
);
1135 static const struct i2c_lock_operations i2c_adapter_lock_ops
= {
1136 .lock_bus
= i2c_adapter_lock_bus
,
1137 .trylock_bus
= i2c_adapter_trylock_bus
,
1138 .unlock_bus
= i2c_adapter_unlock_bus
,
1141 static void i2c_host_notify_irq_teardown(struct i2c_adapter
*adap
)
1143 struct irq_domain
*domain
= adap
->host_notify_domain
;
1144 irq_hw_number_t hwirq
;
1149 for (hwirq
= 0 ; hwirq
< I2C_ADDR_7BITS_COUNT
; hwirq
++)
1150 irq_dispose_mapping(irq_find_mapping(domain
, hwirq
));
1152 irq_domain_remove(domain
);
1153 adap
->host_notify_domain
= NULL
;
1156 static int i2c_host_notify_irq_map(struct irq_domain
*h
,
1158 irq_hw_number_t hw_irq_num
)
1160 irq_set_chip_and_handler(virq
, &dummy_irq_chip
, handle_simple_irq
);
1165 static const struct irq_domain_ops i2c_host_notify_irq_ops
= {
1166 .map
= i2c_host_notify_irq_map
,
1169 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter
*adap
)
1171 struct irq_domain
*domain
;
1173 if (!i2c_check_functionality(adap
, I2C_FUNC_SMBUS_HOST_NOTIFY
))
1176 domain
= irq_domain_create_linear(adap
->dev
.fwnode
,
1177 I2C_ADDR_7BITS_COUNT
,
1178 &i2c_host_notify_irq_ops
, adap
);
1182 adap
->host_notify_domain
= domain
;
1188 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1190 * @adap: the adapter
1191 * @addr: the I2C address of the notifying device
1192 * Context: can't sleep
1194 * Helper function to be called from an I2C bus driver's interrupt
1195 * handler. It will schedule the Host Notify IRQ.
1197 int i2c_handle_smbus_host_notify(struct i2c_adapter
*adap
, unsigned short addr
)
1204 irq
= irq_find_mapping(adap
->host_notify_domain
, addr
);
1208 generic_handle_irq(irq
);
1212 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify
);
1214 static int i2c_register_adapter(struct i2c_adapter
*adap
)
1218 /* Can't register until after driver model init */
1219 if (WARN_ON(!is_registered
)) {
1225 if (WARN(!adap
->name
[0], "i2c adapter has no name"))
1229 pr_err("adapter '%s': no algo supplied!\n", adap
->name
);
1233 if (!adap
->lock_ops
)
1234 adap
->lock_ops
= &i2c_adapter_lock_ops
;
1236 rt_mutex_init(&adap
->bus_lock
);
1237 rt_mutex_init(&adap
->mux_lock
);
1238 mutex_init(&adap
->userspace_clients_lock
);
1239 INIT_LIST_HEAD(&adap
->userspace_clients
);
1241 /* Set default timeout to 1 second if not already set */
1242 if (adap
->timeout
== 0)
1245 /* register soft irqs for Host Notify */
1246 res
= i2c_setup_host_notify_irq_domain(adap
);
1248 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1253 dev_set_name(&adap
->dev
, "i2c-%d", adap
->nr
);
1254 adap
->dev
.bus
= &i2c_bus_type
;
1255 adap
->dev
.type
= &i2c_adapter_type
;
1256 res
= device_register(&adap
->dev
);
1258 pr_err("adapter '%s': can't register device (%d)\n", adap
->name
, res
);
1262 dev_dbg(&adap
->dev
, "adapter [%s] registered\n", adap
->name
);
1264 pm_runtime_no_callbacks(&adap
->dev
);
1265 pm_suspend_ignore_children(&adap
->dev
, true);
1266 pm_runtime_enable(&adap
->dev
);
1268 #ifdef CONFIG_I2C_COMPAT
1269 res
= class_compat_create_link(i2c_adapter_compat_class
, &adap
->dev
,
1272 dev_warn(&adap
->dev
,
1273 "Failed to create compatibility class link\n");
1276 i2c_init_recovery(adap
);
1278 /* create pre-declared device nodes */
1279 of_i2c_register_devices(adap
);
1280 i2c_acpi_register_devices(adap
);
1281 i2c_acpi_install_space_handler(adap
);
1283 if (adap
->nr
< __i2c_first_dynamic_bus_num
)
1284 i2c_scan_static_board_info(adap
);
1286 /* Notify drivers */
1287 mutex_lock(&core_lock
);
1288 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
, __process_new_adapter
);
1289 mutex_unlock(&core_lock
);
1294 mutex_lock(&core_lock
);
1295 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1296 mutex_unlock(&core_lock
);
1301 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1302 * @adap: the adapter to register (with adap->nr initialized)
1303 * Context: can sleep
1305 * See i2c_add_numbered_adapter() for details.
