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.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
18 /* ------------------------------------------------------------------------- */
20 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
21 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
22 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
23 Jean Delvare <khali@linux-fr.org> */
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/errno.h>
28 #include <linux/slab.h>
29 #include <linux/i2c.h>
30 #include <linux/init.h>
31 #include <linux/idr.h>
32 #include <linux/platform_device.h>
33 #include <linux/mutex.h>
34 #include <linux/completion.h>
35 #include <linux/hardirq.h>
36 #include <linux/irqflags.h>
37 #include <asm/uaccess.h>
42 static DEFINE_MUTEX(core_lock
);
43 static DEFINE_IDR(i2c_adapter_idr
);
45 #define is_newstyle_driver(d) ((d)->probe || (d)->remove)
47 /* ------------------------------------------------------------------------- */
49 static const struct i2c_device_id
*i2c_match_id(const struct i2c_device_id
*id
,
50 const struct i2c_client
*client
)
53 if (strcmp(client
->name
, id
->name
) == 0)
60 static int i2c_device_match(struct device
*dev
, struct device_driver
*drv
)
62 struct i2c_client
*client
= to_i2c_client(dev
);
63 struct i2c_driver
*driver
= to_i2c_driver(drv
);
65 /* make legacy i2c drivers bypass driver model probing entirely;
66 * such drivers scan each i2c adapter/bus themselves.
68 if (!is_newstyle_driver(driver
))
71 /* match on an id table if there is one */
73 return i2c_match_id(driver
->id_table
, client
) != NULL
;
80 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
81 static int i2c_device_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
83 struct i2c_client
*client
= to_i2c_client(dev
);
85 /* by definition, legacy drivers can't hotplug */
89 if (add_uevent_var(env
, "MODALIAS=%s%s",
90 I2C_MODULE_PREFIX
, client
->name
))
92 dev_dbg(dev
, "uevent\n");
97 #define i2c_device_uevent NULL
98 #endif /* CONFIG_HOTPLUG */
100 static int i2c_device_probe(struct device
*dev
)
102 struct i2c_client
*client
= to_i2c_client(dev
);
103 struct i2c_driver
*driver
= to_i2c_driver(dev
->driver
);
104 const struct i2c_device_id
*id
;
109 client
->driver
= driver
;
110 dev_dbg(dev
, "probe\n");
112 if (driver
->id_table
)
113 id
= i2c_match_id(driver
->id_table
, client
);
116 status
= driver
->probe(client
, id
);
118 client
->driver
= NULL
;
122 static int i2c_device_remove(struct device
*dev
)
124 struct i2c_client
*client
= to_i2c_client(dev
);
125 struct i2c_driver
*driver
;
131 driver
= to_i2c_driver(dev
->driver
);
132 if (driver
->remove
) {
133 dev_dbg(dev
, "remove\n");
134 status
= driver
->remove(client
);
140 client
->driver
= NULL
;
144 static void i2c_device_shutdown(struct device
*dev
)
146 struct i2c_driver
*driver
;
150 driver
= to_i2c_driver(dev
->driver
);
151 if (driver
->shutdown
)
152 driver
->shutdown(to_i2c_client(dev
));
155 static int i2c_device_suspend(struct device
* dev
, pm_message_t mesg
)
157 struct i2c_driver
*driver
;
161 driver
= to_i2c_driver(dev
->driver
);
162 if (!driver
->suspend
)
164 return driver
->suspend(to_i2c_client(dev
), mesg
);
167 static int i2c_device_resume(struct device
* dev
)
169 struct i2c_driver
*driver
;
173 driver
= to_i2c_driver(dev
->driver
);
176 return driver
->resume(to_i2c_client(dev
));
179 static void i2c_client_release(struct device
*dev
)
181 struct i2c_client
*client
= to_i2c_client(dev
);
182 complete(&client
->released
);
185 static void i2c_client_dev_release(struct device
*dev
)
187 kfree(to_i2c_client(dev
));
190 static ssize_t
show_client_name(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
192 struct i2c_client
*client
= to_i2c_client(dev
);
193 return sprintf(buf
, "%s\n", client
->name
);
196 static ssize_t
show_modalias(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
198 struct i2c_client
*client
= to_i2c_client(dev
);
199 return sprintf(buf
, "%s%s\n", I2C_MODULE_PREFIX
, client
->name
);
202 static struct device_attribute i2c_dev_attrs
[] = {
203 __ATTR(name
, S_IRUGO
, show_client_name
, NULL
),
204 /* modalias helps coldplug: modprobe $(cat .../modalias) */
205 __ATTR(modalias
, S_IRUGO
, show_modalias
, NULL
),
209 static struct bus_type i2c_bus_type
= {
211 .dev_attrs
= i2c_dev_attrs
,
212 .match
= i2c_device_match
,
213 .uevent
= i2c_device_uevent
,
214 .probe
= i2c_device_probe
,
215 .remove
= i2c_device_remove
,
216 .shutdown
= i2c_device_shutdown
,
217 .suspend
= i2c_device_suspend
,
218 .resume
= i2c_device_resume
,
223 * i2c_verify_client - return parameter as i2c_client, or NULL
224 * @dev: device, probably from some driver model iterator
226 * When traversing the driver model tree, perhaps using driver model
227 * iterators like @device_for_each_child(), you can't assume very much
228 * about the nodes you find. Use this function to avoid oopses caused
229 * by wrongly treating some non-I2C device as an i2c_client.
231 struct i2c_client
*i2c_verify_client(struct device
*dev
)
233 return (dev
->bus
== &i2c_bus_type
)
237 EXPORT_SYMBOL(i2c_verify_client
);
241 * i2c_new_device - instantiate an i2c device for use with a new style driver
242 * @adap: the adapter managing the device
243 * @info: describes one I2C device; bus_num is ignored
246 * Create a device to work with a new style i2c driver, where binding is
247 * handled through driver model probe()/remove() methods. This call is not
248 * appropriate for use by mainboad initialization logic, which usually runs
249 * during an arch_initcall() long before any i2c_adapter could exist.
251 * This returns the new i2c client, which may be saved for later use with
252 * i2c_unregister_device(); or NULL to indicate an error.
