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/seq_file.h>
33 #include <linux/platform_device.h>
34 #include <linux/mutex.h>
35 #include <linux/completion.h>
36 #include <asm/uaccess.h>
41 static LIST_HEAD(adapters);
42 static LIST_HEAD(drivers);
43 static DEFINE_MUTEX(core_lists);
44 static DEFINE_IDR(i2c_adapter_idr);
46 #define is_newstyle_driver(d) ((d)->probe || (d)->remove)
48 /* ------------------------------------------------------------------------- */
50 static int i2c_device_match(struct device *dev, struct device_driver *drv)
52 struct i2c_client *client = to_i2c_client(dev);
53 struct i2c_driver *driver = to_i2c_driver(drv);
55 /* make legacy i2c drivers bypass driver model probing entirely;
56 * such drivers scan each i2c adapter/bus themselves.
58 if (!is_newstyle_driver(driver))
61 /* new style drivers use the same kind of driver matching policy
62 * as platform devices or SPI: compare device and driver IDs.
64 return strcmp(client->driver_name, drv->name) == 0;
69 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
70 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
72 struct i2c_client *client = to_i2c_client(dev);
74 /* by definition, legacy drivers can't hotplug */
75 if (dev->driver || !client->driver_name)
78 if (add_uevent_var(env, "MODALIAS=%s", client->driver_name))
80 dev_dbg(dev, "uevent\n");
85 #define i2c_device_uevent NULL
86 #endif /* CONFIG_HOTPLUG */
88 static int i2c_device_probe(struct device *dev)
90 struct i2c_client *client = to_i2c_client(dev);
91 struct i2c_driver *driver = to_i2c_driver(dev->driver);
95 client->driver = driver;
96 dev_dbg(dev, "probe\n");
97 return driver->probe(client);
100 static int i2c_device_remove(struct device *dev)
102 struct i2c_client *client = to_i2c_client(dev);
103 struct i2c_driver *driver;
109 driver = to_i2c_driver(dev->driver);
110 if (driver->remove) {
111 dev_dbg(dev, "remove\n");
112 status = driver->remove(client);
118 client->driver = NULL;
122 static void i2c_device_shutdown(struct device *dev)
124 struct i2c_driver *driver;
128 driver = to_i2c_driver(dev->driver);
129 if (driver->shutdown)
130 driver->shutdown(to_i2c_client(dev));
133 static int i2c_device_suspend(struct device * dev, pm_message_t mesg)
135 struct i2c_driver *driver;
139 driver = to_i2c_driver(dev->driver);
140 if (!driver->suspend)
142 return driver->suspend(to_i2c_client(dev), mesg);
145 static int i2c_device_resume(struct device * dev)
147 struct i2c_driver *driver;
151 driver = to_i2c_driver(dev->driver);
154 return driver->resume(to_i2c_client(dev));
157 static void i2c_client_release(struct device *dev)
159 struct i2c_client *client = to_i2c_client(dev);
160 complete(&client->released);
163 static void i2c_client_dev_release(struct device *dev)
165 kfree(to_i2c_client(dev));
168 static ssize_t show_client_name(struct device *dev, struct device_attribute *attr, char *buf)
170 struct i2c_client *client = to_i2c_client(dev);
171 return sprintf(buf, "%s\n", client->name);
174 static ssize_t show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
176 struct i2c_client *client = to_i2c_client(dev);
177 return client->driver_name
178 ? sprintf(buf, "%s\n", client->driver_name)
182 static struct device_attribute i2c_dev_attrs[] = {
183 __ATTR(name, S_IRUGO, show_client_name, NULL),
184 /* modalias helps coldplug: modprobe $(cat .../modalias) */
185 __ATTR(modalias, S_IRUGO, show_modalias, NULL),
189 static struct bus_type i2c_bus_type = {
191 .dev_attrs = i2c_dev_attrs,
192 .match = i2c_device_match,
193 .uevent = i2c_device_uevent,
194 .probe = i2c_device_probe,
195 .remove = i2c_device_remove,
196 .shutdown = i2c_device_shutdown,
197 .suspend = i2c_device_suspend,
198 .resume = i2c_device_resume,
202 * i2c_new_device - instantiate an i2c device for use with a new style driver
203 * @adap: the adapter managing the device
204 * @info: describes one I2C device; bus_num is ignored
207 * Create a device to work with a new style i2c driver, where binding is
208 * handled through driver model probe()/remove() methods. This call is not
209 * appropriate for use by mainboad initialization logic, which usually runs
210 * during an arch_initcall() long before any i2c_adapter could exist.
212 * This returns the new i2c client, which may be saved for later use with
213 * i2c_unregister_device(); or NULL to indicate an error.
