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 i2c_client
*client
, *_n
;
586 mutex_lock(&core_lock
);
588 /* First make sure that this adapter was ever added */
589 if (idr_find(&i2c_adapter_idr
, adap
->nr
) != adap
) {
590 pr_debug("i2c-core: attempting to delete unregistered "
591 "adapter [%s]\n", adap
->name
);
596 /* Tell drivers about this removal */
597 res
= bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
602 /* detach any active clients. This must be done first, because
603 * it can fail; in which case we give up. */
604 list_for_each_entry_safe(client
, _n
, &adap
->clients
, list
) {
605 struct i2c_driver
*driver
;
607 driver
= client
->driver
;
609 /* new style, follow standard driver model */
610 if (!driver
|| is_newstyle_driver(driver
)) {
611 i2c_unregister_device(client
);
615 /* legacy drivers create and remove clients themselves */
616 if ((res
= driver
->detach_client(client
))) {
617 dev_err(&adap
->dev
, "detach_client failed for client "
618 "[%s] at address 0x%02x\n", client
->name
,
624 /* clean up the sysfs representation */
625 init_completion(&adap
->dev_released
);
626 device_unregister(&adap
->dev
);
628 /* wait for sysfs to drop all references */
629 wait_for_completion(&adap
->dev_released
);
632 idr_remove(&i2c_adapter_idr
, adap
->nr
);
634 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
637 mutex_unlock(&core_lock
);
640 EXPORT_SYMBOL(i2c_del_adapter
);
643 /* ------------------------------------------------------------------------- */
645 static int __attach_adapter(struct device
*dev
, void *data
)
647 struct i2c_adapter
*adapter
= to_i2c_adapter(dev
);
648 struct i2c_driver
*driver
= data
;
650 driver
->attach_adapter(adapter
);
656 * An i2c_driver is used with one or more i2c_client (device) nodes to access
657 * i2c slave chips, on a bus instance associated with some i2c_adapter. There
658 * are two models for binding the driver to its device: "new style" drivers
659 * follow the standard Linux driver model and just respond to probe() calls
660 * issued if the driver core sees they match(); "legacy" drivers create device
664 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
668 /* new style driver methods can't mix with legacy ones */
669 if (is_newstyle_driver(driver
)) {
670 if (driver
->attach_adapter
|| driver
->detach_adapter
671 || driver
->detach_client
) {
673 "i2c-core: driver [%s] is confused\n",
674 driver
->driver
.name
);
679 /* add the driver to the list of i2c drivers in the driver core */
680 driver
->driver
.owner
= owner
;
681 driver
->driver
.bus
= &i2c_bus_type
;
683 /* for new style drivers, when registration returns the driver core
684 * will have called probe() for all matching-but-unbound devices.
686 res
= driver_register(&driver
->driver
);
690 mutex_lock(&core_lock
);
692 pr_debug("i2c-core: driver [%s] registered\n", driver
->driver
.name
);
694 /* legacy drivers scan i2c busses directly */
695 if (driver
->attach_adapter
)
696 class_for_each_device(&i2c_adapter_class
, driver
,
699 mutex_unlock(&core_lock
);
702 EXPORT_SYMBOL(i2c_register_driver
);
704 static int __detach_adapter(struct device
*dev
, void *data
)
706 struct i2c_adapter
*adapter
= to_i2c_adapter(dev
);
707 struct i2c_driver
*driver
= data
;
709 /* Have a look at each adapter, if clients of this driver are still
710 * attached. If so, detach them to be able to kill the driver
713 if (driver
->detach_adapter
) {
714 if (driver
->detach_adapter(adapter
))
715 dev_err(&adapter
->dev
,
716 "detach_adapter failed for driver [%s]\n",
717 driver
->driver
.name
);
719 struct i2c_client
*client
, *_n
;
721 list_for_each_entry_safe(client
, _n
, &adapter
->clients
, list
) {
722 if (client
->driver
!= driver
)
724 dev_dbg(&adapter
->dev
,
725 "detaching client [%s] at 0x%02x\n",
726 client
->name
, client
->addr
);
727 if (driver
->detach_client(client
))
728 dev_err(&adapter
->dev
, "detach_client "
729 "failed for client [%s] at 0x%02x\n",
730 client
->name
, client
->addr
);
738 * i2c_del_driver - unregister I2C driver
739 * @driver: the driver being unregistered
742 void i2c_del_driver(struct i2c_driver
*driver
)
744 mutex_lock(&core_lock
);
746 /* new-style driver? */
747 if (is_newstyle_driver(driver
))
750 class_for_each_device(&i2c_adapter_class
, driver
, __detach_adapter
);
753 driver_unregister(&driver
->driver
);
