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1/* i2c-core.c - a device driver for the iic-bus interface */
2/* ------------------------------------------------------------------------- */
3/* Copyright (C) 1995-99 Simon G. Vogl
4
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.
9
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.
14
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., 51 Franklin Street, Fifth Floor, Boston,
18 MA 02110-1301 USA. */
19/* ------------------------------------------------------------------------- */
20
21/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
22 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
23 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
24 Jean Delvare <khali@linux-fr.org>
25 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
26 Michael Lawnick <michael.lawnick.ext@nsn.com> */
27
28#include <linux/module.h>
29#include <linux/kernel.h>
30#include <linux/errno.h>
31#include <linux/slab.h>
32#include <linux/i2c.h>
33#include <linux/init.h>
34#include <linux/idr.h>
35#include <linux/mutex.h>
36#include <linux/of_device.h>
37#include <linux/completion.h>
38#include <linux/hardirq.h>
39#include <linux/irqflags.h>
40#include <linux/rwsem.h>
41#include <linux/pm_runtime.h>
42#include <asm/uaccess.h>
43
44#include "i2c-core.h"
45
46
47/* core_lock protects i2c_adapter_idr, and guarantees
48 that device detection, deletion of detected devices, and attach_adapter
49 and detach_adapter calls are serialized */
50static DEFINE_MUTEX(core_lock);
51static DEFINE_IDR(i2c_adapter_idr);
52
53static struct device_type i2c_client_type;
54static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
55
56/* ------------------------------------------------------------------------- */
57
58static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
59 const struct i2c_client *client)
60{
61 while (id->name[0]) {
62 if (strcmp(client->name, id->name) == 0)
63 return id;
64 id++;
65 }
66 return NULL;
67}
68
69static int i2c_device_match(struct device *dev, struct device_driver *drv)
70{
71 struct i2c_client *client = i2c_verify_client(dev);
72 struct i2c_driver *driver;
73
74 if (!client)
75 return 0;
76
77 /* Attempt an OF style match */
78 if (of_driver_match_device(dev, drv))
79 return 1;
80
81 driver = to_i2c_driver(drv);
82 /* match on an id table if there is one */
83 if (driver->id_table)
84 return i2c_match_id(driver->id_table, client) != NULL;
85
86 return 0;
87}
88
89#ifdef CONFIG_HOTPLUG
90
91/* uevent helps with hotplug: modprobe -q $(MODALIAS) */
92static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
93{
94 struct i2c_client *client = to_i2c_client(dev);
95
96 if (add_uevent_var(env, "MODALIAS=%s%s",
97 I2C_MODULE_PREFIX, client->name))
98 return -ENOMEM;
99 dev_dbg(dev, "uevent\n");
100 return 0;
101}
102
103#else
104#define i2c_device_uevent NULL
105#endif /* CONFIG_HOTPLUG */
106
107static int i2c_device_probe(struct device *dev)
108{
109 struct i2c_client *client = i2c_verify_client(dev);
110 struct i2c_driver *driver;
111 int status;
112
113 if (!client)
114 return 0;
115
116 driver = to_i2c_driver(dev->driver);
117 if (!driver->probe || !driver->id_table)
118 return -ENODEV;
119 client->driver = driver;
120 if (!device_can_wakeup(&client->dev))
121 device_init_wakeup(&client->dev,
122 client->flags & I2C_CLIENT_WAKE);
123 dev_dbg(dev, "probe\n");
124
125 status = driver->probe(client, i2c_match_id(driver->id_table, client));
126 if (status) {
127 client->driver = NULL;
128 i2c_set_clientdata(client, NULL);
129 }
130 return status;
131}
132
133static int i2c_device_remove(struct device *dev)
134{
135 struct i2c_client *client = i2c_verify_client(dev);
136 struct i2c_driver *driver;
137 int status;
138
139 if (!client || !dev->driver)
140 return 0;
141
142 driver = to_i2c_driver(dev->driver);
143 if (driver->remove) {
144 dev_dbg(dev, "remove\n");
145 status = driver->remove(client);
146 } else {
147 dev->driver = NULL;
148 status = 0;
149 }
150 if (status == 0) {
151 client->driver = NULL;
152 i2c_set_clientdata(client, NULL);
153 }
154 return status;
155}
156
157static void i2c_device_shutdown(struct device *dev)
158{
159 struct i2c_client *client = i2c_verify_client(dev);
160 struct i2c_driver *driver;
161
162 if (!client || !dev->driver)
163 return;
164 driver = to_i2c_driver(dev->driver);
165 if (driver->shutdown)
166 driver->shutdown(client);
167}
168
169#ifdef CONFIG_PM_SLEEP
170static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg)
171{
172 struct i2c_client *client = i2c_verify_client(dev);
173 struct i2c_driver *driver;
174
175 if (!client || !dev->driver)
176 return 0;
177 driver = to_i2c_driver(dev->driver);
178 if (!driver->suspend)
179 return 0;
180 return driver->suspend(client, mesg);
181}
182
183static int i2c_legacy_resume(struct device *dev)
184{
185 struct i2c_client *client = i2c_verify_client(dev);
186 struct i2c_driver *driver;
187
188 if (!client || !dev->driver)
189 return 0;
190 driver = to_i2c_driver(dev->driver);
191 if (!driver->resume)
192 return 0;
193 return driver->resume(client);
194}
195
196static int i2c_device_pm_suspend(struct device *dev)
197{
198 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
199
200 if (pm)
201 return pm_generic_suspend(dev);
202 else
203 return i2c_legacy_suspend(dev, PMSG_SUSPEND);
204}
205
206static int i2c_device_pm_resume(struct device *dev)
207{
208 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
209
210 if (pm)
211 return pm_generic_resume(dev);
212 else
213 return i2c_legacy_resume(dev);
214}
215
216static int i2c_device_pm_freeze(struct device *dev)
217{
218 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
219
220 if (pm)
221 return pm_generic_freeze(dev);
222 else
223 return i2c_legacy_suspend(dev, PMSG_FREEZE);
224}
225
226static int i2c_device_pm_thaw(struct device *dev)
227{
228 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
229
230 if (pm)
231 return pm_generic_thaw(dev);
232 else
233 return i2c_legacy_resume(dev);
234}
235
236static int i2c_device_pm_poweroff(struct device *dev)
237{
238 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
239
240 if (pm)
241 return pm_generic_poweroff(dev);
242 else
243 return i2c_legacy_suspend(dev, PMSG_HIBERNATE);
244}
245
246static int i2c_device_pm_restore(struct device *dev)
247{
248 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
249
250 if (pm)
251 return pm_generic_restore(dev);
252 else
253 return i2c_legacy_resume(dev);
254}
255#else /* !CONFIG_PM_SLEEP */
256#define i2c_device_pm_suspend NULL
257#define i2c_device_pm_resume NULL
258#define i2c_device_pm_freeze NULL
259#define i2c_device_pm_thaw NULL
260#define i2c_device_pm_poweroff NULL
261#define i2c_device_pm_restore NULL
262#endif /* !CONFIG_PM_SLEEP */
263
264static void i2c_client_dev_release(struct device *dev)
265{
266 kfree(to_i2c_client(dev));
267}
268
269static ssize_t
270show_name(struct device *dev, struct device_attribute *attr, char *buf)
271{
272 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
273 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
274}
275
276static ssize_t
277show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
278{
279 struct i2c_client *client = to_i2c_client(dev);
280 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
281}
282
283static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
284static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
285
286static struct attribute *i2c_dev_attrs[] = {
287 &dev_attr_name.attr,
288 /* modalias helps coldplug: modprobe $(cat .../modalias) */
289 &dev_attr_modalias.attr,
290 NULL
291};
292
293static struct attribute_group i2c_dev_attr_group = {
294 .attrs = i2c_dev_attrs,
295};
296
297static const struct attribute_group *i2c_dev_attr_groups[] = {
298 &i2c_dev_attr_group,
299 NULL
300};
301
302static const struct dev_pm_ops i2c_device_pm_ops = {
303 .suspend = i2c_device_pm_suspend,
304 .resume = i2c_device_pm_resume,
305 .freeze = i2c_device_pm_freeze,
306 .thaw = i2c_device_pm_thaw,
307 .poweroff = i2c_device_pm_poweroff,
308 .restore = i2c_device_pm_restore,
309 SET_RUNTIME_PM_OPS(
310 pm_generic_runtime_suspend,
311 pm_generic_runtime_resume,
312 pm_generic_runtime_idle
313 )
314};
315
316struct bus_type i2c_bus_type = {
317 .name = "i2c",
318 .match = i2c_device_match,
319 .probe = i2c_device_probe,
320 .remove = i2c_device_remove,
321 .shutdown = i2c_device_shutdown,
322 .pm = &i2c_device_pm_ops,
323};
324EXPORT_SYMBOL_GPL(i2c_bus_type);
325
326static struct device_type i2c_client_type = {
327 .groups = i2c_dev_attr_groups,
328 .uevent = i2c_device_uevent,
329 .release = i2c_client_dev_release,
330};
331
332
333/**
334 * i2c_verify_client - return parameter as i2c_client, or NULL
335 * @dev: device, probably from some driver model iterator
336 *
337 * When traversing the driver model tree, perhaps using driver model
338 * iterators like @device_for_each_child(), you can't assume very much
339 * about the nodes you find. Use this function to avoid oopses caused
340 * by wrongly treating some non-I2C device as an i2c_client.
