1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Linux I2C core
4 *
5 * Copyright (C) 1995-99 Simon G. Vogl
6 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
7 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
8 * Michael Lawnick <michael.lawnick.ext@nsn.com>
9 *
10 * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
11 */
12
13 #define pr_fmt(fmt) "i2c-core: " fmt
14
15 #include <dt-bindings/i2c/i2c.h>
16 #include <linux/acpi.h>
17 #include <linux/clk/clk-conf.h>
18 #include <linux/completion.h>
19 #include <linux/delay.h>
20 #include <linux/err.h>
21 #include <linux/errno.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/i2c.h>
24 #include <linux/i2c-smbus.h>
25 #include <linux/idr.h>
26 #include <linux/init.h>
27 #include <linux/interrupt.h>
28 #include <linux/irqflags.h>
29 #include <linux/jump_label.h>
30 #include <linux/kernel.h>
31 #include <linux/module.h>
32 #include <linux/mutex.h>
33 #include <linux/of_device.h>
34 #include <linux/of.h>
35 #include <linux/of_irq.h>
36 #include <linux/pinctrl/consumer.h>
37 #include <linux/pm_domain.h>
38 #include <linux/pm_runtime.h>
39 #include <linux/pm_wakeirq.h>
40 #include <linux/property.h>
41 #include <linux/rwsem.h>
42 #include <linux/slab.h>
43
44 #include "i2c-core.h"
45
46 #define CREATE_TRACE_POINTS
47 #include <trace/events/i2c.h>
48
49 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
50 #define I2C_ADDR_OFFSET_SLAVE 0x1000
51
52 #define I2C_ADDR_7BITS_MAX 0x77
53 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
54
55 #define I2C_ADDR_DEVICE_ID 0x7c
56
57 /*
58 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
59 * deletion of detected devices are serialized
60 */
61 static DEFINE_MUTEX(core_lock);
62 static DEFINE_IDR(i2c_adapter_idr);
63
64 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
65
66 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
67 static bool is_registered;
68
i2c_transfer_trace_reg(void)69 int i2c_transfer_trace_reg(void)
70 {
71 static_branch_inc(&i2c_trace_msg_key);
72 return 0;
73 }
74
i2c_transfer_trace_unreg(void)75 void i2c_transfer_trace_unreg(void)
76 {
77 static_branch_dec(&i2c_trace_msg_key);
78 }
79
i2c_freq_mode_string(u32 bus_freq_hz)80 const char *i2c_freq_mode_string(u32 bus_freq_hz)
81 {
82 switch (bus_freq_hz) {
83 case I2C_MAX_STANDARD_MODE_FREQ:
84 return "Standard Mode (100 kHz)";
85 case I2C_MAX_FAST_MODE_FREQ:
86 return "Fast Mode (400 kHz)";
87 case I2C_MAX_FAST_MODE_PLUS_FREQ:
88 return "Fast Mode Plus (1.0 MHz)";
89 case I2C_MAX_TURBO_MODE_FREQ:
90 return "Turbo Mode (1.4 MHz)";
91 case I2C_MAX_HIGH_SPEED_MODE_FREQ:
92 return "High Speed Mode (3.4 MHz)";
93 case I2C_MAX_ULTRA_FAST_MODE_FREQ:
94 return "Ultra Fast Mode (5.0 MHz)";
95 default:
96 return "Unknown Mode";
97 }
98 }
99 EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
100
i2c_match_id(const struct i2c_device_id * id,const struct i2c_client * client)101 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
102 const struct i2c_client *client)
103 {
104 if (!(id && client))
105 return NULL;
106
107 while (id->name[0]) {
108 if (strcmp(client->name, id->name) == 0)
109 return id;
110 id++;
111 }
112 return NULL;
113 }
114 EXPORT_SYMBOL_GPL(i2c_match_id);
115
i2c_device_match(struct device * dev,struct device_driver * drv)116 static int i2c_device_match(struct device *dev, struct device_driver *drv)
117 {
118 struct i2c_client *client = i2c_verify_client(dev);
119 struct i2c_driver *driver;
120
121
122 /* Attempt an OF style match */
123 if (i2c_of_match_device(drv->of_match_table, client))
124 return 1;
125
126 /* Then ACPI style match */
127 if (acpi_driver_match_device(dev, drv))
128 return 1;
129
130 driver = to_i2c_driver(drv);
131
132 /* Finally an I2C match */
133 if (i2c_match_id(driver->id_table, client))
134 return 1;
135
136 return 0;
137 }
138
i2c_device_uevent(struct device * dev,struct kobj_uevent_env * env)139 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
140 {
141 struct i2c_client *client = to_i2c_client(dev);
142 int rc;
143
144 rc = of_device_uevent_modalias(dev, env);
145 if (rc != -ENODEV)
146 return rc;
147
148 rc = acpi_device_uevent_modalias(dev, env);
149 if (rc != -ENODEV)
150 return rc;
151
152 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
153 }
154
155 /* i2c bus recovery routines */
get_scl_gpio_value(struct i2c_adapter * adap)156 static int get_scl_gpio_value(struct i2c_adapter *adap)
157 {
158 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
159 }
160
set_scl_gpio_value(struct i2c_adapter * adap,int val)161 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
162 {
163 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
164 }
165
get_sda_gpio_value(struct i2c_adapter * adap)166 static int get_sda_gpio_value(struct i2c_adapter *adap)
167 {
168 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
169 }
170
set_sda_gpio_value(struct i2c_adapter * adap,int val)171 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
172 {
173 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
174 }
175
i2c_generic_bus_free(struct i2c_adapter * adap)176 static int i2c_generic_bus_free(struct i2c_adapter *adap)
177 {
178 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
179 int ret = -EOPNOTSUPP;
180
181 if (bri->get_bus_free)
182 ret = bri->get_bus_free(adap);
183 else if (bri->get_sda)
184 ret = bri->get_sda(adap);
185
186 if (ret < 0)
187 return ret;
188
189 return ret ? 0 : -EBUSY;
190 }
191
192 /*
193 * We are generating clock pulses. ndelay() determines durating of clk pulses.
194 * We will generate clock with rate 100 KHz and so duration of both clock levels
195 * is: delay in ns = (10^6 / 100) / 2
196 */
197 #define RECOVERY_NDELAY 5000
198 #define RECOVERY_CLK_CNT 9
199
i2c_generic_scl_recovery(struct i2c_adapter * adap)200 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
201 {
202 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
203 int i = 0, scl = 1, ret = 0;
204
205 if (bri->prepare_recovery)
206 bri->prepare_recovery(adap);
207 if (bri->pinctrl)
208 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
209
210 /*
211 * If we can set SDA, we will always create a STOP to ensure additional
212 * pulses will do no harm. This is achieved by letting SDA follow SCL
213 * half a cycle later. Check the 'incomplete_write_byte' fault injector
214 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
215 * here for simplicity.
216 */
217 bri->set_scl(adap, scl);
218 ndelay(RECOVERY_NDELAY);
219 if (bri->set_sda)
220 bri->set_sda(adap, scl);
221 ndelay(RECOVERY_NDELAY / 2);
222
223 /*
224 * By this time SCL is high, as we need to give 9 falling-rising edges
225 */
226 while (i++ < RECOVERY_CLK_CNT * 2) {
227 if (scl) {
228 /* SCL shouldn't be low here */
229 if (!bri->get_scl(adap)) {
230 dev_err(&adap->dev,
231 "SCL is stuck low, exit recovery\n");
232 ret = -EBUSY;
233 break;
234 }
235 }
236
237 scl = !scl;
238 bri->set_scl(adap, scl);
239 /* Creating STOP again, see above */
240 if (scl) {
241 /* Honour minimum tsu:sto */
242 ndelay(RECOVERY_NDELAY);
243 } else {
244 /* Honour minimum tf and thd:dat */
245 ndelay(RECOVERY_NDELAY / 2);
246 }
247 if (bri->set_sda)
248 bri->set_sda(adap, scl);
249 ndelay(RECOVERY_NDELAY / 2);
250
251 if (scl) {
252 ret = i2c_generic_bus_free(adap);
253 if (ret == 0)
254 break;
255 }
256 }
257
258 /* If we can't check bus status, assume recovery worked */
259 if (ret == -EOPNOTSUPP)
260 ret = 0;
261
262 if (bri->unprepare_recovery)
263 bri->unprepare_recovery(adap);
264 if (bri->pinctrl)
265 pinctrl_select_state(bri->pinctrl, bri->pins_default);
266
267 return ret;
268 }
269 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
270
i2c_recover_bus(struct i2c_adapter * adap)271 int i2c_recover_bus(struct i2c_adapter *adap)
272 {
273 if (!adap->bus_recovery_info)
274 return -EBUSY;
275
276 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
277 return adap->bus_recovery_info->recover_bus(adap);
278 }
279 EXPORT_SYMBOL_GPL(i2c_recover_bus);
280
i2c_gpio_init_pinctrl_recovery(struct i2c_adapter * adap)281 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
282 {
283 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
284 struct device *dev = &adap->dev;
285 struct pinctrl *p = bri->pinctrl;
286
287 /*
288 * we can't change states without pinctrl, so remove the states if
289 * populated
290 */
291 if (!p) {
292 bri->pins_default = NULL;
293 bri->pins_gpio = NULL;
294 return;
295 }
296
297 if (!bri->pins_default) {
298 bri->pins_default = pinctrl_lookup_state(p,
299 PINCTRL_STATE_DEFAULT);
300 if (IS_ERR(bri->pins_default)) {
301 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
302 bri->pins_default = NULL;
303 }
304 }
305 if (!bri->pins_gpio) {
306 bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
307 if (IS_ERR(bri->pins_gpio))
308 bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
309
310 if (IS_ERR(bri->pins_gpio)) {
311 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
312 bri->pins_gpio = NULL;
313 }
314 }
315
316 /* for pinctrl state changes, we need all the information */
317 if (bri->pins_default && bri->pins_gpio) {
318 dev_info(dev, "using pinctrl states for GPIO recovery");
319 } else {
320 bri->pinctrl = NULL;
321 bri->pins_default = NULL;
322 bri->pins_gpio = NULL;
323 }
324 }
325
i2c_gpio_init_generic_recovery(struct i2c_adapter * adap)326 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
327 {
328 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
329 struct device *dev = &adap->dev;
330 struct gpio_desc *gpiod;
331 int ret = 0;
332
333 /*
334 * don't touch the recovery information if the driver is not using
335 * generic SCL recovery
336 */
337 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
338 return 0;
339
340 /*
341 * pins might be taken as GPIO, so we should inform pinctrl about
342 * this and move the state to GPIO
343 */
344 if (bri->pinctrl)
345 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
346
347 /*
348 * if there is incomplete or no recovery information, see if generic
349 * GPIO recovery is available
350 */
351 if (!bri->scl_gpiod) {
352 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
353 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
354 ret = -EPROBE_DEFER;
355 goto cleanup_pinctrl_state;
356 }
357 if (!IS_ERR(gpiod)) {
358 bri->scl_gpiod = gpiod;
359 bri->recover_bus = i2c_generic_scl_recovery;
360 dev_info(dev, "using generic GPIOs for recovery\n");
361 }
362 }
363
364 /* SDA GPIOD line is optional, so we care about DEFER only */
365 if (!bri->sda_gpiod) {
366 /*
367 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
368 * have no effect.