1307 static int __i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1311 mutex_lock(&core_lock
);
1312 id
= idr_alloc(&i2c_adapter_idr
, adap
, adap
->nr
, adap
->nr
+ 1, GFP_KERNEL
);
1313 mutex_unlock(&core_lock
);
1314 if (WARN(id
< 0, "couldn't get idr"))
1315 return id
== -ENOSPC
? -EBUSY
: id
;
1317 return i2c_register_adapter(adap
);
1321 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1322 * @adapter: the adapter to add
1323 * Context: can sleep
1325 * This routine is used to declare an I2C adapter when its bus number
1326 * doesn't matter or when its bus number is specified by an dt alias.
1327 * Examples of bases when the bus number doesn't matter: I2C adapters
1328 * dynamically added by USB links or PCI plugin cards.
1330 * When this returns zero, a new bus number was allocated and stored
1331 * in adap->nr, and the specified adapter became available for clients.
1332 * Otherwise, a negative errno value is returned.
1334 int i2c_add_adapter(struct i2c_adapter
*adapter
)
1336 struct device
*dev
= &adapter
->dev
;
1340 id
= of_alias_get_id(dev
->of_node
, "i2c");
1343 return __i2c_add_numbered_adapter(adapter
);
1347 mutex_lock(&core_lock
);
1348 id
= idr_alloc(&i2c_adapter_idr
, adapter
,
1349 __i2c_first_dynamic_bus_num
, 0, GFP_KERNEL
);
1350 mutex_unlock(&core_lock
);
1351 if (WARN(id
< 0, "couldn't get idr"))
1356 return i2c_register_adapter(adapter
);
1358 EXPORT_SYMBOL(i2c_add_adapter
);
1361 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1362 * @adap: the adapter to register (with adap->nr initialized)
1363 * Context: can sleep
1365 * This routine is used to declare an I2C adapter when its bus number
1366 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1367 * or otherwise built in to the system's mainboard, and where i2c_board_info
1368 * is used to properly configure I2C devices.
1370 * If the requested bus number is set to -1, then this function will behave
1371 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1373 * If no devices have pre-been declared for this bus, then be sure to
1374 * register the adapter before any dynamically allocated ones. Otherwise
1375 * the required bus ID may not be available.
1377 * When this returns zero, the specified adapter became available for
1378 * clients using the bus number provided in adap->nr. Also, the table
1379 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1380 * and the appropriate driver model device nodes are created. Otherwise, a
1381 * negative errno value is returned.