255 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
)
257 struct i2c_client
*client
;
260 client
= kzalloc(sizeof *client
, GFP_KERNEL
);
264 client
->adapter
= adap
;
266 client
->dev
.platform_data
= info
->platform_data
;
267 device_init_wakeup(&client
->dev
, info
->flags
& I2C_CLIENT_WAKE
);
269 client
->flags
= info
->flags
& ~I2C_CLIENT_WAKE
;
270 client
->addr
= info
->addr
;
271 client
->irq
= info
->irq
;
273 strlcpy(client
->name
, info
->type
, sizeof(client
->name
));
275 /* a new style driver may be bound to this device when we
276 * return from this function, or any later moment (e.g. maybe
277 * hotplugging will load the driver module). and the device
278 * refcount model is the standard driver model one.
280 status
= i2c_attach_client(client
);
287 EXPORT_SYMBOL_GPL(i2c_new_device
);
291 * i2c_unregister_device - reverse effect of i2c_new_device()
292 * @client: value returned from i2c_new_device()
295 void i2c_unregister_device(struct i2c_client
*client
)
297 struct i2c_adapter
*adapter
= client
->adapter
;
298 struct i2c_driver
*driver
= client
->driver
;
300 if (driver
&& !is_newstyle_driver(driver
)) {
301 dev_err(&client
->dev
, "can't unregister devices "
302 "with legacy drivers\n");
307 mutex_lock(&adapter
->clist_lock
);
308 list_del(&client
->list
);
309 mutex_unlock(&adapter
->clist_lock
);
311 device_unregister(&client
->dev
);
313 EXPORT_SYMBOL_GPL(i2c_unregister_device
);
316 static const struct i2c_device_id dummy_id
[] = {
321 static int dummy_probe(struct i2c_client
*client
,
322 const struct i2c_device_id
*id
)
327 static int dummy_remove(struct i2c_client
*client
)
332 static struct i2c_driver dummy_driver
= {
333 .driver
.name
= "dummy",
334 .probe
= dummy_probe
,
335 .remove
= dummy_remove
,
336 .id_table
= dummy_id
,
340 * i2c_new_dummy - return a new i2c device bound to a dummy driver
341 * @adapter: the adapter managing the device
342 * @address: seven bit address to be used
345 * This returns an I2C client bound to the "dummy" driver, intended for use
346 * with devices that consume multiple addresses. Examples of such chips
347 * include various EEPROMS (like 24c04 and 24c08 models).
349 * These dummy devices have two main uses. First, most I2C and SMBus calls
350 * except i2c_transfer() need a client handle; the dummy will be that handle.
351 * And second, this prevents the specified address from being bound to a
354 * This returns the new i2c client, which should be saved for later use with
355 * i2c_unregister_device(); or NULL to indicate an error.
358 i2c_new_dummy(struct i2c_adapter
*adapter
, u16 address
)
360 struct i2c_board_info info
= {
361 I2C_BOARD_INFO("dummy", address
),
364 return i2c_new_device(adapter
, &info
);
366 EXPORT_SYMBOL_GPL(i2c_new_dummy
);
368 /* ------------------------------------------------------------------------- */
370 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
372 static void i2c_adapter_dev_release(struct device
*dev
)
374 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
375 complete(&adap
->dev_released
);
379 show_adapter_name(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
381 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
382 return sprintf(buf
, "%s\n", adap
->name
);
385 static struct device_attribute i2c_adapter_attrs
[] = {
386 __ATTR(name
, S_IRUGO
, show_adapter_name
, NULL
),
390 static struct class i2c_adapter_class
= {
391 .owner
= THIS_MODULE
,
392 .name
= "i2c-adapter",
393 .dev_attrs
= i2c_adapter_attrs
,
396 static void i2c_scan_static_board_info(struct i2c_adapter
*adapter
)
398 struct i2c_devinfo
*devinfo
;
400 mutex_lock(&__i2c_board_lock
);
401 list_for_each_entry(devinfo
, &__i2c_board_list
, list
) {
402 if (devinfo
->busnum
== adapter
->nr
403 && !i2c_new_device(adapter
,
404 &devinfo
->board_info
))
405 printk(KERN_ERR
"i2c-core: can't create i2c%d-%04x\n",
406 i2c_adapter_id(adapter
),
407 devinfo
->board_info
.addr
);
409 mutex_unlock(&__i2c_board_lock
);
412 static int i2c_do_add_adapter(struct device_driver
*d
, void *data
)
414 struct i2c_driver
*driver
= to_i2c_driver(d
);
415 struct i2c_adapter
*adap
= data
;
417 if (driver
->attach_adapter
) {
418 /* We ignore the return code; if it fails, too bad */
419 driver
->attach_adapter(adap
);
424 static int i2c_register_adapter(struct i2c_adapter
*adap
)
428 mutex_init(&adap
->bus_lock
);
429 mutex_init(&adap
->clist_lock
);
430 INIT_LIST_HEAD(&adap
->clients
);
432 mutex_lock(&core_lock
);
434 /* Add the adapter to the driver core.
435 * If the parent pointer is not set up,
436 * we add this adapter to the host bus.
438 if (adap
->dev
.parent
== NULL
) {
439 adap
->dev
.parent
= &platform_bus
;
440 pr_debug("I2C adapter driver [%s] forgot to specify "
441 "physical device\n", adap
->name
);
443 sprintf(adap
->dev
.bus_id
, "i2c-%d", adap
->nr
);
444 adap
->dev
.release
= &i2c_adapter_dev_release
;
445 adap
->dev
.class = &i2c_adapter_class
;
446 res
= device_register(&adap
->dev
);
450 dev_dbg(&adap
->dev
, "adapter [%s] registered\n", adap
->name
);
452 /* create pre-declared device nodes for new-style drivers */
453 if (adap
->nr
< __i2c_first_dynamic_bus_num
)
454 i2c_scan_static_board_info(adap
);
456 /* let legacy drivers scan this bus for matching devices */
457 dummy
= bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
461 mutex_unlock(&core_lock
);
465 idr_remove(&i2c_adapter_idr
, adap
->nr
);
470 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
471 * @adapter: the adapter to add
474 * This routine is used to declare an I2C adapter when its bus number
475 * doesn't matter. Examples: for I2C adapters dynamically added by
476 * USB links or PCI plugin cards.
478 * When this returns zero, a new bus number was allocated and stored
479 * in adap->nr, and the specified adapter became available for clients.
480 * Otherwise, a negative errno value is returned.