369 */
370 gpiod_direction_output(bri->scl_gpiod, 0);
371 udelay(10);
372 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
373
374 /* Wait a bit in case of a SDA glitch, and then release SCL. */
375 udelay(10);
376 gpiod_direction_output(bri->scl_gpiod, 1);
377
378 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
379 ret = -EPROBE_DEFER;
380 goto cleanup_pinctrl_state;
381 }
382 if (!IS_ERR(gpiod))
383 bri->sda_gpiod = gpiod;
384 }
385
386 cleanup_pinctrl_state:
387 /* change the state of the pins back to their default state */
388 if (bri->pinctrl)
389 pinctrl_select_state(bri->pinctrl, bri->pins_default);
390
391 return ret;
392 }
393
i2c_gpio_init_recovery(struct i2c_adapter * adap)394 static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
395 {
396 i2c_gpio_init_pinctrl_recovery(adap);
397 return i2c_gpio_init_generic_recovery(adap);
398 }
399
i2c_init_recovery(struct i2c_adapter * adap)400 static int i2c_init_recovery(struct i2c_adapter *adap)
401 {
402 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
403 bool is_error_level = true;
404 char *err_str;
405
406 if (!bri)
407 return 0;
408
409 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
410 return -EPROBE_DEFER;
411
412 if (!bri->recover_bus) {
413 err_str = "no suitable method provided";
414 is_error_level = false;
415 goto err;
416 }
417
418 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
419 bri->get_scl = get_scl_gpio_value;
420 bri->set_scl = set_scl_gpio_value;
421 if (bri->sda_gpiod) {
422 bri->get_sda = get_sda_gpio_value;
423 /* FIXME: add proper flag instead of '0' once available */
424 if (gpiod_get_direction(bri->sda_gpiod) == 0)
425 bri->set_sda = set_sda_gpio_value;
426 }
427 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
428 /* Generic SCL recovery */
429 if (!bri->set_scl || !bri->get_scl) {
430 err_str = "no {get|set}_scl() found";
431 goto err;
432 }
433 if (!bri->set_sda && !bri->get_sda) {
434 err_str = "either get_sda() or set_sda() needed";
435 goto err;
436 }
437 }
438
439 return 0;
440 err:
441 if (is_error_level)
442 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
443 else
444 dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
445 adap->bus_recovery_info = NULL;
446
447 return -EINVAL;
448 }
449
i2c_smbus_host_notify_to_irq(const struct i2c_client * client)450 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
451 {
452 struct i2c_adapter *adap = client->adapter;
453 unsigned int irq;
454
455 if (!adap->host_notify_domain)
456 return -ENXIO;
457
458 if (client->flags & I2C_CLIENT_TEN)
459 return -EINVAL;
460
461 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
462
463 return irq > 0 ? irq : -ENXIO;
464 }
465
i2c_device_probe(struct device * dev)466 static int i2c_device_probe(struct device *dev)
467 {
468 struct i2c_client *client = i2c_verify_client(dev);
469 struct i2c_driver *driver;
470 int status;
471
472 if (!client)
473 return 0;
474
475 client->irq = client->init_irq;
476
477 if (!client->irq) {
478 int irq = -ENOENT;
479
480 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
481 dev_dbg(dev, "Using Host Notify IRQ\n");
482 /* Keep adapter active when Host Notify is required */
483 pm_runtime_get_sync(&client->adapter->dev);
484 irq = i2c_smbus_host_notify_to_irq(client);
485 } else if (dev->of_node) {
486 irq = of_irq_get_byname(dev->of_node, "irq");
487 if (irq == -EINVAL || irq == -ENODATA)
488 irq = of_irq_get(dev->of_node, 0);
489 } else if (ACPI_COMPANION(dev)) {
490 irq = i2c_acpi_get_irq(client);
491 }
492 if (irq == -EPROBE_DEFER) {
493 status = irq;
494 goto put_sync_adapter;
495 }
496
497 if (irq < 0)
498 irq = 0;
499
500 client->irq = irq;
501 }
502
503 driver = to_i2c_driver(dev->driver);
504
505 /*
506 * An I2C ID table is not mandatory, if and only if, a suitable OF
507 * or ACPI ID table is supplied for the probing device.
508 */
509 if (!driver->id_table &&
510 !acpi_driver_match_device(dev, dev->driver) &&
511 !i2c_of_match_device(dev->driver->of_match_table, client)) {
512 status = -ENODEV;
513 goto put_sync_adapter;
514 }
515
516 if (client->flags & I2C_CLIENT_WAKE) {
517 int wakeirq;
518
519 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
520 if (wakeirq == -EPROBE_DEFER) {
521 status = wakeirq;
522 goto put_sync_adapter;
523 }
524
525 device_init_wakeup(&client->dev, true);
526
527 if (wakeirq > 0 && wakeirq != client->irq)
528 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
529 else if (client->irq > 0)
530 status = dev_pm_set_wake_irq(dev, client->irq);
531 else
532 status = 0;
533
534 if (status)
535 dev_warn(&client->dev, "failed to set up wakeup irq\n");
536 }
537
538 dev_dbg(dev, "probe\n");
539
540 status = of_clk_set_defaults(dev->of_node, false);
541 if (status < 0)
542 goto err_clear_wakeup_irq;
543
544 status = dev_pm_domain_attach(&client->dev, true);
545 if (status)
546 goto err_clear_wakeup_irq;
547
548 client->devres_group_id = devres_open_group(&client->dev, NULL,
549 GFP_KERNEL);
550 if (!client->devres_group_id) {
551 status = -ENOMEM;
552 goto err_detach_pm_domain;
553 }
554
555 /*
556 * When there are no more users of probe(),
557 * rename probe_new to probe.
558 */
559 if (driver->probe_new)
560 status = driver->probe_new(client);
561 else if (driver->probe)
562 status = driver->probe(client,
563 i2c_match_id(driver->id_table, client));
564 else
565 status = -EINVAL;
566
567 /*
568 * Note that we are not closing the devres group opened above so
569 * even resources that were attached to the device after probe is
570 * run are released when i2c_device_remove() is executed. This is
571 * needed as some drivers would allocate additional resources,
572 * for example when updating firmware.
573 */
574
575 if (status)
576 goto err_release_driver_resources;
577
578 return 0;
579
580 err_release_driver_resources:
581 devres_release_group(&client->dev, client->devres_group_id);
582 err_detach_pm_domain:
583 dev_pm_domain_detach(&client->dev, true);
584 err_clear_wakeup_irq:
585 dev_pm_clear_wake_irq(&client->dev);
586 device_init_wakeup(&client->dev, false);
587 put_sync_adapter:
588 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
589 pm_runtime_put_sync(&client->adapter->dev);
590
591 return status;
592 }
593
i2c_device_remove(struct device * dev)594 static void i2c_device_remove(struct device *dev)
595 {
596 struct i2c_client *client = to_i2c_client(dev);
597 struct i2c_driver *driver;
598
599 driver = to_i2c_driver(dev->driver);
600 if (driver->remove) {
601 int status;
602
603 dev_dbg(dev, "remove\n");
604
605 status = driver->remove(client);
606 if (status)
607 dev_warn(dev, "remove failed (%pe), will be ignored\n", ERR_PTR(status));
608 }
609
610 devres_release_group(&client->dev, client->devres_group_id);
611
612 dev_pm_domain_detach(&client->dev, true);
613
614 dev_pm_clear_wake_irq(&client->dev);
615 device_init_wakeup(&client->dev, false);
616
617 client->irq = 0;
618 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
619 pm_runtime_put(&client->adapter->dev);
620 }
621
i2c_device_shutdown(struct device * dev)622 static void i2c_device_shutdown(struct device *dev)
623 {
624 struct i2c_client *client = i2c_verify_client(dev);
625 struct i2c_driver *driver;
626
627 if (!client || !dev->driver)
628 return;
629 driver = to_i2c_driver(dev->driver);
630 if (driver->shutdown)
631 driver->shutdown(client);
632 else if (client->irq > 0)
633 disable_irq(client->irq);
634 }
635
i2c_client_dev_release(struct device * dev)636 static void i2c_client_dev_release(struct device *dev)
637 {
638 kfree(to_i2c_client(dev));
639 }
640
641 static ssize_t
name_show(struct device * dev,struct device_attribute * attr,char * buf)642 name_show(struct device *dev, struct device_attribute *attr, char *buf)
643 {
644 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
645 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
646 }
647 static DEVICE_ATTR_RO(name);
648
649 static ssize_t
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)650 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
651 {
652 struct i2c_client *client = to_i2c_client(dev);
653 int len;
654
655 len = of_device_modalias(dev, buf, PAGE_SIZE);
656 if (len != -ENODEV)
657 return len;
658
659 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
660 if (len != -ENODEV)
661 return len;
662
663 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
664 }
665 static DEVICE_ATTR_RO(modalias);
666
667 static struct attribute *i2c_dev_attrs[] = {
668 &dev_attr_name.attr,
669 /* modalias helps coldplug: modprobe $(cat .../modalias) */
670 &dev_attr_modalias.attr,
671 NULL
672 };
673 ATTRIBUTE_GROUPS(i2c_dev);
674
675 struct bus_type i2c_bus_type = {
676 .name = "i2c",
677 .match = i2c_device_match,
678 .probe = i2c_device_probe,
679 .remove = i2c_device_remove,
680 .shutdown = i2c_device_shutdown,
681 };
682 EXPORT_SYMBOL_GPL(i2c_bus_type);
683
684 struct device_type i2c_client_type = {
685 .groups = i2c_dev_groups,
686 .uevent = i2c_device_uevent,
687 .release = i2c_client_dev_release,
688 };
689 EXPORT_SYMBOL_GPL(i2c_client_type);
690
691
692 /**
693 * i2c_verify_client - return parameter as i2c_client, or NULL
694 * @dev: device, probably from some driver model iterator
695 *
696 * When traversing the driver model tree, perhaps using driver model
697 * iterators like @device_for_each_child(), you can't assume very much
698 * about the nodes you find. Use this function to avoid oopses caused
699 * by wrongly treating some non-I2C device as an i2c_client.