1383 int i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1385 if (adap
->nr
== -1) /* -1 means dynamically assign bus id */
1386 return i2c_add_adapter(adap
);
1388 return __i2c_add_numbered_adapter(adap
);
1390 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter
);
1392 static void i2c_do_del_adapter(struct i2c_driver
*driver
,
1393 struct i2c_adapter
*adapter
)
1395 struct i2c_client
*client
, *_n
;
1397 /* Remove the devices we created ourselves as the result of hardware
1398 * probing (using a driver's detect method) */
1399 list_for_each_entry_safe(client
, _n
, &driver
->clients
, detected
) {
1400 if (client
->adapter
== adapter
) {
1401 dev_dbg(&adapter
->dev
, "Removing %s at 0x%x\n",
1402 client
->name
, client
->addr
);
1403 list_del(&client
->detected
);
1404 i2c_unregister_device(client
);
1409 static int __unregister_client(struct device
*dev
, void *dummy
)
1411 struct i2c_client
*client
= i2c_verify_client(dev
);
1412 if (client
&& strcmp(client
->name
, "dummy"))
1413 i2c_unregister_device(client
);
1417 static int __unregister_dummy(struct device
*dev
, void *dummy
)
1419 struct i2c_client
*client
= i2c_verify_client(dev
);
1421 i2c_unregister_device(client
);
1425 static int __process_removed_adapter(struct device_driver
*d
, void *data
)
1427 i2c_do_del_adapter(to_i2c_driver(d
), data
);
1432 * i2c_del_adapter - unregister I2C adapter
1433 * @adap: the adapter being unregistered
1434 * Context: can sleep
1436 * This unregisters an I2C adapter which was previously registered
1437 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1439 void i2c_del_adapter(struct i2c_adapter
*adap
)
1441 struct i2c_adapter
*found
;
1442 struct i2c_client
*client
, *next
;
1444 /* First make sure that this adapter was ever added */
1445 mutex_lock(&core_lock
);
1446 found
= idr_find(&i2c_adapter_idr
, adap
->nr
);
1447 mutex_unlock(&core_lock
);
1448 if (found
!= adap
) {
1449 pr_debug("attempting to delete unregistered adapter [%s]\n", adap
->name
);
1453 i2c_acpi_remove_space_handler(adap
);
1454 /* Tell drivers about this removal */
1455 mutex_lock(&core_lock
);
1456 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
1457 __process_removed_adapter
);
1458 mutex_unlock(&core_lock
);
1460 /* Remove devices instantiated from sysfs */
1461 mutex_lock_nested(&adap
->userspace_clients_lock
,
1462 i2c_adapter_depth(adap
));
1463 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1465 dev_dbg(&adap
->dev
, "Removing %s at 0x%x\n", client
->name
,
1467 list_del(&client
->detected
);
1468 i2c_unregister_device(client
);
1470 mutex_unlock(&adap
->userspace_clients_lock
);
1472 /* Detach any active clients. This can't fail, thus we do not
1473 * check the returned value. This is a two-pass process, because
1474 * we can't remove the dummy devices during the first pass: they
1475 * could have been instantiated by real devices wishing to clean
1476 * them up properly, so we give them a chance to do that first. */
1477 device_for_each_child(&adap
->dev
, NULL
, __unregister_client
);
1478 device_for_each_child(&adap
->dev
, NULL
, __unregister_dummy
);
1480 #ifdef CONFIG_I2C_COMPAT
1481 class_compat_remove_link(i2c_adapter_compat_class
, &adap
->dev
,
1485 /* device name is gone after device_unregister */
1486 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
1488 pm_runtime_disable(&adap
->dev
);
1490 i2c_host_notify_irq_teardown(adap
);
1492 /* wait until all references to the device are gone
1494 * FIXME: This is old code and should ideally be replaced by an
1495 * alternative which results in decoupling the lifetime of the struct
1496 * device from the i2c_adapter, like spi or netdev do. Any solution
1497 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1499 init_completion(&adap
->dev_released
);
1500 device_unregister(&adap
->dev
);
1501 wait_for_completion(&adap
->dev_released
);
1504 mutex_lock(&core_lock
);
1505 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1506 mutex_unlock(&core_lock
);
1508 /* Clear the device structure in case this adapter is ever going to be
1510 memset(&adap
->dev
, 0, sizeof(adap
->dev
));
1512 EXPORT_SYMBOL(i2c_del_adapter
);
1515 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1516 * @dev: The device to scan for I2C timing properties
1517 * @t: the i2c_timings struct to be filled with values
1518 * @use_defaults: bool to use sane defaults derived from the I2C specification
1519 * when properties are not found, otherwise use 0
1521 * Scan the device for the generic I2C properties describing timing parameters
1522 * for the signal and fill the given struct with the results. If a property was
1523 * not found and use_defaults was true, then maximum timings are assumed which
1524 * are derived from the I2C specification. If use_defaults is not used, the
1525 * results will be 0, so drivers can apply their own defaults later. The latter
1526 * is mainly intended for avoiding regressions of existing drivers which want
1527 * to switch to this function. New drivers almost always should use the defaults.