216 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
218 struct i2c_client *client;
221 client = kzalloc(sizeof *client, GFP_KERNEL);
225 client->adapter = adap;
227 client->dev.platform_data = info->platform_data;
228 device_init_wakeup(&client->dev, info->flags & I2C_CLIENT_WAKE);
230 client->flags = info->flags & ~I2C_CLIENT_WAKE;
231 client->addr = info->addr;
232 client->irq = info->irq;
234 strlcpy(client->driver_name, info->driver_name,
235 sizeof(client->driver_name));
236 strlcpy(client->name, info->type, sizeof(client->name));
238 /* a new style driver may be bound to this device when we
239 * return from this function, or any later moment (e.g. maybe
240 * hotplugging will load the driver module). and the device
241 * refcount model is the standard driver model one.
243 status = i2c_attach_client(client);
250 EXPORT_SYMBOL_GPL(i2c_new_device);
254 * i2c_unregister_device - reverse effect of i2c_new_device()
255 * @client: value returned from i2c_new_device()
258 void i2c_unregister_device(struct i2c_client *client)
260 struct i2c_adapter *adapter = client->adapter;
261 struct i2c_driver *driver = client->driver;
263 if (driver && !is_newstyle_driver(driver)) {
264 dev_err(&client->dev, "can't unregister devices "
265 "with legacy drivers\n");
270 mutex_lock(&adapter->clist_lock);
271 list_del(&client->list);
272 mutex_unlock(&adapter->clist_lock);
274 device_unregister(&client->dev);
276 EXPORT_SYMBOL_GPL(i2c_unregister_device);
279 /* ------------------------------------------------------------------------- */
281 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
283 static void i2c_adapter_dev_release(struct device *dev)
285 struct i2c_adapter *adap = to_i2c_adapter(dev);
286 complete(&adap->dev_released);
290 show_adapter_name(struct device *dev, struct device_attribute *attr, char *buf)
292 struct i2c_adapter *adap = to_i2c_adapter(dev);
293 return sprintf(buf, "%s\n", adap->name);
296 static struct device_attribute i2c_adapter_attrs[] = {
297 __ATTR(name, S_IRUGO, show_adapter_name, NULL),
301 static struct class i2c_adapter_class = {
302 .owner = THIS_MODULE,
303 .name = "i2c-adapter",
304 .dev_attrs = i2c_adapter_attrs,
307 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
309 struct i2c_devinfo *devinfo;
311 mutex_lock(&__i2c_board_lock);
312 list_for_each_entry(devinfo, &__i2c_board_list, list) {
313 if (devinfo->busnum == adapter->nr
314 && !i2c_new_device(adapter,
315 &devinfo->board_info))
316 printk(KERN_ERR "i2c-core: can't create i2c%d-%04x\n",
317 i2c_adapter_id(adapter),
318 devinfo->board_info.addr);
320 mutex_unlock(&__i2c_board_lock);
323 static int i2c_register_adapter(struct i2c_adapter *adap)
326 struct list_head *item;
327 struct i2c_driver *driver;
329 mutex_init(&adap->bus_lock);
330 mutex_init(&adap->clist_lock);
331 INIT_LIST_HEAD(&adap->clients);
333 mutex_lock(&core_lists);
334 list_add_tail(&adap->list, &adapters);
336 /* Add the adapter to the driver core.
337 * If the parent pointer is not set up,
338 * we add this adapter to the host bus.
340 if (adap->dev.parent == NULL) {
341 adap->dev.parent = &platform_bus;
342 pr_debug("I2C adapter driver [%s] forgot to specify "
343 "physical device\n", adap->name);
345 sprintf(adap->dev.bus_id, "i2c-%d", adap->nr);
346 adap->dev.release = &i2c_adapter_dev_release;
347 adap->dev.class = &i2c_adapter_class;
348 res = device_register(&adap->dev);
352 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
354 /* create pre-declared device nodes for new-style drivers */
355 if (adap->nr < __i2c_first_dynamic_bus_num)
356 i2c_scan_static_board_info(adap);
358 /* let legacy drivers scan this bus for matching devices */
359 list_for_each(item,&drivers) {
360 driver = list_entry(item, struct i2c_driver, list);
361 if (driver->attach_adapter)
362 /* We ignore the return code; if it fails, too bad */
363 driver->attach_adapter(adap);
367 mutex_unlock(&core_lists);
371 list_del(&adap->list);
372 idr_remove(&i2c_adapter_idr, adap->nr);
377 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
378 * @adapter: the adapter to add
381 * This routine is used to declare an I2C adapter when its bus number
382 * doesn't matter. Examples: for I2C adapters dynamically added by
383 * USB links or PCI plugin cards.
385 * When this returns zero, a new bus number was allocated and stored
386 * in adap->nr, and the specified adapter became available for clients.
387 * Otherwise, a negative errno value is returned.
389 int i2c_add_adapter(struct i2c_adapter *adapter)
394 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
397 mutex_lock(&core_lists);
398 /* "above" here means "above or equal to", sigh */
399 res = idr_get_new_above(&i2c_adapter_idr, adapter,
400 __i2c_first_dynamic_bus_num, &id);
401 mutex_unlock(&core_lists);
410 return i2c_register_adapter(adapter);
412 EXPORT_SYMBOL(i2c_add_adapter);
415 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
416 * @adap: the adapter to register (with adap->nr initialized)
419 * This routine is used to declare an I2C adapter when its bus number
420 * matters. Example: for I2C adapters from system-on-chip CPUs, or
421 * otherwise built in to the system's mainboard, and where i2c_board_info
422 * is used to properly configure I2C devices.
