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 /* ----------------------------------------------------
935 * the i2c address scanning function
936 * Will not work for 10-bit addresses!
937 * ----------------------------------------------------
939 static int i2c_probe_address(struct i2c_adapter *adapter, int addr, int kind,
940 int (*found_proc) (struct i2c_adapter *, int, int))
944 /* Make sure the address is valid */
945 if (addr < 0x03 || addr > 0x77) {
946 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
951 /* Skip if already in use */
952 if (i2c_check_addr(adapter, addr))
955 /* Make sure there is something at this address, unless forced */
957 if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
958 I2C_SMBUS_QUICK, NULL) < 0)
961 /* prevent 24RF08 corruption */
962 if ((addr & ~0x0f) == 0x50)
963 i2c_smbus_xfer(adapter, addr, 0, 0, 0,
964 I2C_SMBUS_QUICK, NULL);
967 /* Finally call the custom detection function */
968 err = found_proc(adapter, addr, kind);
969 /* -ENODEV can be returned if there is a chip at the given address
970 but it isn't supported by this chip driver. We catch it here as
971 this isn't an error. */
976 dev_warn(&adapter->dev, "Client creation failed at 0x%x (%d)\n",
981 int i2c_probe(struct i2c_adapter *adapter,
982 struct i2c_client_address_data *address_data,
983 int (*found_proc) (struct i2c_adapter *, int, int))
986 int adap_id = i2c_adapter_id(adapter);
988 /* Force entries are done first, and are not affected by ignore
990 if (address_data->forces) {
991 unsigned short **forces = address_data->forces;
994 for (kind = 0; forces[kind]; kind++) {
995 for (i = 0; forces[kind][i] != I2C_CLIENT_END;
997 if (forces[kind][i] == adap_id
998 || forces[kind][i] == ANY_I2C_BUS) {
999 dev_dbg(&adapter->dev, "found force "
1000 "parameter for adapter %d, "
1001 "addr 0x%02x, kind %d\n",
1002 adap_id, forces[kind][i + 1],
1004 err = i2c_probe_address(adapter,
1005 forces[kind][i + 1],
1014 /* Stop here if we can't use SMBUS_QUICK */
1015 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
1016 if (address_data->probe[0] == I2C_CLIENT_END
1017 && address_data->normal_i2c[0] == I2C_CLIENT_END)
1020 dev_warn(&adapter->dev, "SMBus Quick command not supported, "
1021 "can't probe for chips\n");
1025 /* Probe entries are done second, and are not affected by ignore
1027 for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) {
1028 if (address_data->probe[i] == adap_id
1029 || address_data->probe[i] == ANY_I2C_BUS) {
1030 dev_dbg(&adapter->dev, "found probe parameter for "
1031 "adapter %d, addr 0x%02x\n", adap_id,
1032 address_data->probe[i + 1]);
1033 err = i2c_probe_address(adapter,
1034 address_data->probe[i + 1],
1041 /* Normal entries are done last, unless shadowed by an ignore entry */
1042 for (i = 0; address_data->normal_i2c[i] != I2C_CLIENT_END; i += 1) {
1046 for (j = 0; address_data->ignore[j] != I2C_CLIENT_END;
1048 if ((address_data->ignore[j] == adap_id ||
1049 address_data->ignore[j] == ANY_I2C_BUS)
1050 && address_data->ignore[j + 1]
1051 == address_data->normal_i2c[i]) {
1052 dev_dbg(&adapter->dev, "found ignore "
1053 "parameter for adapter %d, "
1054 "addr 0x%02x\n", adap_id,
1055 address_data->ignore[j + 1]);
1063 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
1064 "addr 0x%02x\n", adap_id,
1065 address_data->normal_i2c[i]);
1066 err = i2c_probe_address(adapter, address_data->normal_i2c[i],
1074 EXPORT_SYMBOL(i2c_probe);
1077 i2c_new_probed_device(struct i2c_adapter *adap,
1078 struct i2c_board_info *info,
1079 unsigned short const *addr_list)
1083 /* Stop here if the bus doesn't support probing */
1084 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) {
1085 dev_err(&adap->dev, "Probing not supported\n");
1089 mutex_lock(&adap->clist_lock);
1090 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
1091 /* Check address validity */
1092 if (addr_list[i] < 0x03 || addr_list[i] > 0x77) {
1093 dev_warn(&adap->dev, "Invalid 7-bit address "
1094 "0x%02x\n", addr_list[i]);
1098 /* Check address availability */
1099 if (__i2c_check_addr(adap, addr_list[i])) {
1100 dev_dbg(&adap->dev, "Address 0x%02x already in "
1101 "use, not probing\n", addr_list[i]);
1105 /* Test address responsiveness
1106 The default probe method is a quick write, but it is known
1107 to corrupt the 24RF08 EEPROMs due to a state machine bug,
1108 and could also irreversibly write-protect some EEPROMs, so
1109 for address ranges 0x30-0x37 and 0x50-0x5f, we use a byte