754 pr_debug("i2c-core: driver [%s] unregistered\n", driver
->driver
.name
);
756 mutex_unlock(&core_lock
);
758 EXPORT_SYMBOL(i2c_del_driver
);
760 /* ------------------------------------------------------------------------- */
762 static int __i2c_check_addr(struct device
*dev
, void *addrp
)
764 struct i2c_client
*client
= i2c_verify_client(dev
);
765 int addr
= *(int *)addrp
;
767 if (client
&& client
->addr
== addr
)
772 static int i2c_check_addr(struct i2c_adapter
*adapter
, int addr
)
774 return device_for_each_child(&adapter
->dev
, &addr
, __i2c_check_addr
);
777 int i2c_attach_client(struct i2c_client
*client
)
779 struct i2c_adapter
*adapter
= client
->adapter
;
782 client
->dev
.parent
= &client
->adapter
->dev
;
783 client
->dev
.bus
= &i2c_bus_type
;
786 client
->dev
.driver
= &client
->driver
->driver
;
788 if (client
->driver
&& !is_newstyle_driver(client
->driver
)) {
789 client
->dev
.release
= i2c_client_release
;
790 client
->dev
.uevent_suppress
= 1;
792 client
->dev
.release
= i2c_client_dev_release
;
794 snprintf(&client
->dev
.bus_id
[0], sizeof(client
->dev
.bus_id
),
795 "%d-%04x", i2c_adapter_id(adapter
), client
->addr
);
796 res
= device_register(&client
->dev
);
800 mutex_lock(&adapter
->clist_lock
);
801 list_add_tail(&client
->list
, &adapter
->clients
);
802 mutex_unlock(&adapter
->clist_lock
);
804 dev_dbg(&adapter
->dev
, "client [%s] registered with bus id %s\n",
805 client
->name
, client
->dev
.bus_id
);
807 if (adapter
->client_register
) {
808 if (adapter
->client_register(client
)) {
809 dev_dbg(&adapter
->dev
, "client_register "
810 "failed for client [%s] at 0x%02x\n",
811 client
->name
, client
->addr
);
818 dev_err(&adapter
->dev
, "Failed to attach i2c client %s at 0x%02x "
819 "(%d)\n", client
->name
, client
->addr
, res
);
822 EXPORT_SYMBOL(i2c_attach_client
);
824 int i2c_detach_client(struct i2c_client
*client
)
826 struct i2c_adapter
*adapter
= client
->adapter
;
829 if (adapter
->client_unregister
) {
830 res
= adapter
->client_unregister(client
);
832 dev_err(&client
->dev
,
833 "client_unregister [%s] failed, "
834 "client not detached\n", client
->name
);
839 mutex_lock(&adapter
->clist_lock
);
840 list_del(&client
->list
);
841 mutex_unlock(&adapter
->clist_lock
);
843 init_completion(&client
->released
);
844 device_unregister(&client
->dev
);
845 wait_for_completion(&client
->released
);
850 EXPORT_SYMBOL(i2c_detach_client
);
853 * i2c_use_client - increments the reference count of the i2c client structure
854 * @client: the client being referenced
856 * Each live reference to a client should be refcounted. The driver model does
857 * that automatically as part of driver binding, so that most drivers don't
858 * need to do this explicitly: they hold a reference until they're unbound
861 * A pointer to the client with the incremented reference counter is returned.
863 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
865 if (client
&& get_device(&client
->dev
))
869 EXPORT_SYMBOL(i2c_use_client
);
872 * i2c_release_client - release a use of the i2c client structure
873 * @client: the client being no longer referenced
875 * Must be called when a user of a client is finished with it.
877 void i2c_release_client(struct i2c_client
*client
)
880 put_device(&client
->dev
);
882 EXPORT_SYMBOL(i2c_release_client
);
889 static int i2c_cmd(struct device
*dev
, void *_arg
)
891 struct i2c_client
*client
= i2c_verify_client(dev
);
892 struct i2c_cmd_arg
*arg
= _arg
;
894 if (client
&& client
->driver
&& client
->driver
->command
)
895 client
->driver
->command(client
, arg
->cmd
, arg
->arg
);
899 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
901 struct i2c_cmd_arg cmd_arg
;
905 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
907 EXPORT_SYMBOL(i2c_clients_command
);
909 static int __init
i2c_init(void)
913 retval
= bus_register(&i2c_bus_type
);
916 retval
= class_register(&i2c_adapter_class
);
919 retval
= i2c_add_driver(&dummy_driver
);
925 class_unregister(&i2c_adapter_class
);
927 bus_unregister(&i2c_bus_type
);
931 static void __exit
i2c_exit(void)
933 i2c_del_driver(&dummy_driver
);
934 class_unregister(&i2c_adapter_class
);
935 bus_unregister(&i2c_bus_type
);
938 subsys_initcall(i2c_init
);
939 module_exit(i2c_exit
);
941 /* ----------------------------------------------------
942 * the functional interface to the i2c busses.
