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/debugfs.h>
20	#include <linux/delay.h>
21	#include <linux/err.h>
22	#include <linux/errno.h>
23	#include <linux/gpio/consumer.h>
24	#include <linux/i2c.h>
25	#include <linux/i2c-smbus.h>
26	#include <linux/idr.h>
27	#include <linux/init.h>
28	#include <linux/interrupt.h>
29	#include <linux/irq.h>
30	#include <linux/jump_label.h>
31	#include <linux/kernel.h>
32	#include <linux/module.h>
33	#include <linux/mutex.h>
34	#include <linux/of_device.h>
35	#include <linux/of.h>
36	#include <linux/pinctrl/consumer.h>
37	#include <linux/pinctrl/devinfo.h>
38	#include <linux/pm_domain.h>
39	#include <linux/pm_runtime.h>
40	#include <linux/pm_wakeirq.h>
41	#include <linux/property.h>
42	#include <linux/rwsem.h>
43	#include <linux/slab.h>
44	#include <linux/string_choices.h>
45
46	#include "i2c-core.h"
47
48	#define CREATE_TRACE_POINTS
49	#include <trace/events/i2c.h>
50
51	#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
52	#define I2C_ADDR_OFFSET_SLAVE 0x1000
53
54	#define I2C_ADDR_7BITS_MAX 0x77
55	#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
56
57	#define I2C_ADDR_DEVICE_ID 0x7c
58
59	/*
60	* core_lock protects i2c_adapter_idr, and guarantees that device detection,
61	* deletion of detected devices are serialized
62	*/
63	static DEFINE_MUTEX(core_lock);
64	static DEFINE_IDR(i2c_adapter_idr);
65
66	static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
67
68	static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
69	static bool is_registered;
70
71	static struct dentry *i2c_debugfs_root;
72
73	int i2c_transfer_trace_reg(void)
74	{
75	static_branch_inc(&i2c_trace_msg_key);
76	return 0;
77	}
78
79	void i2c_transfer_trace_unreg(void)
80	{
81	static_branch_dec(&i2c_trace_msg_key);
82	}
83
84	const char *i2c_freq_mode_string(u32 bus_freq_hz)
85	{
86	switch (bus_freq_hz) {
87	case I2C_MAX_STANDARD_MODE_FREQ:
88	return "Standard Mode (100 kHz)";
89	case I2C_MAX_FAST_MODE_FREQ:
90	return "Fast Mode (400 kHz)";
91	case I2C_MAX_FAST_MODE_PLUS_FREQ:
92	return "Fast Mode Plus (1.0 MHz)";
93	case I2C_MAX_TURBO_MODE_FREQ:
94	return "Turbo Mode (1.4 MHz)";
95	case I2C_MAX_HIGH_SPEED_MODE_FREQ:
96	return "High Speed Mode (3.4 MHz)";
97	case I2C_MAX_ULTRA_FAST_MODE_FREQ:
98	return "Ultra Fast Mode (5.0 MHz)";
99	default:
100	return "Unknown Mode";
101	}
102	}
103	EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
104
105	const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
106	const struct i2c_client *client)
107	{
108	if (!(id && client))
109	return NULL;
110
111	while (id->name[0]) {
112	if (strcmp(client->name, id->name) == 0)
113	return id;
114	id++;
115	}
116	return NULL;
117	}
118	EXPORT_SYMBOL_GPL(i2c_match_id);
119
120	const void *i2c_get_match_data(const struct i2c_client *client)
121	{
122	struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
123	const struct i2c_device_id *match;
124	const void *data;
125
126	data = device_get_match_data(dev: &client->dev);
127	if (!data) {
128	match = i2c_match_id(driver->id_table, client);
129	if (!match)
130	return NULL;
131
132	data = (const void *)match->driver_data;
133	}
134
135	return data;
136	}
137	EXPORT_SYMBOL(i2c_get_match_data);
138
139	static int i2c_device_match(struct device *dev, const struct device_driver *drv)
140	{
141	struct i2c_client *client = i2c_verify_client(dev);
142	const struct i2c_driver *driver;
143
144
145	/* Attempt an OF style match */
146	if (i2c_of_match_device(matches: drv->of_match_table, client))
147	return 1;
148
149	/* Then ACPI style match */
150	if (acpi_driver_match_device(dev, drv))
151	return 1;
152
153	driver = to_i2c_driver(drv);
154
155	/* Finally an I2C match */
156	if (i2c_match_id(driver->id_table, client))
157	return 1;
158
159	return 0;
160	}
161
162	static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
163	{
164	const struct i2c_client *client = to_i2c_client(dev);
165	int rc;
166
167	rc = of_device_uevent_modalias(dev, env);
168	if (rc != -ENODEV)
169	return rc;
170
171	rc = acpi_device_uevent_modalias(dev, env);
172	if (rc != -ENODEV)
173	return rc;
174
175	return add_uevent_var(env, format: "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
176	}
177
178	/* i2c bus recovery routines */
179	static int get_scl_gpio_value(struct i2c_adapter *adap)
180	{
181	return gpiod_get_value_cansleep(desc: adap->bus_recovery_info->scl_gpiod);
182	}
183
184	static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
185	{
186	gpiod_set_value_cansleep(desc: adap->bus_recovery_info->scl_gpiod, value: val);
187	}
188
189	static int get_sda_gpio_value(struct i2c_adapter *adap)
190	{
191	return gpiod_get_value_cansleep(desc: adap->bus_recovery_info->sda_gpiod);
192	}
193
194	static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
195	{
196	gpiod_set_value_cansleep(desc: adap->bus_recovery_info->sda_gpiod, value: val);
197	}
198
199	static int i2c_generic_bus_free(struct i2c_adapter *adap)
200	{
201	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
202	int ret = -EOPNOTSUPP;
203
204	if (bri->get_bus_free)
205	ret = bri->get_bus_free(adap);
206	else if (bri->get_sda)
207	ret = bri->get_sda(adap);
208
209	if (ret < 0)
210	return ret;
211
212	return ret ? 0 : -EBUSY;
213	}
214
215	/*
216	* We are generating clock pulses. ndelay() determines durating of clk pulses.
217	* We will generate clock with rate 100 KHz and so duration of both clock levels
218	* is: delay in ns = (10^6 / 100) / 2
219	*/
220	#define RECOVERY_NDELAY 5000
221	#define RECOVERY_CLK_CNT 9
222
223	int i2c_generic_scl_recovery(struct i2c_adapter *adap)
224	{
225	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
226	int i = 0, scl = 1, ret = 0;
227
228	if (bri->prepare_recovery)
229	bri->prepare_recovery(adap);
230	if (bri->pinctrl)
231	pinctrl_select_state(p: bri->pinctrl, s: bri->pins_gpio);
232
233	/*
234	* If we can set SDA, we will always create a STOP to ensure additional
235	* pulses will do no harm. This is achieved by letting SDA follow SCL
236	* half a cycle later. Check the 'incomplete_write_byte' fault injector
237	* for details. Note that we must honour tsu:sto, 4us, but lets use 5us
238	* here for simplicity.
239	*/
240	bri->set_scl(adap, scl);
241	ndelay(RECOVERY_NDELAY);
242	if (bri->set_sda)
243	bri->set_sda(adap, scl);
244	ndelay(RECOVERY_NDELAY / 2);
245
246	/*
247	* By this time SCL is high, as we need to give 9 falling-rising edges
248	*/
249	while (i++ < RECOVERY_CLK_CNT * 2) {
250	if (scl) {
251	/* SCL shouldn't be low here */
252	if (!bri->get_scl(adap)) {
253	dev_err(&adap->dev,
254	"SCL is stuck low, exit recovery\n");
255	ret = -EBUSY;
256	break;
257	}
258	}
259
260	scl = !scl;
261	bri->set_scl(adap, scl);
262	/* Creating STOP again, see above */
263	if (scl) {
264	/* Honour minimum tsu:sto */
265	ndelay(RECOVERY_NDELAY);
266	} else {
267	/* Honour minimum tf and thd:dat */
268	ndelay(RECOVERY_NDELAY / 2);
269	}
270	if (bri->set_sda)
271	bri->set_sda(adap, scl);
272	ndelay(RECOVERY_NDELAY / 2);
273
274	if (scl) {
275	ret = i2c_generic_bus_free(adap);
276	if (ret == 0)
277	break;
278	}
279	}
280
281	/* If we can't check bus status, assume recovery worked */
282	if (ret == -EOPNOTSUPP)
283	ret = 0;
284
285	if (bri->unprepare_recovery)
286	bri->unprepare_recovery(adap);
287	if (bri->pinctrl)
288	pinctrl_select_state(p: bri->pinctrl, s: bri->pins_default);
289
290	return ret;
291	}
292	EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
293
294	int i2c_recover_bus(struct i2c_adapter *adap)
295	{
296	if (!adap->bus_recovery_info)
297	return -EBUSY;
298
299	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
300	return adap->bus_recovery_info->recover_bus(adap);
301	}
302	EXPORT_SYMBOL_GPL(i2c_recover_bus);
303
304	static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
305	{
306	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
307	struct device *dev = &adap->dev;
308	struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev: dev->parent);
309
310	bri->pinctrl = p;
311
312	/*
313	* we can't change states without pinctrl, so remove the states if
314	* populated
315	*/
316	if (!p) {
317	bri->pins_default = NULL;
318	bri->pins_gpio = NULL;
319	return;
320	}
321
322	if (!bri->pins_default) {
323	bri->pins_default = pinctrl_lookup_state(p,
324	PINCTRL_STATE_DEFAULT);
325	if (IS_ERR(ptr: bri->pins_default)) {
326	dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
327	bri->pins_default = NULL;
328	}
329	}
330	if (!bri->pins_gpio) {
331	bri->pins_gpio = pinctrl_lookup_state(p, name: "gpio");
332	if (IS_ERR(ptr: bri->pins_gpio))
333	bri->pins_gpio = pinctrl_lookup_state(p, name: "recovery");
334
335	if (IS_ERR(ptr: bri->pins_gpio)) {
336	dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
337	bri->pins_gpio = NULL;
338	}
339	}
340
341	/* for pinctrl state changes, we need all the information */
342	if (bri->pins_default && bri->pins_gpio) {
343	dev_info(dev, "using pinctrl states for GPIO recovery");
344	} else {
345	bri->pinctrl = NULL;
346	bri->pins_default = NULL;
347	bri->pins_gpio = NULL;
348	}
349	}
350
351	static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
352	{
353	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
354	struct device *dev = &adap->dev;
355	struct gpio_desc *gpiod;
356	int ret = 0;
357
358	/*
359	* don't touch the recovery information if the driver is not using
360	* generic SCL recovery
361	*/
362	if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
363	return 0;
364
365	/*
366	* pins might be taken as GPIO, so we should inform pinctrl about
367	* this and move the state to GPIO
368	*/
369	if (bri->pinctrl)
370	pinctrl_select_state(p: bri->pinctrl, s: bri->pins_gpio);
371
372	/*
373	* if there is incomplete or no recovery information, see if generic
374	* GPIO recovery is available
375	*/
376	if (!bri->scl_gpiod) {
377	gpiod = devm_gpiod_get(dev, con_id: "scl", flags: GPIOD_OUT_HIGH_OPEN_DRAIN);
378	if (PTR_ERR(ptr: gpiod) == -EPROBE_DEFER) {
379	ret = -EPROBE_DEFER;
380	goto cleanup_pinctrl_state;
381	}
382	if (!IS_ERR(ptr: gpiod)) {
383	bri->scl_gpiod = gpiod;
384	bri->recover_bus = i2c_generic_scl_recovery;
385	dev_info(dev, "using generic GPIOs for recovery\n");
386	}
387	}
388
389	/* SDA GPIOD line is optional, so we care about DEFER only */
390	if (!bri->sda_gpiod) {
391	/*
392	* We have SCL. Pull SCL low and wait a bit so that SDA glitches
393	* have no effect.