482 int i2c_add_adapter(struct i2c_adapter
*adapter
)
487 if (idr_pre_get(&i2c_adapter_idr
, GFP_KERNEL
) == 0)
490 mutex_lock(&core_lock
);
491 /* "above" here means "above or equal to", sigh */
492 res
= idr_get_new_above(&i2c_adapter_idr
, adapter
,
493 __i2c_first_dynamic_bus_num
, &id
);
494 mutex_unlock(&core_lock
);
503 return i2c_register_adapter(adapter
);
505 EXPORT_SYMBOL(i2c_add_adapter
);
508 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
509 * @adap: the adapter to register (with adap->nr initialized)
512 * This routine is used to declare an I2C adapter when its bus number
513 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
514 * or otherwise built in to the system's mainboard, and where i2c_board_info
515 * is used to properly configure I2C devices.
517 * If no devices have pre-been declared for this bus, then be sure to
518 * register the adapter before any dynamically allocated ones. Otherwise
519 * the required bus ID may not be available.
521 * When this returns zero, the specified adapter became available for
522 * clients using the bus number provided in adap->nr. Also, the table
523 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
524 * and the appropriate driver model device nodes are created. Otherwise, a
525 * negative errno value is returned.
527 int i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
532 if (adap
->nr
& ~MAX_ID_MASK
)
536 if (idr_pre_get(&i2c_adapter_idr
, GFP_KERNEL
) == 0)
539 mutex_lock(&core_lock
);
540 /* "above" here means "above or equal to", sigh;
541 * we need the "equal to" result to force the result
543 status
= idr_get_new_above(&i2c_adapter_idr
, adap
, adap
->nr
, &id
);
544 if (status
== 0 && id
!= adap
->nr
) {
546 idr_remove(&i2c_adapter_idr
, id
);
548 mutex_unlock(&core_lock
);
549 if (status
== -EAGAIN
)
553 status
= i2c_register_adapter(adap
);
556 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter
);
558 static int i2c_do_del_adapter(struct device_driver
*d
, void *data
)
560 struct i2c_driver
*driver
= to_i2c_driver(d
);
561 struct i2c_adapter
*adapter
= data
;
564 if (!driver
->detach_adapter
)
566 res
= driver
->detach_adapter(adapter
);
568 dev_err(&adapter
->dev
, "detach_adapter failed (%d) "
569 "for driver [%s]\n", res
, driver
->driver
.name
);
574 * i2c_del_adapter - unregister I2C adapter
575 * @adap: the adapter being unregistered
578 * This unregisters an I2C adapter which was previously registered
579 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
581 int i2c_del_adapter(struct i2c_adapter
*adap
)
583 struct list_head
*item
, *_n
;
584 struct i2c_client
*client
;
587 mutex_lock(&core_lock
);
589 /* First make sure that this adapter was ever added */
590 if (idr_find(&i2c_adapter_idr
, adap
->nr
) != adap
) {
591 pr_debug("i2c-core: attempting to delete unregistered "
592 "adapter [%s]\n", adap
->name
);
597 /* Tell drivers about this removal */
598 res
= bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
603 /* detach any active clients. This must be done first, because
604 * it can fail; in which case we give up. */
605 list_for_each_safe(item
, _n
, &adap
->clients
) {
606 struct i2c_driver
*driver
;
608 client
= list_entry(item
, struct i2c_client
, list
);
609 driver
= client
->driver
;
611 /* new style, follow standard driver model */
612 if (!driver
|| is_newstyle_driver(driver
)) {
613 i2c_unregister_device(client
);
617 /* legacy drivers create and remove clients themselves */
618 if ((res
= driver
->detach_client(client
))) {
619 dev_err(&adap
->dev
, "detach_client failed for client "
620 "[%s] at address 0x%02x\n", client
->name
,
626 /* clean up the sysfs representation */
627 init_completion(&adap
->dev_released
);
628 device_unregister(&adap
->dev
);
630 /* wait for sysfs to drop all references */
631 wait_for_completion(&adap
->dev_released
);
634 idr_remove(&i2c_adapter_idr
, adap
->nr
);
636 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
639 mutex_unlock(&core_lock
);
642 EXPORT_SYMBOL(i2c_del_adapter
);
645 /* ------------------------------------------------------------------------- */
647 static int __attach_adapter(struct device
*dev
, void *data
)
649 struct i2c_adapter
*adapter
= to_i2c_adapter(dev
);
650 struct i2c_driver
*driver
= data
;
652 driver
->attach_adapter(adapter
);
658 * An i2c_driver is used with one or more i2c_client (device) nodes to access
659 * i2c slave chips, on a bus instance associated with some i2c_adapter. There
660 * are two models for binding the driver to its device: "new style" drivers
661 * follow the standard Linux driver model and just respond to probe() calls
662 * issued if the driver core sees they match(); "legacy" drivers create device
666 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
670 /* new style driver methods can't mix with legacy ones */
671 if (is_newstyle_driver(driver
)) {
672 if (driver
->attach_adapter
|| driver
->detach_adapter
673 || driver
->detach_client
) {
675 "i2c-core: driver [%s] is confused\n",
676 driver
->driver
.name
);
681 /* add the driver to the list of i2c drivers in the driver core */
682 driver
->driver
.owner
= owner
;
683 driver
->driver
.bus
= &i2c_bus_type
;
685 /* for new style drivers, when registration returns the driver core
686 * will have called probe() for all matching-but-unbound devices.