1110 read instead. Also, some bus drivers don't implement
1111 quick write, so we fallback to a byte read it that case
1113 if ((addr_list[i] & ~0x07) == 0x30
1114 || (addr_list[i] & ~0x0f) == 0x50
1115 || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) {
1116 if (i2c_smbus_xfer(adap, addr_list[i], 0,
1118 I2C_SMBUS_BYTE, NULL) >= 0)
1121 if (i2c_smbus_xfer(adap, addr_list[i], 0,
1123 I2C_SMBUS_QUICK, NULL) >= 0)
1127 mutex_unlock(&adap->clist_lock);
1129 if (addr_list[i] == I2C_CLIENT_END) {
1130 dev_dbg(&adap->dev, "Probing failed, no device found\n");
1134 info->addr = addr_list[i];
1135 return i2c_new_device(adap, info);
1137 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
1139 struct i2c_adapter* i2c_get_adapter(int id)
1141 struct i2c_adapter *adapter;
1143 mutex_lock(&core_lists);
1144 adapter = (struct i2c_adapter *)idr_find(&i2c_adapter_idr, id);
1145 if (adapter && !try_module_get(adapter->owner))
1148 mutex_unlock(&core_lists);
1151 EXPORT_SYMBOL(i2c_get_adapter);
1153 void i2c_put_adapter(struct i2c_adapter *adap)
1155 module_put(adap->owner);
1157 EXPORT_SYMBOL(i2c_put_adapter);
1159 /* The SMBus parts */
1161 #define POLY (0x1070U << 3)
1167 for(i = 0; i < 8; i++) {
1172 return (u8)(data >> 8);
1175 /* Incremental CRC8 over count bytes in the array pointed to by p */
1176 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
1180 for(i = 0; i < count; i++)
1181 crc = crc8((crc ^ p[i]) << 8);
1185 /* Assume a 7-bit address, which is reasonable for SMBus */
1186 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
1188 /* The address will be sent first */
1189 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
1190 pec = i2c_smbus_pec(pec, &addr, 1);
1192 /* The data buffer follows */
1193 return i2c_smbus_pec(pec, msg->buf, msg->len);
1196 /* Used for write only transactions */
1197 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
1199 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
1203 /* Return <0 on CRC error
1204 If there was a write before this read (most cases) we need to take the
1205 partial CRC from the write part into account.
1206 Note that this function does modify the message (we need to decrease the
1207 message length to hide the CRC byte from the caller). */
1208 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
1210 u8 rpec = msg->buf[--msg->len];
1211 cpec = i2c_smbus_msg_pec(cpec, msg);
1214 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
1221 s32 i2c_smbus_write_quick(struct i2c_client *client, u8 value)
1223 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1224 value,0,I2C_SMBUS_QUICK,NULL);
1226 EXPORT_SYMBOL(i2c_smbus_write_quick);
1228 s32 i2c_smbus_read_byte(struct i2c_client *client)
1230 union i2c_smbus_data data;
1231 if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1232 I2C_SMBUS_READ,0,I2C_SMBUS_BYTE, &data))
1237 EXPORT_SYMBOL(i2c_smbus_read_byte);
1239 s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
1241 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1242 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
1244 EXPORT_SYMBOL(i2c_smbus_write_byte);
1246 s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
1248 union i2c_smbus_data data;
1249 if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1250 I2C_SMBUS_READ,command, I2C_SMBUS_BYTE_DATA,&data))
1255 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
1257 s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
1259 union i2c_smbus_data data;
1261 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1262 I2C_SMBUS_WRITE,command,
1263 I2C_SMBUS_BYTE_DATA,&data);
1265 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
1267 s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
1269 union i2c_smbus_data data;
1270 if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1271 I2C_SMBUS_READ,command, I2C_SMBUS_WORD_DATA, &data))
1276 EXPORT_SYMBOL(i2c_smbus_read_word_data);
1278 s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
1280 union i2c_smbus_data data;
1282 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1283 I2C_SMBUS_WRITE,command,
1284 I2C_SMBUS_WORD_DATA,&data);
1286 EXPORT_SYMBOL(i2c_smbus_write_word_data);
1289 * i2c_smbus_read_block_data - SMBus block read request
1290 * @client: Handle to slave device
1291 * @command: Command byte issued to let the slave know what data should
1293 * @values: Byte array into which data will be read; big enough to hold
1294 * the data returned by the slave. SMBus allows at most 32 bytes.