341 */
342struct i2c_client *i2c_verify_client(struct device *dev)
343{
344 return (dev->type == &i2c_client_type)
345 ? to_i2c_client(dev)
346 : NULL;
347}
348EXPORT_SYMBOL(i2c_verify_client);
349
350
351/* This is a permissive address validity check, I2C address map constraints
352 * are purposely not enforced, except for the general call address. */
353static int i2c_check_client_addr_validity(const struct i2c_client *client)
354{
355 if (client->flags & I2C_CLIENT_TEN) {
356 /* 10-bit address, all values are valid */
357 if (client->addr > 0x3ff)
358 return -EINVAL;
359 } else {
360 /* 7-bit address, reject the general call address */
361 if (client->addr == 0x00 || client->addr > 0x7f)
362 return -EINVAL;
363 }
364 return 0;
365}
366
367/* And this is a strict address validity check, used when probing. If a
368 * device uses a reserved address, then it shouldn't be probed. 7-bit
369 * addressing is assumed, 10-bit address devices are rare and should be
370 * explicitly enumerated. */
371static int i2c_check_addr_validity(unsigned short addr)
372{
373 /*
374 * Reserved addresses per I2C specification:
375 * 0x00 General call address / START byte
376 * 0x01 CBUS address
377 * 0x02 Reserved for different bus format
378 * 0x03 Reserved for future purposes
379 * 0x04-0x07 Hs-mode master code
380 * 0x78-0x7b 10-bit slave addressing
381 * 0x7c-0x7f Reserved for future purposes
382 */
383 if (addr < 0x08 || addr > 0x77)
384 return -EINVAL;
385 return 0;
386}
387
388static int __i2c_check_addr_busy(struct device *dev, void *addrp)
389{
390 struct i2c_client *client = i2c_verify_client(dev);
391 int addr = *(int *)addrp;
392
393 if (client && client->addr == addr)
394 return -EBUSY;
395 return 0;
396}
397
398/* walk up mux tree */
399static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
400{
401 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
402 int result;
403
404 result = device_for_each_child(&adapter->dev, &addr,
405 __i2c_check_addr_busy);
406
407 if (!result && parent)
408 result = i2c_check_mux_parents(parent, addr);
409
410 return result;
411}
412
413/* recurse down mux tree */
414static int i2c_check_mux_children(struct device *dev, void *addrp)
415{
416 int result;
417
418 if (dev->type == &i2c_adapter_type)
419 result = device_for_each_child(dev, addrp,
420 i2c_check_mux_children);
421 else
422 result = __i2c_check_addr_busy(dev, addrp);
423
424 return result;
425}
426
427static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
428{
429 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
430 int result = 0;
431
432 if (parent)
433 result = i2c_check_mux_parents(parent, addr);
434
435 if (!result)
436 result = device_for_each_child(&adapter->dev, &addr,
437 i2c_check_mux_children);
438
439 return result;
440}
441
442/**
443 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
444 * @adapter: Target I2C bus segment
445 */
446void i2c_lock_adapter(struct i2c_adapter *adapter)
447{
448 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
449
450 if (parent)
451 i2c_lock_adapter(parent);
452 else
453 rt_mutex_lock(&adapter->bus_lock);
454}
455EXPORT_SYMBOL_GPL(i2c_lock_adapter);
456
457/**
458 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
459 * @adapter: Target I2C bus segment
460 */
461static int i2c_trylock_adapter(struct i2c_adapter *adapter)
462{
463 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
464
465 if (parent)
466 return i2c_trylock_adapter(parent);
467 else
468 return rt_mutex_trylock(&adapter->bus_lock);
469}
470
471/**
472 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
473 * @adapter: Target I2C bus segment
474 */
475void i2c_unlock_adapter(struct i2c_adapter *adapter)
476{
477 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
478
479 if (parent)
480 i2c_unlock_adapter(parent);
481 else
482 rt_mutex_unlock(&adapter->bus_lock);
483}
484EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
485
486/**
487 * i2c_new_device - instantiate an i2c device
488 * @adap: the adapter managing the device
489 * @info: describes one I2C device; bus_num is ignored
490 * Context: can sleep
491 *
492 * Create an i2c device. Binding is handled through driver model
493 * probe()/remove() methods. A driver may be bound to this device when we
494 * return from this function, or any later moment (e.g. maybe hotplugging will
495 * load the driver module). This call is not appropriate for use by mainboard
496 * initialization logic, which usually runs during an arch_initcall() long
497 * before any i2c_adapter could exist.
498 *
499 * This returns the new i2c client, which may be saved for later use with
500 * i2c_unregister_device(); or NULL to indicate an error.
501 */
502struct i2c_client *
503i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
504{
505 struct i2c_client *client;
506 int status;
507
508 client = kzalloc(sizeof *client, GFP_KERNEL);
509 if (!client)
510 return NULL;
511
512 client->adapter = adap;
513
514 client->dev.platform_data = info->platform_data;
515
516 if (info->archdata)
517 client->dev.archdata = *info->archdata;
518
519 client->flags = info->flags;
520 client->addr = info->addr;
521 client->irq = info->irq;
522
523 strlcpy(client->name, info->type, sizeof(client->name));
524
525 /* Check for address validity */
526 status = i2c_check_client_addr_validity(client);
527 if (status) {
528 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
529 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
530 goto out_err_silent;
531 }
532
533 /* Check for address business */
534 status = i2c_check_addr_busy(adap, client->addr);
535 if (status)
536 goto out_err;
537
538 client->dev.parent = &client->adapter->dev;
539 client->dev.bus = &i2c_bus_type;
540 client->dev.type = &i2c_client_type;
541 client->dev.of_node = info->of_node;
542
543 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
544 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
545 client->addr | ((client->flags & I2C_CLIENT_TEN)
546 ? 0xa000 : 0));
547 status = device_register(&client->dev);
548 if (status)
549 goto out_err;
550
551 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
552 client->name, dev_name(&client->dev));
553
554 return client;
555
556out_err:
557 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
558 "(%d)\n", client->name, client->addr, status);
559out_err_silent:
560 kfree(client);
561 return NULL;
562}
563EXPORT_SYMBOL_GPL(i2c_new_device);
564
565
566/**
567 * i2c_unregister_device - reverse effect of i2c_new_device()
568 * @client: value returned from i2c_new_device()
569 * Context: can sleep
570 */
571void i2c_unregister_device(struct i2c_client *client)
572{
573 device_unregister(&client->dev);
574}
575EXPORT_SYMBOL_GPL(i2c_unregister_device);
576
577
578static const struct i2c_device_id dummy_id[] = {
579 { "dummy", 0 },
580 { },
581};
582
583static int dummy_probe(struct i2c_client *client,
584 const struct i2c_device_id *id)
585{
586 return 0;
587}
588
589static int dummy_remove(struct i2c_client *client)
590{
591 return 0;
592}
593
594static struct i2c_driver dummy_driver = {
595 .driver.name = "dummy",
596 .probe = dummy_probe,
597 .remove = dummy_remove,
598 .id_table = dummy_id,
599};
600
601/**
602 * i2c_new_dummy - return a new i2c device bound to a dummy driver
603 * @adapter: the adapter managing the device
604 * @address: seven bit address to be used
605 * Context: can sleep
606 *
607 * This returns an I2C client bound to the "dummy" driver, intended for use
608 * with devices that consume multiple addresses. Examples of such chips
609 * include various EEPROMS (like 24c04 and 24c08 models).