943 * ----------------------------------------------------
947 * i2c_transfer - execute a single or combined I2C message
948 * @adap: Handle to I2C bus
949 * @msgs: One or more messages to execute before STOP is issued to
950 * terminate the operation; each message begins with a START.
951 * @num: Number of messages to be executed.
953 * Returns negative errno, else the number of messages executed.
955 * Note that there is no requirement that each message be sent to
956 * the same slave address, although that is the most common model.
958 int i2c_transfer(struct i2c_adapter
* adap
, struct i2c_msg
*msgs
, int num
)
962 /* REVISIT the fault reporting model here is weak:
964 * - When we get an error after receiving N bytes from a slave,
965 * there is no way to report "N".
967 * - When we get a NAK after transmitting N bytes to a slave,
968 * there is no way to report "N" ... or to let the master
969 * continue executing the rest of this combined message, if
970 * that's the appropriate response.
972 * - When for example "num" is two and we successfully complete
973 * the first message but get an error part way through the
974 * second, it's unclear whether that should be reported as
975 * one (discarding status on the second message) or errno
976 * (discarding status on the first one).
979 if (adap
->algo
->master_xfer
) {
981 for (ret
= 0; ret
< num
; ret
++) {
982 dev_dbg(&adap
->dev
, "master_xfer[%d] %c, addr=0x%02x, "
983 "len=%d%s\n", ret
, (msgs
[ret
].flags
& I2C_M_RD
)
984 ? 'R' : 'W', msgs
[ret
].addr
, msgs
[ret
].len
,
985 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
989 if (in_atomic() || irqs_disabled()) {
990 ret
= mutex_trylock(&adap
->bus_lock
);
992 /* I2C activity is ongoing. */
995 mutex_lock_nested(&adap
->bus_lock
, adap
->level
);
998 ret
= adap
->algo
->master_xfer(adap
,msgs
,num
);
999 mutex_unlock(&adap
->bus_lock
);
1003 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
1007 EXPORT_SYMBOL(i2c_transfer
);
1010 * i2c_master_send - issue a single I2C message in master transmit mode
1011 * @client: Handle to slave device
1012 * @buf: Data that will be written to the slave
1013 * @count: How many bytes to write
1015 * Returns negative errno, or else the number of bytes written.
1017 int i2c_master_send(struct i2c_client
*client
,const char *buf
,int count
)
1020 struct i2c_adapter
*adap
=client
->adapter
;
1023 msg
.addr
= client
->addr
;
1024 msg
.flags
= client
->flags
& I2C_M_TEN
;
1026 msg
.buf
= (char *)buf
;
1028 ret
= i2c_transfer(adap
, &msg
, 1);
1030 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1031 transmitted, else error code. */
1032 return (ret
== 1) ? count
: ret
;
1034 EXPORT_SYMBOL(i2c_master_send
);
1037 * i2c_master_recv - issue a single I2C message in master receive mode
1038 * @client: Handle to slave device
1039 * @buf: Where to store data read from slave
1040 * @count: How many bytes to read
1042 * Returns negative errno, or else the number of bytes read.
1044 int i2c_master_recv(struct i2c_client
*client
, char *buf
,int count
)
1046 struct i2c_adapter
*adap
=client
->adapter
;
1050 msg
.addr
= client
->addr
;
1051 msg
.flags
= client
->flags
& I2C_M_TEN
;
1052 msg
.flags
|= I2C_M_RD
;
1056 ret
= i2c_transfer(adap
, &msg
, 1);
1058 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1059 transmitted, else error code. */
1060 return (ret
== 1) ? count
: ret
;
1062 EXPORT_SYMBOL(i2c_master_recv
);
1064 /* ----------------------------------------------------
1065 * the i2c address scanning function
1066 * Will not work for 10-bit addresses!