700 */
i2c_verify_client(struct device * dev)701 struct i2c_client *i2c_verify_client(struct device *dev)
702 {
703 return (dev->type == &i2c_client_type)
704 ? to_i2c_client(dev)
705 : NULL;
706 }
707 EXPORT_SYMBOL(i2c_verify_client);
708
709
710 /* Return a unique address which takes the flags of the client into account */
i2c_encode_flags_to_addr(struct i2c_client * client)711 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
712 {
713 unsigned short addr = client->addr;
714
715 /* For some client flags, add an arbitrary offset to avoid collisions */
716 if (client->flags & I2C_CLIENT_TEN)
717 addr |= I2C_ADDR_OFFSET_TEN_BIT;
718
719 if (client->flags & I2C_CLIENT_SLAVE)
720 addr |= I2C_ADDR_OFFSET_SLAVE;
721
722 return addr;
723 }
724
725 /* This is a permissive address validity check, I2C address map constraints
726 * are purposely not enforced, except for the general call address. */
i2c_check_addr_validity(unsigned int addr,unsigned short flags)727 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
728 {
729 if (flags & I2C_CLIENT_TEN) {
730 /* 10-bit address, all values are valid */
731 if (addr > 0x3ff)
732 return -EINVAL;
733 } else {
734 /* 7-bit address, reject the general call address */
735 if (addr == 0x00 || addr > 0x7f)
736 return -EINVAL;
737 }
738 return 0;
739 }
740
741 /* And this is a strict address validity check, used when probing. If a
742 * device uses a reserved address, then it shouldn't be probed. 7-bit
743 * addressing is assumed, 10-bit address devices are rare and should be
744 * explicitly enumerated. */
i2c_check_7bit_addr_validity_strict(unsigned short addr)745 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
746 {
747 /*
748 * Reserved addresses per I2C specification:
749 * 0x00 General call address / START byte
750 * 0x01 CBUS address
751 * 0x02 Reserved for different bus format
752 * 0x03 Reserved for future purposes
753 * 0x04-0x07 Hs-mode master code
754 * 0x78-0x7b 10-bit slave addressing
755 * 0x7c-0x7f Reserved for future purposes
756 */
757 if (addr < 0x08 || addr > 0x77)
758 return -EINVAL;
759 return 0;
760 }
761
__i2c_check_addr_busy(struct device * dev,void * addrp)762 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
763 {
764 struct i2c_client *client = i2c_verify_client(dev);
765 int addr = *(int *)addrp;
766
767 if (client && i2c_encode_flags_to_addr(client) == addr)
768 return -EBUSY;
769 return 0;
770 }
771
772 /* walk up mux tree */
i2c_check_mux_parents(struct i2c_adapter * adapter,int addr)773 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
774 {
775 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
776 int result;
777
778 result = device_for_each_child(&adapter->dev, &addr,
779 __i2c_check_addr_busy);
780
781 if (!result && parent)
782 result = i2c_check_mux_parents(parent, addr);
783
784 return result;
785 }
786
787 /* recurse down mux tree */
i2c_check_mux_children(struct device * dev,void * addrp)788 static int i2c_check_mux_children(struct device *dev, void *addrp)
789 {
790 int result;
791
792 if (dev->type == &i2c_adapter_type)
793 result = device_for_each_child(dev, addrp,
794 i2c_check_mux_children);
795 else
796 result = __i2c_check_addr_busy(dev, addrp);
797
798 return result;
799 }
800
i2c_check_addr_busy(struct i2c_adapter * adapter,int addr)801 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
802 {
803 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
804 int result = 0;
805
806 if (parent)
807 result = i2c_check_mux_parents(parent, addr);
808
809 if (!result)
810 result = device_for_each_child(&adapter->dev, &addr,
811 i2c_check_mux_children);
812
813 return result;
814 }
815
816 /**
817 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
818 * @adapter: Target I2C bus segment
819 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
820 * locks only this branch in the adapter tree
821 */
i2c_adapter_lock_bus(struct i2c_adapter * adapter,unsigned int flags)822 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
823 unsigned int flags)
824 {
825 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
826 }
827
828 /**
829 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
830 * @adapter: Target I2C bus segment
831 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
832 * trylocks only this branch in the adapter tree
833 */
i2c_adapter_trylock_bus(struct i2c_adapter * adapter,unsigned int flags)834 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
835 unsigned int flags)
836 {
837 return rt_mutex_trylock(&adapter->bus_lock);
838 }
839
840 /**
841 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
842 * @adapter: Target I2C bus segment
843 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
844 * unlocks only this branch in the adapter tree
845 */
i2c_adapter_unlock_bus(struct i2c_adapter * adapter,unsigned int flags)846 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
847 unsigned int flags)
848 {
849 rt_mutex_unlock(&adapter->bus_lock);
850 }
851
i2c_dev_set_name(struct i2c_adapter * adap,struct i2c_client * client,struct i2c_board_info const * info)852 static void i2c_dev_set_name(struct i2c_adapter *adap,
853 struct i2c_client *client,
854 struct i2c_board_info const *info)
855 {
856 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
857
858 if (info && info->dev_name) {
859 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
860 return;
861 }
862
863 if (adev) {
864 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
865 return;
866 }
867
868 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
869 i2c_encode_flags_to_addr(client));
870 }
871
i2c_dev_irq_from_resources(const struct resource * resources,unsigned int num_resources)872 int i2c_dev_irq_from_resources(const struct resource *resources,
873 unsigned int num_resources)
874 {
875 struct irq_data *irqd;
876 int i;
877
878 for (i = 0; i < num_resources; i++) {
879 const struct resource *r = &resources[i];
880
881 if (resource_type(r) != IORESOURCE_IRQ)
882 continue;
883
884 if (r->flags & IORESOURCE_BITS) {
885 irqd = irq_get_irq_data(r->start);
886 if (!irqd)
887 break;
888
889 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
890 }
891
892 return r->start;
893 }
894
895 return 0;
896 }
897
898 /**
899 * i2c_new_client_device - instantiate an i2c device
900 * @adap: the adapter managing the device
901 * @info: describes one I2C device; bus_num is ignored
902 * Context: can sleep
903 *
904 * Create an i2c device. Binding is handled through driver model
905 * probe()/remove() methods. A driver may be bound to this device when we
906 * return from this function, or any later moment (e.g. maybe hotplugging will
907 * load the driver module). This call is not appropriate for use by mainboard
908 * initialization logic, which usually runs during an arch_initcall() long
909 * before any i2c_adapter could exist.
910 *
911 * This returns the new i2c client, which may be saved for later use with
912 * i2c_unregister_device(); or an ERR_PTR to describe the error.