688 res
= driver_register(&driver
->driver
);
692 mutex_lock(&core_lock
);
694 pr_debug("i2c-core: driver [%s] registered\n", driver
->driver
.name
);
696 /* legacy drivers scan i2c busses directly */
697 if (driver
->attach_adapter
)
698 class_for_each_device(&i2c_adapter_class
, driver
,
701 mutex_unlock(&core_lock
);
704 EXPORT_SYMBOL(i2c_register_driver
);
706 static int __detach_adapter(struct device
*dev
, void *data
)
708 struct i2c_adapter
*adapter
= to_i2c_adapter(dev
);
709 struct i2c_driver
*driver
= data
;
711 /* Have a look at each adapter, if clients of this driver are still
712 * attached. If so, detach them to be able to kill the driver
715 if (driver
->detach_adapter
) {
716 if (driver
->detach_adapter(adapter
))
717 dev_err(&adapter
->dev
,
718 "detach_adapter failed for driver [%s]\n",
719 driver
->driver
.name
);
721 struct list_head
*item
, *_n
;
722 struct i2c_client
*client
;
724 list_for_each_safe(item
, _n
, &adapter
->clients
) {
725 client
= list_entry(item
, struct i2c_client
, list
);
726 if (client
->driver
!= driver
)
728 dev_dbg(&adapter
->dev
,
729 "detaching client [%s] at 0x%02x\n",
730 client
->name
, client
->addr
);
731 if (driver
->detach_client(client
))
732 dev_err(&adapter
->dev
, "detach_client "
733 "failed for client [%s] at 0x%02x\n",
734 client
->name
, client
->addr
);
742 * i2c_del_driver - unregister I2C driver
743 * @driver: the driver being unregistered
746 void i2c_del_driver(struct i2c_driver
*driver
)
748 mutex_lock(&core_lock
);
750 /* new-style driver? */
751 if (is_newstyle_driver(driver
))
754 class_for_each_device(&i2c_adapter_class
, driver
, __detach_adapter
);
757 driver_unregister(&driver
->driver
);
758 pr_debug("i2c-core: driver [%s] unregistered\n", driver
->driver
.name
);
760 mutex_unlock(&core_lock
);
762 EXPORT_SYMBOL(i2c_del_driver
);
764 /* ------------------------------------------------------------------------- */
766 static int __i2c_check_addr(struct device
*dev
, void *addrp
)
768 struct i2c_client
*client
= i2c_verify_client(dev
);
769 int addr
= *(int *)addrp
;
771 if (client
&& client
->addr
== addr
)
776 static int i2c_check_addr(struct i2c_adapter
*adapter
, int addr
)
778 return device_for_each_child(&adapter
->dev
, &addr
, __i2c_check_addr
);
781 int i2c_attach_client(struct i2c_client
*client
)
783 struct i2c_adapter
*adapter
= client
->adapter
;
786 client
->dev
.parent
= &client
->adapter
->dev
;
787 client
->dev
.bus
= &i2c_bus_type
;
790 client
->dev
.driver
= &client
->driver
->driver
;
792 if (client
->driver
&& !is_newstyle_driver(client
->driver
)) {
793 client
->dev
.release
= i2c_client_release
;
794 client
->dev
.uevent_suppress
= 1;
796 client
->dev
.release
= i2c_client_dev_release
;
798 snprintf(&client
->dev
.bus_id
[0], sizeof(client
->dev
.bus_id
),
799 "%d-%04x", i2c_adapter_id(adapter
), client
->addr
);
800 res
= device_register(&client
->dev
);
804 mutex_lock(&adapter
->clist_lock
);
805 list_add_tail(&client
->list
, &adapter
->clients
);
806 mutex_unlock(&adapter
->clist_lock
);
808 dev_dbg(&adapter
->dev
, "client [%s] registered with bus id %s\n",
809 client
->name
, client
->dev
.bus_id
);
811 if (adapter
->client_register
) {
812 if (adapter
->client_register(client
)) {
813 dev_dbg(&adapter
->dev
, "client_register "
814 "failed for client [%s] at 0x%02x\n",
815 client
->name
, client
->addr
);
822 dev_err(&adapter
->dev
, "Failed to attach i2c client %s at 0x%02x "
823 "(%d)\n", client
->name
, client
->addr
, res
);
826 EXPORT_SYMBOL(i2c_attach_client
);
828 int i2c_detach_client(struct i2c_client
*client
)
830 struct i2c_adapter
*adapter
= client
->adapter
;
833 if (adapter
->client_unregister
) {
834 res
= adapter
->client_unregister(client
);
836 dev_err(&client
->dev
,
837 "client_unregister [%s] failed, "
838 "client not detached\n", client
->name
);
843 mutex_lock(&adapter
->clist_lock
);
844 list_del(&client
->list
);
845 mutex_unlock(&adapter
->clist_lock
);
847 init_completion(&client
->released
);
848 device_unregister(&client
->dev
);
849 wait_for_completion(&client
->released
);
854 EXPORT_SYMBOL(i2c_detach_client
);
857 * i2c_use_client - increments the reference count of the i2c client structure
858 * @client: the client being referenced
860 * Each live reference to a client should be refcounted. The driver model does
861 * that automatically as part of driver binding, so that most drivers don't
862 * need to do this explicitly: they hold a reference until they're unbound
865 * A pointer to the client with the incremented reference counter is returned.
867 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
869 if (client
&& get_device(&client
->dev
))
873 EXPORT_SYMBOL(i2c_use_client
);
876 * i2c_release_client - release a use of the i2c client structure
877 * @client: the client being no longer referenced
879 * Must be called when a user of a client is finished with it.
881 void i2c_release_client(struct i2c_client
*client
)
884 put_device(&client
->dev
);
886 EXPORT_SYMBOL(i2c_release_client
);
893 static int i2c_cmd(struct device
*dev
, void *_arg
)
895 struct i2c_client
*client
= i2c_verify_client(dev
);
896 struct i2c_cmd_arg
*arg
= _arg
;
898 if (client
&& client
->driver
&& client
->driver
->command
)
899 client
->driver
->command(client
, arg
->cmd
, arg
->arg
);
903 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
905 struct i2c_cmd_arg cmd_arg
;
909 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
911 EXPORT_SYMBOL(i2c_clients_command
);
913 static int __init
i2c_init(void)
917 retval
= bus_register(&i2c_bus_type
);
920 retval
= class_register(&i2c_adapter_class
);
923 retval
= i2c_add_driver(&dummy_driver
);
929 class_unregister(&i2c_adapter_class
);
931 bus_unregister(&i2c_bus_type
);
935 static void __exit
i2c_exit(void)
937 i2c_del_driver(&dummy_driver
);
938 class_unregister(&i2c_adapter_class
);
939 bus_unregister(&i2c_bus_type
);
942 subsys_initcall(i2c_init
);
943 module_exit(i2c_exit
);
945 /* ----------------------------------------------------
946 * the functional interface to the i2c busses.
947 * ----------------------------------------------------
951 * i2c_transfer - execute a single or combined I2C message
952 * @adap: Handle to I2C bus
953 * @msgs: One or more messages to execute before STOP is issued to
954 * terminate the operation; each message begins with a START.
955 * @num: Number of messages to be executed.
957 * Returns negative errno, else the number of messages executed.
959 * Note that there is no requirement that each message be sent to
960 * the same slave address, although that is the most common model.
962 int i2c_transfer(struct i2c_adapter
* adap
, struct i2c_msg
*msgs
, int num
)
966 /* REVISIT the fault reporting model here is weak:
968 * - When we get an error after receiving N bytes from a slave,
969 * there is no way to report "N".
971 * - When we get a NAK after transmitting N bytes to a slave,
972 * there is no way to report "N" ... or to let the master
973 * continue executing the rest of this combined message, if
974 * that's the appropriate response.
976 * - When for example "num" is two and we successfully complete
977 * the first message but get an error part way through the
978 * second, it's unclear whether that should be reported as
979 * one (discarding status on the second message) or errno
980 * (discarding status on the first one).