424 * If no devices have pre-been declared for this bus, then be sure to
425 * register the adapter before any dynamically allocated ones. Otherwise
426 * the required bus ID may not be available.
428 * When this returns zero, the specified adapter became available for
429 * clients using the bus number provided in adap->nr. Also, the table
430 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
431 * and the appropriate driver model device nodes are created. Otherwise, a
432 * negative errno value is returned.
434 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
439 if (adap->nr & ~MAX_ID_MASK)
443 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
446 mutex_lock(&core_lists);
447 /* "above" here means "above or equal to", sigh;
448 * we need the "equal to" result to force the result
450 status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id);
451 if (status == 0 && id != adap->nr) {
453 idr_remove(&i2c_adapter_idr, id);
455 mutex_unlock(&core_lists);
456 if (status == -EAGAIN)
460 status = i2c_register_adapter(adap);
463 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
466 * i2c_del_adapter - unregister I2C adapter
467 * @adap: the adapter being unregistered
470 * This unregisters an I2C adapter which was previously registered
471 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
473 int i2c_del_adapter(struct i2c_adapter *adap)
475 struct list_head *item, *_n;
476 struct i2c_adapter *adap_from_list;
477 struct i2c_driver *driver;
478 struct i2c_client *client;
481 mutex_lock(&core_lists);
483 /* First make sure that this adapter was ever added */
484 list_for_each_entry(adap_from_list, &adapters, list) {
485 if (adap_from_list == adap)
488 if (adap_from_list != adap) {
489 pr_debug("i2c-core: attempting to delete unregistered "
490 "adapter [%s]\n", adap->name);
495 list_for_each(item,&drivers) {
496 driver = list_entry(item, struct i2c_driver, list);
497 if (driver->detach_adapter)
498 if ((res = driver->detach_adapter(adap))) {
499 dev_err(&adap->dev, "detach_adapter failed "
501 driver->driver.name);
506 /* detach any active clients. This must be done first, because
507 * it can fail; in which case we give up. */
508 list_for_each_safe(item, _n, &adap->clients) {
509 struct i2c_driver *driver;
511 client = list_entry(item, struct i2c_client, list);
512 driver = client->driver;
514 /* new style, follow standard driver model */
515 if (!driver || is_newstyle_driver(driver)) {
516 i2c_unregister_device(client);
520 /* legacy drivers create and remove clients themselves */
521 if ((res = driver->detach_client(client))) {
522 dev_err(&adap->dev, "detach_client failed for client "
523 "[%s] at address 0x%02x\n", client->name,
529 /* clean up the sysfs representation */
530 init_completion(&adap->dev_released);
531 device_unregister(&adap->dev);
532 list_del(&adap->list);
534 /* wait for sysfs to drop all references */
535 wait_for_completion(&adap->dev_released);
538 idr_remove(&i2c_adapter_idr, adap->nr);
540 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
543 mutex_unlock(&core_lists);
546 EXPORT_SYMBOL(i2c_del_adapter);
549 /* ------------------------------------------------------------------------- */
552 * An i2c_driver is used with one or more i2c_client (device) nodes to access
553 * i2c slave chips, on a bus instance associated with some i2c_adapter. There
554 * are two models for binding the driver to its device: "new style" drivers
555 * follow the standard Linux driver model and just respond to probe() calls
556 * issued if the driver core sees they match(); "legacy" drivers create device
560 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
564 /* new style driver methods can't mix with legacy ones */
565 if (is_newstyle_driver(driver)) {
566 if (driver->attach_adapter || driver->detach_adapter
567 || driver->detach_client) {
569 "i2c-core: driver [%s] is confused\n",
570 driver->driver.name);
575 /* add the driver to the list of i2c drivers in the driver core */
576 driver->driver.owner = owner;
577 driver->driver.bus = &i2c_bus_type;
579 /* for new style drivers, when registration returns the driver core
580 * will have called probe() for all matching-but-unbound devices.