394	*/
395	gpiod_direction_output(desc: bri->scl_gpiod, value: 0);
396	udelay(usec: 10);
397	gpiod = devm_gpiod_get(dev, con_id: "sda", flags: GPIOD_IN);
398
399	/* Wait a bit in case of a SDA glitch, and then release SCL. */
400	udelay(usec: 10);
401	gpiod_direction_output(desc: bri->scl_gpiod, value: 1);
402
403	if (PTR_ERR(ptr: gpiod) == -EPROBE_DEFER) {
404	ret = -EPROBE_DEFER;
405	goto cleanup_pinctrl_state;
406	}
407	if (!IS_ERR(ptr: gpiod))
408	bri->sda_gpiod = gpiod;
409	}
410
411	cleanup_pinctrl_state:
412	/* change the state of the pins back to their default state */
413	if (bri->pinctrl)
414	pinctrl_select_state(p: bri->pinctrl, s: bri->pins_default);
415
416	return ret;
417	}
418
419	static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
420	{
421	i2c_gpio_init_pinctrl_recovery(adap);
422	return i2c_gpio_init_generic_recovery(adap);
423	}
424
425	static int i2c_init_recovery(struct i2c_adapter *adap)
426	{
427	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
428	bool is_error_level = true;
429	char *err_str;
430
431	if (!bri)
432	return 0;
433
434	if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
435	return -EPROBE_DEFER;
436
437	if (!bri->recover_bus) {
438	err_str = "no suitable method provided";
439	is_error_level = false;
440	goto err;
441	}
442
443	if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
444	bri->get_scl = get_scl_gpio_value;
445	bri->set_scl = set_scl_gpio_value;
446	if (bri->sda_gpiod) {
447	bri->get_sda = get_sda_gpio_value;
448	/* FIXME: add proper flag instead of '0' once available */
449	if (gpiod_get_direction(desc: bri->sda_gpiod) == 0)
450	bri->set_sda = set_sda_gpio_value;
451	}
452	} else if (bri->recover_bus == i2c_generic_scl_recovery) {
453	/* Generic SCL recovery */
454	if (!bri->set_scl || !bri->get_scl) {
455	err_str = "no {get|set}_scl() found";
456	goto err;
457	}
458	if (!bri->set_sda && !bri->get_sda) {
459	err_str = "either get_sda() or set_sda() needed";
460	goto err;
461	}
462	}
463
464	return 0;
465	err:
466	if (is_error_level)
467	dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
468	else
469	dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
470	adap->bus_recovery_info = NULL;
471
472	return -EINVAL;
473	}
474
475	static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
476	{
477	struct i2c_adapter *adap = client->adapter;
478	unsigned int irq;
479
480	if (!adap->host_notify_domain)
481	return -ENXIO;
482
483	if (client->flags & I2C_CLIENT_TEN)
484	return -EINVAL;
485
486	irq = irq_create_mapping(domain: adap->host_notify_domain, hwirq: client->addr);
487
488	return irq > 0 ? irq : -ENXIO;
489	}
490
491	static int i2c_device_probe(struct device *dev)
492	{
493	struct fwnode_handle *fwnode = dev_fwnode(dev);
494	struct i2c_client *client = i2c_verify_client(dev);
495	struct i2c_driver *driver;
496	bool do_power_on;
497	int status;
498
499	if (!client)
500	return 0;
501
502	client->irq = client->init_irq;
503
504	if (!client->irq) {
505	int irq = -ENOENT;
506
507	if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
508	dev_dbg(dev, "Using Host Notify IRQ\n");
509	/* Keep adapter active when Host Notify is required */
510	pm_runtime_get_sync(dev: &client->adapter->dev);
511	irq = i2c_smbus_host_notify_to_irq(client);
512	} else if (is_of_node(fwnode)) {
513	irq = fwnode_irq_get_byname(fwnode, name: "irq");
514	if (irq == -EINVAL || irq == -ENODATA)
515	irq = fwnode_irq_get(fwnode, index: 0);
516	} else if (is_acpi_device_node(fwnode)) {
517	bool wake_capable;
518
519	irq = i2c_acpi_get_irq(client, wake_capable: &wake_capable);
520	if (irq > 0 && wake_capable)
521	client->flags |= I2C_CLIENT_WAKE;
522	}
523	if (irq == -EPROBE_DEFER) {
524	status = dev_err_probe(dev, err: irq, fmt: "can't get irq\n");
525	goto put_sync_adapter;
526	}
527
528	if (irq < 0)
529	irq = 0;
530
531	client->irq = irq;
532	}
533
534	driver = to_i2c_driver(dev->driver);
535
536	/*
537	* An I2C ID table is not mandatory, if and only if, a suitable OF
538	* or ACPI ID table is supplied for the probing device.
539	*/
540	if (!driver->id_table &&
541	!acpi_driver_match_device(dev, drv: dev->driver) &&
542	!i2c_of_match_device(matches: dev->driver->of_match_table, client)) {
543	status = -ENODEV;
544	goto put_sync_adapter;
545	}
546
547	if (client->flags & I2C_CLIENT_WAKE) {
548	int wakeirq;
549
550	wakeirq = fwnode_irq_get_byname(fwnode, name: "wakeup");
551	if (wakeirq == -EPROBE_DEFER) {
552	status = dev_err_probe(dev, err: wakeirq, fmt: "can't get wakeirq\n");
553	goto put_sync_adapter;
554	}
555
556	device_init_wakeup(dev: &client->dev, enable: true);
557
558	if (wakeirq > 0 && wakeirq != client->irq)
559	status = dev_pm_set_dedicated_wake_irq(dev, irq: wakeirq);
560	else if (client->irq > 0)
561	status = dev_pm_set_wake_irq(dev, irq: client->irq);
562	else
563	status = 0;
564
565	if (status)
566	dev_warn(&client->dev, "failed to set up wakeup irq\n");
567	}
568
569	dev_dbg(dev, "probe\n");
570
571	status = of_clk_set_defaults(to_of_node(fwnode), clk_supplier: false);
572	if (status < 0)
573	goto err_clear_wakeup_irq;
574
575	do_power_on = !i2c_acpi_waive_d0_probe(dev);
576	status = dev_pm_domain_attach(dev: &client->dev, power_on: do_power_on);
577	if (status)
578	goto err_clear_wakeup_irq;
579
580	client->devres_group_id = devres_open_group(dev: &client->dev, NULL,
581	GFP_KERNEL);
582	if (!client->devres_group_id) {
583	status = -ENOMEM;
584	goto err_detach_pm_domain;
585	}
586
587	client->debugfs = debugfs_create_dir(name: dev_name(dev: &client->dev),
588	parent: client->adapter->debugfs);
589
590	if (driver->probe)
591	status = driver->probe(client);
592	else
593	status = -EINVAL;
594
595	/*
596	* Note that we are not closing the devres group opened above so
597	* even resources that were attached to the device after probe is
598	* run are released when i2c_device_remove() is executed. This is
599	* needed as some drivers would allocate additional resources,
600	* for example when updating firmware.
601	*/
602
603	if (status)
604	goto err_release_driver_resources;
605
606	return 0;
607
608	err_release_driver_resources:
609	debugfs_remove_recursive(dentry: client->debugfs);
610	devres_release_group(dev: &client->dev, id: client->devres_group_id);
611	err_detach_pm_domain:
612	dev_pm_domain_detach(dev: &client->dev, power_off: do_power_on);
613	err_clear_wakeup_irq:
614	dev_pm_clear_wake_irq(dev: &client->dev);
615	device_init_wakeup(dev: &client->dev, enable: false);
616	put_sync_adapter:
617	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
618	pm_runtime_put_sync(dev: &client->adapter->dev);
619
620	return status;
621	}
622
623	static void i2c_device_remove(struct device *dev)
624	{
625	struct i2c_client *client = to_i2c_client(dev);
626	struct i2c_driver *driver;
627
628	driver = to_i2c_driver(dev->driver);
629	if (driver->remove) {
630	dev_dbg(dev, "remove\n");
631
632	driver->remove(client);
633	}
634
635	debugfs_remove_recursive(dentry: client->debugfs);
636
637	devres_release_group(dev: &client->dev, id: client->devres_group_id);
638
639	dev_pm_domain_detach(dev: &client->dev, power_off: true);
640
641	dev_pm_clear_wake_irq(dev: &client->dev);
642	device_init_wakeup(dev: &client->dev, enable: false);
643
644	client->irq = 0;
645	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
646	pm_runtime_put(dev: &client->adapter->dev);
647	}
648
649	static void i2c_device_shutdown(struct device *dev)
650	{
651	struct i2c_client *client = i2c_verify_client(dev);
652	struct i2c_driver *driver;
653
654	if (!client || !dev->driver)
655	return;
656	driver = to_i2c_driver(dev->driver);
657	if (driver->shutdown)
658	driver->shutdown(client);
659	else if (client->irq > 0)
660	disable_irq(irq: client->irq);
661	}
662
663	static void i2c_client_dev_release(struct device *dev)
664	{
665	kfree(to_i2c_client(dev));
666	}
667
668	static ssize_t
669	name_show(struct device *dev, struct device_attribute *attr, char *buf)
670	{
671	return sprintf(buf, fmt: "%s\n", dev->type == &i2c_client_type ?