983 if (adap
->algo
->master_xfer
) {
985 for (ret
= 0; ret
< num
; ret
++) {
986 dev_dbg(&adap
->dev
, "master_xfer[%d] %c, addr=0x%02x, "
987 "len=%d%s\n", ret
, (msgs
[ret
].flags
& I2C_M_RD
)
988 ? 'R' : 'W', msgs
[ret
].addr
, msgs
[ret
].len
,
989 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
993 if (in_atomic() || irqs_disabled()) {
994 ret
= mutex_trylock(&adap
->bus_lock
);
996 /* I2C activity is ongoing. */
999 mutex_lock_nested(&adap
->bus_lock
, adap
->level
);
1002 ret
= adap
->algo
->master_xfer(adap
,msgs
,num
);
1003 mutex_unlock(&adap
->bus_lock
);
1007 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
1011 EXPORT_SYMBOL(i2c_transfer
);
1014 * i2c_master_send - issue a single I2C message in master transmit mode
1015 * @client: Handle to slave device
1016 * @buf: Data that will be written to the slave
1017 * @count: How many bytes to write
1019 * Returns negative errno, or else the number of bytes written.
1021 int i2c_master_send(struct i2c_client
*client
,const char *buf
,int count
)
1024 struct i2c_adapter
*adap
=client
->adapter
;
1027 msg
.addr
= client
->addr
;
1028 msg
.flags
= client
->flags
& I2C_M_TEN
;
1030 msg
.buf
= (char *)buf
;
1032 ret
= i2c_transfer(adap
, &msg
, 1);
1034 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1035 transmitted, else error code. */
1036 return (ret
== 1) ? count
: ret
;
1038 EXPORT_SYMBOL(i2c_master_send
);
1041 * i2c_master_recv - issue a single I2C message in master receive mode
1042 * @client: Handle to slave device
1043 * @buf: Where to store data read from slave
1044 * @count: How many bytes to read
1046 * Returns negative errno, or else the number of bytes read.
1048 int i2c_master_recv(struct i2c_client
*client
, char *buf
,int count
)
1050 struct i2c_adapter
*adap
=client
->adapter
;
1054 msg
.addr
= client
->addr
;
1055 msg
.flags
= client
->flags
& I2C_M_TEN
;
1056 msg
.flags
|= I2C_M_RD
;
1060 ret
= i2c_transfer(adap
, &msg
, 1);
1062 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1063 transmitted, else error code. */
1064 return (ret
== 1) ? count
: ret
;
1066 EXPORT_SYMBOL(i2c_master_recv
);
1068 /* ----------------------------------------------------
1069 * the i2c address scanning function
1070 * Will not work for 10-bit addresses!
1071 * ----------------------------------------------------
1073 static int i2c_probe_address(struct i2c_adapter
*adapter
, int addr
, int kind
,
1074 int (*found_proc
) (struct i2c_adapter
*, int, int))
1078 /* Make sure the address is valid */
1079 if (addr
< 0x03 || addr
> 0x77) {
1080 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
1085 /* Skip if already in use */
1086 if (i2c_check_addr(adapter
, addr
))
1089 /* Make sure there is something at this address, unless forced */
1091 if (i2c_smbus_xfer(adapter
, addr
, 0, 0, 0,
1092 I2C_SMBUS_QUICK
, NULL
) < 0)
1095 /* prevent 24RF08 corruption */
1096 if ((addr
& ~0x0f) == 0x50)
1097 i2c_smbus_xfer(adapter
, addr
, 0, 0, 0,
1098 I2C_SMBUS_QUICK
, NULL
);
1101 /* Finally call the custom detection function */
1102 err
= found_proc(adapter
, addr
, kind
);
1103 /* -ENODEV can be returned if there is a chip at the given address
1104 but it isn't supported by this chip driver. We catch it here as
1105 this isn't an error. */
1110 dev_warn(&adapter
->dev
, "Client creation failed at 0x%x (%d)\n",
1115 int i2c_probe(struct i2c_adapter
*adapter
,
1116 const struct i2c_client_address_data
*address_data
,
1117 int (*found_proc
) (struct i2c_adapter
*, int, int))
1120 int adap_id
= i2c_adapter_id(adapter
);
1122 /* Force entries are done first, and are not affected by ignore
1124 if (address_data
->forces
) {
1125 const unsigned short * const *forces
= address_data
->forces
;
1128 for (kind
= 0; forces
[kind
]; kind
++) {
1129 for (i
= 0; forces
[kind
][i
] != I2C_CLIENT_END
;
1131 if (forces
[kind
][i
] == adap_id
1132 || forces
[kind
][i
] == ANY_I2C_BUS
) {
1133 dev_dbg(&adapter
->dev
, "found force "
1134 "parameter for adapter %d, "
1135 "addr 0x%02x, kind %d\n",
1136 adap_id
, forces
[kind
][i
+ 1],
1138 err
= i2c_probe_address(adapter
,
1139 forces
[kind
][i
+ 1],
1148 /* Stop here if we can't use SMBUS_QUICK */
1149 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_QUICK
)) {
1150 if (address_data
->probe
[0] == I2C_CLIENT_END
1151 && address_data
->normal_i2c
[0] == I2C_CLIENT_END
)
1154 dev_warn(&adapter
->dev
, "SMBus Quick command not supported, "
1155 "can't probe for chips\n");
1159 /* Probe entries are done second, and are not affected by ignore
1161 for (i
= 0; address_data
->probe
[i
] != I2C_CLIENT_END
; i
+= 2) {
1162 if (address_data
->probe
[i
] == adap_id
1163 || address_data
->probe
[i
] == ANY_I2C_BUS
) {
1164 dev_dbg(&adapter
->dev
, "found probe parameter for "
1165 "adapter %d, addr 0x%02x\n", adap_id
,
1166 address_data
->probe
[i
+ 1]);
1167 err
= i2c_probe_address(adapter
,
1168 address_data
->probe
[i
+ 1],
1175 /* Normal entries are done last, unless shadowed by an ignore entry */
1176 for (i
= 0; address_data
->normal_i2c
[i
] != I2C_CLIENT_END
; i
+= 1) {
1180 for (j
= 0; address_data
->ignore
[j
] != I2C_CLIENT_END
;
1182 if ((address_data
->ignore
[j
] == adap_id
||
1183 address_data
->ignore
[j
] == ANY_I2C_BUS
)