582 res = driver_register(&driver->driver);
586 mutex_lock(&core_lists);
588 list_add_tail(&driver->list,&drivers);
589 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
591 /* legacy drivers scan i2c busses directly */
592 if (driver->attach_adapter) {
593 struct i2c_adapter *adapter;
595 list_for_each_entry(adapter, &adapters, list) {
596 driver->attach_adapter(adapter);
600 mutex_unlock(&core_lists);
603 EXPORT_SYMBOL(i2c_register_driver);
606 * i2c_del_driver - unregister I2C driver
607 * @driver: the driver being unregistered
610 void i2c_del_driver(struct i2c_driver *driver)
612 struct list_head *item1, *item2, *_n;
613 struct i2c_client *client;
614 struct i2c_adapter *adap;
616 mutex_lock(&core_lists);
618 /* new-style driver? */
619 if (is_newstyle_driver(driver))
622 /* Have a look at each adapter, if clients of this driver are still
623 * attached. If so, detach them to be able to kill the driver
626 list_for_each(item1,&adapters) {
627 adap = list_entry(item1, struct i2c_adapter, list);
628 if (driver->detach_adapter) {
629 if (driver->detach_adapter(adap)) {
630 dev_err(&adap->dev, "detach_adapter failed "
632 driver->driver.name);
635 list_for_each_safe(item2, _n, &adap->clients) {
636 client = list_entry(item2, struct i2c_client, list);
637 if (client->driver != driver)
639 dev_dbg(&adap->dev, "detaching client [%s] "
640 "at 0x%02x\n", client->name,
642 if (driver->detach_client(client)) {
643 dev_err(&adap->dev, "detach_client "
644 "failed for client [%s] at "
645 "0x%02x\n", client->name,
653 driver_unregister(&driver->driver);
654 list_del(&driver->list);
655 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
657 mutex_unlock(&core_lists);
659 EXPORT_SYMBOL(i2c_del_driver);
661 /* ------------------------------------------------------------------------- */
663 static int __i2c_check_addr(struct i2c_adapter *adapter, unsigned int addr)
665 struct list_head *item;
666 struct i2c_client *client;
668 list_for_each(item,&adapter->clients) {
669 client = list_entry(item, struct i2c_client, list);
670 if (client->addr == addr)
676 int i2c_check_addr(struct i2c_adapter *adapter, int addr)
680 mutex_lock(&adapter->clist_lock);
681 rval = __i2c_check_addr(adapter, addr);
682 mutex_unlock(&adapter->clist_lock);
686 EXPORT_SYMBOL(i2c_check_addr);
688 int i2c_attach_client(struct i2c_client *client)
690 struct i2c_adapter *adapter = client->adapter;
693 mutex_lock(&adapter->clist_lock);
694 if (__i2c_check_addr(client->adapter, client->addr)) {
698 list_add_tail(&client->list,&adapter->clients);
700 client->usage_count = 0;
702 client->dev.parent = &client->adapter->dev;
703 client->dev.bus = &i2c_bus_type;
706 client->dev.driver = &client->driver->driver;
708 if (client->driver && !is_newstyle_driver(client->driver)) {
709 client->dev.release = i2c_client_release;
710 client->dev.uevent_suppress = 1;
712 client->dev.release = i2c_client_dev_release;
714 snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id),
715 "%d-%04x", i2c_adapter_id(adapter), client->addr);
716 dev_dbg(&adapter->dev, "client [%s] registered with bus id %s\n",
717 client->name, client->dev.bus_id);
718 res = device_register(&client->dev);
721 mutex_unlock(&adapter->clist_lock);
723 if (adapter->client_register) {
724 if (adapter->client_register(client)) {
725 dev_dbg(&adapter->dev, "client_register "
726 "failed for client [%s] at 0x%02x\n",
727 client->name, client->addr);
734 list_del(&client->list);
735 dev_err(&adapter->dev, "Failed to attach i2c client %s at 0x%02x "
736 "(%d)\n", client->name, client->addr, res);
738 mutex_unlock(&adapter->clist_lock);
741 EXPORT_SYMBOL(i2c_attach_client);
743 int i2c_detach_client(struct i2c_client *client)
745 struct i2c_adapter *adapter = client->adapter;
748 if (client->usage_count > 0) {
749 dev_warn(&client->dev, "Client [%s] still busy, "
750 "can't detach\n", client->name);
754 if (adapter->client_unregister) {
755 res = adapter->client_unregister(client);
757 dev_err(&client->dev,
758 "client_unregister [%s] failed, "
759 "client not detached\n", client->name);
764 mutex_lock(&adapter->clist_lock);
765 list_del(&client->list);
766 init_completion(&client->released);
767 device_unregister(&client->dev);
768 mutex_unlock(&adapter->clist_lock);
769 wait_for_completion(&client->released);
774 EXPORT_SYMBOL(i2c_detach_client);
776 static int i2c_inc_use_client(struct i2c_client *client)
779 if (!try_module_get(client->driver->driver.owner))
781 if (!try_module_get(client->adapter->owner)) {
782 module_put(client->driver->driver.owner);
789 static void i2c_dec_use_client(struct i2c_client *client)
791 module_put(client->driver->driver.owner);
792 module_put(client->adapter->owner);
795 int i2c_use_client(struct i2c_client *client)
799 ret = i2c_inc_use_client(client);
803 client->usage_count++;
807 EXPORT_SYMBOL(i2c_use_client);
809 int i2c_release_client(struct i2c_client *client)
811 if (!client->usage_count) {
812 pr_debug("i2c-core: %s used one too many times\n",
817 client->usage_count--;
818 i2c_dec_use_client(client);
822 EXPORT_SYMBOL(i2c_release_client);
824 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
826 struct list_head *item;
827 struct i2c_client *client;
829 mutex_lock(&adap->clist_lock);
830 list_for_each(item,&adap->clients) {
831 client = list_entry(item, struct i2c_client, list);
832 if (!try_module_get(client->driver->driver.owner))
834 if (NULL != client->driver->command) {
835 mutex_unlock(&adap->clist_lock);
836 client->driver->command(client,cmd,arg);
837 mutex_lock(&adap->clist_lock);
839 module_put(client->driver->driver.owner);
841 mutex_unlock(&adap->clist_lock);
843 EXPORT_SYMBOL(i2c_clients_command);
845 static int __init i2c_init(void)
849 retval = bus_register(&i2c_bus_type);
852 return class_register(&i2c_adapter_class);
855 static void __exit i2c_exit(void)
857 class_unregister(&i2c_adapter_class);
858 bus_unregister(&i2c_bus_type);
861 subsys_initcall(i2c_init);
862 module_exit(i2c_exit);
864 /* ----------------------------------------------------
865 * the functional interface to the i2c busses.