1530 void i2c_parse_fw_timings(struct device
*dev
, struct i2c_timings
*t
, bool use_defaults
)
1534 memset(t
, 0, sizeof(*t
));
1536 ret
= device_property_read_u32(dev
, "clock-frequency", &t
->bus_freq_hz
);
1537 if (ret
&& use_defaults
)
1538 t
->bus_freq_hz
= 100000;
1540 ret
= device_property_read_u32(dev
, "i2c-scl-rising-time-ns", &t
->scl_rise_ns
);
1541 if (ret
&& use_defaults
) {
1542 if (t
->bus_freq_hz
<= 100000)
1543 t
->scl_rise_ns
= 1000;
1544 else if (t
->bus_freq_hz
<= 400000)
1545 t
->scl_rise_ns
= 300;
1547 t
->scl_rise_ns
= 120;
1550 ret
= device_property_read_u32(dev
, "i2c-scl-falling-time-ns", &t
->scl_fall_ns
);
1551 if (ret
&& use_defaults
) {
1552 if (t
->bus_freq_hz
<= 400000)
1553 t
->scl_fall_ns
= 300;
1555 t
->scl_fall_ns
= 120;
1558 device_property_read_u32(dev
, "i2c-scl-internal-delay-ns", &t
->scl_int_delay_ns
);
1560 ret
= device_property_read_u32(dev
, "i2c-sda-falling-time-ns", &t
->sda_fall_ns
);
1561 if (ret
&& use_defaults
)
1562 t
->sda_fall_ns
= t
->scl_fall_ns
;
1564 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings
);
1566 /* ------------------------------------------------------------------------- */
1568 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *))
1572 mutex_lock(&core_lock
);
1573 res
= bus_for_each_dev(&i2c_bus_type
, NULL
, data
, fn
);
1574 mutex_unlock(&core_lock
);
1578 EXPORT_SYMBOL_GPL(i2c_for_each_dev
);
1580 static int __process_new_driver(struct device
*dev
, void *data
)
1582 if (dev
->type
!= &i2c_adapter_type
)
1584 return i2c_do_add_adapter(data
, to_i2c_adapter(dev
));
1588 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1589 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1592 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
1596 /* Can't register until after driver model init */
1597 if (WARN_ON(!is_registered
))
1600 /* add the driver to the list of i2c drivers in the driver core */
1601 driver
->driver
.owner
= owner
;
1602 driver
->driver
.bus
= &i2c_bus_type
;
1603 INIT_LIST_HEAD(&driver
->clients
);
1605 /* When registration returns, the driver core
1606 * will have called probe() for all matching-but-unbound devices.
1608 res
= driver_register(&driver
->driver
);
1612 pr_debug("driver [%s] registered\n", driver
->driver
.name
);
1614 /* Walk the adapters that are already present */
1615 i2c_for_each_dev(driver
, __process_new_driver
);
1619 EXPORT_SYMBOL(i2c_register_driver
);
1621 static int __process_removed_driver(struct device
*dev
, void *data
)
1623 if (dev
->type
== &i2c_adapter_type
)
1624 i2c_do_del_adapter(data
, to_i2c_adapter(dev
));
1629 * i2c_del_driver - unregister I2C driver
1630 * @driver: the driver being unregistered
1631 * Context: can sleep
1633 void i2c_del_driver(struct i2c_driver
*driver
)
1635 i2c_for_each_dev(driver
, __process_removed_driver
);
1637 driver_unregister(&driver
->driver
);
1638 pr_debug("driver [%s] unregistered\n", driver
->driver
.name
);
1640 EXPORT_SYMBOL(i2c_del_driver
);
1642 /* ------------------------------------------------------------------------- */
1645 * i2c_use_client - increments the reference count of the i2c client structure
1646 * @client: the client being referenced
1648 * Each live reference to a client should be refcounted. The driver model does
1649 * that automatically as part of driver binding, so that most drivers don't
1650 * need to do this explicitly: they hold a reference until they're unbound
1653 * A pointer to the client with the incremented reference counter is returned.
1655 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
1657 if (client
&& get_device(&client
->dev
))
1661 EXPORT_SYMBOL(i2c_use_client
);
1664 * i2c_release_client - release a use of the i2c client structure
1665 * @client: the client being no longer referenced
1667 * Must be called when a user of a client is finished with it.