913 */
914 struct i2c_client *
i2c_new_client_device(struct i2c_adapter * adap,struct i2c_board_info const * info)915 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
916 {
917 struct i2c_client *client;
918 int status;
919
920 client = kzalloc(sizeof *client, GFP_KERNEL);
921 if (!client)
922 return ERR_PTR(-ENOMEM);
923
924 client->adapter = adap;
925
926 client->dev.platform_data = info->platform_data;
927 client->flags = info->flags;
928 client->addr = info->addr;
929
930 client->init_irq = info->irq;
931 if (!client->init_irq)
932 client->init_irq = i2c_dev_irq_from_resources(info->resources,
933 info->num_resources);
934
935 strlcpy(client->name, info->type, sizeof(client->name));
936
937 status = i2c_check_addr_validity(client->addr, client->flags);
938 if (status) {
939 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
940 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
941 goto out_err_silent;
942 }
943
944 /* Check for address business */
945 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
946 if (status)
947 goto out_err;
948
949 client->dev.parent = &client->adapter->dev;
950 client->dev.bus = &i2c_bus_type;
951 client->dev.type = &i2c_client_type;
952 client->dev.of_node = of_node_get(info->of_node);
953 client->dev.fwnode = info->fwnode;
954
955 i2c_dev_set_name(adap, client, info);
956
957 if (info->swnode) {
958 status = device_add_software_node(&client->dev, info->swnode);
959 if (status) {
960 dev_err(&adap->dev,
961 "Failed to add software node to client %s: %d\n",
962 client->name, status);
963 goto out_err_put_of_node;
964 }
965 }
966
967 status = device_register(&client->dev);
968 if (status)
969 goto out_remove_swnode;
970
971 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
972 client->name, dev_name(&client->dev));
973
974 return client;
975
976 out_remove_swnode:
977 device_remove_software_node(&client->dev);
978 out_err_put_of_node:
979 of_node_put(info->of_node);
980 out_err:
981 dev_err(&adap->dev,
982 "Failed to register i2c client %s at 0x%02x (%d)\n",
983 client->name, client->addr, status);
984 out_err_silent:
985 kfree(client);
986 return ERR_PTR(status);
987 }
988 EXPORT_SYMBOL_GPL(i2c_new_client_device);
989
990 /**
991 * i2c_unregister_device - reverse effect of i2c_new_*_device()
992 * @client: value returned from i2c_new_*_device()
993 * Context: can sleep
994 */
i2c_unregister_device(struct i2c_client * client)995 void i2c_unregister_device(struct i2c_client *client)
996 {
997 if (IS_ERR_OR_NULL(client))
998 return;
999
1000 if (client->dev.of_node) {
1001 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1002 of_node_put(client->dev.of_node);
1003 }
1004
1005 if (ACPI_COMPANION(&client->dev))
1006 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1007 device_remove_software_node(&client->dev);
1008 device_unregister(&client->dev);
1009 }
1010 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1011
1012
1013 static const struct i2c_device_id dummy_id[] = {
1014 { "dummy", 0 },
1015 { },
1016 };
1017
dummy_probe(struct i2c_client * client,const struct i2c_device_id * id)1018 static int dummy_probe(struct i2c_client *client,
1019 const struct i2c_device_id *id)
1020 {
1021 return 0;
1022 }
1023
dummy_remove(struct i2c_client * client)1024 static int dummy_remove(struct i2c_client *client)
1025 {
1026 return 0;
1027 }
1028
1029 static struct i2c_driver dummy_driver = {
1030 .driver.name = "dummy",
1031 .probe = dummy_probe,
1032 .remove = dummy_remove,
1033 .id_table = dummy_id,
1034 };
1035
1036 /**
1037 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1038 * @adapter: the adapter managing the device
1039 * @address: seven bit address to be used
1040 * Context: can sleep
1041 *
1042 * This returns an I2C client bound to the "dummy" driver, intended for use
1043 * with devices that consume multiple addresses. Examples of such chips
1044 * include various EEPROMS (like 24c04 and 24c08 models).
1045 *
1046 * These dummy devices have two main uses. First, most I2C and SMBus calls
1047 * except i2c_transfer() need a client handle; the dummy will be that handle.
1048 * And second, this prevents the specified address from being bound to a
1049 * different driver.
1050 *
1051 * This returns the new i2c client, which should be saved for later use with
1052 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1053 */
i2c_new_dummy_device(struct i2c_adapter * adapter,u16 address)1054 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1055 {
1056 struct i2c_board_info info = {
1057 I2C_BOARD_INFO("dummy", address),
1058 };
1059
1060 return i2c_new_client_device(adapter, &info);
1061 }
1062 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1063
devm_i2c_release_dummy(void * client)1064 static void devm_i2c_release_dummy(void *client)
1065 {
1066 i2c_unregister_device(client);
1067 }
1068
1069 /**
1070 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1071 * @dev: device the managed resource is bound to
1072 * @adapter: the adapter managing the device
1073 * @address: seven bit address to be used
1074 * Context: can sleep
1075 *
1076 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1077 * new i2c client or an ERR_PTR in case of an error.
1078 */
devm_i2c_new_dummy_device(struct device * dev,struct i2c_adapter * adapter,u16 address)1079 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1080 struct i2c_adapter *adapter,
1081 u16 address)
1082 {
1083 struct i2c_client *client;
1084 int ret;
1085
1086 client = i2c_new_dummy_device(adapter, address);
1087 if (IS_ERR(client))
1088 return client;
1089
1090 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1091 if (ret)
1092 return ERR_PTR(ret);
1093
1094 return client;
1095 }
1096 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1097
1098 /**
1099 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1100 * and create the associated device
1101 * @client: Handle to the primary client
1102 * @name: Handle to specify which secondary address to get
1103 * @default_addr: Used as a fallback if no secondary address was specified
1104 * Context: can sleep
1105 *
1106 * I2C clients can be composed of multiple I2C slaves bound together in a single
1107 * component. The I2C client driver then binds to the master I2C slave and needs
1108 * to create I2C dummy clients to communicate with all the other slaves.
1109 *
1110 * This function creates and returns an I2C dummy client whose I2C address is
1111 * retrieved from the platform firmware based on the given slave name. If no
1112 * address is specified by the firmware default_addr is used.
1113 *
1114 * On DT-based platforms the address is retrieved from the "reg" property entry
1115 * cell whose "reg-names" value matches the slave name.
1116 *
1117 * This returns the new i2c client, which should be saved for later use with
1118 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1119 */
i2c_new_ancillary_device(struct i2c_client * client,const char * name,u16 default_addr)1120 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1121 const char *name,
1122 u16 default_addr)
1123 {
1124 struct device_node *np = client->dev.of_node;
1125 u32 addr = default_addr;
1126 int i;
1127
1128 if (np) {
1129 i = of_property_match_string(np, "reg-names", name);
1130 if (i >= 0)
1131 of_property_read_u32_index(np, "reg", i, &addr);
1132 }
1133
1134 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1135 return i2c_new_dummy_device(client->adapter, addr);
1136 }
1137 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1138
1139 /* ------------------------------------------------------------------------- */
1140
1141 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1142
i2c_adapter_dev_release(struct device * dev)1143 static void i2c_adapter_dev_release(struct device *dev)
1144 {
1145 struct i2c_adapter *adap = to_i2c_adapter(dev);
1146 complete(&adap->dev_released);
1147 }
1148
i2c_adapter_depth(struct i2c_adapter * adapter)1149 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1150 {
1151 unsigned int depth = 0;
1152
1153 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1154 depth++;
1155
1156 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1157 "adapter depth exceeds lockdep subclass limit\n");
1158
1159 return depth;
1160 }
1161 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1162
1163 /*
1164 * Let users instantiate I2C devices through sysfs. This can be used when
1165 * platform initialization code doesn't contain the proper data for
1166 * whatever reason. Also useful for drivers that do device detection and
1167 * detection fails, either because the device uses an unexpected address,
1168 * or this is a compatible device with different ID register values.
1169 *
1170 * Parameter checking may look overzealous, but we really don't want
1171 * the user to provide incorrect parameters.
1172 */
1173 static ssize_t
new_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1174 new_device_store(struct device *dev, struct device_attribute *attr,
1175 const char *buf, size_t count)
1176 {
1177 struct i2c_adapter *adap = to_i2c_adapter(dev);
1178 struct i2c_board_info info;
1179 struct i2c_client *client;
1180 char *blank, end;
1181 int res;
1182
1183 memset(&info, 0, sizeof(struct i2c_board_info));
1184
1185 blank = strchr(buf, ' ');
1186 if (!blank) {
1187 dev_err(dev, "%s: Missing parameters\n", "new_device");
1188 return -EINVAL;
1189 }
1190 if (blank - buf > I2C_NAME_SIZE - 1) {
1191 dev_err(dev, "%s: Invalid device name\n", "new_device");
1192 return -EINVAL;
1193 }
1194 memcpy(info.type, buf, blank - buf);
1195
1196 /* Parse remaining parameters, reject extra parameters */
1197 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1198 if (res < 1) {
1199 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1200 return -EINVAL;
1201 }
1202 if (res > 1 && end != '\n') {
1203 dev_err(dev, "%s: Extra parameters\n", "new_device");
1204 return -EINVAL;
1205 }
1206
1207 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1208 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1209 info.flags |= I2C_CLIENT_TEN;
1210 }
1211
1212 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1213 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1214 info.flags |= I2C_CLIENT_SLAVE;
1215 }
1216
1217 client = i2c_new_client_device(adap, &info);
1218 if (IS_ERR(client))
1219 return PTR_ERR(client);
1220
1221 /* Keep track of the added device */
1222 mutex_lock(&adap->userspace_clients_lock);
1223 list_add_tail(&client->detected, &adap->userspace_clients);
1224 mutex_unlock(&adap->userspace_clients_lock);
1225 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1226 info.type, info.addr);
1227
1228 return count;
1229 }
1230 static DEVICE_ATTR_WO(new_device);
1231
1232 /*
1233 * And of course let the users delete the devices they instantiated, if
1234 * they got it wrong. This interface can only be used to delete devices
1235 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1236 * don't delete devices to which some kernel code still has references.
1237 *
1238 * Parameter checking may look overzealous, but we really don't want
1239 * the user to delete the wrong device.