866 * ----------------------------------------------------
869 int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num)
873 if (adap->algo->master_xfer) {
875 for (ret = 0; ret < num; ret++) {
876 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
877 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
878 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
879 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
883 mutex_lock_nested(&adap->bus_lock, adap->level);
884 ret = adap->algo->master_xfer(adap,msgs,num);
885 mutex_unlock(&adap->bus_lock);
889 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
893 EXPORT_SYMBOL(i2c_transfer);
895 int i2c_master_send(struct i2c_client *client,const char *buf ,int count)
898 struct i2c_adapter *adap=client->adapter;
901 msg.addr = client->addr;
902 msg.flags = client->flags & I2C_M_TEN;
904 msg.buf = (char *)buf;
906 ret = i2c_transfer(adap, &msg, 1);
908 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
909 transmitted, else error code. */
910 return (ret == 1) ? count : ret;
912 EXPORT_SYMBOL(i2c_master_send);
914 int i2c_master_recv(struct i2c_client *client, char *buf ,int count)
916 struct i2c_adapter *adap=client->adapter;
920 msg.addr = client->addr;
921 msg.flags = client->flags & I2C_M_TEN;
922 msg.flags |= I2C_M_RD;
926 ret = i2c_transfer(adap, &msg, 1);
928 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
929 transmitted, else error code. */
930 return (ret == 1) ? count : ret;
932 EXPORT_SYMBOL(i2c_master_recv);
934 int i2c_control(struct i2c_client *client,
935 unsigned int cmd, unsigned long arg)
938 struct i2c_adapter *adap = client->adapter;
940 dev_dbg(&client->adapter->dev, "i2c ioctl, cmd: 0x%x, arg: %#lx\n", cmd, arg);
949 if (adap->algo->algo_control!=NULL)
950 ret = adap->algo->algo_control(adap,cmd,arg);
954 EXPORT_SYMBOL(i2c_control);
956 /* ----------------------------------------------------
957 * the i2c address scanning function
958 * Will not work for 10-bit addresses!
959 * ----------------------------------------------------
961 static int i2c_probe_address(struct i2c_adapter *adapter, int addr, int kind,
962 int (*found_proc) (struct i2c_adapter *, int, int))
966 /* Make sure the address is valid */
967 if (addr < 0x03 || addr > 0x77) {
968 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
973 /* Skip if already in use */
974 if (i2c_check_addr(adapter, addr))
977 /* Make sure there is something at this address, unless forced */
979 if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
980 I2C_SMBUS_QUICK, NULL) < 0)
983 /* prevent 24RF08 corruption */
984 if ((addr & ~0x0f) == 0x50)
985 i2c_smbus_xfer(adapter, addr, 0, 0, 0,
986 I2C_SMBUS_QUICK, NULL);
989 /* Finally call the custom detection function */
990 err = found_proc(adapter, addr, kind);
991 /* -ENODEV can be returned if there is a chip at the given address
992 but it isn't supported by this chip driver. We catch it here as
993 this isn't an error. */
998 dev_warn(&adapter->dev, "Client creation failed at 0x%x (%d)\n",
1003 int i2c_probe(struct i2c_adapter *adapter,
1004 struct i2c_client_address_data *address_data,
1005 int (*found_proc) (struct i2c_adapter *, int, int))
1008 int adap_id = i2c_adapter_id(adapter);
1010 /* Force entries are done first, and are not affected by ignore
1012 if (address_data->forces) {
1013 unsigned short **forces = address_data->forces;
1016 for (kind = 0; forces[kind]; kind++) {
1017 for (i = 0; forces[kind][i] != I2C_CLIENT_END;
1019 if (forces[kind][i] == adap_id
1020 || forces[kind][i] == ANY_I2C_BUS) {
1021 dev_dbg(&adapter->dev, "found force "
1022 "parameter for adapter %d, "
1023 "addr 0x%02x, kind %d\n",
1024 adap_id, forces[kind][i + 1],
1026 err = i2c_probe_address(adapter,
1027 forces[kind][i + 1],
1036 /* Stop here if we can't use SMBUS_QUICK */
1037 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
1038 if (address_data->probe[0] == I2C_CLIENT_END
1039 && address_data->normal_i2c[0] == I2C_CLIENT_END)
1042 dev_warn(&adapter->dev, "SMBus Quick command not supported, "
1043 "can't probe for chips\n");
1047 /* Probe entries are done second, and are not affected by ignore
1049 for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) {