672	to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
673	}
674	static DEVICE_ATTR_RO(name);
675
676	static ssize_t
677	modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
678	{
679	struct i2c_client *client = to_i2c_client(dev);
680	int len;
681
682	len = of_device_modalias(dev, str: buf, PAGE_SIZE);
683	if (len != -ENODEV)
684	return len;
685
686	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
687	if (len != -ENODEV)
688	return len;
689
690	return sprintf(buf, fmt: "%s%s\n", I2C_MODULE_PREFIX, client->name);
691	}
692	static DEVICE_ATTR_RO(modalias);
693
694	static struct attribute *i2c_dev_attrs[] = {
695	&dev_attr_name.attr,
696	/* modalias helps coldplug: modprobe $(cat .../modalias) */
697	&dev_attr_modalias.attr,
698	NULL
699	};
700	ATTRIBUTE_GROUPS(i2c_dev);
701
702	const struct bus_type i2c_bus_type = {
703	.name = "i2c",
704	.match = i2c_device_match,
705	.probe = i2c_device_probe,
706	.remove = i2c_device_remove,
707	.shutdown = i2c_device_shutdown,
708	};
709	EXPORT_SYMBOL_GPL(i2c_bus_type);
710
711	const struct device_type i2c_client_type = {
712	.groups = i2c_dev_groups,
713	.uevent = i2c_device_uevent,
714	.release = i2c_client_dev_release,
715	};
716	EXPORT_SYMBOL_GPL(i2c_client_type);
717
718
719	/**
720	* i2c_verify_client - return parameter as i2c_client, or NULL
721	* @dev: device, probably from some driver model iterator
722	*
723	* When traversing the driver model tree, perhaps using driver model
724	* iterators like @device_for_each_child(), you can't assume very much
725	* about the nodes you find. Use this function to avoid oopses caused
726	* by wrongly treating some non-I2C device as an i2c_client.
727	*/
728	struct i2c_client *i2c_verify_client(struct device *dev)
729	{
730	return (dev->type == &i2c_client_type)
731	? to_i2c_client(dev)
732	: NULL;
733	}
734	EXPORT_SYMBOL(i2c_verify_client);
735
736
737	/* Return a unique address which takes the flags of the client into account */
738	static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
739	{
740	unsigned short addr = client->addr;
741
742	/* For some client flags, add an arbitrary offset to avoid collisions */
743	if (client->flags & I2C_CLIENT_TEN)
744	addr |= I2C_ADDR_OFFSET_TEN_BIT;
745
746	if (client->flags & I2C_CLIENT_SLAVE)
747	addr |= I2C_ADDR_OFFSET_SLAVE;
748
749	return addr;
750	}
751
752	/* This is a permissive address validity check, I2C address map constraints
753	* are purposely not enforced, except for the general call address. */
754	static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
755	{
756	if (flags & I2C_CLIENT_TEN) {
757	/* 10-bit address, all values are valid */
758	if (addr > 0x3ff)
759	return -EINVAL;
760	} else {
761	/* 7-bit address, reject the general call address */
762	if (addr == 0x00 || addr > 0x7f)
763	return -EINVAL;
764	}
765	return 0;
766	}
767
768	/* And this is a strict address validity check, used when probing. If a
769	* device uses a reserved address, then it shouldn't be probed. 7-bit
770	* addressing is assumed, 10-bit address devices are rare and should be
771	* explicitly enumerated. */
772	int i2c_check_7bit_addr_validity_strict(unsigned short addr)
773	{
774	/*
775	* Reserved addresses per I2C specification:
776	* 0x00 General call address / START byte
777	* 0x01 CBUS address
778	* 0x02 Reserved for different bus format
779	* 0x03 Reserved for future purposes
780	* 0x04-0x07 Hs-mode master code
781	* 0x78-0x7b 10-bit slave addressing
782	* 0x7c-0x7f Reserved for future purposes
783	*/
784	if (addr < 0x08 || addr > 0x77)
785	return -EINVAL;
786	return 0;
787	}
788
789	static int __i2c_check_addr_busy(struct device *dev, void *addrp)
790	{
791	struct i2c_client *client = i2c_verify_client(dev);
792	int addr = *(int *)addrp;
793
794	if (client && i2c_encode_flags_to_addr(client) == addr)
795	return -EBUSY;
796	return 0;
797	}
798
799	/* walk up mux tree */
800	static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
801	{
802	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
803	int result;
804
805	result = device_for_each_child(parent: &adapter->dev, data: &addr,
806	fn: __i2c_check_addr_busy);
807
808	if (!result && parent)
809	result = i2c_check_mux_parents(adapter: parent, addr);
810
811	return result;
812	}
813
814	/* recurse down mux tree */
815	static int i2c_check_mux_children(struct device *dev, void *addrp)
816	{
817	int result;
818
819	if (dev->type == &i2c_adapter_type)
820	result = device_for_each_child(parent: dev, data: addrp,
821	fn: i2c_check_mux_children);
822	else
823	result = __i2c_check_addr_busy(dev, addrp);
824
825	return result;
826	}
827
828	static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
829	{
830	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
831	int result = 0;
832
833	if (parent)
834	result = i2c_check_mux_parents(adapter: parent, addr);
835
836	if (!result)
837	result = device_for_each_child(parent: &adapter->dev, data: &addr,
838	fn: i2c_check_mux_children);
839
840	return result;
841	}
842
843	/**
844	* i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
845	* @adapter: Target I2C bus segment
846	* @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
847	* locks only this branch in the adapter tree
848	*/
849	static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
850	unsigned int flags)
851	{
852	rt_mutex_lock_nested(lock: &adapter->bus_lock, subclass: i2c_adapter_depth(adapter));
853	}
854
855	/**
856	* i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
857	* @adapter: Target I2C bus segment
858	* @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
859	* trylocks only this branch in the adapter tree
860	*/
861	static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
862	unsigned int flags)
863	{
864	return rt_mutex_trylock(lock: &adapter->bus_lock);
865	}
866
867	/**
868	* i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
869	* @adapter: Target I2C bus segment
870	* @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
871	* unlocks only this branch in the adapter tree
872	*/
873	static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
874	unsigned int flags)
875	{
876	rt_mutex_unlock(lock: &adapter->bus_lock);
877	}
878
879	static void i2c_dev_set_name(struct i2c_adapter *adap,
880	struct i2c_client *client,
881	struct i2c_board_info const *info)
882	{
883	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
884
885	if (info && info->dev_name) {
886	dev_set_name(dev: &client->dev, name: "i2c-%s", info->dev_name);
887	return;
888	}
889
890	if (adev) {
891	dev_set_name(dev: &client->dev, name: "i2c-%s", acpi_dev_name(adev));
892	return;
893	}
894
895	dev_set_name(dev: &client->dev, name: "%d-%04x", i2c_adapter_id(adap),
896	i2c_encode_flags_to_addr(client));
897	}
898
899	int i2c_dev_irq_from_resources(const struct resource *resources,
900	unsigned int num_resources)
901	{
902	struct irq_data *irqd;
903	int i;
904
905	for (i = 0; i < num_resources; i++) {
906	const struct resource *r = &resources[i];
907
908	if (resource_type(res: r) != IORESOURCE_IRQ)
909	continue;
910
911	if (r->flags & IORESOURCE_BITS) {
912	irqd = irq_get_irq_data(irq: r->start);
913	if (!irqd)
914	break;
915
916	irqd_set_trigger_type(d: irqd, type: r->flags & IORESOURCE_BITS);
917	}
918
919	return r->start;
920	}
921
922	return 0;
923	}
924
925	/*
926	* Serialize device instantiation in case it can be instantiated explicitly
927	* and by auto-detection
928	*/
929	static int i2c_lock_addr(struct i2c_adapter *adap, unsigned short addr,
930	unsigned short flags)
931	{
932	if (!(flags & I2C_CLIENT_TEN) &&
933	test_and_set_bit(nr: addr, addr: adap->addrs_in_instantiation))
934	return -EBUSY;
935
936	return 0;
937	}
938
939	static void i2c_unlock_addr(struct i2c_adapter *adap, unsigned short addr,
940	unsigned short flags)
941	{
942	if (!(flags & I2C_CLIENT_TEN))
943	clear_bit(nr: addr, addr: adap->addrs_in_instantiation);
944	}
945
946	/**
947	* i2c_new_client_device - instantiate an i2c device
948	* @adap: the adapter managing the device
949	* @info: describes one I2C device; bus_num is ignored
950	* Context: can sleep
951	*
952	* Create an i2c device. Binding is handled through driver model
953	* probe()/remove() methods. A driver may be bound to this device when we
954	* return from this function, or any later moment (e.g. maybe hotplugging will
955	* load the driver module). This call is not appropriate for use by mainboard
956	* initialization logic, which usually runs during an arch_initcall() long
957	* before any i2c_adapter could exist.
958	*
959	* This returns the new i2c client, which may be saved for later use with
960	* i2c_unregister_device(); or an ERR_PTR to describe the error.
961	*/
962	struct i2c_client *
963	i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
964	{
965	struct fwnode_handle *fwnode = info->fwnode;
966	struct i2c_client *client;
967	bool need_put = false;
968	int status;
969
970	client = kzalloc(sizeof *client, GFP_KERNEL);
971	if (!client)
972	return ERR_PTR(error: -ENOMEM);
973
974	client->adapter = adap;
975
976	client->dev.platform_data = info->platform_data;
977	client->flags = info->flags;
978	client->addr = info->addr;
979
980	client->init_irq = info->irq;
981	if (!client->init_irq)
982	client->init_irq = i2c_dev_irq_from_resources(resources: info->resources,
983	num_resources: info->num_resources);
984
985	strscpy(client->name, info->type, sizeof(client->name));
986
987	status = i2c_check_addr_validity(addr: client->addr, flags: client->flags);
988	if (status) {
989	dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
990	client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
991	goto out_err_silent;
992	}
993
994	status = i2c_lock_addr(adap, addr: client->addr, flags: client->flags);
995	if (status)
996	goto out_err_silent;
997
998	/* Check for address business */
999	status = i2c_check_addr_busy(adapter: adap, addr: i2c_encode_flags_to_addr(client));
1000	if (status)
1001	goto out_err;
1002
1003	client->dev.parent = &client->adapter->dev;
1004	client->dev.bus = &i2c_bus_type;
1005	client->dev.type = &i2c_client_type;
1006
1007	device_enable_async_suspend(dev: &client->dev);
1008
1009	device_set_node(dev: &client->dev, fwnode: fwnode_handle_get(fwnode));
1010
1011	if (info->swnode) {
1012	status = device_add_software_node(dev: &client->dev, node: info->swnode);
1013	if (status) {
1014	dev_err(&adap->dev,
1015	"Failed to add software node to client %s: %d\n",
1016	client->name, status);
1017	goto out_err_put_fwnode;
1018	}
1019	}
1020
1021	i2c_dev_set_name(adap, client, info);
1022	status = device_register(dev: &client->dev);
1023	if (status)
1024	goto out_remove_swnode;
1025
1026	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
1027	client->name, dev_name(&client->dev));
1028
1029	i2c_unlock_addr(adap, addr: client->addr, flags: client->flags);
1030
1031	return client;
1032
1033	out_remove_swnode:
1034	device_remove_software_node(dev: &client->dev);
1035	need_put = true;
1036	out_err_put_fwnode:
1037	fwnode_handle_put(fwnode);
1038	out_err:
1039	dev_err(&adap->dev,
1040	"Failed to register i2c client %s at 0x%02x (%d)\n",
1041	client->name, client->addr, status);
1042	i2c_unlock_addr(adap, addr: client->addr, flags: client->flags);
1043	out_err_silent:
1044	if (need_put)
1045	put_device(dev: &client->dev);
1046	else
1047	kfree(objp: client);
1048	return ERR_PTR(error: status);
1049	}
1050	EXPORT_SYMBOL_GPL(i2c_new_client_device);
1051
1052	/**
1053	* i2c_unregister_device - reverse effect of i2c_new_*_device()
1054	* @client: value returned from i2c_new_*_device()
1055	* Context: can sleep
1056	*/
1057	void i2c_unregister_device(struct i2c_client *client)
1058	{
1059	struct fwnode_handle *fwnode;
1060
1061	if (IS_ERR_OR_NULL(ptr: client))
1062	return;
1063
1064	fwnode = dev_fwnode(&client->dev);
1065	if (is_of_node(fwnode))
1066	of_node_clear_flag(to_of_node(fwnode), OF_POPULATED);
1067	else if (is_acpi_device_node(fwnode))
1068	acpi_device_clear_enumerated(to_acpi_device_node(fwnode));
1069	fwnode_handle_put(fwnode);
1070
1071	device_remove_software_node(dev: &client->dev);
1072	device_unregister(dev: &client->dev);
1073	}
1074	EXPORT_SYMBOL_GPL(i2c_unregister_device);
1075
1076	/**
1077	* i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1078	* @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1079	*
1080	* Look up and return the &struct i2c_client corresponding to the @fwnode.