1184 && address_data
->ignore
[j
+ 1]
1185 == address_data
->normal_i2c
[i
]) {
1186 dev_dbg(&adapter
->dev
, "found ignore "
1187 "parameter for adapter %d, "
1188 "addr 0x%02x\n", adap_id
,
1189 address_data
->ignore
[j
+ 1]);
1197 dev_dbg(&adapter
->dev
, "found normal entry for adapter %d, "
1198 "addr 0x%02x\n", adap_id
,
1199 address_data
->normal_i2c
[i
]);
1200 err
= i2c_probe_address(adapter
, address_data
->normal_i2c
[i
],
1208 EXPORT_SYMBOL(i2c_probe
);
1211 i2c_new_probed_device(struct i2c_adapter
*adap
,
1212 struct i2c_board_info
*info
,
1213 unsigned short const *addr_list
)
1217 /* Stop here if the bus doesn't support probing */
1218 if (!i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
)) {
1219 dev_err(&adap
->dev
, "Probing not supported\n");
1223 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
1224 /* Check address validity */
1225 if (addr_list
[i
] < 0x03 || addr_list
[i
] > 0x77) {
1226 dev_warn(&adap
->dev
, "Invalid 7-bit address "
1227 "0x%02x\n", addr_list
[i
]);
1231 /* Check address availability */
1232 if (i2c_check_addr(adap
, addr_list
[i
])) {
1233 dev_dbg(&adap
->dev
, "Address 0x%02x already in "
1234 "use, not probing\n", addr_list
[i
]);
1238 /* Test address responsiveness
1239 The default probe method is a quick write, but it is known
1240 to corrupt the 24RF08 EEPROMs due to a state machine bug,
1241 and could also irreversibly write-protect some EEPROMs, so
1242 for address ranges 0x30-0x37 and 0x50-0x5f, we use a byte
1243 read instead. Also, some bus drivers don't implement
1244 quick write, so we fallback to a byte read it that case
1246 if ((addr_list
[i
] & ~0x07) == 0x30
1247 || (addr_list
[i
] & ~0x0f) == 0x50
1248 || !i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
)) {
1249 if (i2c_smbus_xfer(adap
, addr_list
[i
], 0,
1251 I2C_SMBUS_BYTE
, NULL
) >= 0)
1254 if (i2c_smbus_xfer(adap
, addr_list
[i
], 0,
1256 I2C_SMBUS_QUICK
, NULL
) >= 0)
1261 if (addr_list
[i
] == I2C_CLIENT_END
) {
1262 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
1266 info
->addr
= addr_list
[i
];
1267 return i2c_new_device(adap
, info
);
1269 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
1271 struct i2c_adapter
* i2c_get_adapter(int id
)
1273 struct i2c_adapter
*adapter
;
1275 mutex_lock(&core_lock
);
1276 adapter
= (struct i2c_adapter
*)idr_find(&i2c_adapter_idr
, id
);
1277 if (adapter
&& !try_module_get(adapter
->owner
))
1280 mutex_unlock(&core_lock
);
1283 EXPORT_SYMBOL(i2c_get_adapter
);
1285 void i2c_put_adapter(struct i2c_adapter
*adap
)
1287 module_put(adap
->owner
);
1289 EXPORT_SYMBOL(i2c_put_adapter
);
1291 /* The SMBus parts */
1293 #define POLY (0x1070U << 3)
1299 for(i
= 0; i
< 8; i
++) {
1304 return (u8
)(data
>> 8);
1307 /* Incremental CRC8 over count bytes in the array pointed to by p */
1308 static u8
i2c_smbus_pec(u8 crc
, u8
*p
, size_t count
)
1312 for(i
= 0; i
< count
; i
++)
1313 crc
= crc8((crc
^ p
[i
]) << 8);
1317 /* Assume a 7-bit address, which is reasonable for SMBus */
1318 static u8
i2c_smbus_msg_pec(u8 pec
, struct i2c_msg
*msg
)
1320 /* The address will be sent first */
1321 u8 addr
= (msg
->addr
<< 1) | !!(msg
->flags
& I2C_M_RD
);
1322 pec
= i2c_smbus_pec(pec
, &addr
, 1);
1324 /* The data buffer follows */
1325 return i2c_smbus_pec(pec
, msg
->buf
, msg
->len
);
1328 /* Used for write only transactions */
1329 static inline void i2c_smbus_add_pec(struct i2c_msg
*msg
)
1331 msg
->buf
[msg
->len
] = i2c_smbus_msg_pec(0, msg
);
1335 /* Return <0 on CRC error
1336 If there was a write before this read (most cases) we need to take the
1337 partial CRC from the write part into account.
1338 Note that this function does modify the message (we need to decrease the
1339 message length to hide the CRC byte from the caller). */
1340 static int i2c_smbus_check_pec(u8 cpec
, struct i2c_msg
*msg
)
1342 u8 rpec
= msg
->buf
[--msg
->len
];
1343 cpec
= i2c_smbus_msg_pec(cpec
, msg
);
1346 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
1354 * i2c_smbus_read_byte - SMBus "receive byte" protocol
1355 * @client: Handle to slave device
1357 * This executes the SMBus "receive byte" protocol, returning negative errno
1358 * else the byte received from the device.
1360 s32
i2c_smbus_read_byte(struct i2c_client
*client
)
1362 union i2c_smbus_data data
;
1365 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1367 I2C_SMBUS_BYTE
, &data
);
1368 return (status
< 0) ? status
: data
.byte
;
1370 EXPORT_SYMBOL(i2c_smbus_read_byte
);
1373 * i2c_smbus_write_byte - SMBus "send byte" protocol
1374 * @client: Handle to slave device
1375 * @value: Byte to be sent
1377 * This executes the SMBus "send byte" protocol, returning negative errno
1378 * else zero on success.
1380 s32
i2c_smbus_write_byte(struct i2c_client
*client
, u8 value
)
1382 return i2c_smbus_xfer(client
->adapter
,client
->addr
,client
->flags
,
1383 I2C_SMBUS_WRITE
, value
, I2C_SMBUS_BYTE
, NULL
);
1385 EXPORT_SYMBOL(i2c_smbus_write_byte
);
1388 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
1389 * @client: Handle to slave device
1390 * @command: Byte interpreted by slave
1392 * This executes the SMBus "read byte" protocol, returning negative errno
1393 * else a data byte received from the device.