1669 void i2c_release_client(struct i2c_client
*client
)
1672 put_device(&client
->dev
);
1674 EXPORT_SYMBOL(i2c_release_client
);
1676 struct i2c_cmd_arg
{
1681 static int i2c_cmd(struct device
*dev
, void *_arg
)
1683 struct i2c_client
*client
= i2c_verify_client(dev
);
1684 struct i2c_cmd_arg
*arg
= _arg
;
1685 struct i2c_driver
*driver
;
1687 if (!client
|| !client
->dev
.driver
)
1690 driver
= to_i2c_driver(client
->dev
.driver
);
1691 if (driver
->command
)
1692 driver
->command(client
, arg
->cmd
, arg
->arg
);
1696 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
1698 struct i2c_cmd_arg cmd_arg
;
1702 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
1704 EXPORT_SYMBOL(i2c_clients_command
);
1706 static int __init
i2c_init(void)
1710 retval
= of_alias_get_highest_id("i2c");
1712 down_write(&__i2c_board_lock
);
1713 if (retval
>= __i2c_first_dynamic_bus_num
)
1714 __i2c_first_dynamic_bus_num
= retval
+ 1;
1715 up_write(&__i2c_board_lock
);
1717 retval
= bus_register(&i2c_bus_type
);
1721 is_registered
= true;
1723 #ifdef CONFIG_I2C_COMPAT
1724 i2c_adapter_compat_class
= class_compat_register("i2c-adapter");
1725 if (!i2c_adapter_compat_class
) {
1730 retval
= i2c_add_driver(&dummy_driver
);
1734 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
1735 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier
));
1736 if (IS_ENABLED(CONFIG_ACPI
))
1737 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier
));
1742 #ifdef CONFIG_I2C_COMPAT
1743 class_compat_unregister(i2c_adapter_compat_class
);
1746 is_registered
= false;
1747 bus_unregister(&i2c_bus_type
);
1751 static void __exit
i2c_exit(void)
1753 if (IS_ENABLED(CONFIG_ACPI
))
1754 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier
));
1755 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
1756 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier
));
1757 i2c_del_driver(&dummy_driver
);
1758 #ifdef CONFIG_I2C_COMPAT
1759 class_compat_unregister(i2c_adapter_compat_class
);
1761 bus_unregister(&i2c_bus_type
);
1762 tracepoint_synchronize_unregister();
1765 /* We must initialize early, because some subsystems register i2c drivers
1766 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1768 postcore_initcall(i2c_init
);
1769 module_exit(i2c_exit
);
1771 /* ----------------------------------------------------
1772 * the functional interface to the i2c busses.
1773 * ----------------------------------------------------
1776 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1777 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1779 static int i2c_quirk_error(struct i2c_adapter
*adap
, struct i2c_msg
*msg
, char *err_msg
)
1781 dev_err_ratelimited(&adap
->dev
, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1782 err_msg
, msg
->addr
, msg
->len
,
1783 msg
->flags
& I2C_M_RD
? "read" : "write");
1787 static int i2c_check_for_quirks(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
1789 const struct i2c_adapter_quirks
*q
= adap
->quirks
;
1790 int max_num
= q
->max_num_msgs
, i
;
1791 bool do_len_check
= true;
1793 if (q
->flags
& I2C_AQ_COMB
) {
1796 /* special checks for combined messages */
1798 if (q
->flags
& I2C_AQ_COMB_WRITE_FIRST
&& msgs
[0].flags
& I2C_M_RD
)
1799 return i2c_quirk_error(adap
, &msgs
[0], "1st comb msg must be write");
1801 if (q
->flags
& I2C_AQ_COMB_READ_SECOND
&& !(msgs
[1].flags
& I2C_M_RD
))
1802 return i2c_quirk_error(adap
, &msgs
[1], "2nd comb msg must be read");
1804 if (q
->flags
& I2C_AQ_COMB_SAME_ADDR
&& msgs
[0].addr
!= msgs
[1].addr
)
1805 return i2c_quirk_error(adap
, &msgs
[0], "comb msg only to same addr");
1807 if (i2c_quirk_exceeded(msgs
[0].len
, q
->max_comb_1st_msg_len
))
1808 return i2c_quirk_error(adap
, &msgs
[0], "msg too long");
1810 if (i2c_quirk_exceeded(msgs
[1].len
, q
->max_comb_2nd_msg_len
))
1811 return i2c_quirk_error(adap
, &msgs
[1], "msg too long");
1813 do_len_check
= false;
1817 if (i2c_quirk_exceeded(num
, max_num
))
1818 return i2c_quirk_error(adap
, &msgs
[0], "too many messages");
1820 for (i
= 0; i
< num
; i
++) {
1821 u16 len
= msgs
[i
].len
;
1823 if (msgs
[i
].flags
& I2C_M_RD
) {
1824 if (do_len_check
&& i2c_quirk_exceeded(len
, q
->max_read_len
))
1825 return i2c_quirk_error(adap
, &msgs
[i
], "msg too long");
1827 if (do_len_check
&& i2c_quirk_exceeded(len
, q
->max_write_len
))
1828 return i2c_quirk_error(adap
, &msgs
[i
], "msg too long");
1836 * __i2c_transfer - unlocked flavor of i2c_transfer
1837 * @adap: Handle to I2C bus
1838 * @msgs: One or more messages to execute before STOP is issued to
1839 * terminate the operation; each message begins with a START.