1081	* If no client can be found, or @fwnode is NULL, this returns NULL.
1082	*
1083	* The user must call put_device(&client->dev) once done with the i2c client.
1084	*/
1085	struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1086	{
1087	struct i2c_client *client;
1088	struct device *dev;
1089
1090	if (!fwnode)
1091	return NULL;
1092
1093	dev = bus_find_device_by_fwnode(bus: &i2c_bus_type, fwnode);
1094	if (!dev)
1095	return NULL;
1096
1097	client = i2c_verify_client(dev);
1098	if (!client)
1099	put_device(dev);
1100
1101	return client;
1102	}
1103	EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1104
1105
1106	static const struct i2c_device_id dummy_id[] = {
1107	{ .name: "dummy", },
1108	{ "smbus_host_notify", },
1109	{ }
1110	};
1111
1112	static int dummy_probe(struct i2c_client *client)
1113	{
1114	return 0;
1115	}
1116
1117	static struct i2c_driver dummy_driver = {
1118	.driver.name = "dummy",
1119	.probe = dummy_probe,
1120	.id_table = dummy_id,
1121	};
1122
1123	/**
1124	* i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1125	* @adapter: the adapter managing the device
1126	* @address: seven bit address to be used
1127	* Context: can sleep
1128	*
1129	* This returns an I2C client bound to the "dummy" driver, intended for use
1130	* with devices that consume multiple addresses. Examples of such chips
1131	* include various EEPROMS (like 24c04 and 24c08 models).
1132	*
1133	* These dummy devices have two main uses. First, most I2C and SMBus calls
1134	* except i2c_transfer() need a client handle; the dummy will be that handle.
1135	* And second, this prevents the specified address from being bound to a
1136	* different driver.
1137	*
1138	* This returns the new i2c client, which should be saved for later use with
1139	* i2c_unregister_device(); or an ERR_PTR to describe the error.
1140	*/
1141	struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1142	{
1143	struct i2c_board_info info = {
1144	I2C_BOARD_INFO("dummy", address),
1145	};
1146
1147	return i2c_new_client_device(adapter, &info);
1148	}
1149	EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1150
1151	static void devm_i2c_release_dummy(void *client)
1152	{
1153	i2c_unregister_device(client);
1154	}
1155
1156	/**
1157	* devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1158	* @dev: device the managed resource is bound to
1159	* @adapter: the adapter managing the device
1160	* @address: seven bit address to be used
1161	* Context: can sleep
1162	*
1163	* This is the device-managed version of @i2c_new_dummy_device. It returns the
1164	* new i2c client or an ERR_PTR in case of an error.
1165	*/
1166	struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1167	struct i2c_adapter *adapter,
1168	u16 address)
1169	{
1170	struct i2c_client *client;
1171	int ret;
1172
1173	client = i2c_new_dummy_device(adapter, address);
1174	if (IS_ERR(ptr: client))
1175	return client;
1176
1177	ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1178	if (ret)
1179	return ERR_PTR(error: ret);
1180
1181	return client;
1182	}
1183	EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1184
1185	/**
1186	* i2c_new_ancillary_device - Helper to get the instantiated secondary address
1187	* and create the associated device
1188	* @client: Handle to the primary client
1189	* @name: Handle to specify which secondary address to get
1190	* @default_addr: Used as a fallback if no secondary address was specified
1191	* Context: can sleep
1192	*
1193	* I2C clients can be composed of multiple I2C slaves bound together in a single
1194	* component. The I2C client driver then binds to the master I2C slave and needs
1195	* to create I2C dummy clients to communicate with all the other slaves.
1196	*
1197	* This function creates and returns an I2C dummy client whose I2C address is
1198	* retrieved from the platform firmware based on the given slave name. If no
1199	* address is specified by the firmware default_addr is used.
1200	*
1201	* On DT-based platforms the address is retrieved from the "reg" property entry
1202	* cell whose "reg-names" value matches the slave name.
1203	*
1204	* This returns the new i2c client, which should be saved for later use with
1205	* i2c_unregister_device(); or an ERR_PTR to describe the error.
1206	*/
1207	struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1208	const char *name,
1209	u16 default_addr)
1210	{
1211	struct device_node *np = client->dev.of_node;
1212	u32 addr = default_addr;
1213	int i;
1214
1215	i = of_property_match_string(np, propname: "reg-names", string: name);
1216	if (i >= 0)
1217	of_property_read_u32_index(np, propname: "reg", index: i, out_value: &addr);
1218
1219	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1220	return i2c_new_dummy_device(client->adapter, addr);
1221	}
1222	EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1223
1224	/* ------------------------------------------------------------------------- */
1225
1226	/* I2C bus adapters -- one roots each I2C or SMBUS segment */
1227
1228	static void i2c_adapter_dev_release(struct device *dev)
1229	{
1230	struct i2c_adapter *adap = to_i2c_adapter(dev);
1231	complete(&adap->dev_released);
1232	}
1233
1234	unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1235	{
1236	unsigned int depth = 0;
1237	struct device *parent;
1238
1239	for (parent = adapter->dev.parent; parent; parent = parent->parent)
1240	if (parent->type == &i2c_adapter_type)
1241	depth++;
1242
1243	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1244	"adapter depth exceeds lockdep subclass limit\n");
1245
1246	return depth;
1247	}
1248	EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1249
1250	/*
1251	* Let users instantiate I2C devices through sysfs. This can be used when
1252	* platform initialization code doesn't contain the proper data for
1253	* whatever reason. Also useful for drivers that do device detection and
1254	* detection fails, either because the device uses an unexpected address,
1255	* or this is a compatible device with different ID register values.
1256	*
1257	* Parameter checking may look overzealous, but we really don't want
1258	* the user to provide incorrect parameters.
1259	*/
1260	static ssize_t
1261	new_device_store(struct device *dev, struct device_attribute *attr,
1262	const char *buf, size_t count)
1263	{
1264	struct i2c_adapter *adap = to_i2c_adapter(dev);
1265	struct i2c_board_info info;
1266	struct i2c_client *client;
1267	char *blank, end;
1268	int res;
1269
1270	memset(&info, 0, sizeof(struct i2c_board_info));
1271
1272	blank = strchr(buf, ' ');
1273	if (!blank) {
1274	dev_err(dev, "%s: Missing parameters\n", "new_device");
1275	return -EINVAL;
1276	}
1277	if (blank - buf > I2C_NAME_SIZE - 1) {
1278	dev_err(dev, "%s: Invalid device name\n", "new_device");
1279	return -EINVAL;
1280	}
1281	memcpy(info.type, buf, blank - buf);
1282
1283	/* Parse remaining parameters, reject extra parameters */
1284	res = sscanf(++blank, "%hi%c", &info.addr, &end);
1285	if (res < 1) {
1286	dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1287	return -EINVAL;
1288	}
1289	if (res > 1 && end != '\n') {
1290	dev_err(dev, "%s: Extra parameters\n", "new_device");
1291	return -EINVAL;
1292	}
1293
1294	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1295	info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1296	info.flags |= I2C_CLIENT_TEN;
1297	}
1298
1299	if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1300	info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1301	info.flags |= I2C_CLIENT_SLAVE;
1302	}
1303
1304	client = i2c_new_client_device(adap, &info);
1305	if (IS_ERR(ptr: client))
1306	return PTR_ERR(ptr: client);
1307
1308	/* Keep track of the added device */
1309	mutex_lock(&adap->userspace_clients_lock);
1310	list_add_tail(new: &client->detected, head: &adap->userspace_clients);
1311	mutex_unlock(lock: &adap->userspace_clients_lock);
1312	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1313	info.type, info.addr);
1314
1315	return count;
1316	}
1317	static DEVICE_ATTR_WO(new_device);
1318
1319	/*
1320	* And of course let the users delete the devices they instantiated, if
1321	* they got it wrong. This interface can only be used to delete devices
1322	* instantiated by i2c_sysfs_new_device above. This guarantees that we
1323	* don't delete devices to which some kernel code still has references.
1324	*
1325	* Parameter checking may look overzealous, but we really don't want
1326	* the user to delete the wrong device.
1327	*/
1328	static ssize_t
1329	delete_device_store(struct device *dev, struct device_attribute *attr,
1330	const char *buf, size_t count)
1331	{
1332	struct i2c_adapter *adap = to_i2c_adapter(dev);
1333	struct i2c_client *client, *next;
1334	unsigned short addr;
1335	char end;
1336	int res;
1337
1338	/* Parse parameters, reject extra parameters */
1339	res = sscanf(buf, "%hi%c", &addr, &end);
1340	if (res < 1) {
1341	dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1342	return -EINVAL;
1343	}
1344	if (res > 1 && end != '\n') {
1345	dev_err(dev, "%s: Extra parameters\n", "delete_device");
1346	return -EINVAL;
1347	}
1348
1349	/* Make sure the device was added through sysfs */
1350	res = -ENOENT;
1351	mutex_lock_nested(lock: &adap->userspace_clients_lock,
1352	subclass: i2c_adapter_depth(adap));
1353	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1354	detected) {
1355	if (i2c_encode_flags_to_addr(client) == addr) {
1356	dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1357	"delete_device", client->name, client->addr);
1358
1359	list_del(entry: &client->detected);
1360	i2c_unregister_device(client);
1361	res = count;
1362	break;
1363	}
1364	}
1365	mutex_unlock(lock: &adap->userspace_clients_lock);
1366
1367	if (res < 0)
1368	dev_err(dev, "%s: Can't find device in list\n",
1369	"delete_device");
1370	return res;
1371	}
1372	static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1373	delete_device_store);
1374
1375	static struct attribute *i2c_adapter_attrs[] = {
1376	&dev_attr_name.attr,
1377	&dev_attr_new_device.attr,
1378	&dev_attr_delete_device.attr,
1379	NULL
1380	};
1381	ATTRIBUTE_GROUPS(i2c_adapter);
1382
1383	const struct device_type i2c_adapter_type = {
1384	.groups = i2c_adapter_groups,
1385	.release = i2c_adapter_dev_release,
1386	};
1387	EXPORT_SYMBOL_GPL(i2c_adapter_type);
1388
1389	/**
1390	* i2c_verify_adapter - return parameter as i2c_adapter or NULL
1391	* @dev: device, probably from some driver model iterator
1392	*
1393	* When traversing the driver model tree, perhaps using driver model
1394	* iterators like @device_for_each_child(), you can't assume very much
1395	* about the nodes you find. Use this function to avoid oopses caused
1396	* by wrongly treating some non-I2C device as an i2c_adapter.