610 *
611 * These dummy devices have two main uses. First, most I2C and SMBus calls
612 * except i2c_transfer() need a client handle; the dummy will be that handle.
613 * And second, this prevents the specified address from being bound to a
614 * different driver.
615 *
616 * This returns the new i2c client, which should be saved for later use with
617 * i2c_unregister_device(); or NULL to indicate an error.
618 */
619struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
620{
621 struct i2c_board_info info = {
622 I2C_BOARD_INFO("dummy", address),
623 };
624
625 return i2c_new_device(adapter, &info);
626}
627EXPORT_SYMBOL_GPL(i2c_new_dummy);
628
629/* ------------------------------------------------------------------------- */
630
631/* I2C bus adapters -- one roots each I2C or SMBUS segment */
632
633static void i2c_adapter_dev_release(struct device *dev)
634{
635 struct i2c_adapter *adap = to_i2c_adapter(dev);
636 complete(&adap->dev_released);
637}
638
639/*
640 * Let users instantiate I2C devices through sysfs. This can be used when
641 * platform initialization code doesn't contain the proper data for
642 * whatever reason. Also useful for drivers that do device detection and
643 * detection fails, either because the device uses an unexpected address,
644 * or this is a compatible device with different ID register values.
645 *
646 * Parameter checking may look overzealous, but we really don't want
647 * the user to provide incorrect parameters.
648 */
649static ssize_t
650i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
651 const char *buf, size_t count)
652{
653 struct i2c_adapter *adap = to_i2c_adapter(dev);
654 struct i2c_board_info info;
655 struct i2c_client *client;
656 char *blank, end;
657 int res;
658
659 memset(&info, 0, sizeof(struct i2c_board_info));
660
661 blank = strchr(buf, ' ');
662 if (!blank) {
663 dev_err(dev, "%s: Missing parameters\n", "new_device");
664 return -EINVAL;
665 }
666 if (blank - buf > I2C_NAME_SIZE - 1) {
667 dev_err(dev, "%s: Invalid device name\n", "new_device");
668 return -EINVAL;
669 }
670 memcpy(info.type, buf, blank - buf);
671
672 /* Parse remaining parameters, reject extra parameters */
673 res = sscanf(++blank, "%hi%c", &info.addr, &end);
674 if (res < 1) {
675 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
676 return -EINVAL;
677 }
678 if (res > 1 && end != '\n') {
679 dev_err(dev, "%s: Extra parameters\n", "new_device");
680 return -EINVAL;
681 }
682
683 client = i2c_new_device(adap, &info);
684 if (!client)
685 return -EINVAL;
686
687 /* Keep track of the added device */
688 mutex_lock(&adap->userspace_clients_lock);
689 list_add_tail(&client->detected, &adap->userspace_clients);
690 mutex_unlock(&adap->userspace_clients_lock);
691 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
692 info.type, info.addr);
693
694 return count;
695}
696
697/*
698 * And of course let the users delete the devices they instantiated, if
699 * they got it wrong. This interface can only be used to delete devices
700 * instantiated by i2c_sysfs_new_device above. This guarantees that we
701 * don't delete devices to which some kernel code still has references.
702 *
703 * Parameter checking may look overzealous, but we really don't want
704 * the user to delete the wrong device.
705 */
706static ssize_t
707i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
708 const char *buf, size_t count)
709{
710 struct i2c_adapter *adap = to_i2c_adapter(dev);
711 struct i2c_client *client, *next;
712 unsigned short addr;
713 char end;
714 int res;
715
716 /* Parse parameters, reject extra parameters */
717 res = sscanf(buf, "%hi%c", &addr, &end);
718 if (res < 1) {
719 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
720 return -EINVAL;
721 }
722 if (res > 1 && end != '\n') {
723 dev_err(dev, "%s: Extra parameters\n", "delete_device");
724 return -EINVAL;
725 }
726
727 /* Make sure the device was added through sysfs */
728 res = -ENOENT;
729 mutex_lock(&adap->userspace_clients_lock);
730 list_for_each_entry_safe(client, next, &adap->userspace_clients,
731 detected) {
732 if (client->addr == addr) {
733 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
734 "delete_device", client->name, client->addr);
735
736 list_del(&client->detected);
737 i2c_unregister_device(client);
738 res = count;
739 break;
740 }
741 }
742 mutex_unlock(&adap->userspace_clients_lock);
743
744 if (res < 0)
745 dev_err(dev, "%s: Can't find device in list\n",
746 "delete_device");
747 return res;
748}
749
750static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
751static DEVICE_ATTR(delete_device, S_IWUSR, NULL, i2c_sysfs_delete_device);
752
753static struct attribute *i2c_adapter_attrs[] = {
754 &dev_attr_name.attr,
755 &dev_attr_new_device.attr,
756 &dev_attr_delete_device.attr,
757 NULL
758};
759
760static struct attribute_group i2c_adapter_attr_group = {
761 .attrs = i2c_adapter_attrs,
762};
763
764static const struct attribute_group *i2c_adapter_attr_groups[] = {
765 &i2c_adapter_attr_group,
766 NULL
767};
768
769struct device_type i2c_adapter_type = {
770 .groups = i2c_adapter_attr_groups,
771 .release = i2c_adapter_dev_release,
772};
773EXPORT_SYMBOL_GPL(i2c_adapter_type);
774
775/**
776 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
777 * @dev: device, probably from some driver model iterator
778 *
779 * When traversing the driver model tree, perhaps using driver model
780 * iterators like @device_for_each_child(), you can't assume very much
781 * about the nodes you find. Use this function to avoid oopses caused
782 * by wrongly treating some non-I2C device as an i2c_adapter.
783 */
784struct i2c_adapter *i2c_verify_adapter(struct device *dev)
785{
786 return (dev->type == &i2c_adapter_type)
787 ? to_i2c_adapter(dev)
788 : NULL;
789}
790EXPORT_SYMBOL(i2c_verify_adapter);
791
792#ifdef CONFIG_I2C_COMPAT
793static struct class_compat *i2c_adapter_compat_class;
794#endif
795
796static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
797{
798 struct i2c_devinfo *devinfo;
799
800 down_read(&__i2c_board_lock);
801 list_for_each_entry(devinfo, &__i2c_board_list, list) {
802 if (devinfo->busnum == adapter->nr
803 && !i2c_new_device(adapter,
804 &devinfo->board_info))
805 dev_err(&adapter->dev,
806 "Can't create device at 0x%02x\n",
807 devinfo->board_info.addr);
808 }
809 up_read(&__i2c_board_lock);
810}
811
812static int i2c_do_add_adapter(struct i2c_driver *driver,
813 struct i2c_adapter *adap)
814{
815 /* Detect supported devices on that bus, and instantiate them */
816 i2c_detect(adap, driver);
817
818 /* Let legacy drivers scan this bus for matching devices */
819 if (driver->attach_adapter) {
820 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
821 driver->driver.name);
822 dev_warn(&adap->dev, "Please use another way to instantiate "
823 "your i2c_client\n");
824 /* We ignore the return code; if it fails, too bad */
825 driver->attach_adapter(adap);
826 }
827 return 0;
828}
829
830static int __process_new_adapter(struct device_driver *d, void *data)
831{
832 return i2c_do_add_adapter(to_i2c_driver(d), data);
833}
834
835static int i2c_register_adapter(struct i2c_adapter *adap)
836{
837 int res = 0;
838
839 /* Can't register until after driver model init */
840 if (unlikely(WARN_ON(!i2c_bus_type.p))) {
841 res = -EAGAIN;
842 goto out_list;
843 }
844
845 /* Sanity checks */
846 if (unlikely(adap->name[0] == '\0')) {
847 pr_err("i2c-core: Attempt to register an adapter with "
848 "no name!\n");
849 return -EINVAL;
850 }
851 if (unlikely(!adap->algo)) {
852 pr_err("i2c-core: Attempt to register adapter '%s' with "
853 "no algo!\n", adap->name);
854 return -EINVAL;
855 }
856
857 rt_mutex_init(&adap->bus_lock);
858 mutex_init(&adap->userspace_clients_lock);
859 INIT_LIST_HEAD(&adap->userspace_clients);
860
861 /* Set default timeout to 1 second if not already set */
862 if (adap->timeout == 0)
863 adap->timeout = HZ;
864
865 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
866 adap->dev.bus = &i2c_bus_type;
867 adap->dev.type = &i2c_adapter_type;
868 res = device_register(&adap->dev);
869 if (res)
870 goto out_list;
871
872 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
873
874#ifdef CONFIG_I2C_COMPAT
875 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
876 adap->dev.parent);
877 if (res)
878 dev_warn(&adap->dev,
879 "Failed to create compatibility class link\n");
880#endif
881
882 /* create pre-declared device nodes */
883 if (adap->nr < __i2c_first_dynamic_bus_num)
884 i2c_scan_static_board_info(adap);
885
886 /* Notify drivers */
887 mutex_lock(&core_lock);
888 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
889 mutex_unlock(&core_lock);
890
891 return 0;
892
893out_list:
894 mutex_lock(&core_lock);
895 idr_remove(&i2c_adapter_idr, adap->nr);
896 mutex_unlock(&core_lock);
897 return res;
898}
899
900/**
901 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
902 * @adapter: the adapter to add
903 * Context: can sleep
904 *
905 * This routine is used to declare an I2C adapter when its bus number
906 * doesn't matter. Examples: for I2C adapters dynamically added by
907 * USB links or PCI plugin cards.