1395 s32
i2c_smbus_read_byte_data(struct i2c_client
*client
, u8 command
)
1397 union i2c_smbus_data data
;
1400 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1401 I2C_SMBUS_READ
, command
,
1402 I2C_SMBUS_BYTE_DATA
, &data
);
1403 return (status
< 0) ? status
: data
.byte
;
1405 EXPORT_SYMBOL(i2c_smbus_read_byte_data
);
1408 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
1409 * @client: Handle to slave device
1410 * @command: Byte interpreted by slave
1411 * @value: Byte being written
1413 * This executes the SMBus "write byte" protocol, returning negative errno
1414 * else zero on success.
1416 s32
i2c_smbus_write_byte_data(struct i2c_client
*client
, u8 command
, u8 value
)
1418 union i2c_smbus_data data
;
1420 return i2c_smbus_xfer(client
->adapter
,client
->addr
,client
->flags
,
1421 I2C_SMBUS_WRITE
,command
,
1422 I2C_SMBUS_BYTE_DATA
,&data
);
1424 EXPORT_SYMBOL(i2c_smbus_write_byte_data
);
1427 * i2c_smbus_read_word_data - SMBus "read word" protocol
1428 * @client: Handle to slave device
1429 * @command: Byte interpreted by slave
1431 * This executes the SMBus "read word" protocol, returning negative errno
1432 * else a 16-bit unsigned "word" received from the device.
1434 s32
i2c_smbus_read_word_data(struct i2c_client
*client
, u8 command
)
1436 union i2c_smbus_data data
;
1439 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1440 I2C_SMBUS_READ
, command
,
1441 I2C_SMBUS_WORD_DATA
, &data
);
1442 return (status
< 0) ? status
: data
.word
;
1444 EXPORT_SYMBOL(i2c_smbus_read_word_data
);
1447 * i2c_smbus_write_word_data - SMBus "write word" protocol
1448 * @client: Handle to slave device
1449 * @command: Byte interpreted by slave
1450 * @value: 16-bit "word" being written
1452 * This executes the SMBus "write word" protocol, returning negative errno
1453 * else zero on success.
1455 s32
i2c_smbus_write_word_data(struct i2c_client
*client
, u8 command
, u16 value
)
1457 union i2c_smbus_data data
;
1459 return i2c_smbus_xfer(client
->adapter
,client
->addr
,client
->flags
,
1460 I2C_SMBUS_WRITE
,command
,
1461 I2C_SMBUS_WORD_DATA
,&data
);
1463 EXPORT_SYMBOL(i2c_smbus_write_word_data
);
1466 * i2c_smbus_read_block_data - SMBus "block read" protocol
1467 * @client: Handle to slave device
1468 * @command: Byte interpreted by slave
1469 * @values: Byte array into which data will be read; big enough to hold
1470 * the data returned by the slave. SMBus allows at most 32 bytes.
1472 * This executes the SMBus "block read" protocol, returning negative errno
1473 * else the number of data bytes in the slave's response.
1475 * Note that using this function requires that the client's adapter support
1476 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
1477 * support this; its emulation through I2C messaging relies on a specific
1478 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
1480 s32
i2c_smbus_read_block_data(struct i2c_client
*client
, u8 command
,
1483 union i2c_smbus_data data
;
1486 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1487 I2C_SMBUS_READ
, command
,
1488 I2C_SMBUS_BLOCK_DATA
, &data
);
1492 memcpy(values
, &data
.block
[1], data
.block
[0]);
1493 return data
.block
[0];
1495 EXPORT_SYMBOL(i2c_smbus_read_block_data
);
1498 * i2c_smbus_write_block_data - SMBus "block write" protocol
1499 * @client: Handle to slave device
1500 * @command: Byte interpreted by slave
1501 * @length: Size of data block; SMBus allows at most 32 bytes
1502 * @values: Byte array which will be written.
1504 * This executes the SMBus "block write" protocol, returning negative errno
1505 * else zero on success.
1507 s32
i2c_smbus_write_block_data(struct i2c_client
*client
, u8 command
,
1508 u8 length
, const u8
*values
)
1510 union i2c_smbus_data data
;
1512 if (length
> I2C_SMBUS_BLOCK_MAX
)
1513 length
= I2C_SMBUS_BLOCK_MAX
;
1514 data
.block
[0] = length
;
1515 memcpy(&data
.block
[1], values
, length
);
1516 return i2c_smbus_xfer(client
->adapter
,client
->addr
,client
->flags
,
1517 I2C_SMBUS_WRITE
,command
,
1518 I2C_SMBUS_BLOCK_DATA
,&data
);
1520 EXPORT_SYMBOL(i2c_smbus_write_block_data
);
1522 /* Returns the number of read bytes */
1523 s32
i2c_smbus_read_i2c_block_data(struct i2c_client
*client
, u8 command
,
1524 u8 length
, u8
*values
)
1526 union i2c_smbus_data data
;
1529 if (length
> I2C_SMBUS_BLOCK_MAX
)
1530 length
= I2C_SMBUS_BLOCK_MAX
;
1531 data
.block
[0] = length
;
1532 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1533 I2C_SMBUS_READ
, command
,
1534 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
1538 memcpy(values
, &data
.block
[1], data
.block
[0]);
1539 return data
.block
[0];
1541 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data
);
1543 s32
i2c_smbus_write_i2c_block_data(struct i2c_client
*client
, u8 command
,
1544 u8 length
, const u8
*values
)
1546 union i2c_smbus_data data
;
1548 if (length
> I2C_SMBUS_BLOCK_MAX
)
1549 length
= I2C_SMBUS_BLOCK_MAX
;
1550 data
.block
[0] = length
;
1551 memcpy(data
.block
+ 1, values
, length
);
1552 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1553 I2C_SMBUS_WRITE
, command
,
1554 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
1556 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data
);
1558 /* Simulate a SMBus command using the i2c protocol
1559 No checking of parameters is done! */