1397	*/
1398	struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1399	{
1400	return (dev->type == &i2c_adapter_type)
1401	? to_i2c_adapter(dev)
1402	: NULL;
1403	}
1404	EXPORT_SYMBOL(i2c_verify_adapter);
1405
1406	static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1407	{
1408	struct i2c_devinfo *devinfo;
1409
1410	down_read(sem: &__i2c_board_lock);
1411	list_for_each_entry(devinfo, &__i2c_board_list, list) {
1412	if (devinfo->busnum == adapter->nr &&
1413	IS_ERR(ptr: i2c_new_client_device(adapter, &devinfo->board_info)))
1414	dev_err(&adapter->dev,
1415	"Can't create device at 0x%02x\n",
1416	devinfo->board_info.addr);
1417	}
1418	up_read(sem: &__i2c_board_lock);
1419	}
1420
1421	static int i2c_do_add_adapter(struct i2c_driver *driver,
1422	struct i2c_adapter *adap)
1423	{
1424	/* Detect supported devices on that bus, and instantiate them */
1425	i2c_detect(adapter: adap, driver);
1426
1427	return 0;
1428	}
1429
1430	static int __process_new_adapter(struct device_driver *d, void *data)
1431	{
1432	return i2c_do_add_adapter(to_i2c_driver(d), adap: data);
1433	}
1434
1435	static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1436	.lock_bus = i2c_adapter_lock_bus,
1437	.trylock_bus = i2c_adapter_trylock_bus,
1438	.unlock_bus = i2c_adapter_unlock_bus,
1439	};
1440
1441	static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1442	{
1443	struct irq_domain *domain = adap->host_notify_domain;
1444	irq_hw_number_t hwirq;
1445
1446	if (!domain)
1447	return;
1448
1449	for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1450	irq_dispose_mapping(virq: irq_find_mapping(domain, hwirq));
1451
1452	irq_domain_remove(domain);
1453	adap->host_notify_domain = NULL;
1454	}
1455
1456	static int i2c_host_notify_irq_map(struct irq_domain *h,
1457	unsigned int virq,
1458	irq_hw_number_t hw_irq_num)
1459	{
1460	irq_set_chip_and_handler(irq: virq, chip: &dummy_irq_chip, handle: handle_simple_irq);
1461
1462	return 0;
1463	}
1464
1465	static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1466	.map = i2c_host_notify_irq_map,
1467	};
1468
1469	static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1470	{
1471	struct irq_domain *domain;
1472
1473	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1474	return 0;
1475
1476	domain = irq_domain_create_linear(fwnode: adap->dev.parent->fwnode,
1477	I2C_ADDR_7BITS_COUNT,
1478	ops: &i2c_host_notify_irq_ops, host_data: adap);
1479	if (!domain)
1480	return -ENOMEM;
1481
1482	adap->host_notify_domain = domain;
1483
1484	return 0;
1485	}
1486
1487	/**
1488	* i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1489	* I2C client.
1490	* @adap: the adapter
1491	* @addr: the I2C address of the notifying device
1492	* Context: can't sleep
1493	*
1494	* Helper function to be called from an I2C bus driver's interrupt
1495	* handler. It will schedule the Host Notify IRQ.
1496	*/
1497	int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1498	{
1499	int irq;
1500
1501	if (!adap)
1502	return -EINVAL;
1503
1504	dev_dbg(&adap->dev, "Detected HostNotify from address 0x%02x", addr);
1505
1506	irq = irq_find_mapping(domain: adap->host_notify_domain, hwirq: addr);
1507	if (irq <= 0)
1508	return -ENXIO;
1509
1510	generic_handle_irq_safe(irq);
1511
1512	return 0;
1513	}
1514	EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1515
1516	static int i2c_register_adapter(struct i2c_adapter *adap)
1517	{
1518	int res = -EINVAL;
1519
1520	/* Can't register until after driver model init */
1521	if (WARN_ON(!is_registered)) {
1522	res = -EAGAIN;
1523	goto out_list;
1524	}
1525
1526	/* Sanity checks */
1527	if (WARN(!adap->name[0], "i2c adapter has no name"))
1528	goto out_list;
1529
1530	if (!adap->algo) {
1531	pr_err("adapter '%s': no algo supplied!\n", adap->name);
1532	goto out_list;
1533	}
1534
1535	if (!adap->lock_ops)
1536	adap->lock_ops = &i2c_adapter_lock_ops;
1537
1538	adap->locked_flags = 0;
1539	rt_mutex_init(&adap->bus_lock);
1540	rt_mutex_init(&adap->mux_lock);
1541	mutex_init(&adap->userspace_clients_lock);
1542	INIT_LIST_HEAD(list: &adap->userspace_clients);
1543
1544	/* Set default timeout to 1 second if not already set */
1545	if (adap->timeout == 0)
1546	adap->timeout = HZ;
1547
1548	/* register soft irqs for Host Notify */
1549	res = i2c_setup_host_notify_irq_domain(adap);
1550	if (res) {
1551	pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1552	adap->name, res);
1553	goto out_list;
1554	}
1555
1556	dev_set_name(dev: &adap->dev, name: "i2c-%d", adap->nr);
1557	adap->dev.bus = &i2c_bus_type;
1558	adap->dev.type = &i2c_adapter_type;
1559	device_initialize(dev: &adap->dev);
1560
1561	/*
1562	* This adapter can be used as a parent immediately after device_add(),
1563	* setup runtime-pm (especially ignore-children) before hand.
1564	*/
1565	device_enable_async_suspend(dev: &adap->dev);
1566	pm_runtime_no_callbacks(dev: &adap->dev);
1567	pm_suspend_ignore_children(dev: &adap->dev, enable: true);
1568	pm_runtime_enable(dev: &adap->dev);
1569
1570	res = device_add(dev: &adap->dev);
1571	if (res) {
1572	pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1573	put_device(dev: &adap->dev);
1574	goto out_list;
1575	}
1576
1577	adap->debugfs = debugfs_create_dir(name: dev_name(dev: &adap->dev), parent: i2c_debugfs_root);
1578
1579	res = i2c_setup_smbus_alert(adap);
1580	if (res)
1581	goto out_reg;
1582
1583	res = i2c_init_recovery(adap);
1584	if (res == -EPROBE_DEFER)
1585	goto out_reg;
1586
1587	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1588
1589	/* create pre-declared device nodes */
1590	of_i2c_register_devices(adap);
1591	i2c_acpi_install_space_handler(adapter: adap);
1592	i2c_acpi_register_devices(adap);
1593
1594	if (adap->nr < __i2c_first_dynamic_bus_num)
1595	i2c_scan_static_board_info(adapter: adap);
1596
1597	/* Notify drivers */
1598	mutex_lock(&core_lock);
1599	bus_for_each_drv(bus: &i2c_bus_type, NULL, data: adap, fn: __process_new_adapter);
1600	mutex_unlock(lock: &core_lock);
1601
1602	return 0;
1603
1604	out_reg:
1605	debugfs_remove_recursive(dentry: adap->debugfs);
1606	init_completion(x: &adap->dev_released);
1607	device_unregister(dev: &adap->dev);
1608	wait_for_completion(&adap->dev_released);
1609	out_list:
1610	mutex_lock(&core_lock);
1611	idr_remove(&i2c_adapter_idr, id: adap->nr);
1612	mutex_unlock(lock: &core_lock);
1613	return res;
1614	}
1615
1616	/**
1617	* __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1618	* @adap: the adapter to register (with adap->nr initialized)
1619	* Context: can sleep
1620	*
1621	* See i2c_add_numbered_adapter() for details.
1622	*/
1623	static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1624	{
1625	int id;
1626
1627	mutex_lock(&core_lock);
1628	id = idr_alloc(&i2c_adapter_idr, ptr: adap, start: adap->nr, end: adap->nr + 1, GFP_KERNEL);
1629	mutex_unlock(lock: &core_lock);
1630	if (WARN(id < 0, "couldn't get idr"))
1631	return id == -ENOSPC ? -EBUSY : id;
1632
1633	return i2c_register_adapter(adap);
1634	}
1635
1636	/**
1637	* i2c_add_adapter - declare i2c adapter, use dynamic bus number
1638	* @adapter: the adapter to add
1639	* Context: can sleep
1640	*
1641	* This routine is used to declare an I2C adapter when its bus number
1642	* doesn't matter or when its bus number is specified by an dt alias.
1643	* Examples of bases when the bus number doesn't matter: I2C adapters
1644	* dynamically added by USB links or PCI plugin cards.
1645	*
1646	* When this returns zero, a new bus number was allocated and stored
1647	* in adap->nr, and the specified adapter became available for clients.
1648	* Otherwise, a negative errno value is returned.
1649	*/
1650	int i2c_add_adapter(struct i2c_adapter *adapter)
1651	{
1652	struct device *dev = &adapter->dev;
1653	int id;
1654
1655	id = of_alias_get_id(np: dev->of_node, stem: "i2c");
1656	if (id >= 0) {
1657	adapter->nr = id;
1658	return __i2c_add_numbered_adapter(adap: adapter);
1659	}
1660
1661	mutex_lock(&core_lock);
1662	id = idr_alloc(&i2c_adapter_idr, ptr: adapter,
1663	start: __i2c_first_dynamic_bus_num, end: 0, GFP_KERNEL);
1664	mutex_unlock(lock: &core_lock);
1665	if (WARN(id < 0, "couldn't get idr"))
1666	return id;
1667
1668	adapter->nr = id;
1669
1670	return i2c_register_adapter(adap: adapter);
1671	}
1672	EXPORT_SYMBOL(i2c_add_adapter);
1673
1674	/**
1675	* i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1676	* @adap: the adapter to register (with adap->nr initialized)
1677	* Context: can sleep
1678	*
1679	* This routine is used to declare an I2C adapter when its bus number
1680	* matters. For example, use it for I2C adapters from system-on-chip CPUs,
1681	* or otherwise built in to the system's mainboard, and where i2c_board_info
1682	* is used to properly configure I2C devices.
1683	*
1684	* If the requested bus number is set to -1, then this function will behave
1685	* identically to i2c_add_adapter, and will dynamically assign a bus number.
1686	*
1687	* If no devices have pre-been declared for this bus, then be sure to
1688	* register the adapter before any dynamically allocated ones. Otherwise
1689	* the required bus ID may not be available.