1050 if (address_data->probe[i] == adap_id
1051 || address_data->probe[i] == ANY_I2C_BUS) {
1052 dev_dbg(&adapter->dev, "found probe parameter for "
1053 "adapter %d, addr 0x%02x\n", adap_id,
1054 address_data->probe[i + 1]);
1055 err = i2c_probe_address(adapter,
1056 address_data->probe[i + 1],
1063 /* Normal entries are done last, unless shadowed by an ignore entry */
1064 for (i = 0; address_data->normal_i2c[i] != I2C_CLIENT_END; i += 1) {
1068 for (j = 0; address_data->ignore[j] != I2C_CLIENT_END;
1070 if ((address_data->ignore[j] == adap_id ||
1071 address_data->ignore[j] == ANY_I2C_BUS)
1072 && address_data->ignore[j + 1]
1073 == address_data->normal_i2c[i]) {
1074 dev_dbg(&adapter->dev, "found ignore "
1075 "parameter for adapter %d, "
1076 "addr 0x%02x\n", adap_id,
1077 address_data->ignore[j + 1]);
1085 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
1086 "addr 0x%02x\n", adap_id,
1087 address_data->normal_i2c[i]);
1088 err = i2c_probe_address(adapter, address_data->normal_i2c[i],
1096 EXPORT_SYMBOL(i2c_probe);
1099 i2c_new_probed_device(struct i2c_adapter *adap,
1100 struct i2c_board_info *info,
1101 unsigned short const *addr_list)
1105 /* Stop here if the bus doesn't support probing */
1106 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) {
1107 dev_err(&adap->dev, "Probing not supported\n");
1111 mutex_lock(&adap->clist_lock);
1112 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
1113 /* Check address validity */
1114 if (addr_list[i] < 0x03 || addr_list[i] > 0x77) {
1115 dev_warn(&adap->dev, "Invalid 7-bit address "
1116 "0x%02x\n", addr_list[i]);
1120 /* Check address availability */
1121 if (__i2c_check_addr(adap, addr_list[i])) {
1122 dev_dbg(&adap->dev, "Address 0x%02x already in "
1123 "use, not probing\n", addr_list[i]);
1127 /* Test address responsiveness
1128 The default probe method is a quick write, but it is known
1129 to corrupt the 24RF08 EEPROMs due to a state machine bug,
1130 and could also irreversibly write-protect some EEPROMs, so
1131 for address ranges 0x30-0x37 and 0x50-0x5f, we use a byte
1132 read instead. Also, some bus drivers don't implement
1133 quick write, so we fallback to a byte read it that case
1135 if ((addr_list[i] & ~0x07) == 0x30
1136 || (addr_list[i] & ~0x0f) == 0x50
1137 || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) {
1138 if (i2c_smbus_xfer(adap, addr_list[i], 0,
1140 I2C_SMBUS_BYTE, NULL) >= 0)
1143 if (i2c_smbus_xfer(adap, addr_list[i], 0,
1145 I2C_SMBUS_QUICK, NULL) >= 0)
1149 mutex_unlock(&adap->clist_lock);
1151 if (addr_list[i] == I2C_CLIENT_END) {
1152 dev_dbg(&adap->dev, "Probing failed, no device found\n");
1156 info->addr = addr_list[i];
1157 return i2c_new_device(adap, info);
1159 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
1161 struct i2c_adapter* i2c_get_adapter(int id)
1163 struct i2c_adapter *adapter;
1165 mutex_lock(&core_lists);
1166 adapter = (struct i2c_adapter *)idr_find(&i2c_adapter_idr, id);
1167 if (adapter && !try_module_get(adapter->owner))
1170 mutex_unlock(&core_lists);
1173 EXPORT_SYMBOL(i2c_get_adapter);
1175 void i2c_put_adapter(struct i2c_adapter *adap)
1177 module_put(adap->owner);
1179 EXPORT_SYMBOL(i2c_put_adapter);
1181 /* The SMBus parts */
1183 #define POLY (0x1070U << 3)
1189 for(i = 0; i < 8; i++) {
1194 return (u8)(data >> 8);
1197 /* Incremental CRC8 over count bytes in the array pointed to by p */
1198 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
1202 for(i = 0; i < count; i++)
1203 crc = crc8((crc ^ p[i]) << 8);
1207 /* Assume a 7-bit address, which is reasonable for SMBus */
1208 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
1210 /* The address will be sent first */
1211 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
1212 pec = i2c_smbus_pec(pec, &addr, 1);
1214 /* The data buffer follows */
1215 return i2c_smbus_pec(pec, msg->buf, msg->len);
1218 /* Used for write only transactions */
1219 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
1221 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
1225 /* Return <0 on CRC error
1226 If there was a write before this read (most cases) we need to take the
1227 partial CRC from the write part into account.