908 *
909 * When this returns zero, a new bus number was allocated and stored
910 * in adap->nr, and the specified adapter became available for clients.
911 * Otherwise, a negative errno value is returned.
912 */
913int i2c_add_adapter(struct i2c_adapter *adapter)
914{
915 int id, res = 0;
916
917retry:
918 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
919 return -ENOMEM;
920
921 mutex_lock(&core_lock);
922 /* "above" here means "above or equal to", sigh */
923 res = idr_get_new_above(&i2c_adapter_idr, adapter,
924 __i2c_first_dynamic_bus_num, &id);
925 mutex_unlock(&core_lock);
926
927 if (res < 0) {
928 if (res == -EAGAIN)
929 goto retry;
930 return res;
931 }
932
933 adapter->nr = id;
934 return i2c_register_adapter(adapter);
935}
936EXPORT_SYMBOL(i2c_add_adapter);
937
938/**
939 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
940 * @adap: the adapter to register (with adap->nr initialized)
941 * Context: can sleep
942 *
943 * This routine is used to declare an I2C adapter when its bus number
944 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
945 * or otherwise built in to the system's mainboard, and where i2c_board_info
946 * is used to properly configure I2C devices.
947 *
948 * If the requested bus number is set to -1, then this function will behave
949 * identically to i2c_add_adapter, and will dynamically assign a bus number.
950 *
951 * If no devices have pre-been declared for this bus, then be sure to
952 * register the adapter before any dynamically allocated ones. Otherwise
953 * the required bus ID may not be available.
954 *
955 * When this returns zero, the specified adapter became available for
956 * clients using the bus number provided in adap->nr. Also, the table
957 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
958 * and the appropriate driver model device nodes are created. Otherwise, a
959 * negative errno value is returned.
960 */
961int i2c_add_numbered_adapter(struct i2c_adapter *adap)
962{
963 int id;
964 int status;
965
966 if (adap->nr == -1) /* -1 means dynamically assign bus id */
967 return i2c_add_adapter(adap);
968 if (adap->nr & ~MAX_ID_MASK)
969 return -EINVAL;
970
971retry:
972 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
973 return -ENOMEM;
974
975 mutex_lock(&core_lock);
976 /* "above" here means "above or equal to", sigh;
977 * we need the "equal to" result to force the result
978 */
979 status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id);
980 if (status == 0 && id != adap->nr) {
981 status = -EBUSY;
982 idr_remove(&i2c_adapter_idr, id);
983 }
984 mutex_unlock(&core_lock);
985 if (status == -EAGAIN)
986 goto retry;
987
988 if (status == 0)
989 status = i2c_register_adapter(adap);
990 return status;
991}
992EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
993
994static int i2c_do_del_adapter(struct i2c_driver *driver,
995 struct i2c_adapter *adapter)
996{
997 struct i2c_client *client, *_n;
998 int res;
999
1000 /* Remove the devices we created ourselves as the result of hardware
1001 * probing (using a driver's detect method) */
1002 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1003 if (client->adapter == adapter) {
1004 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1005 client->name, client->addr);
1006 list_del(&client->detected);
1007 i2c_unregister_device(client);
1008 }
1009 }
1010
1011 if (!driver->detach_adapter)
1012 return 0;
1013 dev_warn(&adapter->dev, "%s: detach_adapter method is deprecated\n",
1014 driver->driver.name);
1015 res = driver->detach_adapter(adapter);
1016 if (res)
1017 dev_err(&adapter->dev, "detach_adapter failed (%d) "
1018 "for driver [%s]\n", res, driver->driver.name);
1019 return res;
1020}
1021
1022static int __unregister_client(struct device *dev, void *dummy)
1023{
1024 struct i2c_client *client = i2c_verify_client(dev);
1025 if (client && strcmp(client->name, "dummy"))
1026 i2c_unregister_device(client);
1027 return 0;
1028}
1029
1030static int __unregister_dummy(struct device *dev, void *dummy)
1031{
1032 struct i2c_client *client = i2c_verify_client(dev);
1033 if (client)
1034 i2c_unregister_device(client);
1035 return 0;
1036}
1037
1038static int __process_removed_adapter(struct device_driver *d, void *data)
1039{
1040 return i2c_do_del_adapter(to_i2c_driver(d), data);
1041}
1042
1043/**
1044 * i2c_del_adapter - unregister I2C adapter
1045 * @adap: the adapter being unregistered
1046 * Context: can sleep
1047 *
1048 * This unregisters an I2C adapter which was previously registered
1049 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1050 */
1051int i2c_del_adapter(struct i2c_adapter *adap)
1052{
1053 int res = 0;
1054 struct i2c_adapter *found;
1055 struct i2c_client *client, *next;
1056
1057 /* First make sure that this adapter was ever added */
1058 mutex_lock(&core_lock);
1059 found = idr_find(&i2c_adapter_idr, adap->nr);
1060 mutex_unlock(&core_lock);
1061 if (found != adap) {
1062 pr_debug("i2c-core: attempting to delete unregistered "
1063 "adapter [%s]\n", adap->name);
1064 return -EINVAL;
1065 }
1066
1067 /* Tell drivers about this removal */
1068 mutex_lock(&core_lock);
1069 res = bus_for_each_drv(&i2c_bus_type, NULL, adap,
1070 __process_removed_adapter);
1071 mutex_unlock(&core_lock);
1072 if (res)
1073 return res;
1074
1075 /* Remove devices instantiated from sysfs */
1076 mutex_lock(&adap->userspace_clients_lock);
1077 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1078 detected) {
1079 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1080 client->addr);
1081 list_del(&client->detected);
1082 i2c_unregister_device(client);
1083 }
1084 mutex_unlock(&adap->userspace_clients_lock);
1085
1086 /* Detach any active clients. This can't fail, thus we do not
1087 * check the returned value. This is a two-pass process, because
1088 * we can't remove the dummy devices during the first pass: they
1089 * could have been instantiated by real devices wishing to clean
1090 * them up properly, so we give them a chance to do that first. */
1091 res = device_for_each_child(&adap->dev, NULL, __unregister_client);
1092 res = device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1093
1094#ifdef CONFIG_I2C_COMPAT
1095 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1096 adap->dev.parent);
1097#endif
1098
1099 /* device name is gone after device_unregister */
1100 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1101
1102 /* clean up the sysfs representation */
1103 init_completion(&adap->dev_released);
1104 device_unregister(&adap->dev);
1105
1106 /* wait for sysfs to drop all references */
1107 wait_for_completion(&adap->dev_released);
1108
1109 /* free bus id */
1110 mutex_lock(&core_lock);
1111 idr_remove(&i2c_adapter_idr, adap->nr);
1112 mutex_unlock(&core_lock);
1113
1114 /* Clear the device structure in case this adapter is ever going to be
1115 added again */
1116 memset(&adap->dev, 0, sizeof(adap->dev));
1117
1118 return 0;
1119}
1120EXPORT_SYMBOL(i2c_del_adapter);
1121
1122
1123/* ------------------------------------------------------------------------- */
1124
1125int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1126{
1127 int res;
1128
1129 mutex_lock(&core_lock);
1130 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1131 mutex_unlock(&core_lock);
1132
1133 return res;
1134}
1135EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1136
1137static int __process_new_driver(struct device *dev, void *data)
1138{
1139 if (dev->type != &i2c_adapter_type)
1140 return 0;
1141 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1142}
1143
1144/*
1145 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1146 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1147 */
1148
1149int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1150{
1151 int res;
1152
1153 /* Can't register until after driver model init */
1154 if (unlikely(WARN_ON(!i2c_bus_type.p)))
1155 return -EAGAIN;
1156
1157 /* add the driver to the list of i2c drivers in the driver core */
1158 driver->driver.owner = owner;
1159 driver->driver.bus = &i2c_bus_type;
1160
1161 /* When registration returns, the driver core
1162 * will have called probe() for all matching-but-unbound devices.