1690	*
1691	* When this returns zero, the specified adapter became available for
1692	* clients using the bus number provided in adap->nr. Also, the table
1693	* of I2C devices pre-declared using i2c_register_board_info() is scanned,
1694	* and the appropriate driver model device nodes are created. Otherwise, a
1695	* negative errno value is returned.
1696	*/
1697	int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1698	{
1699	if (adap->nr == -1) /* -1 means dynamically assign bus id */
1700	return i2c_add_adapter(adap);
1701
1702	return __i2c_add_numbered_adapter(adap);
1703	}
1704	EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1705
1706	static void i2c_do_del_adapter(struct i2c_driver *driver,
1707	struct i2c_adapter *adapter)
1708	{
1709	struct i2c_client *client, *_n;
1710
1711	/* Remove the devices we created ourselves as the result of hardware
1712	* probing (using a driver's detect method) */
1713	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1714	if (client->adapter == adapter) {
1715	dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1716	client->name, client->addr);
1717	list_del(entry: &client->detected);
1718	i2c_unregister_device(client);
1719	}
1720	}
1721	}
1722
1723	static int __unregister_client(struct device *dev, void *dummy)
1724	{
1725	struct i2c_client *client = i2c_verify_client(dev);
1726	if (client && strcmp(client->name, "dummy"))
1727	i2c_unregister_device(client);
1728	return 0;
1729	}
1730
1731	static int __unregister_dummy(struct device *dev, void *dummy)
1732	{
1733	struct i2c_client *client = i2c_verify_client(dev);
1734	i2c_unregister_device(client);
1735	return 0;
1736	}
1737
1738	static int __process_removed_adapter(struct device_driver *d, void *data)
1739	{
1740	i2c_do_del_adapter(to_i2c_driver(d), adapter: data);
1741	return 0;
1742	}
1743
1744	/**
1745	* i2c_del_adapter - unregister I2C adapter
1746	* @adap: the adapter being unregistered
1747	* Context: can sleep
1748	*
1749	* This unregisters an I2C adapter which was previously registered
1750	* by @i2c_add_adapter or @i2c_add_numbered_adapter.
1751	*/
1752	void i2c_del_adapter(struct i2c_adapter *adap)
1753	{
1754	struct i2c_adapter *found;
1755	struct i2c_client *client, *next;
1756
1757	/* First make sure that this adapter was ever added */
1758	mutex_lock(&core_lock);
1759	found = idr_find(&i2c_adapter_idr, id: adap->nr);
1760	mutex_unlock(lock: &core_lock);
1761	if (found != adap) {
1762	pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1763	return;
1764	}
1765
1766	i2c_acpi_remove_space_handler(adapter: adap);
1767	/* Tell drivers about this removal */
1768	mutex_lock(&core_lock);
1769	bus_for_each_drv(bus: &i2c_bus_type, NULL, data: adap,
1770	fn: __process_removed_adapter);
1771	mutex_unlock(lock: &core_lock);
1772
1773	/* Remove devices instantiated from sysfs */
1774	mutex_lock_nested(lock: &adap->userspace_clients_lock,
1775	subclass: i2c_adapter_depth(adap));
1776	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1777	detected) {
1778	dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1779	client->addr);
1780	list_del(entry: &client->detected);
1781	i2c_unregister_device(client);
1782	}
1783	mutex_unlock(lock: &adap->userspace_clients_lock);
1784
1785	/* Detach any active clients. This can't fail, thus we do not
1786	* check the returned value. This is a two-pass process, because
1787	* we can't remove the dummy devices during the first pass: they
1788	* could have been instantiated by real devices wishing to clean
1789	* them up properly, so we give them a chance to do that first. */
1790	device_for_each_child(parent: &adap->dev, NULL, fn: __unregister_client);
1791	device_for_each_child(parent: &adap->dev, NULL, fn: __unregister_dummy);
1792
1793	/* device name is gone after device_unregister */
1794	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1795
1796	pm_runtime_disable(dev: &adap->dev);
1797
1798	i2c_host_notify_irq_teardown(adap);
1799
1800	debugfs_remove_recursive(dentry: adap->debugfs);
1801
1802	/* wait until all references to the device are gone
1803	*
1804	* FIXME: This is old code and should ideally be replaced by an
1805	* alternative which results in decoupling the lifetime of the struct
1806	* device from the i2c_adapter, like spi or netdev do. Any solution
1807	* should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1808	*/
1809	init_completion(x: &adap->dev_released);
1810	device_unregister(dev: &adap->dev);
1811	wait_for_completion(&adap->dev_released);
1812
1813	/* free bus id */
1814	mutex_lock(&core_lock);
1815	idr_remove(&i2c_adapter_idr, id: adap->nr);
1816	mutex_unlock(lock: &core_lock);
1817
1818	/* Clear the device structure in case this adapter is ever going to be
1819	added again */
1820	memset(&adap->dev, 0, sizeof(adap->dev));
1821	}
1822	EXPORT_SYMBOL(i2c_del_adapter);
1823
1824	static void devm_i2c_del_adapter(void *adapter)
1825	{
1826	i2c_del_adapter(adapter);
1827	}
1828
1829	/**
1830	* devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1831	* @dev: managing device for adding this I2C adapter
1832	* @adapter: the adapter to add
1833	* Context: can sleep
1834	*
1835	* Add adapter with dynamic bus number, same with i2c_add_adapter()
1836	* but the adapter will be auto deleted on driver detach.
1837	*/
1838	int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1839	{
1840	int ret;
1841
1842	ret = i2c_add_adapter(adapter);
1843	if (ret)
1844	return ret;
1845
1846	return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1847	}
1848	EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1849
1850	static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1851	{
1852	if (dev_fwnode(dev) == data)
1853	return 1;
1854
1855	if (dev->parent && dev_fwnode(dev->parent) == data)
1856	return 1;
1857
1858	return 0;
1859	}
1860
1861	/**
1862	* i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1863	* @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1864	*
1865	* Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1866	* If no adapter can be found, or @fwnode is NULL, this returns NULL.
1867	*
1868	* The user must call put_device(&adapter->dev) once done with the i2c adapter.
1869	*/
1870	struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1871	{
1872	struct i2c_adapter *adapter;
1873	struct device *dev;
1874
1875	if (!fwnode)
1876	return NULL;
1877
1878	dev = bus_find_device(bus: &i2c_bus_type, NULL, data: fwnode,
1879	match: i2c_dev_or_parent_fwnode_match);
1880	if (!dev)
1881	return NULL;
1882
1883	adapter = i2c_verify_adapter(dev);
1884	if (!adapter)
1885	put_device(dev);
1886
1887	return adapter;
1888	}
1889	EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1890
1891	/**
1892	* i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1893	* @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1894	*
1895	* Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1896	* and increment the adapter module's use count. If no adapter can be found,
1897	* or @fwnode is NULL, this returns NULL.
1898	*
1899	* The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1900	* Note that this is different from i2c_find_adapter_by_node().
1901	*/
1902	struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1903	{
1904	struct i2c_adapter *adapter;
1905
1906	adapter = i2c_find_adapter_by_fwnode(fwnode);
1907	if (!adapter)
1908	return NULL;
1909
1910	if (!try_module_get(module: adapter->owner)) {
1911	put_device(dev: &adapter->dev);
1912	adapter = NULL;
1913	}
1914
1915	return adapter;
1916	}
1917	EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1918
1919	static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1920	u32 def_val, bool use_def)
1921	{
1922	int ret;
1923
1924	ret = device_property_read_u32(dev, propname: prop_name, val: cur_val_p);
1925	if (ret && use_def)
1926	*cur_val_p = def_val;
1927
1928	dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1929	}
1930
1931	/**
1932	* i2c_parse_fw_timings - get I2C related timing parameters from firmware
1933	* @dev: The device to scan for I2C timing properties
1934	* @t: the i2c_timings struct to be filled with values
1935	* @use_defaults: bool to use sane defaults derived from the I2C specification
1936	* when properties are not found, otherwise don't update
1937	*
1938	* Scan the device for the generic I2C properties describing timing parameters
1939	* for the signal and fill the given struct with the results. If a property was
1940	* not found and use_defaults was true, then maximum timings are assumed which
1941	* are derived from the I2C specification. If use_defaults is not used, the
1942	* results will be as before, so drivers can apply their own defaults before
1943	* calling this helper. The latter is mainly intended for avoiding regressions
1944	* of existing drivers which want to switch to this function. New drivers
1945	* almost always should use the defaults.
1946	*/
1947	void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1948	{
1949	bool u = use_defaults;
1950	u32 d;
1951
1952	i2c_parse_timing(dev, prop_name: "clock-frequency", cur_val_p: &t->bus_freq_hz,
1953	I2C_MAX_STANDARD_MODE_FREQ, use_def: u);
1954
1955	d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1956	t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1957	i2c_parse_timing(dev, prop_name: "i2c-scl-rising-time-ns", cur_val_p: &t->scl_rise_ns, def_val: d, use_def: u);
1958
1959	d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1960	i2c_parse_timing(dev, prop_name: "i2c-scl-falling-time-ns", cur_val_p: &t->scl_fall_ns, def_val: d, use_def: u);
1961
1962	i2c_parse_timing(dev, prop_name: "i2c-scl-internal-delay-ns",
1963	cur_val_p: &t->scl_int_delay_ns, def_val: 0, use_def: u);
1964	i2c_parse_timing(dev, prop_name: "i2c-sda-falling-time-ns", cur_val_p: &t->sda_fall_ns,
1965	def_val: t->scl_fall_ns, use_def: u);
1966	i2c_parse_timing(dev, prop_name: "i2c-sda-hold-time-ns", cur_val_p: &t->sda_hold_ns, def_val: 0, use_def: u);
1967	i2c_parse_timing(dev, prop_name: "i2c-digital-filter-width-ns",
1968	cur_val_p: &t->digital_filter_width_ns, def_val: 0, use_def: u);
1969	i2c_parse_timing(dev, prop_name: "i2c-analog-filter-cutoff-frequency",
1970	cur_val_p: &t->analog_filter_cutoff_freq_hz, def_val: 0, use_def: u);
1971	}
1972	EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1973
1974	/* ------------------------------------------------------------------------- */
1975
1976	int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1977	{
1978	int res;
1979
1980	mutex_lock(&core_lock);
1981	res = bus_for_each_dev(bus: &i2c_bus_type, NULL, data, fn);
1982	mutex_unlock(lock: &core_lock);
1983
1984	return res;
1985	}
1986	EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1987
1988	static int __process_new_driver(struct device *dev, void *data)
1989	{
1990	if (dev->type != &i2c_adapter_type)
1991	return 0;
1992	return i2c_do_add_adapter(driver: data, to_i2c_adapter(dev));
1993	}
1994
1995	/*
1996	* An i2c_driver is used with one or more i2c_client (device) nodes to access
1997	* i2c slave chips, on a bus instance associated with some i2c_adapter.