1240 */
1241 static ssize_t
delete_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1242 delete_device_store(struct device *dev, struct device_attribute *attr,
1243 const char *buf, size_t count)
1244 {
1245 struct i2c_adapter *adap = to_i2c_adapter(dev);
1246 struct i2c_client *client, *next;
1247 unsigned short addr;
1248 char end;
1249 int res;
1250
1251 /* Parse parameters, reject extra parameters */
1252 res = sscanf(buf, "%hi%c", &addr, &end);
1253 if (res < 1) {
1254 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1255 return -EINVAL;
1256 }
1257 if (res > 1 && end != '\n') {
1258 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1259 return -EINVAL;
1260 }
1261
1262 /* Make sure the device was added through sysfs */
1263 res = -ENOENT;
1264 mutex_lock_nested(&adap->userspace_clients_lock,
1265 i2c_adapter_depth(adap));
1266 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1267 detected) {
1268 if (i2c_encode_flags_to_addr(client) == addr) {
1269 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1270 "delete_device", client->name, client->addr);
1271
1272 list_del(&client->detected);
1273 i2c_unregister_device(client);
1274 res = count;
1275 break;
1276 }
1277 }
1278 mutex_unlock(&adap->userspace_clients_lock);
1279
1280 if (res < 0)
1281 dev_err(dev, "%s: Can't find device in list\n",
1282 "delete_device");
1283 return res;
1284 }
1285 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1286 delete_device_store);
1287
1288 static struct attribute *i2c_adapter_attrs[] = {
1289 &dev_attr_name.attr,
1290 &dev_attr_new_device.attr,
1291 &dev_attr_delete_device.attr,
1292 NULL
1293 };
1294 ATTRIBUTE_GROUPS(i2c_adapter);
1295
1296 struct device_type i2c_adapter_type = {
1297 .groups = i2c_adapter_groups,
1298 .release = i2c_adapter_dev_release,
1299 };
1300 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1301
1302 /**
1303 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1304 * @dev: device, probably from some driver model iterator
1305 *
1306 * When traversing the driver model tree, perhaps using driver model
1307 * iterators like @device_for_each_child(), you can't assume very much
1308 * about the nodes you find. Use this function to avoid oopses caused
1309 * by wrongly treating some non-I2C device as an i2c_adapter.
1310 */
i2c_verify_adapter(struct device * dev)1311 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1312 {
1313 return (dev->type == &i2c_adapter_type)
1314 ? to_i2c_adapter(dev)
1315 : NULL;
1316 }
1317 EXPORT_SYMBOL(i2c_verify_adapter);
1318
1319 #ifdef CONFIG_I2C_COMPAT
1320 static struct class_compat *i2c_adapter_compat_class;
1321 #endif
1322
i2c_scan_static_board_info(struct i2c_adapter * adapter)1323 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1324 {
1325 struct i2c_devinfo *devinfo;
1326
1327 down_read(&__i2c_board_lock);
1328 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1329 if (devinfo->busnum == adapter->nr &&
1330 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1331 dev_err(&adapter->dev,
1332 "Can't create device at 0x%02x\n",
1333 devinfo->board_info.addr);
1334 }
1335 up_read(&__i2c_board_lock);
1336 }
1337
i2c_do_add_adapter(struct i2c_driver * driver,struct i2c_adapter * adap)1338 static int i2c_do_add_adapter(struct i2c_driver *driver,
1339 struct i2c_adapter *adap)
1340 {
1341 /* Detect supported devices on that bus, and instantiate them */
1342 i2c_detect(adap, driver);
1343
1344 return 0;
1345 }
1346
__process_new_adapter(struct device_driver * d,void * data)1347 static int __process_new_adapter(struct device_driver *d, void *data)
1348 {
1349 return i2c_do_add_adapter(to_i2c_driver(d), data);
1350 }
1351
1352 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1353 .lock_bus = i2c_adapter_lock_bus,
1354 .trylock_bus = i2c_adapter_trylock_bus,
1355 .unlock_bus = i2c_adapter_unlock_bus,
1356 };
1357
i2c_host_notify_irq_teardown(struct i2c_adapter * adap)1358 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1359 {
1360 struct irq_domain *domain = adap->host_notify_domain;
1361 irq_hw_number_t hwirq;
1362
1363 if (!domain)
1364 return;
1365
1366 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1367 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1368
1369 irq_domain_remove(domain);
1370 adap->host_notify_domain = NULL;
1371 }
1372
i2c_host_notify_irq_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw_irq_num)1373 static int i2c_host_notify_irq_map(struct irq_domain *h,
1374 unsigned int virq,
1375 irq_hw_number_t hw_irq_num)
1376 {
1377 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1378
1379 return 0;
1380 }
1381
1382 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1383 .map = i2c_host_notify_irq_map,
1384 };
1385
i2c_setup_host_notify_irq_domain(struct i2c_adapter * adap)1386 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1387 {
1388 struct irq_domain *domain;
1389
1390 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1391 return 0;
1392
1393 domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1394 I2C_ADDR_7BITS_COUNT,
1395 &i2c_host_notify_irq_ops, adap);
1396 if (!domain)
1397 return -ENOMEM;
1398
1399 adap->host_notify_domain = domain;
1400
1401 return 0;
1402 }
1403
1404 /**
1405 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1406 * I2C client.
1407 * @adap: the adapter
1408 * @addr: the I2C address of the notifying device
1409 * Context: can't sleep
1410 *
1411 * Helper function to be called from an I2C bus driver's interrupt
1412 * handler. It will schedule the Host Notify IRQ.
1413 */
i2c_handle_smbus_host_notify(struct i2c_adapter * adap,unsigned short addr)1414 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1415 {
1416 int irq;
1417
1418 if (!adap)
1419 return -EINVAL;
1420
1421 irq = irq_find_mapping(adap->host_notify_domain, addr);
1422 if (irq <= 0)
1423 return -ENXIO;
1424
1425 generic_handle_irq(irq);
1426
1427 return 0;
1428 }
1429 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1430
i2c_register_adapter(struct i2c_adapter * adap)1431 static int i2c_register_adapter(struct i2c_adapter *adap)
1432 {
1433 int res = -EINVAL;
1434
1435 /* Can't register until after driver model init */
1436 if (WARN_ON(!is_registered)) {
1437 res = -EAGAIN;
1438 goto out_list;
1439 }
1440
1441 /* Sanity checks */
1442 if (WARN(!adap->name[0], "i2c adapter has no name"))
1443 goto out_list;
1444
1445 if (!adap->algo) {
1446 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1447 goto out_list;
1448 }
1449
1450 if (!adap->lock_ops)
1451 adap->lock_ops = &i2c_adapter_lock_ops;
1452
1453 adap->locked_flags = 0;
1454 rt_mutex_init(&adap->bus_lock);
1455 rt_mutex_init(&adap->mux_lock);
1456 mutex_init(&adap->userspace_clients_lock);
1457 INIT_LIST_HEAD(&adap->userspace_clients);
1458
1459 /* Set default timeout to 1 second if not already set */
1460 if (adap->timeout == 0)
1461 adap->timeout = HZ;
1462
1463 /* register soft irqs for Host Notify */
1464 res = i2c_setup_host_notify_irq_domain(adap);
1465 if (res) {
1466 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1467 adap->name, res);
1468 goto out_list;
1469 }
1470
1471 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1472 adap->dev.bus = &i2c_bus_type;
1473 adap->dev.type = &i2c_adapter_type;
1474 res = device_register(&adap->dev);
1475 if (res) {
1476 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1477 goto out_list;
1478 }
1479
1480 res = of_i2c_setup_smbus_alert(adap);
1481 if (res)
1482 goto out_reg;
1483
1484 pm_runtime_no_callbacks(&adap->dev);
1485 pm_suspend_ignore_children(&adap->dev, true);
1486 pm_runtime_enable(&adap->dev);
1487
1488 res = i2c_init_recovery(adap);
1489 if (res == -EPROBE_DEFER)
1490 goto out_reg;
1491
1492 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1493
1494 #ifdef CONFIG_I2C_COMPAT
1495 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1496 adap->dev.parent);
1497 if (res)
1498 dev_warn(&adap->dev,
1499 "Failed to create compatibility class link\n");
1500 #endif
1501
1502 /* create pre-declared device nodes */
1503 of_i2c_register_devices(adap);
1504 i2c_acpi_install_space_handler(adap);
1505 i2c_acpi_register_devices(adap);
1506
1507 if (adap->nr < __i2c_first_dynamic_bus_num)
1508 i2c_scan_static_board_info(adap);
1509
1510 /* Notify drivers */
1511 mutex_lock(&core_lock);
1512 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1513 mutex_unlock(&core_lock);
1514
1515 return 0;
1516
1517 out_reg:
1518 init_completion(&adap->dev_released);
1519 device_unregister(&adap->dev);
1520 wait_for_completion(&adap->dev_released);
1521 out_list:
1522 mutex_lock(&core_lock);
1523 idr_remove(&i2c_adapter_idr, adap->nr);
1524 mutex_unlock(&core_lock);
1525 return res;
1526 }
1527
1528 /**
1529 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1530 * @adap: the adapter to register (with adap->nr initialized)
1531 * Context: can sleep
1532 *
1533 * See i2c_add_numbered_adapter() for details.
1534 */
__i2c_add_numbered_adapter(struct i2c_adapter * adap)1535 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1536 {
1537 int id;
1538
1539 mutex_lock(&core_lock);
1540 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1541 mutex_unlock(&core_lock);
1542 if (WARN(id < 0, "couldn't get idr"))
1543 return id == -ENOSPC ? -EBUSY : id;
1544
1545 return i2c_register_adapter(adap);
1546 }
1547
1548 /**
1549 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1550 * @adapter: the adapter to add
1551 * Context: can sleep
1552 *
1553 * This routine is used to declare an I2C adapter when its bus number
1554 * doesn't matter or when its bus number is specified by an dt alias.
1555 * Examples of bases when the bus number doesn't matter: I2C adapters
1556 * dynamically added by USB links or PCI plugin cards.
1557 *
1558 * When this returns zero, a new bus number was allocated and stored
1559 * in adap->nr, and the specified adapter became available for clients.
1560 * Otherwise, a negative errno value is returned.
1561 */
i2c_add_adapter(struct i2c_adapter * adapter)1562 int i2c_add_adapter(struct i2c_adapter *adapter)
1563 {
1564 struct device *dev = &adapter->dev;
1565 int id;
1566
1567 if (dev->of_node) {
1568 id = of_alias_get_id(dev->of_node, "i2c");
1569 if (id >= 0) {
1570 adapter->nr = id;
1571 return __i2c_add_numbered_adapter(adapter);
1572 }
1573 }
1574
1575 mutex_lock(&core_lock);
1576 id = idr_alloc(&i2c_adapter_idr, adapter,
1577 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1578 mutex_unlock(&core_lock);
1579 if (WARN(id < 0, "couldn't get idr"))
1580 return id;
1581
1582 adapter->nr = id;
1583
1584 return i2c_register_adapter(adapter);
1585 }
1586 EXPORT_SYMBOL(i2c_add_adapter);
1587
1588 /**
1589 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1590 * @adap: the adapter to register (with adap->nr initialized)
1591 * Context: can sleep
1592 *
1593 * This routine is used to declare an I2C adapter when its bus number
1594 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1595 * or otherwise built in to the system's mainboard, and where i2c_board_info
1596 * is used to properly configure I2C devices.