1067 * ----------------------------------------------------
1069 static int i2c_probe_address(struct i2c_adapter
*adapter
, int addr
, int kind
,
1070 int (*found_proc
) (struct i2c_adapter
*, int, int))
1074 /* Make sure the address is valid */
1075 if (addr
< 0x03 || addr
> 0x77) {
1076 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
1081 /* Skip if already in use */
1082 if (i2c_check_addr(adapter
, addr
))
1085 /* Make sure there is something at this address, unless forced */
1087 if (i2c_smbus_xfer(adapter
, addr
, 0, 0, 0,
1088 I2C_SMBUS_QUICK
, NULL
) < 0)
1091 /* prevent 24RF08 corruption */
1092 if ((addr
& ~0x0f) == 0x50)
1093 i2c_smbus_xfer(adapter
, addr
, 0, 0, 0,
1094 I2C_SMBUS_QUICK
, NULL
);
1097 /* Finally call the custom detection function */
1098 err
= found_proc(adapter
, addr
, kind
);
1099 /* -ENODEV can be returned if there is a chip at the given address
1100 but it isn't supported by this chip driver. We catch it here as
1101 this isn't an error. */
1106 dev_warn(&adapter
->dev
, "Client creation failed at 0x%x (%d)\n",
1111 int i2c_probe(struct i2c_adapter
*adapter
,
1112 const struct i2c_client_address_data
*address_data
,
1113 int (*found_proc
) (struct i2c_adapter
*, int, int))
1116 int adap_id
= i2c_adapter_id(adapter
);
1118 /* Force entries are done first, and are not affected by ignore
1120 if (address_data
->forces
) {
1121 const unsigned short * const *forces
= address_data
->forces
;
1124 for (kind
= 0; forces
[kind
]; kind
++) {
1125 for (i
= 0; forces
[kind
][i
] != I2C_CLIENT_END
;
1127 if (forces
[kind
][i
] == adap_id
1128 || forces
[kind
][i
] == ANY_I2C_BUS
) {
1129 dev_dbg(&adapter
->dev
, "found force "
1130 "parameter for adapter %d, "
1131 "addr 0x%02x, kind %d\n",
1132 adap_id
, forces
[kind
][i
+ 1],
1134 err
= i2c_probe_address(adapter
,
1135 forces
[kind
][i
+ 1],
1144 /* Stop here if we can't use SMBUS_QUICK */
1145 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_QUICK
)) {
1146 if (address_data
->probe
[0] == I2C_CLIENT_END
1147 && address_data
->normal_i2c
[0] == I2C_CLIENT_END
)
1150 dev_warn(&adapter
->dev
, "SMBus Quick command not supported, "
1151 "can't probe for chips\n");
1155 /* Probe entries are done second, and are not affected by ignore
1157 for (i
= 0; address_data
->probe
[i
] != I2C_CLIENT_END
; i
+= 2) {
1158 if (address_data
->probe
[i
] == adap_id
1159 || address_data
->probe
[i
] == ANY_I2C_BUS
) {
1160 dev_dbg(&adapter
->dev
, "found probe parameter for "
1161 "adapter %d, addr 0x%02x\n", adap_id
,
1162 address_data
->probe
[i
+ 1]);
1163 err
= i2c_probe_address(adapter
,
1164 address_data
->probe
[i
+ 1],
1171 /* Normal entries are done last, unless shadowed by an ignore entry */
1172 for (i
= 0; address_data
->normal_i2c
[i
] != I2C_CLIENT_END
; i
+= 1) {
1176 for (j
= 0; address_data
->ignore
[j
] != I2C_CLIENT_END
;
1178 if ((address_data
->ignore
[j
] == adap_id
||
1179 address_data
->ignore
[j
] == ANY_I2C_BUS
)
1180 && address_data
->ignore
[j
+ 1]
1181 == address_data
->normal_i2c
[i
]) {
1182 dev_dbg(&adapter
->dev
, "found ignore "
1183 "parameter for adapter %d, "
1184 "addr 0x%02x\n", adap_id
,
1185 address_data
->ignore
[j
+ 1]);
1193 dev_dbg(&adapter
->dev
, "found normal entry for adapter %d, "
1194 "addr 0x%02x\n", adap_id
,
1195 address_data
->normal_i2c
[i
]);
1196 err
= i2c_probe_address(adapter
, address_data
->normal_i2c
[i
],
1204 EXPORT_SYMBOL(i2c_probe
);
1207 i2c_new_probed_device(struct i2c_adapter
*adap
,
1208 struct i2c_board_info
*info
,
1209 unsigned short const *addr_list
)
1213 /* Stop here if the bus doesn't support probing */
1214 if (!i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
)) {
1215 dev_err(&adap
->dev
, "Probing not supported\n");
1219 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
1220 /* Check address validity */