1560 static s32
i2c_smbus_xfer_emulated(struct i2c_adapter
* adapter
, u16 addr
,
1561 unsigned short flags
,
1562 char read_write
, u8 command
, int size
,
1563 union i2c_smbus_data
* data
)
1565 /* So we need to generate a series of msgs. In the case of writing, we
1566 need to use only one message; when reading, we need two. We initialize
1567 most things with sane defaults, to keep the code below somewhat
1569 unsigned char msgbuf0
[I2C_SMBUS_BLOCK_MAX
+3];
1570 unsigned char msgbuf1
[I2C_SMBUS_BLOCK_MAX
+2];
1571 int num
= read_write
== I2C_SMBUS_READ
?2:1;
1572 struct i2c_msg msg
[2] = { { addr
, flags
, 1, msgbuf0
},
1573 { addr
, flags
| I2C_M_RD
, 0, msgbuf1
}
1579 msgbuf0
[0] = command
;
1581 case I2C_SMBUS_QUICK
:
1583 /* Special case: The read/write field is used as data */
1584 msg
[0].flags
= flags
| (read_write
==I2C_SMBUS_READ
)?I2C_M_RD
:0;
1587 case I2C_SMBUS_BYTE
:
1588 if (read_write
== I2C_SMBUS_READ
) {
1589 /* Special case: only a read! */
1590 msg
[0].flags
= I2C_M_RD
| flags
;
1594 case I2C_SMBUS_BYTE_DATA
:
1595 if (read_write
== I2C_SMBUS_READ
)
1599 msgbuf0
[1] = data
->byte
;
1602 case I2C_SMBUS_WORD_DATA
:
1603 if (read_write
== I2C_SMBUS_READ
)
1607 msgbuf0
[1] = data
->word
& 0xff;
1608 msgbuf0
[2] = data
->word
>> 8;
1611 case I2C_SMBUS_PROC_CALL
:
1612 num
= 2; /* Special case */
1613 read_write
= I2C_SMBUS_READ
;
1616 msgbuf0
[1] = data
->word
& 0xff;
1617 msgbuf0
[2] = data
->word
>> 8;
1619 case I2C_SMBUS_BLOCK_DATA
:
1620 if (read_write
== I2C_SMBUS_READ
) {
1621 msg
[1].flags
|= I2C_M_RECV_LEN
;
1622 msg
[1].len
= 1; /* block length will be added by
1623 the underlying bus driver */
1625 msg
[0].len
= data
->block
[0] + 2;
1626 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 2) {
1627 dev_err(&adapter
->dev
,
1628 "Invalid block write size %d\n",
1632 for (i
= 1; i
< msg
[0].len
; i
++)
1633 msgbuf0
[i
] = data
->block
[i
-1];
1636 case I2C_SMBUS_BLOCK_PROC_CALL
:
1637 num
= 2; /* Another special case */
1638 read_write
= I2C_SMBUS_READ
;
1639 if (data
->block
[0] > I2C_SMBUS_BLOCK_MAX
) {
1640 dev_err(&adapter
->dev
,
1641 "Invalid block write size %d\n",
1645 msg
[0].len
= data
->block
[0] + 2;
1646 for (i
= 1; i
< msg
[0].len
; i
++)
1647 msgbuf0
[i
] = data
->block
[i
-1];
1648 msg
[1].flags
|= I2C_M_RECV_LEN
;
1649 msg
[1].len
= 1; /* block length will be added by
1650 the underlying bus driver */
1652 case I2C_SMBUS_I2C_BLOCK_DATA
:
1653 if (read_write
== I2C_SMBUS_READ
) {
1654 msg
[1].len
= data
->block
[0];
1656 msg
[0].len
= data
->block
[0] + 1;
1657 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 1) {
1658 dev_err(&adapter
->dev
,
1659 "Invalid block write size %d\n",
1663 for (i
= 1; i
<= data
->block
[0]; i
++)
1664 msgbuf0
[i
] = data
->block
[i
];
1668 dev_err(&adapter
->dev
, "Unsupported transaction %d\n", size
);
1672 i
= ((flags
& I2C_CLIENT_PEC
) && size
!= I2C_SMBUS_QUICK
1673 && size
!= I2C_SMBUS_I2C_BLOCK_DATA
);
1675 /* Compute PEC if first message is a write */
1676 if (!(msg
[0].flags
& I2C_M_RD
)) {
1677 if (num
== 1) /* Write only */
1678 i2c_smbus_add_pec(&msg
[0]);
1679 else /* Write followed by read */
1680 partial_pec
= i2c_smbus_msg_pec(0, &msg
[0]);
1682 /* Ask for PEC if last message is a read */
1683 if (msg
[num
-1].flags
& I2C_M_RD
)
1687 status
= i2c_transfer(adapter
, msg
, num
);
1691 /* Check PEC if last message is a read */
1692 if (i
&& (msg
[num
-1].flags
& I2C_M_RD
)) {
1693 status
= i2c_smbus_check_pec(partial_pec
, &msg
[num
-1]);
1698 if (read_write
== I2C_SMBUS_READ
)
1700 case I2C_SMBUS_BYTE
:
1701 data
->byte
= msgbuf0
[0];
1703 case I2C_SMBUS_BYTE_DATA
:
1704 data
->byte
= msgbuf1
[0];
1706 case I2C_SMBUS_WORD_DATA
:
1707 case I2C_SMBUS_PROC_CALL
:
1708 data
->word
= msgbuf1
[0] | (msgbuf1
[1] << 8);
1710 case I2C_SMBUS_I2C_BLOCK_DATA
:
1711 for (i
= 0; i
< data
->block
[0]; i
++)
1712 data
->block
[i
+1] = msgbuf1
[i
];
1714 case I2C_SMBUS_BLOCK_DATA
:
1715 case I2C_SMBUS_BLOCK_PROC_CALL
:
1716 for (i
= 0; i
< msgbuf1
[0] + 1; i
++)
1717 data
->block
[i
] = msgbuf1
[i
];
1724 * i2c_smbus_xfer - execute SMBus protocol operations
1725 * @adapter: Handle to I2C bus
1726 * @addr: Address of SMBus slave on that bus
1727 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
1728 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
1729 * @command: Byte interpreted by slave, for protocols which use such bytes
1730 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
1731 * @data: Data to be read or written
1733 * This executes an SMBus protocol operation, and returns a negative
1734 * errno code else zero on success.
1736 s32
i2c_smbus_xfer(struct i2c_adapter
* adapter
, u16 addr
, unsigned short flags
,
1737 char read_write
, u8 command
, int protocol
,
1738 union i2c_smbus_data
* data
)
1742 flags
&= I2C_M_TEN
| I2C_CLIENT_PEC
;
1744 if (adapter
->algo
->smbus_xfer
) {
1745 mutex_lock(&adapter
->bus_lock
);
1746 res
= adapter
->algo
->smbus_xfer(adapter
,addr
,flags
,read_write
,
1747 command
, protocol
, data
);
1748 mutex_unlock(&adapter
->bus_lock
);
1750 res
= i2c_smbus_xfer_emulated(adapter
,addr
,flags
,read_write
,
1751 command
, protocol
, data
);
1755 EXPORT_SYMBOL(i2c_smbus_xfer
);
1757 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
1758 MODULE_DESCRIPTION("I2C-Bus main module");
1759 MODULE_LICENSE("GPL");