1163 */
1164 res = driver_register(&driver->driver);
1165 if (res)
1166 return res;
1167
1168 /* Drivers should switch to dev_pm_ops instead. */
1169 if (driver->suspend)
1170 pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
1171 driver->driver.name);
1172 if (driver->resume)
1173 pr_warn("i2c-core: driver [%s] using legacy resume method\n",
1174 driver->driver.name);
1175
1176 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
1177
1178 INIT_LIST_HEAD(&driver->clients);
1179 /* Walk the adapters that are already present */
1180 i2c_for_each_dev(driver, __process_new_driver);
1181
1182 return 0;
1183}
1184EXPORT_SYMBOL(i2c_register_driver);
1185
1186static int __process_removed_driver(struct device *dev, void *data)
1187{
1188 if (dev->type != &i2c_adapter_type)
1189 return 0;
1190 return i2c_do_del_adapter(data, to_i2c_adapter(dev));
1191}
1192
1193/**
1194 * i2c_del_driver - unregister I2C driver
1195 * @driver: the driver being unregistered
1196 * Context: can sleep
1197 */
1198void i2c_del_driver(struct i2c_driver *driver)
1199{
1200 i2c_for_each_dev(driver, __process_removed_driver);
1201
1202 driver_unregister(&driver->driver);
1203 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
1204}
1205EXPORT_SYMBOL(i2c_del_driver);
1206
1207/* ------------------------------------------------------------------------- */
1208
1209/**
1210 * i2c_use_client - increments the reference count of the i2c client structure
1211 * @client: the client being referenced
1212 *
1213 * Each live reference to a client should be refcounted. The driver model does
1214 * that automatically as part of driver binding, so that most drivers don't
1215 * need to do this explicitly: they hold a reference until they're unbound
1216 * from the device.
1217 *
1218 * A pointer to the client with the incremented reference counter is returned.
1219 */
1220struct i2c_client *i2c_use_client(struct i2c_client *client)
1221{
1222 if (client && get_device(&client->dev))
1223 return client;
1224 return NULL;
1225}
1226EXPORT_SYMBOL(i2c_use_client);
1227
1228/**
1229 * i2c_release_client - release a use of the i2c client structure
1230 * @client: the client being no longer referenced
1231 *
1232 * Must be called when a user of a client is finished with it.
1233 */
1234void i2c_release_client(struct i2c_client *client)
1235{
1236 if (client)
1237 put_device(&client->dev);
1238}
1239EXPORT_SYMBOL(i2c_release_client);
1240
1241struct i2c_cmd_arg {
1242 unsigned cmd;
1243 void *arg;
1244};
1245
1246static int i2c_cmd(struct device *dev, void *_arg)
1247{
1248 struct i2c_client *client = i2c_verify_client(dev);
1249 struct i2c_cmd_arg *arg = _arg;
1250
1251 if (client && client->driver && client->driver->command)
1252 client->driver->command(client, arg->cmd, arg->arg);
1253 return 0;
1254}
1255
1256void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1257{
1258 struct i2c_cmd_arg cmd_arg;
1259
1260 cmd_arg.cmd = cmd;
1261 cmd_arg.arg = arg;
1262 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1263}
1264EXPORT_SYMBOL(i2c_clients_command);
1265
1266static int __init i2c_init(void)
1267{
1268 int retval;
1269
1270 retval = bus_register(&i2c_bus_type);
1271 if (retval)
1272 return retval;
1273#ifdef CONFIG_I2C_COMPAT
1274 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1275 if (!i2c_adapter_compat_class) {
1276 retval = -ENOMEM;
1277 goto bus_err;
1278 }
1279#endif
1280 retval = i2c_add_driver(&dummy_driver);
1281 if (retval)
1282 goto class_err;
1283 return 0;
1284
1285class_err:
1286#ifdef CONFIG_I2C_COMPAT
1287 class_compat_unregister(i2c_adapter_compat_class);
1288bus_err:
1289#endif
1290 bus_unregister(&i2c_bus_type);
1291 return retval;
1292}
1293
1294static void __exit i2c_exit(void)
1295{
1296 i2c_del_driver(&dummy_driver);
1297#ifdef CONFIG_I2C_COMPAT
1298 class_compat_unregister(i2c_adapter_compat_class);
1299#endif
1300 bus_unregister(&i2c_bus_type);
1301}
1302
1303/* We must initialize early, because some subsystems register i2c drivers
1304 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1305 */
1306postcore_initcall(i2c_init);
1307module_exit(i2c_exit);
1308
1309/* ----------------------------------------------------
1310 * the functional interface to the i2c busses.
1311 * ----------------------------------------------------
1312 */
1313
1314/**
1315 * i2c_transfer - execute a single or combined I2C message
1316 * @adap: Handle to I2C bus
1317 * @msgs: One or more messages to execute before STOP is issued to
1318 * terminate the operation; each message begins with a START.
1319 * @num: Number of messages to be executed.
1320 *
1321 * Returns negative errno, else the number of messages executed.
1322 *
1323 * Note that there is no requirement that each message be sent to
1324 * the same slave address, although that is the most common model.
1325 */
1326int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1327{
1328 unsigned long orig_jiffies;
1329 int ret, try;
1330
1331 /* REVISIT the fault reporting model here is weak:
1332 *
1333 * - When we get an error after receiving N bytes from a slave,
1334 * there is no way to report "N".
1335 *
1336 * - When we get a NAK after transmitting N bytes to a slave,
1337 * there is no way to report "N" ... or to let the master
1338 * continue executing the rest of this combined message, if
1339 * that's the appropriate response.
1340 *
1341 * - When for example "num" is two and we successfully complete
1342 * the first message but get an error part way through the
1343 * second, it's unclear whether that should be reported as
1344 * one (discarding status on the second message) or errno
1345 * (discarding status on the first one).
1346 */
1347
1348 if (adap->algo->master_xfer) {
1349#ifdef DEBUG
1350 for (ret = 0; ret < num; ret++) {
1351 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
1352 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
1353 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
1354 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1355 }
1356#endif
1357
1358 if (in_atomic() || irqs_disabled()) {
1359 ret = i2c_trylock_adapter(adap);
1360 if (!ret)
1361 /* I2C activity is ongoing. */
1362 return -EAGAIN;
1363 } else {
1364 i2c_lock_adapter(adap);
1365 }
1366
1367 /* Retry automatically on arbitration loss */
1368 orig_jiffies = jiffies;
1369 for (ret = 0, try = 0; try <= adap->retries; try++) {
1370 ret = adap->algo->master_xfer(adap, msgs, num);
1371 if (ret != -EAGAIN)
1372 break;
1373 if (time_after(jiffies, orig_jiffies + adap->timeout))
1374 break;
1375 }
1376 i2c_unlock_adapter(adap);
1377
1378 return ret;
1379 } else {
1380 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1381 return -EOPNOTSUPP;
1382 }
1383}
1384EXPORT_SYMBOL(i2c_transfer);
1385
1386/**
1387 * i2c_master_send - issue a single I2C message in master transmit mode
1388 * @client: Handle to slave device
1389 * @buf: Data that will be written to the slave
1390 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1391 *
1392 * Returns negative errno, or else the number of bytes written.