1597 *
1598 * If the requested bus number is set to -1, then this function will behave
1599 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1600 *
1601 * If no devices have pre-been declared for this bus, then be sure to
1602 * register the adapter before any dynamically allocated ones. Otherwise
1603 * the required bus ID may not be available.
1604 *
1605 * When this returns zero, the specified adapter became available for
1606 * clients using the bus number provided in adap->nr. Also, the table
1607 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1608 * and the appropriate driver model device nodes are created. Otherwise, a
1609 * negative errno value is returned.
1610 */
i2c_add_numbered_adapter(struct i2c_adapter * adap)1611 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1612 {
1613 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1614 return i2c_add_adapter(adap);
1615
1616 return __i2c_add_numbered_adapter(adap);
1617 }
1618 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1619
i2c_do_del_adapter(struct i2c_driver * driver,struct i2c_adapter * adapter)1620 static void i2c_do_del_adapter(struct i2c_driver *driver,
1621 struct i2c_adapter *adapter)
1622 {
1623 struct i2c_client *client, *_n;
1624
1625 /* Remove the devices we created ourselves as the result of hardware
1626 * probing (using a driver's detect method) */
1627 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1628 if (client->adapter == adapter) {
1629 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1630 client->name, client->addr);
1631 list_del(&client->detected);
1632 i2c_unregister_device(client);
1633 }
1634 }
1635 }
1636
__unregister_client(struct device * dev,void * dummy)1637 static int __unregister_client(struct device *dev, void *dummy)
1638 {
1639 struct i2c_client *client = i2c_verify_client(dev);
1640 if (client && strcmp(client->name, "dummy"))
1641 i2c_unregister_device(client);
1642 return 0;
1643 }
1644
__unregister_dummy(struct device * dev,void * dummy)1645 static int __unregister_dummy(struct device *dev, void *dummy)
1646 {
1647 struct i2c_client *client = i2c_verify_client(dev);
1648 i2c_unregister_device(client);
1649 return 0;
1650 }
1651
__process_removed_adapter(struct device_driver * d,void * data)1652 static int __process_removed_adapter(struct device_driver *d, void *data)
1653 {
1654 i2c_do_del_adapter(to_i2c_driver(d), data);
1655 return 0;
1656 }
1657
1658 /**
1659 * i2c_del_adapter - unregister I2C adapter
1660 * @adap: the adapter being unregistered
1661 * Context: can sleep
1662 *
1663 * This unregisters an I2C adapter which was previously registered
1664 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1665 */
i2c_del_adapter(struct i2c_adapter * adap)1666 void i2c_del_adapter(struct i2c_adapter *adap)
1667 {
1668 struct i2c_adapter *found;
1669 struct i2c_client *client, *next;
1670
1671 /* First make sure that this adapter was ever added */
1672 mutex_lock(&core_lock);
1673 found = idr_find(&i2c_adapter_idr, adap->nr);
1674 mutex_unlock(&core_lock);
1675 if (found != adap) {
1676 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1677 return;
1678 }
1679
1680 i2c_acpi_remove_space_handler(adap);
1681 /* Tell drivers about this removal */
1682 mutex_lock(&core_lock);
1683 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1684 __process_removed_adapter);
1685 mutex_unlock(&core_lock);
1686
1687 /* Remove devices instantiated from sysfs */
1688 mutex_lock_nested(&adap->userspace_clients_lock,
1689 i2c_adapter_depth(adap));
1690 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1691 detected) {
1692 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1693 client->addr);
1694 list_del(&client->detected);
1695 i2c_unregister_device(client);
1696 }
1697 mutex_unlock(&adap->userspace_clients_lock);
1698
1699 /* Detach any active clients. This can't fail, thus we do not
1700 * check the returned value. This is a two-pass process, because
1701 * we can't remove the dummy devices during the first pass: they
1702 * could have been instantiated by real devices wishing to clean
1703 * them up properly, so we give them a chance to do that first. */
1704 device_for_each_child(&adap->dev, NULL, __unregister_client);
1705 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1706
1707 #ifdef CONFIG_I2C_COMPAT
1708 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1709 adap->dev.parent);
1710 #endif
1711
1712 /* device name is gone after device_unregister */
1713 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1714
1715 pm_runtime_disable(&adap->dev);
1716
1717 i2c_host_notify_irq_teardown(adap);
1718
1719 /* wait until all references to the device are gone
1720 *
1721 * FIXME: This is old code and should ideally be replaced by an
1722 * alternative which results in decoupling the lifetime of the struct
1723 * device from the i2c_adapter, like spi or netdev do. Any solution
1724 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1725 */
1726 init_completion(&adap->dev_released);
1727 device_unregister(&adap->dev);
1728 wait_for_completion(&adap->dev_released);
1729
1730 /* free bus id */
1731 mutex_lock(&core_lock);
1732 idr_remove(&i2c_adapter_idr, adap->nr);
1733 mutex_unlock(&core_lock);
1734
1735 /* Clear the device structure in case this adapter is ever going to be
1736 added again */
1737 memset(&adap->dev, 0, sizeof(adap->dev));
1738 }
1739 EXPORT_SYMBOL(i2c_del_adapter);
1740
devm_i2c_del_adapter(void * adapter)1741 static void devm_i2c_del_adapter(void *adapter)
1742 {
1743 i2c_del_adapter(adapter);
1744 }
1745
1746 /**
1747 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1748 * @dev: managing device for adding this I2C adapter
1749 * @adapter: the adapter to add
1750 * Context: can sleep
1751 *
1752 * Add adapter with dynamic bus number, same with i2c_add_adapter()
1753 * but the adapter will be auto deleted on driver detach.
1754 */
devm_i2c_add_adapter(struct device * dev,struct i2c_adapter * adapter)1755 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1756 {
1757 int ret;
1758
1759 ret = i2c_add_adapter(adapter);
1760 if (ret)
1761 return ret;
1762
1763 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1764 }
1765 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1766
i2c_parse_timing(struct device * dev,char * prop_name,u32 * cur_val_p,u32 def_val,bool use_def)1767 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1768 u32 def_val, bool use_def)
1769 {
1770 int ret;
1771
1772 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1773 if (ret && use_def)
1774 *cur_val_p = def_val;
1775
1776 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1777 }
1778
1779 /**
1780 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1781 * @dev: The device to scan for I2C timing properties
1782 * @t: the i2c_timings struct to be filled with values
1783 * @use_defaults: bool to use sane defaults derived from the I2C specification
1784 * when properties are not found, otherwise don't update
1785 *
1786 * Scan the device for the generic I2C properties describing timing parameters
1787 * for the signal and fill the given struct with the results. If a property was
1788 * not found and use_defaults was true, then maximum timings are assumed which
1789 * are derived from the I2C specification. If use_defaults is not used, the
1790 * results will be as before, so drivers can apply their own defaults before
1791 * calling this helper. The latter is mainly intended for avoiding regressions
1792 * of existing drivers which want to switch to this function. New drivers
1793 * almost always should use the defaults.
1794 */
i2c_parse_fw_timings(struct device * dev,struct i2c_timings * t,bool use_defaults)1795 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1796 {
1797 bool u = use_defaults;
1798 u32 d;
1799
1800 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1801 I2C_MAX_STANDARD_MODE_FREQ, u);
1802
1803 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1804 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1805 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1806
1807 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1808 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1809
1810 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1811 &t->scl_int_delay_ns, 0, u);
1812 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1813 t->scl_fall_ns, u);
1814 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1815 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1816 &t->digital_filter_width_ns, 0, u);
1817 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1818 &t->analog_filter_cutoff_freq_hz, 0, u);
1819 }
1820 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1821
1822 /* ------------------------------------------------------------------------- */
1823
i2c_for_each_dev(void * data,int (* fn)(struct device * dev,void * data))1824 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1825 {
1826 int res;
1827
1828 mutex_lock(&core_lock);
1829 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1830 mutex_unlock(&core_lock);
1831
1832 return res;
1833 }
1834 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1835
__process_new_driver(struct device * dev,void * data)1836 static int __process_new_driver(struct device *dev, void *data)
1837 {
1838 if (dev->type != &i2c_adapter_type)
1839 return 0;
1840 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1841 }
1842
1843 /*
1844 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1845 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1846 */
1847
i2c_register_driver(struct module * owner,struct i2c_driver * driver)1848 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1849 {
1850 int res;
1851
1852 /* Can't register until after driver model init */
1853 if (WARN_ON(!is_registered))
1854 return -EAGAIN;
1855
1856 /* add the driver to the list of i2c drivers in the driver core */
1857 driver->driver.owner = owner;
1858 driver->driver.bus = &i2c_bus_type;
1859 INIT_LIST_HEAD(&driver->clients);
1860
1861 /* When registration returns, the driver core
1862 * will have called probe() for all matching-but-unbound devices.