1296 * Returns the number of bytes read in the slave's response, else a
1297 * negative number to indicate some kind of error.
1299 * Note that using this function requires that the client's adapter support
1300 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
1301 * support this; its emulation through I2C messaging relies on a specific
1302 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
1304 s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command,
1307 union i2c_smbus_data data;
1309 if (i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1310 I2C_SMBUS_READ, command,
1311 I2C_SMBUS_BLOCK_DATA, &data))
1314 memcpy(values, &data.block[1], data.block[0]);
1315 return data.block[0];
1317 EXPORT_SYMBOL(i2c_smbus_read_block_data);
1319 s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
1320 u8 length, const u8 *values)
1322 union i2c_smbus_data data;
1324 if (length > I2C_SMBUS_BLOCK_MAX)
1325 length = I2C_SMBUS_BLOCK_MAX;
1326 data.block[0] = length;
1327 memcpy(&data.block[1], values, length);
1328 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1329 I2C_SMBUS_WRITE,command,
1330 I2C_SMBUS_BLOCK_DATA,&data);
1332 EXPORT_SYMBOL(i2c_smbus_write_block_data);
1334 /* Returns the number of read bytes */
1335 s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
1336 u8 length, u8 *values)
1338 union i2c_smbus_data data;
1340 if (length > I2C_SMBUS_BLOCK_MAX)
1341 length = I2C_SMBUS_BLOCK_MAX;
1342 data.block[0] = length;
1343 if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1344 I2C_SMBUS_READ,command,
1345 I2C_SMBUS_I2C_BLOCK_DATA,&data))
1348 memcpy(values, &data.block[1], data.block[0]);
1349 return data.block[0];
1351 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
1353 s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client, u8 command,
1354 u8 length, const u8 *values)
1356 union i2c_smbus_data data;
1358 if (length > I2C_SMBUS_BLOCK_MAX)
1359 length = I2C_SMBUS_BLOCK_MAX;
1360 data.block[0] = length;
1361 memcpy(data.block + 1, values, length);
1362 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1363 I2C_SMBUS_WRITE, command,
1364 I2C_SMBUS_I2C_BLOCK_DATA, &data);
1366 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
1368 /* Simulate a SMBus command using the i2c protocol
1369 No checking of parameters is done! */
1370 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
1371 unsigned short flags,
1372 char read_write, u8 command, int size,
1373 union i2c_smbus_data * data)
1375 /* So we need to generate a series of msgs. In the case of writing, we
1376 need to use only one message; when reading, we need two. We initialize
1377 most things with sane defaults, to keep the code below somewhat
1379 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
1380 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
1381 int num = read_write == I2C_SMBUS_READ?2:1;
1382 struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
1383 { addr, flags | I2C_M_RD, 0, msgbuf1 }
1388 msgbuf0[0] = command;
1390 case I2C_SMBUS_QUICK:
1392 /* Special case: The read/write field is used as data */
1393 msg[0].flags = flags | (read_write==I2C_SMBUS_READ)?I2C_M_RD:0;
1396 case I2C_SMBUS_BYTE:
1397 if (read_write == I2C_SMBUS_READ) {
1398 /* Special case: only a read! */
1399 msg[0].flags = I2C_M_RD | flags;
1403 case I2C_SMBUS_BYTE_DATA:
1404 if (read_write == I2C_SMBUS_READ)
1408 msgbuf0[1] = data->byte;
1411 case I2C_SMBUS_WORD_DATA:
1412 if (read_write == I2C_SMBUS_READ)
