summaryrefslogtreecommitdiff
path: root/drivers/i2c/i2c-core-acpi.c
blob: 7c3b4740b94b644509ae3658fa2eda4885086bba (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
/*
 * Linux I2C core ACPI support code
 *
 * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "i2c-core.h"

struct i2c_acpi_handler_data {
	struct acpi_connection_info info;
	struct i2c_adapter *adapter;
};

struct gsb_buffer {
	u8	status;
	u8	len;
	union {
		u16	wdata;
		u8	bdata;
		u8	data[0];
	};
} __packed;

struct i2c_acpi_lookup {
	struct i2c_board_info *info;
	acpi_handle adapter_handle;
	acpi_handle device_handle;
	acpi_handle search_handle;
	int n;
	int index;
	u32 speed;
	u32 min_speed;
};

static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
{
	struct i2c_acpi_lookup *lookup = data;
	struct i2c_board_info *info = lookup->info;
	struct acpi_resource_i2c_serialbus *sb;
	acpi_status status;

	if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
		return 1;

	sb = &ares->data.i2c_serial_bus;
	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
		return 1;

	if (lookup->index != -1 && lookup->n++ != lookup->index)
		return 1;

	status = acpi_get_handle(lookup->device_handle,
				 sb->resource_source.string_ptr,
				 &lookup->adapter_handle);
	if (!ACPI_SUCCESS(status))
		return 1;

	info->addr = sb->slave_address;
	lookup->speed = sb->connection_speed;
	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
		info->flags |= I2C_CLIENT_TEN;

	return 1;
}

static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
	/*
	 * ACPI video acpi_devices, which are handled by the acpi-video driver
	 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
	 */
	{ ACPI_VIDEO_HID, 0 },
	{}
};

static int i2c_acpi_do_lookup(struct acpi_device *adev,
			      struct i2c_acpi_lookup *lookup)
{
	struct i2c_board_info *info = lookup->info;
	struct list_head resource_list;
	int ret;

	if (acpi_bus_get_status(adev) || !adev->status.present ||
	    acpi_device_enumerated(adev))
		return -EINVAL;

	if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
		return -ENODEV;

	memset(info, 0, sizeof(*info));
	lookup->device_handle = acpi_device_handle(adev);

	/* Look up for I2cSerialBus resource */
	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list,
				     i2c_acpi_fill_info, lookup);
	acpi_dev_free_resource_list(&resource_list);

	if (ret < 0 || !info->addr)
		return -EINVAL;

	return 0;
}

static int i2c_acpi_get_info(struct acpi_device *adev,
			     struct i2c_board_info *info,
			     struct i2c_adapter *adapter,
			     acpi_handle *adapter_handle)
{
	struct list_head resource_list;
	struct resource_entry *entry;
	struct i2c_acpi_lookup lookup;
	int ret;

	memset(&lookup, 0, sizeof(lookup));
	lookup.info = info;
	lookup.index = -1;

	ret = i2c_acpi_do_lookup(adev, &lookup);
	if (ret)
		return ret;

	if (adapter) {
		/* The adapter must match the one in I2cSerialBus() connector */
		if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
			return -ENODEV;
	} else {
		struct acpi_device *adapter_adev;

		/* The adapter must be present */
		if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
			return -ENODEV;
		if (acpi_bus_get_status(adapter_adev) ||
		    !adapter_adev->status.present)
			return -ENODEV;
	}

	info->fwnode = acpi_fwnode_handle(adev);
	if (adapter_handle)
		*adapter_handle = lookup.adapter_handle;

	/* Then fill IRQ number if any */
	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
	if (ret < 0)
		return -EINVAL;

	resource_list_for_each_entry(entry, &resource_list) {
		if (resource_type(entry->res) == IORESOURCE_IRQ) {
			info->irq = entry->res->start;
			break;
		}
	}

	acpi_dev_free_resource_list(&resource_list);

	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
			  sizeof(info->type));

	return 0;
}

static void i2c_acpi_register_device(struct i2c_adapter *adapter,
				     struct acpi_device *adev,
				     struct i2c_board_info *info)
{
	adev->power.flags.ignore_parent = true;
	acpi_device_set_enumerated(adev);

	if (!i2c_new_device(adapter, info)) {
		adev->power.flags.ignore_parent = false;
		dev_err(&adapter->dev,
			"failed to add I2C device %s from ACPI\n",
			dev_name(&adev->dev));
	}
}

static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
				       void *data, void **return_value)
{
	struct i2c_adapter *adapter = data;
	struct acpi_device *adev;
	struct i2c_board_info info;

	if (acpi_bus_get_device(handle, &adev))
		return AE_OK;

	if (i2c_acpi_get_info(adev, &info, adapter, NULL))
		return AE_OK;

	i2c_acpi_register_device(adapter, adev, &info);

	return AE_OK;
}

#define I2C_ACPI_MAX_SCAN_DEPTH 32

/**
 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
 * @adap: pointer to adapter
 *
 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
 * namespace. When a device is found it will be added to the Linux device
 * model and bound to the corresponding ACPI handle.
 */
void i2c_acpi_register_devices(struct i2c_adapter *adap)
{
	acpi_status status;

	if (!has_acpi_companion(&adap->dev))
		return;