1863 */
1864 res = driver_register(&driver->driver);
1865 if (res)
1866 return res;
1867
1868 pr_debug("driver [%s] registered\n", driver->driver.name);
1869
1870 /* Walk the adapters that are already present */
1871 i2c_for_each_dev(driver, __process_new_driver);
1872
1873 return 0;
1874 }
1875 EXPORT_SYMBOL(i2c_register_driver);
1876
__process_removed_driver(struct device * dev,void * data)1877 static int __process_removed_driver(struct device *dev, void *data)
1878 {
1879 if (dev->type == &i2c_adapter_type)
1880 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1881 return 0;
1882 }
1883
1884 /**
1885 * i2c_del_driver - unregister I2C driver
1886 * @driver: the driver being unregistered
1887 * Context: can sleep
1888 */
i2c_del_driver(struct i2c_driver * driver)1889 void i2c_del_driver(struct i2c_driver *driver)
1890 {
1891 i2c_for_each_dev(driver, __process_removed_driver);
1892
1893 driver_unregister(&driver->driver);
1894 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1895 }
1896 EXPORT_SYMBOL(i2c_del_driver);
1897
1898 /* ------------------------------------------------------------------------- */
1899
1900 struct i2c_cmd_arg {
1901 unsigned cmd;
1902 void *arg;
1903 };
1904
i2c_cmd(struct device * dev,void * _arg)1905 static int i2c_cmd(struct device *dev, void *_arg)
1906 {
1907 struct i2c_client *client = i2c_verify_client(dev);
1908 struct i2c_cmd_arg *arg = _arg;
1909 struct i2c_driver *driver;
1910
1911 if (!client || !client->dev.driver)
1912 return 0;
1913
1914 driver = to_i2c_driver(client->dev.driver);
1915 if (driver->command)
1916 driver->command(client, arg->cmd, arg->arg);
1917 return 0;
1918 }
1919
i2c_clients_command(struct i2c_adapter * adap,unsigned int cmd,void * arg)1920 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1921 {
1922 struct i2c_cmd_arg cmd_arg;
1923
1924 cmd_arg.cmd = cmd;
1925 cmd_arg.arg = arg;
1926 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1927 }
1928 EXPORT_SYMBOL(i2c_clients_command);
1929
i2c_init(void)1930 static int __init i2c_init(void)
1931 {
1932 int retval;
1933
1934 retval = of_alias_get_highest_id("i2c");
1935
1936 down_write(&__i2c_board_lock);
1937 if (retval >= __i2c_first_dynamic_bus_num)
1938 __i2c_first_dynamic_bus_num = retval + 1;
1939 up_write(&__i2c_board_lock);
1940
1941 retval = bus_register(&i2c_bus_type);
1942 if (retval)
1943 return retval;
1944
1945 is_registered = true;
1946
1947 #ifdef CONFIG_I2C_COMPAT
1948 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1949 if (!i2c_adapter_compat_class) {
1950 retval = -ENOMEM;
1951 goto bus_err;
1952 }
1953 #endif
1954 retval = i2c_add_driver(&dummy_driver);
1955 if (retval)
1956 goto class_err;
1957
1958 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1959 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1960 if (IS_ENABLED(CONFIG_ACPI))
1961 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1962
1963 return 0;
1964
1965 class_err:
1966 #ifdef CONFIG_I2C_COMPAT
1967 class_compat_unregister(i2c_adapter_compat_class);
1968 bus_err:
1969 #endif
1970 is_registered = false;
1971 bus_unregister(&i2c_bus_type);
1972 return retval;
1973 }
1974
i2c_exit(void)1975 static void __exit i2c_exit(void)
1976 {
1977 if (IS_ENABLED(CONFIG_ACPI))
1978 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1979 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1980 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1981 i2c_del_driver(&dummy_driver);
1982 #ifdef CONFIG_I2C_COMPAT
1983 class_compat_unregister(i2c_adapter_compat_class);
1984 #endif
1985 bus_unregister(&i2c_bus_type);
1986 tracepoint_synchronize_unregister();
1987 }
1988
1989 /* We must initialize early, because some subsystems register i2c drivers
1990 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1991 */
1992 postcore_initcall(i2c_init);
1993 module_exit(i2c_exit);
1994
1995 /* ----------------------------------------------------
1996 * the functional interface to the i2c busses.
1997 * ----------------------------------------------------
1998 */
1999
2000 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2001 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2002
i2c_quirk_error(struct i2c_adapter * adap,struct i2c_msg * msg,char * err_msg)2003 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2004 {
2005 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2006 err_msg, msg->addr, msg->len,
2007 msg->flags & I2C_M_RD ? "read" : "write");
2008 return -EOPNOTSUPP;
2009 }
2010
i2c_check_for_quirks(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2011 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2012 {
2013 const struct i2c_adapter_quirks *q = adap->quirks;
2014 int max_num = q->max_num_msgs, i;
2015 bool do_len_check = true;
2016
2017 if (q->flags & I2C_AQ_COMB) {
2018 max_num = 2;
2019
2020 /* special checks for combined messages */
2021 if (num == 2) {
2022 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2023 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2024
2025 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2026 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2027
2028 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2029 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2030
2031 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2032 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2033
2034 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2035 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2036
2037 do_len_check = false;
2038 }
2039 }
2040
2041 if (i2c_quirk_exceeded(num, max_num))
2042 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2043
2044 for (i = 0; i < num; i++) {
2045 u16 len = msgs[i].len;
2046
2047 if (msgs[i].flags & I2C_M_RD) {
2048 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2049 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2050
2051 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2052 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2053 } else {
2054 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2055 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2056
2057 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2058 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2059 }
2060 }
2061
2062 return 0;
2063 }
2064
2065 /**
2066 * __i2c_transfer - unlocked flavor of i2c_transfer
2067 * @adap: Handle to I2C bus
2068 * @msgs: One or more messages to execute before STOP is issued to
2069 * terminate the operation; each message begins with a START.
2070 * @num: Number of messages to be executed.
2071 *
2072 * Returns negative errno, else the number of messages executed.
2073 *
2074 * Adapter lock must be held when calling this function. No debug logging
2075 * takes place. adap->algo->master_xfer existence isn't checked.
2076 */
__i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2077 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2078 {
2079 unsigned long orig_jiffies;
2080 int ret, try;
2081
2082 if (WARN_ON(!msgs || num < 1))
2083 return -EINVAL;
2084
2085 ret = __i2c_check_suspended(adap);
2086 if (ret)
2087 return ret;
2088
2089 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2090 return -EOPNOTSUPP;
2091
2092 /*
2093 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2094 * enabled. This is an efficient way of keeping the for-loop from
2095 * being executed when not needed.
2096 */
2097 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2098 int i;
2099 for (i = 0; i < num; i++)
2100 if (msgs[i].flags & I2C_M_RD)
2101 trace_i2c_read(adap, &msgs[i], i);
2102 else
2103 trace_i2c_write(adap, &msgs[i], i);
2104 }
2105
2106 /* Retry automatically on arbitration loss */
2107 orig_jiffies = jiffies;
2108 for (ret = 0, try = 0; try <= adap->retries; try++) {
2109 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2110 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2111 else
2112 ret = adap->algo->master_xfer(adap, msgs, num);
2113
2114 if (ret != -EAGAIN)
2115 break;
2116 if (time_after(jiffies, orig_jiffies + adap->timeout))
2117 break;
2118 }
2119
2120 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2121 int i;
2122 for (i = 0; i < ret; i++)
2123 if (msgs[i].flags & I2C_M_RD)
2124 trace_i2c_reply(adap, &msgs[i], i);
2125 trace_i2c_result(adap, num, ret);
2126 }
2127
2128 return ret;
2129 }
2130 EXPORT_SYMBOL(__i2c_transfer);
2131
2132 /**
2133 * i2c_transfer - execute a single or combined I2C message
2134 * @adap: Handle to I2C bus
2135 * @msgs: One or more messages to execute before STOP is issued to
2136 * terminate the operation; each message begins with a START.
2137 * @num: Number of messages to be executed.
2138 *
2139 * Returns negative errno, else the number of messages executed.
2140 *
2141 * Note that there is no requirement that each message be sent to
2142 * the same slave address, although that is the most common model.
2143 */
i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2144 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2145 {
2146 int ret;
2147
2148 if (!adap->algo->master_xfer) {
2149 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2150 return -EOPNOTSUPP;
2151 }
2152
2153 /* REVISIT the fault reporting model here is weak:
2154 *
2155 * - When we get an error after receiving N bytes from a slave,
2156 * there is no way to report "N".
2157 *
2158 * - When we get a NAK after transmitting N bytes to a slave,
2159 * there is no way to report "N" ... or to let the master
2160 * continue executing the rest of this combined message, if
2161 * that's the appropriate response.
2162 *
2163 * - When for example "num" is two and we successfully complete
2164 * the first message but get an error part way through the
2165 * second, it's unclear whether that should be reported as
2166 * one (discarding status on the second message) or errno
2167 * (discarding status on the first one).
2168 */
2169 ret = __i2c_lock_bus_helper(adap);
2170 if (ret)
2171 return ret;
2172
2173 ret = __i2c_transfer(adap, msgs, num);
2174 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2175
2176 return ret;
2177 }
2178 EXPORT_SYMBOL(i2c_transfer);
2179
2180 /**
2181 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2182 * to/from a buffer
2183 * @client: Handle to slave device
2184 * @buf: Where the data is stored
2185 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2186 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2187 *
2188 * Returns negative errno, or else the number of bytes transferred.
2189 */
i2c_transfer_buffer_flags(const struct i2c_client * client,char * buf,int count,u16 flags)2190 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2191 int count, u16 flags)
2192 {
2193 int ret;
2194 struct i2c_msg msg = {
2195 .addr = client->addr,
2196 .flags = flags | (client->flags & I2C_M_TEN),
2197 .len = count,
2198 .buf = buf,
2199 };
2200
2201 ret = i2c_transfer(client->adapter, &msg, 1);
2202
2203 /*
2204 * If everything went ok (i.e. 1 msg transferred), return #bytes
2205 * transferred, else error code.
2206 */
2207 return (ret == 1) ? count : ret;
2208 }
2209 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2210
2211 /**
2212 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2213 * @client: The device to query
2214 * @id: The queried information
2215 *
2216 * Returns negative errno on error, zero on success.