1416 msgbuf0[1] = data->word & 0xff;
1417 msgbuf0[2] = data->word >> 8;
1420 case I2C_SMBUS_PROC_CALL:
1421 num = 2; /* Special case */
1422 read_write = I2C_SMBUS_READ;
1425 msgbuf0[1] = data->word & 0xff;
1426 msgbuf0[2] = data->word >> 8;
1428 case I2C_SMBUS_BLOCK_DATA:
1429 if (read_write == I2C_SMBUS_READ) {
1430 msg[1].flags |= I2C_M_RECV_LEN;
1431 msg[1].len = 1; /* block length will be added by
1432 the underlying bus driver */
1434 msg[0].len = data->block[0] + 2;
1435 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
1436 dev_err(&adapter->dev, "smbus_access called with "
1437 "invalid block write size (%d)\n",
1441 for (i = 1; i < msg[0].len; i++)
1442 msgbuf0[i] = data->block[i-1];
1445 case I2C_SMBUS_BLOCK_PROC_CALL:
1446 num = 2; /* Another special case */
1447 read_write = I2C_SMBUS_READ;
1448 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
1449 dev_err(&adapter->dev, "%s called with invalid "
1450 "block proc call size (%d)\n", __FUNCTION__,
1454 msg[0].len = data->block[0] + 2;
1455 for (i = 1; i < msg[0].len; i++)
1456 msgbuf0[i] = data->block[i-1];
1457 msg[1].flags |= I2C_M_RECV_LEN;
1458 msg[1].len = 1; /* block length will be added by
1459 the underlying bus driver */
1461 case I2C_SMBUS_I2C_BLOCK_DATA:
1462 if (read_write == I2C_SMBUS_READ) {
1463 msg[1].len = data->block[0];
1465 msg[0].len = data->block[0] + 1;
1466 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
1467 dev_err(&adapter->dev, "i2c_smbus_xfer_emulated called with "
1468 "invalid block write size (%d)\n",
1472 for (i = 1; i <= data->block[0]; i++)
1473 msgbuf0[i] = data->block[i];
1477 dev_err(&adapter->dev, "smbus_access called with invalid size (%d)\n",
1482 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
1483 && size != I2C_SMBUS_I2C_BLOCK_DATA);
1485 /* Compute PEC if first message is a write */
1486 if (!(msg[0].flags & I2C_M_RD)) {
1487 if (num == 1) /* Write only */
1488 i2c_smbus_add_pec(&msg[0]);
1489 else /* Write followed by read */
1490 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
1492 /* Ask for PEC if last message is a read */
1493 if (msg[num-1].flags & I2C_M_RD)
1497 if (i2c_transfer(adapter, msg, num) < 0)
1500 /* Check PEC if last message is a read */
1501 if (i && (msg[num-1].flags & I2C_M_RD)) {
1502 if (i2c_smbus_check_pec(partial_pec, &msg[num-1]) < 0)
1506 if (read_write == I2C_SMBUS_READ)
1508 case I2C_SMBUS_BYTE:
1509 data->byte = msgbuf0[0];
1511 case I2C_SMBUS_BYTE_DATA:
1512 data->byte = msgbuf1[0];
1514 case I2C_SMBUS_WORD_DATA:
1515 case I2C_SMBUS_PROC_CALL:
1516 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
1518 case I2C_SMBUS_I2C_BLOCK_DATA:
1519 for (i = 0; i < data->block[0]; i++)
1520 data->block[i+1] = msgbuf1[i];
1522 case I2C_SMBUS_BLOCK_DATA:
1523 case I2C_SMBUS_BLOCK_PROC_CALL:
1524 for (i = 0; i < msgbuf1[0] + 1; i++)
1525 data->block[i] = msgbuf1[i];
1532 s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags,
1533 char read_write, u8 command, int size,
1534 union i2c_smbus_data * data)
1538 flags &= I2C_M_TEN | I2C_CLIENT_PEC;
1540 if (adapter->algo->smbus_xfer) {
1541 mutex_lock(&adapter->bus_lock);
1542 res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write,
1544 mutex_unlock(&adapter->bus_lock);
1546 res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write,
1551 EXPORT_SYMBOL(i2c_smbus_xfer);
1553 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
1554 MODULE_DESCRIPTION("I2C-Bus main module");
1555 MODULE_LICENSE("GPL");