1393 */
1394int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1395{
1396 int ret;
1397 struct i2c_adapter *adap = client->adapter;
1398 struct i2c_msg msg;
1399
1400 msg.addr = client->addr;
1401 msg.flags = client->flags & I2C_M_TEN;
1402 msg.len = count;
1403 msg.buf = (char *)buf;
1404
1405 ret = i2c_transfer(adap, &msg, 1);
1406
1407 /*
1408 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1409 * transmitted, else error code.
1410 */
1411 return (ret == 1) ? count : ret;
1412}
1413EXPORT_SYMBOL(i2c_master_send);
1414
1415/**
1416 * i2c_master_recv - issue a single I2C message in master receive mode
1417 * @client: Handle to slave device
1418 * @buf: Where to store data read from slave
1419 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1420 *
1421 * Returns negative errno, or else the number of bytes read.
1422 */
1423int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
1424{
1425 struct i2c_adapter *adap = client->adapter;
1426 struct i2c_msg msg;
1427 int ret;
1428
1429 msg.addr = client->addr;
1430 msg.flags = client->flags & I2C_M_TEN;
1431 msg.flags |= I2C_M_RD;
1432 msg.len = count;
1433 msg.buf = buf;
1434
1435 ret = i2c_transfer(adap, &msg, 1);
1436
1437 /*
1438 * If everything went ok (i.e. 1 msg received), return #bytes received,
1439 * else error code.
1440 */
1441 return (ret == 1) ? count : ret;
1442}
1443EXPORT_SYMBOL(i2c_master_recv);
1444
1445/* ----------------------------------------------------
1446 * the i2c address scanning function
1447 * Will not work for 10-bit addresses!
1448 * ----------------------------------------------------
1449 */
1450
1451/*
1452 * Legacy default probe function, mostly relevant for SMBus. The default
1453 * probe method is a quick write, but it is known to corrupt the 24RF08
1454 * EEPROMs due to a state machine bug, and could also irreversibly
1455 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1456 * we use a short byte read instead. Also, some bus drivers don't implement
1457 * quick write, so we fallback to a byte read in that case too.
1458 * On x86, there is another special case for FSC hardware monitoring chips,
1459 * which want regular byte reads (address 0x73.) Fortunately, these are the
1460 * only known chips using this I2C address on PC hardware.
1461 * Returns 1 if probe succeeded, 0 if not.
1462 */
1463static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
1464{
1465 int err;
1466 union i2c_smbus_data dummy;
1467
1468#ifdef CONFIG_X86
1469 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
1470 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
1471 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1472 I2C_SMBUS_BYTE_DATA, &dummy);
1473 else
1474#endif
1475 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
1476 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
1477 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
1478 I2C_SMBUS_QUICK, NULL);
1479 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
1480 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1481 I2C_SMBUS_BYTE, &dummy);
1482 else {
1483 dev_warn(&adap->dev, "No suitable probing method supported\n");
1484 err = -EOPNOTSUPP;
1485 }
1486
1487 return err >= 0;
1488}
1489
1490static int i2c_detect_address(struct i2c_client *temp_client,
1491 struct i2c_driver *driver)
1492{
1493 struct i2c_board_info info;
1494 struct i2c_adapter *adapter = temp_client->adapter;
1495 int addr = temp_client->addr;
1496 int err;
1497
1498 /* Make sure the address is valid */
1499 err = i2c_check_addr_validity(addr);
1500 if (err) {
1501 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
1502 addr);
1503 return err;
1504 }
1505
1506 /* Skip if already in use */
1507 if (i2c_check_addr_busy(adapter, addr))
1508 return 0;
1509
1510 /* Make sure there is something at this address */
1511 if (!i2c_default_probe(adapter, addr))
1512 return 0;
1513
1514 /* Finally call the custom detection function */
1515 memset(&info, 0, sizeof(struct i2c_board_info));
1516 info.addr = addr;
1517 err = driver->detect(temp_client, &info);
1518 if (err) {
1519 /* -ENODEV is returned if the detection fails. We catch it
1520 here as this isn't an error. */
1521 return err == -ENODEV ? 0 : err;
1522 }
1523
1524 /* Consistency check */
1525 if (info.type[0] == '\0') {
1526 dev_err(&adapter->dev, "%s detection function provided "
1527 "no name for 0x%x\n", driver->driver.name,
1528 addr);
1529 } else {
1530 struct i2c_client *client;
1531
1532 /* Detection succeeded, instantiate the device */
1533 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
1534 info.type, info.addr);
1535 client = i2c_new_device(adapter, &info);
1536 if (client)
1537 list_add_tail(&client->detected, &driver->clients);
1538 else
1539 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
1540 info.type, info.addr);
1541 }
1542 return 0;
1543}
1544
1545static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
1546{
1547 const unsigned short *address_list;
1548 struct i2c_client *temp_client;
1549 int i, err = 0;
1550 int adap_id = i2c_adapter_id(adapter);
1551
1552 address_list = driver->address_list;
1553 if (!driver->detect || !address_list)
1554 return 0;
1555
1556 /* Stop here if the classes do not match */
1557 if (!(adapter->class & driver->class))
1558 return 0;
1559
1560 /* Set up a temporary client to help detect callback */
1561 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
1562 if (!temp_client)
1563 return -ENOMEM;
1564 temp_client->adapter = adapter;
1565
1566 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
1567 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
1568 "addr 0x%02x\n", adap_id, address_list[i]);
1569 temp_client->addr = address_list[i];
1570 err = i2c_detect_address(temp_client, driver);
1571 if (unlikely(err))
1572 break;
1573 }
1574
1575 kfree(temp_client);
1576 return err;
1577}
1578
1579int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
1580{
1581 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1582 I2C_SMBUS_QUICK, NULL) >= 0;
1583}
1584EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
1585
1586struct i2c_client *
1587i2c_new_probed_device(struct i2c_adapter *adap,
1588 struct i2c_board_info *info,
1589 unsigned short const *addr_list,
1590 int (*probe)(struct i2c_adapter *, unsigned short addr))
1591{
1592 int i;
1593
1594 if (!probe)
1595 probe = i2c_default_probe;
1596
1597 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
1598 /* Check address validity */
1599 if (i2c_check_addr_validity(addr_list[i]) < 0) {
1600 dev_warn(&adap->dev, "Invalid 7-bit address "
1601 "0x%02x\n", addr_list[i]);
1602 continue;
1603 }
1604
1605 /* Check address availability */
1606 if (i2c_check_addr_busy(adap, addr_list[i])) {
1607 dev_dbg(&adap->dev, "Address 0x%02x already in "
1608 "use, not probing\n", addr_list[i]);
1609 continue;
1610 }
1611
1612 /* Test address responsiveness */
1613 if (probe(adap, addr_list[i]))
1614 break;
1615 }
1616
1617 if (addr_list[i] == I2C_CLIENT_END) {
1618 dev_dbg(&adap->dev, "Probing failed, no device found\n");
1619 return NULL;
1620 }
1621
1622 info->addr = addr_list[i];
1623 return i2c_new_device(adap, info);
1624}
1625EXPORT_SYMBOL_GPL(i2c_new_probed_device);
1626
1627struct i2c_adapter *i2c_get_adapter(int nr)
1628{
1629 struct i2c_adapter *adapter;
1630
1631 mutex_lock(&core_lock);
1632 adapter = idr_find(&i2c_adapter_idr, nr);
1633 if (adapter && !try_module_get(adapter->owner))
1634 adapter = NULL;
1635
1636 mutex_unlock(&core_lock);
1637 return adapter;
1638}
1639EXPORT_SYMBOL(i2c_get_adapter);
1640
1641void i2c_put_adapter(struct i2c_adapter *adap)
1642{
1643 module_put(adap->owner);
1644}
1645EXPORT_SYMBOL(i2c_put_adapter);
1646
1647/* The SMBus parts */
1648
1649#define POLY (0x1070U << 3)
1650static u8 crc8(u16 data)
1651{
1652 int i;
1653
1654 for (i = 0; i < 8; i++) {
1655 if (data & 0x8000)
1656 data = data ^ POLY;
1657 data = data << 1;
1658 }
1659 return (u8)(data >> 8);
1660}
1661
1662/* Incremental CRC8 over count bytes in the array pointed to by p */
1663static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
1664{
1665 int i;
1666
1667 for (i = 0; i < count; i++)
1668 crc = crc8((crc ^ p[i]) << 8);
1669 return crc;
1670}
1671
1672/* Assume a 7-bit address, which is reasonable for SMBus */
1673static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
1674{
1675 /* The address will be sent first */
1676 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
1677 pec = i2c_smbus_pec(pec, &addr, 1);
1678
1679 /* The data buffer follows */
1680 return i2c_smbus_pec(pec, msg->buf, msg->len);
1681}
1682
1683/* Used for write only transactions */
1684static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
1685{
1686 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
1687 msg->len++;
1688}
1689
1690/* Return <0 on CRC error
1691 If there was a write before this read (most cases) we need to take the
1692 partial CRC from the write part into account.