1221 if (addr_list
[i
] < 0x03 || addr_list
[i
] > 0x77) {
1222 dev_warn(&adap
->dev
, "Invalid 7-bit address "
1223 "0x%02x\n", addr_list
[i
]);
1227 /* Check address availability */
1228 if (i2c_check_addr(adap
, addr_list
[i
])) {
1229 dev_dbg(&adap
->dev
, "Address 0x%02x already in "
1230 "use, not probing\n", addr_list
[i
]);
1234 /* Test address responsiveness
1235 The default probe method is a quick write, but it is known
1236 to corrupt the 24RF08 EEPROMs due to a state machine bug,
1237 and could also irreversibly write-protect some EEPROMs, so
1238 for address ranges 0x30-0x37 and 0x50-0x5f, we use a byte
1239 read instead. Also, some bus drivers don't implement
1240 quick write, so we fallback to a byte read it that case
1242 if ((addr_list
[i
] & ~0x07) == 0x30
1243 || (addr_list
[i
] & ~0x0f) == 0x50
1244 || !i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
)) {
1245 if (i2c_smbus_xfer(adap
, addr_list
[i
], 0,
1247 I2C_SMBUS_BYTE
, NULL
) >= 0)
1250 if (i2c_smbus_xfer(adap
, addr_list
[i
], 0,
1252 I2C_SMBUS_QUICK
, NULL
) >= 0)
1257 if (addr_list
[i
] == I2C_CLIENT_END
) {
1258 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
1262 info
->addr
= addr_list
[i
];
1263 return i2c_new_device(adap
, info
);
1265 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
1267 struct i2c_adapter
* i2c_get_adapter(int id
)
1269 struct i2c_adapter
*adapter
;
1271 mutex_lock(&core_lock
);
1272 adapter
= (struct i2c_adapter
*)idr_find(&i2c_adapter_idr
, id
);
1273 if (adapter
&& !try_module_get(adapter
->owner
))
1276 mutex_unlock(&core_lock
);
1279 EXPORT_SYMBOL(i2c_get_adapter
);
1281 void i2c_put_adapter(struct i2c_adapter
*adap
)
1283 module_put(adap
->owner
);
1285 EXPORT_SYMBOL(i2c_put_adapter
);
1287 /* The SMBus parts */
1289 #define POLY (0x1070U << 3)
1295 for(i
= 0; i
< 8; i
++) {
1300 return (u8
)(data
>> 8);
1303 /* Incremental CRC8 over count bytes in the array pointed to by p */
1304 static u8
i2c_smbus_pec(u8 crc
, u8
*p
, size_t count
)
1308 for(i
= 0; i
< count
; i
++)
1309 crc
= crc8((crc
^ p
[i
]) << 8);
1313 /* Assume a 7-bit address, which is reasonable for SMBus */
1314 static u8
i2c_smbus_msg_pec(u8 pec
, struct i2c_msg
*msg
)
1316 /* The address will be sent first */
1317 u8 addr
= (msg
->addr
<< 1) | !!(msg
->flags
& I2C_M_RD
);
1318 pec
= i2c_smbus_pec(pec
, &addr
, 1);
1320 /* The data buffer follows */
1321 return i2c_smbus_pec(pec
, msg
->buf
, msg
->len
);
1324 /* Used for write only transactions */
1325 static inline void i2c_smbus_add_pec(struct i2c_msg
*msg
)
1327 msg
->buf
[msg
->len
] = i2c_smbus_msg_pec(0, msg
);
1331 /* Return <0 on CRC error
1332 If there was a write before this read (most cases) we need to take the
1333 partial CRC from the write part into account.
1334 Note that this function does modify the message (we need to decrease the
1335 message length to hide the CRC byte from the caller). */
1336 static int i2c_smbus_check_pec(u8 cpec
, struct i2c_msg
*msg
)
1338 u8 rpec
= msg
->buf
[--msg
->len
];
1339 cpec
= i2c_smbus_msg_pec(cpec
, msg
);
1342 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
1350 * i2c_smbus_read_byte - SMBus "receive byte" protocol
1351 * @client: Handle to slave device
1353 * This executes the SMBus "receive byte" protocol, returning negative errno
1354 * else the byte received from the device.
1356 s32
i2c_smbus_read_byte(struct i2c_client
*client
)
1358 union i2c_smbus_data data
;
1361 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1363 I2C_SMBUS_BYTE
, &data
);
1364 return (status
< 0) ? status
: data
.byte
;
1366 EXPORT_SYMBOL(i2c_smbus_read_byte
);
1369 * i2c_smbus_write_byte - SMBus "send byte" protocol
1370 * @client: Handle to slave device
1371 * @value: Byte to be sent
1373 * This executes the SMBus "send byte" protocol, returning negative errno
1374 * else zero on success.