1840 * @num: Number of messages to be executed.
1842 * Returns negative errno, else the number of messages executed.
1844 * Adapter lock must be held when calling this function. No debug logging
1845 * takes place. adap->algo->master_xfer existence isn't checked.
1847 int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
1849 unsigned long orig_jiffies
;
1852 if (adap
->quirks
&& i2c_check_for_quirks(adap
, msgs
, num
))
1855 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1856 * enabled. This is an efficient way of keeping the for-loop from
1857 * being executed when not needed.
1859 if (static_key_false(&i2c_trace_msg
)) {
1861 for (i
= 0; i
< num
; i
++)
1862 if (msgs
[i
].flags
& I2C_M_RD
)
1863 trace_i2c_read(adap
, &msgs
[i
], i
);
1865 trace_i2c_write(adap
, &msgs
[i
], i
);
1868 /* Retry automatically on arbitration loss */
1869 orig_jiffies
= jiffies
;
1870 for (ret
= 0, try = 0; try <= adap
->retries
; try++) {
1871 ret
= adap
->algo
->master_xfer(adap
, msgs
, num
);
1874 if (time_after(jiffies
, orig_jiffies
+ adap
->timeout
))
1878 if (static_key_false(&i2c_trace_msg
)) {
1880 for (i
= 0; i
< ret
; i
++)
1881 if (msgs
[i
].flags
& I2C_M_RD
)
1882 trace_i2c_reply(adap
, &msgs
[i
], i
);
1883 trace_i2c_result(adap
, i
, ret
);
1888 EXPORT_SYMBOL(__i2c_transfer
);
1891 * i2c_transfer - execute a single or combined I2C message
1892 * @adap: Handle to I2C bus
1893 * @msgs: One or more messages to execute before STOP is issued to
1894 * terminate the operation; each message begins with a START.
1895 * @num: Number of messages to be executed.
1897 * Returns negative errno, else the number of messages executed.
1899 * Note that there is no requirement that each message be sent to
1900 * the same slave address, although that is the most common model.
1902 int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
1906 /* REVISIT the fault reporting model here is weak:
1908 * - When we get an error after receiving N bytes from a slave,
1909 * there is no way to report "N".
1911 * - When we get a NAK after transmitting N bytes to a slave,
1912 * there is no way to report "N" ... or to let the master
1913 * continue executing the rest of this combined message, if
1914 * that's the appropriate response.
1916 * - When for example "num" is two and we successfully complete
1917 * the first message but get an error part way through the
1918 * second, it's unclear whether that should be reported as
1919 * one (discarding status on the second message) or errno
1920 * (discarding status on the first one).
1923 if (adap
->algo
->master_xfer
) {
1925 for (ret
= 0; ret
< num
; ret
++) {
1927 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1928 ret
, (msgs
[ret
].flags
& I2C_M_RD
) ? 'R' : 'W',
1929 msgs
[ret
].addr
, msgs
[ret
].len
,
1930 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
1934 if (in_atomic() || irqs_disabled()) {
1935 ret
= i2c_trylock_bus(adap
, I2C_LOCK_SEGMENT
);
1937 /* I2C activity is ongoing. */
1940 i2c_lock_bus(adap
, I2C_LOCK_SEGMENT
);
1943 ret
= __i2c_transfer(adap
, msgs
, num
);
1944 i2c_unlock_bus(adap
, I2C_LOCK_SEGMENT
);
1948 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
1952 EXPORT_SYMBOL(i2c_transfer
);
1955 * i2c_master_send - issue a single I2C message in master transmit mode
1956 * @client: Handle to slave device
1957 * @buf: Data that will be written to the slave
1958 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1960 * Returns negative errno, or else the number of bytes written.