2217 */
i2c_get_device_id(const struct i2c_client * client,struct i2c_device_identity * id)2218 int i2c_get_device_id(const struct i2c_client *client,
2219 struct i2c_device_identity *id)
2220 {
2221 struct i2c_adapter *adap = client->adapter;
2222 union i2c_smbus_data raw_id;
2223 int ret;
2224
2225 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2226 return -EOPNOTSUPP;
2227
2228 raw_id.block[0] = 3;
2229 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2230 I2C_SMBUS_READ, client->addr << 1,
2231 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2232 if (ret)
2233 return ret;
2234
2235 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2236 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2237 id->die_revision = raw_id.block[3] & 0x7;
2238 return 0;
2239 }
2240 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2241
2242 /* ----------------------------------------------------
2243 * the i2c address scanning function
2244 * Will not work for 10-bit addresses!
2245 * ----------------------------------------------------
2246 */
2247
2248 /*
2249 * Legacy default probe function, mostly relevant for SMBus. The default
2250 * probe method is a quick write, but it is known to corrupt the 24RF08
2251 * EEPROMs due to a state machine bug, and could also irreversibly
2252 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2253 * we use a short byte read instead. Also, some bus drivers don't implement
2254 * quick write, so we fallback to a byte read in that case too.
2255 * On x86, there is another special case for FSC hardware monitoring chips,
2256 * which want regular byte reads (address 0x73.) Fortunately, these are the
2257 * only known chips using this I2C address on PC hardware.
2258 * Returns 1 if probe succeeded, 0 if not.
2259 */
i2c_default_probe(struct i2c_adapter * adap,unsigned short addr)2260 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2261 {
2262 int err;
2263 union i2c_smbus_data dummy;
2264
2265 #ifdef CONFIG_X86
2266 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2267 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2268 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2269 I2C_SMBUS_BYTE_DATA, &dummy);
2270 else
2271 #endif
2272 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2273 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2274 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2275 I2C_SMBUS_QUICK, NULL);
2276 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2277 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2278 I2C_SMBUS_BYTE, &dummy);
2279 else {
2280 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2281 addr);
2282 err = -EOPNOTSUPP;
2283 }
2284
2285 return err >= 0;
2286 }
2287
i2c_detect_address(struct i2c_client * temp_client,struct i2c_driver * driver)2288 static int i2c_detect_address(struct i2c_client *temp_client,
2289 struct i2c_driver *driver)
2290 {
2291 struct i2c_board_info info;
2292 struct i2c_adapter *adapter = temp_client->adapter;
2293 int addr = temp_client->addr;
2294 int err;
2295
2296 /* Make sure the address is valid */
2297 err = i2c_check_7bit_addr_validity_strict(addr);
2298 if (err) {
2299 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2300 addr);
2301 return err;
2302 }
2303
2304 /* Skip if already in use (7 bit, no need to encode flags) */
2305 if (i2c_check_addr_busy(adapter, addr))
2306 return 0;
2307
2308 /* Make sure there is something at this address */
2309 if (!i2c_default_probe(adapter, addr))
2310 return 0;
2311
2312 /* Finally call the custom detection function */
2313 memset(&info, 0, sizeof(struct i2c_board_info));
2314 info.addr = addr;
2315 err = driver->detect(temp_client, &info);
2316 if (err) {
2317 /* -ENODEV is returned if the detection fails. We catch it
2318 here as this isn't an error. */
2319 return err == -ENODEV ? 0 : err;
2320 }
2321
2322 /* Consistency check */
2323 if (info.type[0] == '\0') {
2324 dev_err(&adapter->dev,
2325 "%s detection function provided no name for 0x%x\n",
2326 driver->driver.name, addr);
2327 } else {
2328 struct i2c_client *client;
2329
2330 /* Detection succeeded, instantiate the device */
2331 if (adapter->class & I2C_CLASS_DEPRECATED)
2332 dev_warn(&adapter->dev,
2333 "This adapter will soon drop class based instantiation of devices. "
2334 "Please make sure client 0x%02x gets instantiated by other means. "
2335 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2336 info.addr);
2337
2338 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2339 info.type, info.addr);
2340 client = i2c_new_client_device(adapter, &info);
2341 if (!IS_ERR(client))
2342 list_add_tail(&client->detected, &driver->clients);
2343 else
2344 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2345 info.type, info.addr);
2346 }
2347 return 0;
2348 }
2349
i2c_detect(struct i2c_adapter * adapter,struct i2c_driver * driver)2350 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2351 {
2352 const unsigned short *address_list;
2353 struct i2c_client *temp_client;
2354 int i, err = 0;
2355
2356 address_list = driver->address_list;
2357 if (!driver->detect || !address_list)
2358 return 0;
2359
2360 /* Warn that the adapter lost class based instantiation */
2361 if (adapter->class == I2C_CLASS_DEPRECATED) {
2362 dev_dbg(&adapter->dev,
2363 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2364 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2365 driver->driver.name);
2366 return 0;
2367 }
2368
2369 /* Stop here if the classes do not match */
2370 if (!(adapter->class & driver->class))
2371 return 0;
2372
2373 /* Set up a temporary client to help detect callback */
2374 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2375 if (!temp_client)
2376 return -ENOMEM;
2377 temp_client->adapter = adapter;
2378
2379 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2380 dev_dbg(&adapter->dev,
2381 "found normal entry for adapter %d, addr 0x%02x\n",
2382 i2c_adapter_id(adapter), address_list[i]);
2383 temp_client->addr = address_list[i];
2384 err = i2c_detect_address(temp_client, driver);
2385 if (unlikely(err))
2386 break;
2387 }
2388
2389 kfree(temp_client);
2390 return err;
2391 }
2392
i2c_probe_func_quick_read(struct i2c_adapter * adap,unsigned short addr)2393 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2394 {
2395 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2396 I2C_SMBUS_QUICK, NULL) >= 0;
2397 }
2398 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2399
2400 struct i2c_client *
i2c_new_scanned_device(struct i2c_adapter * adap,struct i2c_board_info * info,unsigned short const * addr_list,int (* probe)(struct i2c_adapter * adap,unsigned short addr))2401 i2c_new_scanned_device(struct i2c_adapter *adap,
2402 struct i2c_board_info *info,
2403 unsigned short const *addr_list,
2404 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2405 {
2406 int i;
2407
2408 if (!probe)
2409 probe = i2c_default_probe;
2410
2411 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2412 /* Check address validity */
2413 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2414 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2415 addr_list[i]);
2416 continue;
2417 }
2418
2419 /* Check address availability (7 bit, no need to encode flags) */
2420 if (i2c_check_addr_busy(adap, addr_list[i])) {
2421 dev_dbg(&adap->dev,
2422 "Address 0x%02x already in use, not probing\n",
2423 addr_list[i]);
2424 continue;
2425 }
2426
2427 /* Test address responsiveness */
2428 if (probe(adap, addr_list[i]))
2429 break;
2430 }
2431
2432 if (addr_list[i] == I2C_CLIENT_END) {
2433 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2434 return ERR_PTR(-ENODEV);
2435 }
2436
2437 info->addr = addr_list[i];
2438 return i2c_new_client_device(adap, info);
2439 }
2440 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2441
i2c_get_adapter(int nr)2442 struct i2c_adapter *i2c_get_adapter(int nr)
2443 {
2444 struct i2c_adapter *adapter;
2445
2446 mutex_lock(&core_lock);
2447 adapter = idr_find(&i2c_adapter_idr, nr);
2448 if (!adapter)
2449 goto exit;
2450
2451 if (try_module_get(adapter->owner))
2452 get_device(&adapter->dev);
2453 else
2454 adapter = NULL;
2455
2456 exit:
2457 mutex_unlock(&core_lock);
2458 return adapter;
2459 }
2460 EXPORT_SYMBOL(i2c_get_adapter);
2461
i2c_put_adapter(struct i2c_adapter * adap)2462 void i2c_put_adapter(struct i2c_adapter *adap)
2463 {
2464 if (!adap)
2465 return;
2466
2467 module_put(adap->owner);
2468 /* Should be last, otherwise we risk use-after-free with 'adap' */
2469 put_device(&adap->dev);
2470 }
2471 EXPORT_SYMBOL(i2c_put_adapter);
2472
2473 /**
2474 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2475 * @msg: the message to be checked
2476 * @threshold: the minimum number of bytes for which using DMA makes sense.
2477 * Should at least be 1.
2478 *
2479 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2480 * Or a valid pointer to be used with DMA. After use, release it by
2481 * calling i2c_put_dma_safe_msg_buf().
2482 *
2483 * This function must only be called from process context!
2484 */
i2c_get_dma_safe_msg_buf(struct i2c_msg * msg,unsigned int threshold)2485 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2486 {
2487 /* also skip 0-length msgs for bogus thresholds of 0 */
2488 if (!threshold)
2489 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2490 msg->addr);
2491 if (msg->len < threshold || msg->len == 0)
2492 return NULL;
2493
2494 if (msg->flags & I2C_M_DMA_SAFE)
2495 return msg->buf;
2496
2497 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2498 msg->addr, msg->len);
2499
2500 if (msg->flags & I2C_M_RD)
2501 return kzalloc(msg->len, GFP_KERNEL);
2502 else
2503 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2504 }
2505 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2506
2507 /**
2508 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2509 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2510 * @msg: the message which the buffer corresponds to
2511 * @xferred: bool saying if the message was transferred
2512 */
i2c_put_dma_safe_msg_buf(u8 * buf,struct i2c_msg * msg,bool xferred)2513 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2514 {
2515 if (!buf || buf == msg->buf)
2516 return;
2517
2518 if (xferred && msg->flags & I2C_M_RD)
2519 memcpy(msg->buf, buf, msg->len);
2520
2521 kfree(buf);
2522 }
2523 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2524
2525 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2526 MODULE_DESCRIPTION("I2C-Bus main module");
2527 MODULE_LICENSE("GPL");
2528