1376 s32
i2c_smbus_write_byte(struct i2c_client
*client
, u8 value
)
1378 return i2c_smbus_xfer(client
->adapter
,client
->addr
,client
->flags
,
1379 I2C_SMBUS_WRITE
, value
, I2C_SMBUS_BYTE
, NULL
);
1381 EXPORT_SYMBOL(i2c_smbus_write_byte
);
1384 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
1385 * @client: Handle to slave device
1386 * @command: Byte interpreted by slave
1388 * This executes the SMBus "read byte" protocol, returning negative errno
1389 * else a data byte received from the device.
1391 s32
i2c_smbus_read_byte_data(struct i2c_client
*client
, u8 command
)
1393 union i2c_smbus_data data
;
1396 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1397 I2C_SMBUS_READ
, command
,
1398 I2C_SMBUS_BYTE_DATA
, &data
);
1399 return (status
< 0) ? status
: data
.byte
;
1401 EXPORT_SYMBOL(i2c_smbus_read_byte_data
);
1404 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
1405 * @client: Handle to slave device
1406 * @command: Byte interpreted by slave
1407 * @value: Byte being written
1409 * This executes the SMBus "write byte" protocol, returning negative errno
1410 * else zero on success.
1412 s32
i2c_smbus_write_byte_data(struct i2c_client
*client
, u8 command
, u8 value
)
1414 union i2c_smbus_data data
;
1416 return i2c_smbus_xfer(client
->adapter
,client
->addr
,client
->flags
,
1417 I2C_SMBUS_WRITE
,command
,
1418 I2C_SMBUS_BYTE_DATA
,&data
);
1420 EXPORT_SYMBOL(i2c_smbus_write_byte_data
);
1423 * i2c_smbus_read_word_data - SMBus "read word" protocol
1424 * @client: Handle to slave device
1425 * @command: Byte interpreted by slave
1427 * This executes the SMBus "read word" protocol, returning negative errno
1428 * else a 16-bit unsigned "word" received from the device.
1430 s32
i2c_smbus_read_word_data(struct i2c_client
*client
, u8 command
)
1432 union i2c_smbus_data data
;
1435 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1436 I2C_SMBUS_READ
, command
,
1437 I2C_SMBUS_WORD_DATA
, &data
);
1438 return (status
< 0) ? status
: data
.word
;
1440 EXPORT_SYMBOL(i2c_smbus_read_word_data
);
1443 * i2c_smbus_write_word_data - SMBus "write word" protocol
1444 * @client: Handle to slave device
1445 * @command: Byte interpreted by slave
1446 * @value: 16-bit "word" being written
1448 * This executes the SMBus "write word" protocol, returning negative errno
1449 * else zero on success.
1451 s32
i2c_smbus_write_word_data(struct i2c_client
*client
, u8 command
, u16 value
)
1453 union i2c_smbus_data data
;
1455 return i2c_smbus_xfer(client
->adapter
,client
->addr
,client
->flags
,
1456 I2C_SMBUS_WRITE
,command
,
1457 I2C_SMBUS_WORD_DATA
,&data
);
1459 EXPORT_SYMBOL(i2c_smbus_write_word_data
);
1462 * i2c_smbus_read_block_data - SMBus "block read" protocol
1463 * @client: Handle to slave device
1464 * @command: Byte interpreted by slave
1465 * @values: Byte array into which data will be read; big enough to hold
1466 * the data returned by the slave. SMBus allows at most 32 bytes.
1468 * This executes the SMBus "block read" protocol, returning negative errno
1469 * else the number of data bytes in the slave's response.
1471 * Note that using this function requires that the client's adapter support
1472 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
1473 * support this; its emulation through I2C messaging relies on a specific
1474 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
1476 s32
i2c_smbus_read_block_data(struct i2c_client
*client
, u8 command
,
1479 union i2c_smbus_data data
;
1482 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1483 I2C_SMBUS_READ
, command
,
1484 I2C_SMBUS_BLOCK_DATA
, &data
);
1488 memcpy(values
, &data
.block
[1], data
.block
[0]);
1489 return data
.block
[0];
1491 EXPORT_SYMBOL(i2c_smbus_read_block_data
);
1494 * i2c_smbus_write_block_data - SMBus "block write" protocol
1495 * @client: Handle to slave device
1496 * @command: Byte interpreted by slave
1497 * @length: Size of data block; SMBus allows at most 32 bytes
1498 * @values: Byte array which will be written.
1500 * This executes the SMBus "block write" protocol, returning negative errno
1501 * else zero on success.