1962 int i2c_master_send(const struct i2c_client
*client
, const char *buf
, int count
)
1965 struct i2c_adapter
*adap
= client
->adapter
;
1968 msg
.addr
= client
->addr
;
1969 msg
.flags
= client
->flags
& I2C_M_TEN
;
1971 msg
.buf
= (char *)buf
;
1973 ret
= i2c_transfer(adap
, &msg
, 1);
1976 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1977 * transmitted, else error code.
1979 return (ret
== 1) ? count
: ret
;
1981 EXPORT_SYMBOL(i2c_master_send
);
1984 * i2c_master_recv - issue a single I2C message in master receive mode
1985 * @client: Handle to slave device
1986 * @buf: Where to store data read from slave
1987 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1989 * Returns negative errno, or else the number of bytes read.
1991 int i2c_master_recv(const struct i2c_client
*client
, char *buf
, int count
)
1993 struct i2c_adapter
*adap
= client
->adapter
;
1997 msg
.addr
= client
->addr
;
1998 msg
.flags
= client
->flags
& I2C_M_TEN
;
1999 msg
.flags
|= I2C_M_RD
;
2003 ret
= i2c_transfer(adap
, &msg
, 1);
2006 * If everything went ok (i.e. 1 msg received), return #bytes received,
2009 return (ret
== 1) ? count
: ret
;
2011 EXPORT_SYMBOL(i2c_master_recv
);
2013 /* ----------------------------------------------------
2014 * the i2c address scanning function
2015 * Will not work for 10-bit addresses!
2016 * ----------------------------------------------------
2020 * Legacy default probe function, mostly relevant for SMBus. The default
2021 * probe method is a quick write, but it is known to corrupt the 24RF08
2022 * EEPROMs due to a state machine bug, and could also irreversibly
2023 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2024 * we use a short byte read instead. Also, some bus drivers don't implement
2025 * quick write, so we fallback to a byte read in that case too.
2026 * On x86, there is another special case for FSC hardware monitoring chips,
2027 * which want regular byte reads (address 0x73.) Fortunately, these are the
2028 * only known chips using this I2C address on PC hardware.
2029 * Returns 1 if probe succeeded, 0 if not.
2031 static int i2c_default_probe(struct i2c_adapter
*adap
, unsigned short addr
)
2034 union i2c_smbus_data dummy
;
2037 if (addr
== 0x73 && (adap
->class & I2C_CLASS_HWMON
)
2038 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE_DATA
))
2039 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2040 I2C_SMBUS_BYTE_DATA
, &dummy
);
2043 if (!((addr
& ~0x07) == 0x30 || (addr
& ~0x0f) == 0x50)
2044 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
))
2045 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_WRITE
, 0,
2046 I2C_SMBUS_QUICK
, NULL
);
2047 else if (i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
))
2048 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2049 I2C_SMBUS_BYTE
, &dummy
);
2051 dev_warn(&adap
->dev
, "No suitable probing method supported for address 0x%02X\n",
2059 static int i2c_detect_address(struct i2c_client
*temp_client
,
2060 struct i2c_driver
*driver
)
2062 struct i2c_board_info info
;
2063 struct i2c_adapter
*adapter
= temp_client
->adapter
;
2064 int addr
= temp_client
->addr
;
2067 /* Make sure the address is valid */
2068 err
= i2c_check_7bit_addr_validity_strict(addr
);
2070 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
2075 /* Skip if already in use (7 bit, no need to encode flags) */
2076 if (i2c_check_addr_busy(adapter
, addr
))
2079 /* Make sure there is something at this address */
2080 if (!i2c_default_probe(adapter
, addr
))
2083 /* Finally call the custom detection function */
2084 memset(&info
, 0, sizeof(struct i2c_board_info
));
2086 err
= driver
->detect(temp_client
, &info
);
2088 /* -ENODEV is returned if the detection fails. We catch it
2089 here as this isn't an error. */
2090 return err