1693 Note that this function does modify the message (we need to decrease the
1694 message length to hide the CRC byte from the caller). */
1695static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
1696{
1697 u8 rpec = msg->buf[--msg->len];
1698 cpec = i2c_smbus_msg_pec(cpec, msg);
1699
1700 if (rpec != cpec) {
1701 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
1702 rpec, cpec);
1703 return -EBADMSG;
1704 }
1705 return 0;
1706}
1707
1708/**
1709 * i2c_smbus_read_byte - SMBus "receive byte" protocol
1710 * @client: Handle to slave device
1711 *
1712 * This executes the SMBus "receive byte" protocol, returning negative errno
1713 * else the byte received from the device.
1714 */
1715s32 i2c_smbus_read_byte(const struct i2c_client *client)
1716{
1717 union i2c_smbus_data data;
1718 int status;
1719
1720 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1721 I2C_SMBUS_READ, 0,
1722 I2C_SMBUS_BYTE, &data);
1723 return (status < 0) ? status : data.byte;
1724}
1725EXPORT_SYMBOL(i2c_smbus_read_byte);
1726
1727/**
1728 * i2c_smbus_write_byte - SMBus "send byte" protocol
1729 * @client: Handle to slave device
1730 * @value: Byte to be sent
1731 *
1732 * This executes the SMBus "send byte" protocol, returning negative errno
1733 * else zero on success.
1734 */
1735s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
1736{
1737 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1738 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
1739}
1740EXPORT_SYMBOL(i2c_smbus_write_byte);
1741
1742/**
1743 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
1744 * @client: Handle to slave device
1745 * @command: Byte interpreted by slave
1746 *
1747 * This executes the SMBus "read byte" protocol, returning negative errno
1748 * else a data byte received from the device.
1749 */
1750s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
1751{
1752 union i2c_smbus_data data;
1753 int status;
1754
1755 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1756 I2C_SMBUS_READ, command,
1757 I2C_SMBUS_BYTE_DATA, &data);
1758 return (status < 0) ? status : data.byte;
1759}
1760EXPORT_SYMBOL(i2c_smbus_read_byte_data);
1761
1762/**
1763 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
1764 * @client: Handle to slave device
1765 * @command: Byte interpreted by slave
1766 * @value: Byte being written
1767 *
1768 * This executes the SMBus "write byte" protocol, returning negative errno
1769 * else zero on success.
1770 */
1771s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
1772 u8 value)
1773{
1774 union i2c_smbus_data data;
1775 data.byte = value;
1776 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1777 I2C_SMBUS_WRITE, command,
1778 I2C_SMBUS_BYTE_DATA, &data);
1779}
1780EXPORT_SYMBOL(i2c_smbus_write_byte_data);
1781
1782/**
1783 * i2c_smbus_read_word_data - SMBus "read word" protocol
1784 * @client: Handle to slave device
1785 * @command: Byte interpreted by slave
1786 *
1787 * This executes the SMBus "read word" protocol, returning negative errno
1788 * else a 16-bit unsigned "word" received from the device.
1789 */
1790s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
1791{
1792 union i2c_smbus_data data;
1793 int status;
1794
1795 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1796 I2C_SMBUS_READ, command,
1797 I2C_SMBUS_WORD_DATA, &data);
1798 return (status < 0) ? status : data.word;
1799}
1800EXPORT_SYMBOL(i2c_smbus_read_word_data);
1801
1802/**
1803 * i2c_smbus_write_word_data - SMBus "write word" protocol
1804 * @client: Handle to slave device
1805 * @command: Byte interpreted by slave
1806 * @value: 16-bit "word" being written
1807 *
1808 * This executes the SMBus "write word" protocol, returning negative errno
1809 * else zero on success.
1810 */
1811s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
1812 u16 value)
1813{
1814 union i2c_smbus_data data;
1815 data.word = value;
1816 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1817 I2C_SMBUS_WRITE, command,
1818 I2C_SMBUS_WORD_DATA, &data);
1819}
1820EXPORT_SYMBOL(i2c_smbus_write_word_data);
1821
1822/**
1823 * i2c_smbus_process_call - SMBus "process call" protocol
1824 * @client: Handle to slave device
1825 * @command: Byte interpreted by slave
1826 * @value: 16-bit "word" being written
1827 *
1828 * This executes the SMBus "process call" protocol, returning negative errno
1829 * else a 16-bit unsigned "word" received from the device.
1830 */
1831s32 i2c_smbus_process_call(const struct i2c_client *client, u8 command,
1832 u16 value)
1833{
1834 union i2c_smbus_data data;
1835 int status;
1836 data.word = value;
1837
1838 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1839 I2C_SMBUS_WRITE, command,
1840 I2C_SMBUS_PROC_CALL, &data);
1841 return (status < 0) ? status : data.word;
1842}
1843EXPORT_SYMBOL(i2c_smbus_process_call);
1844
1845/**
1846 * i2c_smbus_read_block_data - SMBus "block read" protocol
1847 * @client: Handle to slave device
1848 * @command: Byte interpreted by slave
1849 * @values: Byte array into which data will be read; big enough to hold
1850 * the data returned by the slave. SMBus allows at most 32 bytes.
1851 *
1852 * This executes the SMBus "block read" protocol, returning negative errno
1853 * else the number of data bytes in the slave's response.
1854 *
1855 * Note that using this function requires that the client's adapter support
1856 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
1857 * support this; its emulation through I2C messaging relies on a specific
1858 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
1859 */
1860s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
1861 u8 *values)
1862{
1863 union i2c_smbus_data data;
1864 int status;
1865
1866 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1867 I2C_SMBUS_READ, command,
1868 I2C_SMBUS_BLOCK_DATA, &data);
1869 if (status)
1870 return status;
1871
1872 memcpy(values, &data.block[1], data.block[0]);
1873 return data.block[0];
1874}
1875EXPORT_SYMBOL(i2c_smbus_read_block_data);
1876
1877/**
1878 * i2c_smbus_write_block_data - SMBus "block write" protocol
1879 * @client: Handle to slave device
1880 * @command: Byte interpreted by slave
1881 * @length: Size of data block; SMBus allows at most 32 bytes
1882 * @values: Byte array which will be written.
1883 *
1884 * This executes the SMBus "block write" protocol, returning negative errno
1885 * else zero on success.