1228 Note that this function does modify the message (we need to decrease the
1229 message length to hide the CRC byte from the caller). */
1230 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
1232 u8 rpec = msg->buf[--msg->len];
1233 cpec = i2c_smbus_msg_pec(cpec, msg);
1236 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
1243 s32 i2c_smbus_write_quick(struct i2c_client *client, u8 value)
1245 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1246 value,0,I2C_SMBUS_QUICK,NULL);
1248 EXPORT_SYMBOL(i2c_smbus_write_quick);
1250 s32 i2c_smbus_read_byte(struct i2c_client *client)
1252 union i2c_smbus_data data;
1253 if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1254 I2C_SMBUS_READ,0,I2C_SMBUS_BYTE, &data))
1259 EXPORT_SYMBOL(i2c_smbus_read_byte);
1261 s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
1263 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1264 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
1266 EXPORT_SYMBOL(i2c_smbus_write_byte);
1268 s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
1270 union i2c_smbus_data data;
1271 if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1272 I2C_SMBUS_READ,command, I2C_SMBUS_BYTE_DATA,&data))
1277 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
1279 s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
1281 union i2c_smbus_data data;
1283 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1284 I2C_SMBUS_WRITE,command,
1285 I2C_SMBUS_BYTE_DATA,&data);
1287 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
1289 s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
1291 union i2c_smbus_data data;
1292 if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1293 I2C_SMBUS_READ,command, I2C_SMBUS_WORD_DATA, &data))
1298 EXPORT_SYMBOL(i2c_smbus_read_word_data);
1300 s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
1302 union i2c_smbus_data data;
1304 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1305 I2C_SMBUS_WRITE,command,
1306 I2C_SMBUS_WORD_DATA,&data);
1308 EXPORT_SYMBOL(i2c_smbus_write_word_data);
1311 * i2c_smbus_read_block_data - SMBus block read request
1312 * @client: Handle to slave device
1313 * @command: Command byte issued to let the slave know what data should
1315 * @values: Byte array into which data will be read; big enough to hold
1316 * the data returned by the slave. SMBus allows at most 32 bytes.
1318 * Returns the number of bytes read in the slave's response, else a
1319 * negative number to indicate some kind of error.
1321 * Note that using this function requires that the client's adapter support
1322 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
1323 * support this; its emulation through I2C messaging relies on a specific
1324 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
1326 s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command,
1329 union i2c_smbus_data data;
1331 if (i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1332 I2C_SMBUS_READ, command,
1333 I2C_SMBUS_BLOCK_DATA, &data))
1336 memcpy(values, &data.block[1], data.block[0]);
1337 return data.block[0];
1339 EXPORT_SYMBOL(i2c_smbus_read_block_data);
1341 s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
1342 u8 length, const u8 *values)
1344 union i2c_smbus_data data;
1346 if (length > I2C_SMBUS_BLOCK_MAX)
1347 length = I2C_SMBUS_BLOCK_MAX;
1348 data.block[0] = length;
1349 memcpy(&data.block[1], values, length);
1350 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1351 I2C_SMBUS_WRITE,command,
1352 I2C_SMBUS_BLOCK_DATA,&data);
1354 EXPORT_SYMBOL(i2c_smbus_write_block_data);
1356 /* Returns the number of read bytes */
1357 s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
1358 u8 length, u8 *values)
1360 union i2c_smbus_data data;
1362 if (length > I2C_SMBUS_BLOCK_MAX)
1363 length = I2C_SMBUS_BLOCK_MAX;
1364 data.block[0] = length;
1365 if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1366 I2C_SMBUS_READ,command,
1367 I2C_SMBUS_I2C_BLOCK_DATA,&data))
1370 memcpy(values, &data.block[1], data.block[0]);
1371 return data.block[0];
1373 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
1375 s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client, u8 command,
1376 u8 length, const u8 *values)
1378 union i2c_smbus_data data;
1380 if (length > I2C_SMBUS_BLOCK_MAX)
1381 length = I2C_SMBUS_BLOCK_MAX;
1382 data.block[0] = length;
1383 memcpy(data.block + 1, values, length);
1384 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1385 I2C_SMBUS_WRITE, command,
1386 I2C_SMBUS_I2C_BLOCK_DATA, &data);
1388 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
1390 /* Simulate a SMBus command using the i2c protocol