== -ENODEV
? 0 : err
;
2093 /* Consistency check */
2094 if (info
.type
[0] == '\0') {
2095 dev_err(&adapter
->dev
,
2096 "%s detection function provided no name for 0x%x\n",
2097 driver
->driver
.name
, addr
);
2099 struct i2c_client
*client
;
2101 /* Detection succeeded, instantiate the device */
2102 if (adapter
->class & I2C_CLASS_DEPRECATED
)
2103 dev_warn(&adapter
->dev
,
2104 "This adapter will soon drop class based instantiation of devices. "
2105 "Please make sure client 0x%02x gets instantiated by other means. "
2106 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2109 dev_dbg(&adapter
->dev
, "Creating %s at 0x%02x\n",
2110 info
.type
, info
.addr
);
2111 client
= i2c_new_device(adapter
, &info
);
2113 list_add_tail(&client
->detected
, &driver
->clients
);
2115 dev_err(&adapter
->dev
, "Failed creating %s at 0x%02x\n",
2116 info
.type
, info
.addr
);
2121 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
)
2123 const unsigned short *address_list
;
2124 struct i2c_client
*temp_client
;
2126 int adap_id
= i2c_adapter_id(adapter
);
2128 address_list
= driver
->address_list
;
2129 if (!driver
->detect
|| !address_list
)
2132 /* Warn that the adapter lost class based instantiation */
2133 if (adapter
->class == I2C_CLASS_DEPRECATED
) {
2134 dev_dbg(&adapter
->dev
,
2135 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2136 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2137 driver
->driver
.name
);
2141 /* Stop here if the classes do not match */
2142 if (!(adapter
->class & driver
->class))
2145 /* Set up a temporary client to help detect callback */
2146 temp_client
= kzalloc(sizeof(struct i2c_client
), GFP_KERNEL
);
2149 temp_client
->adapter
= adapter
;
2151 for (i
= 0; address_list
[i
] != I2C_CLIENT_END
; i
+= 1) {
2152 dev_dbg(&adapter
->dev
,
2153 "found normal entry for adapter %d, addr 0x%02x\n",
2154 adap_id
, address_list
[i
]);
2155 temp_client
->addr
= address_list
[i
];
2156 err
= i2c_detect_address(temp_client
, driver
);
2165 int i2c_probe_func_quick_read(struct i2c_adapter
*adap
, unsigned short addr
)
2167 return i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2168 I2C_SMBUS_QUICK
, NULL
) >= 0;
2170 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read
);
2173 i2c_new_probed_device(struct i2c_adapter
*adap
,
2174 struct i2c_board_info
*info
,
2175 unsigned short const *addr_list
,
2176 int (*probe
)(struct i2c_adapter
*, unsigned short addr
))
2181 probe
= i2c_default_probe
;
2183 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
2184 /* Check address validity */
2185 if (i2c_check_7bit_addr_validity_strict(addr_list
[i
]) < 0) {
2186 dev_warn(&adap
->dev
, "Invalid 7-bit address 0x%02x\n",
2191 /* Check address availability (7 bit, no need to encode flags) */
2192 if (i2c_check_addr_busy(adap
, addr_list
[i
])) {
2194 "Address 0x%02x already in use, not probing\n",
2199 /* Test address responsiveness */
2200 if (probe(adap
, addr_list
[i
]))
2204 if (addr_list
[i
] == I2C_CLIENT_END
) {
2205 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
2209 info
->addr
= addr_list
[i
];
2210 return i2c_new_device(adap
, info
);
2212 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
2214 struct i2c_adapter
*i2c_get_adapter(int nr
)
2216 struct i2c_adapter
*adapter
;
2218 mutex_lock(&core_lock
);
2219 adapter
= idr_find(&i2c_adapter_idr
, nr
);
2223 if (try_module_get(adapter
->owner
))
2224 get_device(&adapter
->dev
);
2229 mutex_unlock(&core_lock
);
2232 EXPORT_SYMBOL(i2c_get_adapter
);
2234 void i2c_put_adapter(struct i2c_adapter
*adap
)
2239 put_device(&adap
->dev
);
2240 module_put(adap
->owner
);
2242 EXPORT_SYMBOL(i2c_put_adapter
);
2244 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2245 MODULE_DESCRIPTION("I2C-Bus main module");
2246 MODULE_LICENSE("GPL");