1503 s32
i2c_smbus_write_block_data(struct i2c_client
*client
, u8 command
,
1504 u8 length
, const u8
*values
)
1506 union i2c_smbus_data data
;
1508 if (length
> I2C_SMBUS_BLOCK_MAX
)
1509 length
= I2C_SMBUS_BLOCK_MAX
;
1510 data
.block
[0] = length
;
1511 memcpy(&data
.block
[1], values
, length
);
1512 return i2c_smbus_xfer(client
->adapter
,client
->addr
,client
->flags
,
1513 I2C_SMBUS_WRITE
,command
,
1514 I2C_SMBUS_BLOCK_DATA
,&data
);
1516 EXPORT_SYMBOL(i2c_smbus_write_block_data
);
1518 /* Returns the number of read bytes */
1519 s32
i2c_smbus_read_i2c_block_data(struct i2c_client
*client
, u8 command
,
1520 u8 length
, u8
*values
)
1522 union i2c_smbus_data data
;
1525 if (length
> I2C_SMBUS_BLOCK_MAX
)
1526 length
= I2C_SMBUS_BLOCK_MAX
;
1527 data
.block
[0] = length
;
1528 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1529 I2C_SMBUS_READ
, command
,
1530 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
1534 memcpy(values
, &data
.block
[1], data
.block
[0]);
1535 return data
.block
[0];
1537 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data
);
1539 s32
i2c_smbus_write_i2c_block_data(struct i2c_client
*client
, u8 command
,
1540 u8 length
, const u8
*values
)
1542 union i2c_smbus_data data
;
1544 if (length
> I2C_SMBUS_BLOCK_MAX
)
1545 length
= I2C_SMBUS_BLOCK_MAX
;
1546 data
.block
[0] = length
;
1547 memcpy(data
.block
+ 1, values
, length
);
1548 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1549 I2C_SMBUS_WRITE
, command
,
1550 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
1552 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data
);
1554 /* Simulate a SMBus command using the i2c protocol
1555 No checking of parameters is done! */
1556 static s32
i2c_smbus_xfer_emulated(struct i2c_adapter
* adapter
, u16 addr
,
1557 unsigned short flags
,
1558 char read_write
, u8 command
, int size
,
1559 union i2c_smbus_data
* data
)
1561 /* So we need to generate a series of msgs. In the case of writing, we
1562 need to use only one message; when reading, we need two. We initialize
1563 most things with sane defaults, to keep the code below somewhat
1565 unsigned char msgbuf0
[I2C_SMBUS_BLOCK_MAX
+3];
1566 unsigned char msgbuf1
[I2C_SMBUS_BLOCK_MAX
+2];
1567 int num
= read_write
== I2C_SMBUS_READ
?2:1;
1568 struct i2c_msg msg
[2] = { { addr
, flags
, 1, msgbuf0
},
1569 { addr
, flags
| I2C_M_RD
, 0, msgbuf1
}
1575 msgbuf0
[0] = command
;
1577 case I2C_SMBUS_QUICK
:
1579 /* Special case: The read/write field is used as data */
1580 msg
[0].flags
= flags
| (read_write
==I2C_SMBUS_READ
)?I2C_M_RD
:0;
1583 case I2C_SMBUS_BYTE
:
1584 if (read_write
== I2C_SMBUS_READ
) {
1585 /* Special case: only a read! */
1586 msg
[0].flags
= I2C_M_RD
| flags
;
1590 case I2C_SMBUS_BYTE_DATA
:
1591 if (read_write
== I2C_SMBUS_READ
)
1595 msgbuf0
[1] = data
->byte
;
1598 case I2C_SMBUS_WORD_DATA
:
1599 if (read_write
== I2C_SMBUS_READ
)
1603 msgbuf0
[1] = data
->word
& 0xff;
1604 msgbuf0
[2] = data
->word
>> 8;
1607 case I2C_SMBUS_PROC_CALL
:
1608 num
= 2; /* Special case */
1609 read_write
= I2C_SMBUS_READ
;
1612 msgbuf0
[1] = data
->word
& 0xff;
1613 msgbuf0
[2] = data
->word
>> 8;
1615 case I2C_SMBUS_BLOCK_DATA
:
1616 if (read_write
== I2C_SMBUS_READ
) {
1617 msg
[1].flags
|= I2C_M_RECV_LEN
;
1618 msg
[1].len
= 1; /* block length will be added by
1619 the underlying bus driver */
1621 msg
[0].len
= data
->block
[0] + 2;
1622 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 2) {
1623 dev_err(&adapter
->dev
,
1624 "Invalid block write size %d\n",