1391 No checking of parameters is done! */
1392 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
1393 unsigned short flags,
1394 char read_write, u8 command, int size,
1395 union i2c_smbus_data * data)
1397 /* So we need to generate a series of msgs. In the case of writing, we
1398 need to use only one message; when reading, we need two. We initialize
1399 most things with sane defaults, to keep the code below somewhat
1401 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
1402 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
1403 int num = read_write == I2C_SMBUS_READ?2:1;
1404 struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
1405 { addr, flags | I2C_M_RD, 0, msgbuf1 }
1410 msgbuf0[0] = command;
1412 case I2C_SMBUS_QUICK:
1414 /* Special case: The read/write field is used as data */
1415 msg[0].flags = flags | (read_write==I2C_SMBUS_READ)?I2C_M_RD:0;
1418 case I2C_SMBUS_BYTE:
1419 if (read_write == I2C_SMBUS_READ) {
1420 /* Special case: only a read! */
1421 msg[0].flags = I2C_M_RD | flags;
1425 case I2C_SMBUS_BYTE_DATA:
1426 if (read_write == I2C_SMBUS_READ)
1430 msgbuf0[1] = data->byte;
1433 case I2C_SMBUS_WORD_DATA:
1434 if (read_write == I2C_SMBUS_READ)
1438 msgbuf0[1] = data->word & 0xff;
1439 msgbuf0[2] = data->word >> 8;
1442 case I2C_SMBUS_PROC_CALL:
1443 num = 2; /* Special case */
1444 read_write = I2C_SMBUS_READ;
1447 msgbuf0[1] = data->word & 0xff;
1448 msgbuf0[2] = data->word >> 8;
1450 case I2C_SMBUS_BLOCK_DATA:
1451 if (read_write == I2C_SMBUS_READ) {
1452 msg[1].flags |= I2C_M_RECV_LEN;
1453 msg[1].len = 1; /* block length will be added by
1454 the underlying bus driver */
1456 msg[0].len = data->block[0] + 2;
1457 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
1458 dev_err(&adapter->dev, "smbus_access called with "
1459 "invalid block write size (%d)\n",
1463 for (i = 1; i < msg[0].len; i++)
1464 msgbuf0[i] = data->block[i-1];
1467 case I2C_SMBUS_BLOCK_PROC_CALL:
1468 num = 2; /* Another special case */
1469 read_write = I2C_SMBUS_READ;
1470 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
1471 dev_err(&adapter->dev, "%s called with invalid "
1472 "block proc call size (%d)\n", __FUNCTION__,
1476 msg[0].len = data->block[0] + 2;
1477 for (i = 1; i < msg[0].len; i++)
1478 msgbuf0[i] = data->block[i-1];
1479 msg[1].flags |= I2C_M_RECV_LEN;
1480 msg[1].len = 1; /* block length will be added by
1481 the underlying bus driver */
1483 case I2C_SMBUS_I2C_BLOCK_DATA:
1484 if (read_write == I2C_SMBUS_READ) {
1485 msg[1].len = data->block[0];
1487 msg[0].len = data->block[0] + 1;
1488 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
1489 dev_err(&adapter->dev, "i2c_smbus_xfer_emulated called with "
1490 "invalid block write size (%d)\n",
1494 for (i = 1; i <= data->block[0]; i++)
1495 msgbuf0[i] = data->block[i];
1499 dev_err(&adapter->dev, "smbus_access called with invalid size (%d)\n",
1504 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
1505 && size != I2C_SMBUS_I2C_BLOCK_DATA);
1507 /* Compute PEC if first message is a write */
1508 if (!(msg[0].flags & I2C_M_RD)) {
1509 if (num == 1) /* Write only */
1510 i2c_smbus_add_pec(&msg[0]);
1511 else /* Write followed by read */
1512 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
1514 /* Ask for PEC if last message is a read */
1515 if (msg[num-1].flags & I2C_M_RD)
1519 if (i2c_transfer(adapter, msg, num) < 0)
1522 /* Check PEC if last message is a read */
1523 if (i && (msg[num-1].flags & I2C_M_RD)) {
1524 if (i2c_smbus_check_pec(partial_pec, &msg[num-1]) < 0)
1528 if (read_write == I2C_SMBUS_READ)
1530 case I2C_SMBUS_BYTE:
1531 data->byte = msgbuf0[0];
1533 case I2C_SMBUS_BYTE_DATA:
1534 data->byte = msgbuf1[0];
1536 case I2C_SMBUS_WORD_DATA:
1537 case I2C_SMBUS_PROC_CALL:
1538 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
1540 case I2C_SMBUS_I2C_BLOCK_DATA:
1541 for (i = 0; i < data->block[0]; i++)
1542 data->block[i+1] = msgbuf1[i];
1544 case I2C_SMBUS_BLOCK_DATA:
1545 case I2C_SMBUS_BLOCK_PROC_CALL:
1546 for (i = 0; i < msgbuf1[0] + 1; i++)
1547 data->block[i] = msgbuf1[i];
1554 s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags,
1555 char read_write, u8 command, int size,
1556 union i2c_smbus_data * data)
1560 flags &= I2C_M_TEN | I2C_CLIENT_PEC;
1562 if (adapter->algo->smbus_xfer) {
1563 mutex_lock(&adapter->bus_lock);
1564 res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write,
1566 mutex_unlock(&adapter->bus_lock);
1568 res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write,
1573 EXPORT_SYMBOL(i2c_smbus_xfer);
1575 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
1576 MODULE_DESCRIPTION("I2C-Bus main module");
1577 MODULE_LICENSE("GPL");