1998	*/
1999
2000	int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
2001	{
2002	int res;
2003
2004	/* Can't register until after driver model init */
2005	if (WARN_ON(!is_registered))
2006	return -EAGAIN;
2007
2008	/* add the driver to the list of i2c drivers in the driver core */
2009	driver->driver.owner = owner;
2010	driver->driver.bus = &i2c_bus_type;
2011	INIT_LIST_HEAD(list: &driver->clients);
2012
2013	/* When registration returns, the driver core
2014	* will have called probe() for all matching-but-unbound devices.
2015	*/
2016	res = driver_register(drv: &driver->driver);
2017	if (res)
2018	return res;
2019
2020	pr_debug("driver [%s] registered\n", driver->driver.name);
2021
2022	/* Walk the adapters that are already present */
2023	i2c_for_each_dev(driver, __process_new_driver);
2024
2025	return 0;
2026	}
2027	EXPORT_SYMBOL(i2c_register_driver);
2028
2029	static int __process_removed_driver(struct device *dev, void *data)
2030	{
2031	if (dev->type == &i2c_adapter_type)
2032	i2c_do_del_adapter(driver: data, to_i2c_adapter(dev));
2033	return 0;
2034	}
2035
2036	/**
2037	* i2c_del_driver - unregister I2C driver
2038	* @driver: the driver being unregistered
2039	* Context: can sleep
2040	*/
2041	void i2c_del_driver(struct i2c_driver *driver)
2042	{
2043	i2c_for_each_dev(driver, __process_removed_driver);
2044
2045	driver_unregister(drv: &driver->driver);
2046	pr_debug("driver [%s] unregistered\n", driver->driver.name);
2047	}
2048	EXPORT_SYMBOL(i2c_del_driver);
2049
2050	/* ------------------------------------------------------------------------- */
2051
2052	struct i2c_cmd_arg {
2053	unsigned cmd;
2054	void *arg;
2055	};
2056
2057	static int i2c_cmd(struct device *dev, void *_arg)
2058	{
2059	struct i2c_client *client = i2c_verify_client(dev);
2060	struct i2c_cmd_arg *arg = _arg;
2061	struct i2c_driver *driver;
2062
2063	if (!client || !client->dev.driver)
2064	return 0;
2065
2066	driver = to_i2c_driver(client->dev.driver);
2067	if (driver->command)
2068	driver->command(client, arg->cmd, arg->arg);
2069	return 0;
2070	}
2071
2072	void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2073	{
2074	struct i2c_cmd_arg cmd_arg;
2075
2076	cmd_arg.cmd = cmd;
2077	cmd_arg.arg = arg;
2078	device_for_each_child(parent: &adap->dev, data: &cmd_arg, fn: i2c_cmd);
2079	}
2080	EXPORT_SYMBOL(i2c_clients_command);
2081
2082	static int __init i2c_init(void)
2083	{
2084	int retval;
2085
2086	retval = of_alias_get_highest_id(stem: "i2c");
2087
2088	down_write(sem: &__i2c_board_lock);
2089	if (retval >= __i2c_first_dynamic_bus_num)
2090	__i2c_first_dynamic_bus_num = retval + 1;
2091	up_write(sem: &__i2c_board_lock);
2092
2093	retval = bus_register(bus: &i2c_bus_type);
2094	if (retval)
2095	return retval;
2096
2097	is_registered = true;
2098
2099	i2c_debugfs_root = debugfs_create_dir(name: "i2c", NULL);
2100
2101	retval = i2c_add_driver(&dummy_driver);
2102	if (retval)
2103	goto class_err;
2104
2105	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2106	WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2107	if (IS_ENABLED(CONFIG_ACPI))
2108	WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2109
2110	return 0;
2111
2112	class_err:
2113	is_registered = false;
2114	bus_unregister(bus: &i2c_bus_type);
2115	return retval;
2116	}
2117
2118	static void __exit i2c_exit(void)
2119	{
2120	if (IS_ENABLED(CONFIG_ACPI))
2121	WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2122	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2123	WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2124	i2c_del_driver(&dummy_driver);
2125	debugfs_remove_recursive(dentry: i2c_debugfs_root);
2126	bus_unregister(bus: &i2c_bus_type);
2127	tracepoint_synchronize_unregister();
2128	}
2129
2130	/* We must initialize early, because some subsystems register i2c drivers
2131	* in subsys_initcall() code, but are linked (and initialized) before i2c.
2132	*/
2133	postcore_initcall(i2c_init);
2134	module_exit(i2c_exit);
2135
2136	/* ----------------------------------------------------
2137	* the functional interface to the i2c busses.
2138	* ----------------------------------------------------
2139	*/
2140
2141	/* Check if val is exceeding the quirk IFF quirk is non 0 */
2142	#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2143
2144	static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2145	{
2146	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2147	err_msg, msg->addr, msg->len,
2148	str_read_write(msg->flags & I2C_M_RD));
2149	return -EOPNOTSUPP;
2150	}
2151
2152	static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2153	{
2154	const struct i2c_adapter_quirks *q = adap->quirks;
2155	int max_num = q->max_num_msgs, i;
2156	bool do_len_check = true;
2157
2158	if (q->flags & I2C_AQ_COMB) {
2159	max_num = 2;
2160
2161	/* special checks for combined messages */
2162	if (num == 2) {
2163	if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2164	return i2c_quirk_error(adap, msg: &msgs[0], err_msg: "1st comb msg must be write");
2165
2166	if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2167	return i2c_quirk_error(adap, msg: &msgs[1], err_msg: "2nd comb msg must be read");
2168
2169	if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2170	return i2c_quirk_error(adap, msg: &msgs[0], err_msg: "comb msg only to same addr");
2171
2172	if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2173	return i2c_quirk_error(adap, msg: &msgs[0], err_msg: "msg too long");
2174
2175	if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2176	return i2c_quirk_error(adap, msg: &msgs[1], err_msg: "msg too long");
2177
2178	do_len_check = false;
2179	}
2180	}
2181
2182	if (i2c_quirk_exceeded(num, max_num))
2183	return i2c_quirk_error(adap, msg: &msgs[0], err_msg: "too many messages");
2184
2185	for (i = 0; i < num; i++) {
2186	u16 len = msgs[i].len;
2187
2188	if (msgs[i].flags & I2C_M_RD) {
2189	if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2190	return i2c_quirk_error(adap, msg: &msgs[i], err_msg: "msg too long");
2191
2192	if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2193	return i2c_quirk_error(adap, msg: &msgs[i], err_msg: "no zero length");
2194	} else {
2195	if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2196	return i2c_quirk_error(adap, msg: &msgs[i], err_msg: "msg too long");
2197
2198	if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2199	return i2c_quirk_error(adap, msg: &msgs[i], err_msg: "no zero length");
2200	}
2201	}
2202
2203	return 0;
2204	}
2205
2206	/**
2207	* __i2c_transfer - unlocked flavor of i2c_transfer
2208	* @adap: Handle to I2C bus
2209	* @msgs: One or more messages to execute before STOP is issued to
2210	* terminate the operation; each message begins with a START.
2211	* @num: Number of messages to be executed.
2212	*
2213	* Returns negative errno, else the number of messages executed.
2214	*
2215	* Adapter lock must be held when calling this function. No debug logging
2216	* takes place.
2217	*/
2218	int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2219	{
2220	unsigned long orig_jiffies;
2221	int ret, try;
2222
2223	if (!adap->algo->master_xfer) {
2224	dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2225	return -EOPNOTSUPP;
2226	}
2227
2228	if (WARN_ON(!msgs || num < 1))
2229	return -EINVAL;
2230
2231	ret = __i2c_check_suspended(adap);
2232	if (ret)
2233	return ret;
2234
2235	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2236	return -EOPNOTSUPP;
2237
2238	/*
2239	* i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2240	* enabled. This is an efficient way of keeping the for-loop from
2241	* being executed when not needed.
2242	*/
2243	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2244	int i;
2245	for (i = 0; i < num; i++)
2246	if (msgs[i].flags & I2C_M_RD)
2247	trace_i2c_read(adap, msg: &msgs[i], num: i);
2248	else
2249	trace_i2c_write(adap, msg: &msgs[i], num: i);
2250	}
2251
2252	/* Retry automatically on arbitration loss */
2253	orig_jiffies = jiffies;
2254	for (ret = 0, try = 0; try <= adap->retries; try++) {
2255	if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2256	ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2257	else
2258	ret = adap->algo->master_xfer(adap, msgs, num);
2259
2260	if (ret != -EAGAIN)
2261	break;
2262	if (time_after(jiffies, orig_jiffies + adap->timeout))
2263	break;
2264	}
2265
2266	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2267	int i;
2268	for (i = 0; i < ret; i++)
2269	if (msgs[i].flags & I2C_M_RD)
2270	trace_i2c_reply(adap, msg: &msgs[i], num: i);
2271	trace_i2c_result(adap, num, ret);
2272	}
2273
2274	return ret;
2275	}
2276	EXPORT_SYMBOL(__i2c_transfer);
2277
2278	/**
2279	* i2c_transfer - execute a single or combined I2C message
2280	* @adap: Handle to I2C bus
2281	* @msgs: One or more messages to execute before STOP is issued to
2282	* terminate the operation; each message begins with a START.
2283	* @num: Number of messages to be executed.
2284	*
2285	* Returns negative errno, else the number of messages executed.
2286	*
2287	* Note that there is no requirement that each message be sent to
2288	* the same slave address, although that is the most common model.
2289	*/
2290	int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2291	{
2292	int ret;
2293
2294	/* REVISIT the fault reporting model here is weak:
2295	*
2296	* - When we get an error after receiving N bytes from a slave,
2297	* there is no way to report "N".
2298	*
2299	* - When we get a NAK after transmitting N bytes to a slave,
2300	* there is no way to report "N" ... or to let the master
2301	* continue executing the rest of this combined message, if
2302	* that's the appropriate response.
2303	*
2304	* - When for example "num" is two and we successfully complete
2305	* the first message but get an error part way through the
2306	* second, it's unclear whether that should be reported as
2307	* one (discarding status on the second message) or errno
2308	* (discarding status on the first one).
2309	*/
2310	ret = __i2c_lock_bus_helper(adap);
2311	if (ret)
2312	return ret;
2313
2314	ret = __i2c_transfer(adap, msgs, num);
2315	i2c_unlock_bus(adapter: adap, I2C_LOCK_SEGMENT);
2316
2317	return ret;
2318	}
2319	EXPORT_SYMBOL(i2c_transfer);
2320
2321	/**
2322	* i2c_transfer_buffer_flags - issue a single I2C message transferring data
2323	* to/from a buffer
2324	* @client: Handle to slave device
2325	* @buf: Where the data is stored
2326	* @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2327	* @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2328	*
2329	* Returns negative errno, or else the number of bytes transferred.
2330	*/
2331	int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2332	int count, u16 flags)
2333	{
2334	int ret;
2335	struct i2c_msg msg = {
2336	.addr = client->addr,
2337	.flags = flags | (client->flags & I2C_M_TEN),
2338	.len = count,
2339	.buf = buf,
2340	};
2341
2342	ret = i2c_transfer(client->adapter, &msg, 1);
2343
2344	/*
2345	* If everything went ok (i.e. 1 msg transferred), return #bytes
2346	* transferred, else error code.