1886 */
1887s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
1888 u8 length, const u8 *values)
1889{
1890 union i2c_smbus_data data;
1891
1892 if (length > I2C_SMBUS_BLOCK_MAX)
1893 length = I2C_SMBUS_BLOCK_MAX;
1894 data.block[0] = length;
1895 memcpy(&data.block[1], values, length);
1896 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1897 I2C_SMBUS_WRITE, command,
1898 I2C_SMBUS_BLOCK_DATA, &data);
1899}
1900EXPORT_SYMBOL(i2c_smbus_write_block_data);
1901
1902/* Returns the number of read bytes */
1903s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
1904 u8 length, u8 *values)
1905{
1906 union i2c_smbus_data data;
1907 int status;
1908
1909 if (length > I2C_SMBUS_BLOCK_MAX)
1910 length = I2C_SMBUS_BLOCK_MAX;
1911 data.block[0] = length;
1912 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1913 I2C_SMBUS_READ, command,
1914 I2C_SMBUS_I2C_BLOCK_DATA, &data);
1915 if (status < 0)
1916 return status;
1917
1918 memcpy(values, &data.block[1], data.block[0]);
1919 return data.block[0];
1920}
1921EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
1922
1923s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
1924 u8 length, const u8 *values)
1925{
1926 union i2c_smbus_data data;
1927
1928 if (length > I2C_SMBUS_BLOCK_MAX)
1929 length = I2C_SMBUS_BLOCK_MAX;
1930 data.block[0] = length;
1931 memcpy(data.block + 1, values, length);
1932 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1933 I2C_SMBUS_WRITE, command,
1934 I2C_SMBUS_I2C_BLOCK_DATA, &data);
1935}
1936EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
1937
1938/* Simulate a SMBus command using the i2c protocol
1939 No checking of parameters is done! */
1940static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
1941 unsigned short flags,
1942 char read_write, u8 command, int size,
1943 union i2c_smbus_data *data)
1944{
1945 /* So we need to generate a series of msgs. In the case of writing, we
1946 need to use only one message; when reading, we need two. We initialize
1947 most things with sane defaults, to keep the code below somewhat
1948 simpler. */
1949 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
1950 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
1951 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
1952 struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
1953 { addr, flags | I2C_M_RD, 0, msgbuf1 }
1954 };
1955 int i;
1956 u8 partial_pec = 0;
1957 int status;
1958
1959 msgbuf0[0] = command;
1960 switch (size) {
1961 case I2C_SMBUS_QUICK:
1962 msg[0].len = 0;
1963 /* Special case: The read/write field is used as data */
1964 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
1965 I2C_M_RD : 0);
1966 num = 1;
1967 break;
1968 case I2C_SMBUS_BYTE:
1969 if (read_write == I2C_SMBUS_READ) {
1970 /* Special case: only a read! */
1971 msg[0].flags = I2C_M_RD | flags;
1972 num = 1;
1973 }
1974 break;
1975 case I2C_SMBUS_BYTE_DATA:
1976 if (read_write == I2C_SMBUS_READ)
1977 msg[1].len = 1;
1978 else {
1979 msg[0].len = 2;
1980 msgbuf0[1] = data->byte;
1981 }
1982 break;
1983 case I2C_SMBUS_WORD_DATA:
1984 if (read_write == I2C_SMBUS_READ)
1985 msg[1].len = 2;
1986 else {
1987 msg[0].len = 3;
1988 msgbuf0[1] = data->word & 0xff;
1989 msgbuf0[2] = data->word >> 8;
1990 }
1991 break;
1992 case I2C_SMBUS_PROC_CALL:
1993 num = 2; /* Special case */
1994 read_write = I2C_SMBUS_READ;
1995 msg[0].len = 3;
1996 msg[1].len = 2;
1997 msgbuf0[1] = data->word & 0xff;
1998 msgbuf0[2] = data->word >> 8;
1999 break;
2000 case I2C_SMBUS_BLOCK_DATA:
2001 if (read_write == I2C_SMBUS_READ) {
2002 msg[1].flags |= I2C_M_RECV_LEN;
2003 msg[1].len = 1; /* block length will be added by
2004 the underlying bus driver */
2005 } else {
2006 msg[0].len = data->block[0] + 2;
2007 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
2008 dev_err(&adapter->dev,
2009 "Invalid block write size %d\n",
2010 data->block[0]);
2011 return -EINVAL;
2012 }
2013 for (i = 1; i < msg[0].len; i++)
2014 msgbuf0[i] = data->block[i-1];
2015 }
2016 break;
2017 case I2C_SMBUS_BLOCK_PROC_CALL:
2018 num = 2; /* Another special case */
2019 read_write = I2C_SMBUS_READ;
2020 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
2021 dev_err(&adapter->dev,
2022 "Invalid block write size %d\n",
2023 data->block[0]);
2024 return -EINVAL;
2025 }
2026 msg[0].len = data->block[0] + 2;
2027 for (i = 1; i < msg[0].len; i++)
2028 msgbuf0[i] = data->block[i-1];
2029 msg[1].flags |= I2C_M_RECV_LEN;
2030 msg[1].len = 1; /* block length will be added by
2031 the underlying bus driver */
2032 break;
2033 case I2C_SMBUS_I2C_BLOCK_DATA:
2034 if (read_write == I2C_SMBUS_READ) {
2035 msg[1].len = data->block[0];
2036 } else {
2037 msg[0].len = data->block[0] + 1;
2038 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
2039 dev_err(&adapter->dev,
2040 "Invalid block write size %d\n",
2041 data->block[0]);
2042 return -EINVAL;
2043 }
2044 for (i = 1; i <= data->block[0]; i++)
2045 msgbuf0[i] = data->block[i];
2046 }
2047 break;
2048 default:
2049 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
2050 return -EOPNOTSUPP;
2051 }
2052
2053 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
2054 && size != I2C_SMBUS_I2C_BLOCK_DATA);
2055 if (i) {
2056 /* Compute PEC if first message is a write */
2057 if (!(msg[0].flags & I2C_M_RD)) {
2058 if (num == 1) /* Write only */
2059 i2c_smbus_add_pec(&msg[0]);
2060 else /* Write followed by read */
2061 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
2062 }
2063 /* Ask for PEC if last message is a read */
2064 if (msg[num-1].flags & I2C_M_RD)
2065 msg[num-1].len++;
2066 }
2067
2068 status = i2c_transfer(adapter, msg, num);
2069 if (status < 0)
2070 return status;
2071
2072 /* Check PEC if last message is a read */
2073 if (i && (msg[num-1].flags & I2C_M_RD)) {
2074 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
2075 if (status < 0)
2076 return status;
2077 }
2078
2079 if (read_write == I2C_SMBUS_READ)
2080 switch (size) {
2081 case I2C_SMBUS_BYTE:
2082 data->byte = msgbuf0[0];
2083 break;
2084 case I2C_SMBUS_BYTE_DATA:
2085 data->byte = msgbuf1[0];
2086 break;
2087 case I2C_SMBUS_WORD_DATA:
2088 case I2C_SMBUS_PROC_CALL:
2089 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
2090 break;
2091 case I2C_SMBUS_I2C_BLOCK_DATA:
2092 for (i = 0; i < data->block[0]; i++)
2093 data->block[i+1] = msgbuf1[i];
2094 break;
2095 case I2C_SMBUS_BLOCK_DATA:
2096 case I2C_SMBUS_BLOCK_PROC_CALL:
2097 for (i = 0; i < msgbuf1[0] + 1; i++)
2098 data->block[i] = msgbuf1[i];
2099 break;
2100 }
2101 return 0;
2102}
2103
2104/**
2105 * i2c_smbus_xfer - execute SMBus protocol operations
2106 * @adapter: Handle to I2C bus
2107 * @addr: Address of SMBus slave on that bus
2108 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2109 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2110 * @command: Byte interpreted by slave, for protocols which use such bytes
2111 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2112 * @data: Data to be read or written
2113 *
2114 * This executes an SMBus protocol operation, and returns a negative
2115 * errno code else zero on success.
2116 */
2117s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
2118 char read_write, u8 command, int protocol,
2119 union i2c_smbus_data *data)
2120{
2121 unsigned long orig_jiffies;
2122 int try;
2123 s32 res;
2124
2125 flags &= I2C_M_TEN | I2C_CLIENT_PEC;
2126
2127 if (adapter->algo->smbus_xfer) {
2128 i2c_lock_adapter(adapter);
2129
2130 /* Retry automatically on arbitration loss */
2131 orig_jiffies = jiffies;
2132 for (res = 0, try = 0; try <= adapter->retries; try++) {
2133 res = adapter->algo->smbus_xfer(adapter, addr, flags,
2134 read_write, command,
2135 protocol, data);
2136 if (res != -EAGAIN)
2137 break;
2138 if (time_after(jiffies,
2139 orig_jiffies + adapter->timeout))
2140 break;
2141 }
2142 i2c_unlock_adapter(adapter);
2143 } else
2144 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
2145 command, protocol, data);
2146
2147 return res;
2148}
2149EXPORT_SYMBOL(i2c_smbus_xfer);
2150
2151MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2152MODULE_DESCRIPTION("I2C-Bus main module");
2153MODULE_LICENSE("GPL");