1628 for (i
= 1; i
< msg
[0].len
; i
++)
1629 msgbuf0
[i
] = data
->block
[i
-1];
1632 case I2C_SMBUS_BLOCK_PROC_CALL
:
1633 num
= 2; /* Another special case */
1634 read_write
= I2C_SMBUS_READ
;
1635 if (data
->block
[0] > I2C_SMBUS_BLOCK_MAX
) {
1636 dev_err(&adapter
->dev
,
1637 "Invalid block write size %d\n",
1641 msg
[0].len
= data
->block
[0] + 2;
1642 for (i
= 1; i
< msg
[0].len
; i
++)
1643 msgbuf0
[i
] = data
->block
[i
-1];
1644 msg
[1].flags
|= I2C_M_RECV_LEN
;
1645 msg
[1].len
= 1; /* block length will be added by
1646 the underlying bus driver */
1648 case I2C_SMBUS_I2C_BLOCK_DATA
:
1649 if (read_write
== I2C_SMBUS_READ
) {
1650 msg
[1].len
= data
->block
[0];
1652 msg
[0].len
= data
->block
[0] + 1;
1653 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 1) {
1654 dev_err(&adapter
->dev
,
1655 "Invalid block write size %d\n",
1659 for (i
= 1; i
<= data
->block
[0]; i
++)
1660 msgbuf0
[i
] = data
->block
[i
];
1664 dev_err(&adapter
->dev
, "Unsupported transaction %d\n", size
);
1668 i
= ((flags
& I2C_CLIENT_PEC
) && size
!= I2C_SMBUS_QUICK
1669 && size
!= I2C_SMBUS_I2C_BLOCK_DATA
);
1671 /* Compute PEC if first message is a write */
1672 if (!(msg
[0].flags
& I2C_M_RD
)) {
1673 if (num
== 1) /* Write only */
1674 i2c_smbus_add_pec(&msg
[0]);
1675 else /* Write followed by read */
1676 partial_pec
= i2c_smbus_msg_pec(0, &msg
[0]);
1678 /* Ask for PEC if last message is a read */
1679 if (msg
[num
-1].flags
& I2C_M_RD
)
1683 status
= i2c_transfer(adapter
, msg
, num
);
1687 /* Check PEC if last message is a read */
1688 if (i
&& (msg
[num
-1].flags
& I2C_M_RD
)) {
1689 status
= i2c_smbus_check_pec(partial_pec
, &msg
[num
-1]);
1694 if (read_write
== I2C_SMBUS_READ
)
1696 case I2C_SMBUS_BYTE
:
1697 data
->byte
= msgbuf0
[0];
1699 case I2C_SMBUS_BYTE_DATA
:
1700 data
->byte
= msgbuf1
[0];
1702 case I2C_SMBUS_WORD_DATA
:
1703 case I2C_SMBUS_PROC_CALL
:
1704 data
->word
= msgbuf1
[0] | (msgbuf1
[1] << 8);
1706 case I2C_SMBUS_I2C_BLOCK_DATA
:
1707 for (i
= 0; i
< data
->block
[0]; i
++)
1708 data
->block
[i
+1] = msgbuf1
[i
];
1710 case I2C_SMBUS_BLOCK_DATA
:
1711 case I2C_SMBUS_BLOCK_PROC_CALL
:
1712 for (i
= 0; i
< msgbuf1
[0] + 1; i
++)
1713 data
->block
[i
] = msgbuf1
[i
];
1720 * i2c_smbus_xfer - execute SMBus protocol operations
1721 * @adapter: Handle to I2C bus
1722 * @addr: Address of SMBus slave on that bus
1723 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
1724 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
1725 * @command: Byte interpreted by slave, for protocols which use such bytes
1726 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
1727 * @data: Data to be read or written
1729 * This executes an SMBus protocol operation, and returns a negative
1730 * errno code else zero on success.
1732 s32
i2c_smbus_xfer(struct i2c_adapter
* adapter
, u16 addr
, unsigned short flags
,
1733 char read_write
, u8 command
, int protocol
,
1734 union i2c_smbus_data
* data
)
1738 flags
&= I2C_M_TEN
| I2C_CLIENT_PEC
;
1740 if (adapter
->algo
->smbus_xfer
) {
1741 mutex_lock(&adapter
->bus_lock
);
1742 res
= adapter
->algo
->smbus_xfer(adapter
,addr
,flags
,read_write
,
1743 command
, protocol
, data
);
1744 mutex_unlock(&adapter
->bus_lock
);
1746 res
= i2c_smbus_xfer_emulated(adapter
,addr
,flags
,read_write
,
1747 command
, protocol
, data
);
1751 EXPORT_SYMBOL(i2c_smbus_xfer
);
1753 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
1754 MODULE_DESCRIPTION("I2C-Bus main module");
1755 MODULE_LICENSE("GPL");