2347	*/
2348	return (ret == 1) ? count : ret;
2349	}
2350	EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2351
2352	/**
2353	* i2c_get_device_id - get manufacturer, part id and die revision of a device
2354	* @client: The device to query
2355	* @id: The queried information
2356	*
2357	* Returns negative errno on error, zero on success.
2358	*/
2359	int i2c_get_device_id(const struct i2c_client *client,
2360	struct i2c_device_identity *id)
2361	{
2362	struct i2c_adapter *adap = client->adapter;
2363	union i2c_smbus_data raw_id;
2364	int ret;
2365
2366	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2367	return -EOPNOTSUPP;
2368
2369	raw_id.block[0] = 3;
2370	ret = i2c_smbus_xfer(adapter: adap, I2C_ADDR_DEVICE_ID, flags: 0,
2371	I2C_SMBUS_READ, command: client->addr << 1,
2372	I2C_SMBUS_I2C_BLOCK_DATA, data: &raw_id);
2373	if (ret)
2374	return ret;
2375
2376	id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2377	id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2378	id->die_revision = raw_id.block[3] & 0x7;
2379	return 0;
2380	}
2381	EXPORT_SYMBOL_GPL(i2c_get_device_id);
2382
2383	/**
2384	* i2c_client_get_device_id - get the driver match table entry of a device
2385	* @client: the device to query. The device must be bound to a driver
2386	*
2387	* Returns a pointer to the matching entry if found, NULL otherwise.
2388	*/
2389	const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2390	{
2391	const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2392
2393	return i2c_match_id(drv->id_table, client);
2394	}
2395	EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2396
2397	/* ----------------------------------------------------
2398	* the i2c address scanning function
2399	* Will not work for 10-bit addresses!
2400	* ----------------------------------------------------
2401	*/
2402
2403	/*
2404	* Legacy default probe function, mostly relevant for SMBus. The default
2405	* probe method is a quick write, but it is known to corrupt the 24RF08
2406	* EEPROMs due to a state machine bug, and could also irreversibly
2407	* write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2408	* we use a short byte read instead. Also, some bus drivers don't implement
2409	* quick write, so we fallback to a byte read in that case too.
2410	* On x86, there is another special case for FSC hardware monitoring chips,
2411	* which want regular byte reads (address 0x73.) Fortunately, these are the
2412	* only known chips using this I2C address on PC hardware.
2413	* Returns 1 if probe succeeded, 0 if not.
2414	*/
2415	static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2416	{
2417	int err;
2418	union i2c_smbus_data dummy;
2419
2420	#ifdef CONFIG_X86
2421	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2422	&& i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2423	err = i2c_smbus_xfer(adapter: adap, addr, flags: 0, I2C_SMBUS_READ, command: 0,
2424	I2C_SMBUS_BYTE_DATA, data: &dummy);
2425	else
2426	#endif
2427	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2428	&& i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2429	err = i2c_smbus_xfer(adapter: adap, addr, flags: 0, I2C_SMBUS_WRITE, command: 0,
2430	I2C_SMBUS_QUICK, NULL);
2431	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2432	err = i2c_smbus_xfer(adapter: adap, addr, flags: 0, I2C_SMBUS_READ, command: 0,
2433	I2C_SMBUS_BYTE, data: &dummy);
2434	else {
2435	dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2436	addr);
2437	err = -EOPNOTSUPP;
2438	}
2439
2440	return err >= 0;
2441	}
2442
2443	static int i2c_detect_address(struct i2c_client *temp_client,
2444	struct i2c_driver *driver)
2445	{
2446	struct i2c_board_info info;
2447	struct i2c_adapter *adapter = temp_client->adapter;
2448	int addr = temp_client->addr;
2449	int err;
2450
2451	/* Make sure the address is valid */
2452	err = i2c_check_7bit_addr_validity_strict(addr);
2453	if (err) {
2454	dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2455	addr);
2456	return err;
2457	}
2458
2459	/* Skip if already in use (7 bit, no need to encode flags) */
2460	if (i2c_check_addr_busy(adapter, addr))
2461	return 0;
2462
2463	/* Make sure there is something at this address */
2464	if (!i2c_default_probe(adap: adapter, addr))
2465	return 0;
2466
2467	/* Finally call the custom detection function */
2468	memset(&info, 0, sizeof(struct i2c_board_info));
2469	info.addr = addr;
2470	err = driver->detect(temp_client, &info);
2471	if (err) {
2472	/* -ENODEV is returned if the detection fails. We catch it
2473	here as this isn't an error. */
2474	return err == -ENODEV ? 0 : err;
2475	}
2476
2477	/* Consistency check */
2478	if (info.type[0] == '\0') {
2479	dev_err(&adapter->dev,
2480	"%s detection function provided no name for 0x%x\n",
2481	driver->driver.name, addr);
2482	} else {
2483	struct i2c_client *client;
2484
2485	/* Detection succeeded, instantiate the device */
2486	if (adapter->class & I2C_CLASS_DEPRECATED)
2487	dev_warn(&adapter->dev,
2488	"This adapter will soon drop class based instantiation of devices. "
2489	"Please make sure client 0x%02x gets instantiated by other means. "
2490	"Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2491	info.addr);
2492
2493	dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2494	info.type, info.addr);
2495	client = i2c_new_client_device(adapter, &info);
2496	if (!IS_ERR(ptr: client))
2497	list_add_tail(new: &client->detected, head: &driver->clients);
2498	else
2499	dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2500	info.type, info.addr);
2501	}
2502	return 0;
2503	}
2504
2505	static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2506	{
2507	const unsigned short *address_list;
2508	struct i2c_client *temp_client;
2509	int i, err = 0;
2510
2511	address_list = driver->address_list;
2512	if (!driver->detect || !address_list)
2513	return 0;
2514
2515	/* Warn that the adapter lost class based instantiation */
2516	if (adapter->class == I2C_CLASS_DEPRECATED) {
2517	dev_dbg(&adapter->dev,
2518	"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2519	"If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2520	driver->driver.name);
2521	return 0;
2522	}
2523
2524	/* Stop here if the classes do not match */
2525	if (!(adapter->class & driver->class))
2526	return 0;
2527
2528	/* Set up a temporary client to help detect callback */
2529	temp_client = kzalloc(sizeof(*temp_client), GFP_KERNEL);
2530	if (!temp_client)
2531	return -ENOMEM;
2532
2533	temp_client->adapter = adapter;
2534
2535	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2536	dev_dbg(&adapter->dev,
2537	"found normal entry for adapter %d, addr 0x%02x\n",
2538	i2c_adapter_id(adapter), address_list[i]);
2539	temp_client->addr = address_list[i];
2540	err = i2c_detect_address(temp_client, driver);
2541	if (unlikely(err))
2542	break;
2543	}
2544
2545	kfree(objp: temp_client);
2546
2547	return err;
2548	}
2549
2550	int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2551	{
2552	return i2c_smbus_xfer(adapter: adap, addr, flags: 0, I2C_SMBUS_READ, command: 0,
2553	I2C_SMBUS_QUICK, NULL) >= 0;
2554	}
2555	EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2556
2557	struct i2c_client *
2558	i2c_new_scanned_device(struct i2c_adapter *adap,
2559	struct i2c_board_info *info,
2560	unsigned short const *addr_list,
2561	int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2562	{
2563	int i;
2564
2565	if (!probe)
2566	probe = i2c_default_probe;
2567
2568	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2569	/* Check address validity */
2570	if (i2c_check_7bit_addr_validity_strict(addr: addr_list[i]) < 0) {
2571	dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2572	addr_list[i]);
2573	continue;
2574	}
2575
2576	/* Check address availability (7 bit, no need to encode flags) */
2577	if (i2c_check_addr_busy(adapter: adap, addr: addr_list[i])) {
2578	dev_dbg(&adap->dev,
2579	"Address 0x%02x already in use, not probing\n",
2580	addr_list[i]);
2581	continue;
2582	}
2583
2584	/* Test address responsiveness */
2585	if (probe(adap, addr_list[i]))
2586	break;
2587	}
2588
2589	if (addr_list[i] == I2C_CLIENT_END) {
2590	dev_dbg(&adap->dev, "Probing failed, no device found\n");
2591	return ERR_PTR(error: -ENODEV);
2592	}
2593
2594	info->addr = addr_list[i];
2595	return i2c_new_client_device(adap, info);
2596	}
2597	EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2598
2599	struct i2c_adapter *i2c_get_adapter(int nr)
2600	{
2601	struct i2c_adapter *adapter;
2602
2603	mutex_lock(&core_lock);
2604	adapter = idr_find(&i2c_adapter_idr, id: nr);
2605	if (!adapter)
2606	goto exit;
2607
2608	if (try_module_get(module: adapter->owner))
2609	get_device(dev: &adapter->dev);
2610	else
2611	adapter = NULL;
2612
2613	exit:
2614	mutex_unlock(lock: &core_lock);
2615	return adapter;
2616	}
2617	EXPORT_SYMBOL(i2c_get_adapter);
2618
2619	void i2c_put_adapter(struct i2c_adapter *adap)
2620	{
2621	if (!adap)
2622	return;
2623
2624	module_put(module: adap->owner);
2625	/* Should be last, otherwise we risk use-after-free with 'adap' */
2626	put_device(dev: &adap->dev);
2627	}
2628	EXPORT_SYMBOL(i2c_put_adapter);
2629
2630	/**
2631	* i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2632	* @msg: the message to be checked
2633	* @threshold: the minimum number of bytes for which using DMA makes sense.
2634	* Should at least be 1.
2635	*
2636	* Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2637	* Or a valid pointer to be used with DMA. After use, release it by
2638	* calling i2c_put_dma_safe_msg_buf().
2639	*
2640	* This function must only be called from process context!
2641	*/
2642	u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2643	{
2644	/* also skip 0-length msgs for bogus thresholds of 0 */
2645	if (!threshold)
2646	pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2647	msg->addr);
2648	if (msg->len < threshold || msg->len == 0)
2649	return NULL;
2650
2651	if (msg->flags & I2C_M_DMA_SAFE)
2652	return msg->buf;
2653
2654	pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2655	msg->addr, msg->len);
2656
2657	if (msg->flags & I2C_M_RD)
2658	return kzalloc(msg->len, GFP_KERNEL);
2659	else
2660	return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2661	}
2662	EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2663
2664	/**
2665	* i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2666	* @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2667	* @msg: the message which the buffer corresponds to
2668	* @xferred: bool saying if the message was transferred
2669	*/
2670	void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2671	{
2672	if (!buf || buf == msg->buf)
2673	return;
2674
2675	if (xferred && msg->flags & I2C_M_RD)
2676	memcpy(msg->buf, buf, msg->len);
2677
2678	kfree(objp: buf);
2679	}
2680	EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2681
2682	MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2683	MODULE_DESCRIPTION("I2C-Bus main module");
2684	MODULE_LICENSE("GPL");
2685