	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
				     I2C_ACPI_MAX_SCAN_DEPTH,
				     i2c_acpi_add_device, NULL,
				     adap, NULL);
	if (ACPI_FAILURE(status))
		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
}

const struct acpi_device_id *
i2c_acpi_match_device(const struct acpi_device_id *matches,
		      struct i2c_client *client)
{
	if (!(client && matches))
		return NULL;

	return acpi_match_device(matches, &client->dev);
}

static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
					   void *data, void **return_value)
{
	struct i2c_acpi_lookup *lookup = data;
	struct acpi_device *adev;

	if (acpi_bus_get_device(handle, &adev))
		return AE_OK;

	if (i2c_acpi_do_lookup(adev, lookup))
		return AE_OK;

	if (lookup->search_handle != lookup->adapter_handle)
		return AE_OK;

	if (lookup->speed <= lookup->min_speed)
		lookup->min_speed = lookup->speed;

	return AE_OK;
}

/**
 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
 * @dev: The device owning the bus
 *
 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
 * devices connected to this bus and use the speed of slowest device.
 *
 * Returns the speed in Hz or zero
 */
u32 i2c_acpi_find_bus_speed(struct device *dev)
{
	struct i2c_acpi_lookup lookup;
	struct i2c_board_info dummy;
	acpi_status status;

	if (!has_acpi_companion(dev))
		return 0;

	memset(&lookup, 0, sizeof(lookup));
	lookup.search_handle = ACPI_HANDLE(dev);
	lookup.min_speed = UINT_MAX;
	lookup.info = &dummy;
	lookup.index = -1;

	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
				     I2C_ACPI_MAX_SCAN_DEPTH,
				     i2c_acpi_lookup_speed, NULL,
				     &lookup, NULL);

	if (ACPI_FAILURE(status)) {
		dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
		return 0;
	}

	return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
}
EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);

static int i2c_acpi_find_match_adapter(struct device *dev, void *data)
{
	struct i2c_adapter *adapter = i2c_verify_adapter(dev);

	if (!adapter)
		return 0;

	return ACPI_HANDLE(dev) == (acpi_handle)data;
}

static int i2c_acpi_find_match_device(struct device *dev, void *data)
{
	return ACPI_COMPANION(dev) == data;
}

static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
{
	struct device *dev;

	dev = bus_find_device(&i2c_bus_type, NULL, handle,
			      i2c_acpi_find_match_adapter);
	return dev ? i2c_verify_adapter(dev) : NULL;
}

static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
{
	struct device *dev;

	dev = bus_find_device(&i2c_bus_type, NULL, adev,
			      i2c_acpi_find_match_device);
	return dev ? i2c_verify_client(dev) : NULL;
}

static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
			   void *arg)
{
	struct acpi_device *adev = arg;
	struct i2c_board_info info;
	acpi_handle adapter_handle;
	struct i2c_adapter *adapter;
	struct i2c_client *client;

	switch (value) {
	case ACPI_RECONFIG_DEVICE_ADD:
		if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
			break;

		adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
		if (!adapter)
			break;

		i2c_acpi_register_device(adapter, adev, &info);
		break;
	case ACPI_RECONFIG_DEVICE_REMOVE:
		if (!acpi_device_enumerated(adev))
			break;

		client = i2c_acpi_find_client_by_adev(adev);
		if (!client)
			break;

		i2c_unregister_device(client);
		put_device(&client->dev);
		break;
	}

	return NOTIFY_OK;
}

struct notifier_block i2c_acpi_notifier = {
	.notifier_call = i2c_acpi_notify,
};

/**
 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
 * @dev:     Device owning the ACPI resources to get the client from
 * @index:   Index of ACPI resource to get
 * @info:    describes the I2C device; note this is modified (addr gets set)
 * Context: can sleep
 *
 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
 * resources, in that case this function can be used to create an i2c-client
 * for other I2cSerialBus resources in the Current Resource Settings table.
 *
 * Also see i2c_new_device, which this function calls to create the i2c-client.
 *
 * Returns a pointer to the new i2c-client, or NULL if the adapter is not found.
 */
struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
				       struct i2c_board_info *info)
{
	struct i2c_acpi_lookup lookup;
	struct i2c_adapter *adapter;
	struct acpi_device *adev;
	LIST_HEAD(resource_list);
	int ret;

	adev = ACPI_COMPANION(dev);
	if (!adev)
		return NULL;

	memset(&lookup, 0, sizeof(lookup));
	lookup.info = info;
	lookup.device_handle = acpi_device_handle(adev);
	lookup.index = index;

	ret = acpi_dev_get_resources(adev, &resource_list,
				     i2c_acpi_fill_info, &lookup);
	acpi_dev_free_resource_list(&resource_list);

	if (ret < 0 || !info->addr)
		return NULL;

	adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
	if (!adapter)
		return NULL;

	return i2c_new_device(adapter, info);
}
EXPORT_SYMBOL_GPL(i2c_acpi_new_device);

#ifdef CONFIG_ACPI_I2C_OPREGION
static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
		u8 cmd, u8 *data, u8 data_len)
{

	struct i2c_msg msgs[2];
	int ret;
	u8 *buffer;

	buffer = kzalloc(data_len, GFP_KERNEL);
	if (!buffer)
		return AE_NO_MEMORY;

	msgs[0].addr = client->addr;
	msgs[0].flags = client->flags;
	msgs[0].len = 1;
	msgs[0].buf = &cmd;

	msgs[1].addr = client->addr;
	msgs[1].flags = client->flags | I2C_M_RD;
	msgs[1].len = data_len;
	msgs[1].buf = buffer;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0) {
		/* Getting a NACK is unfortunately normal with some DSTDs */
		if (ret == -EREMOTEIO)
			dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
				data_len, client->addr, cmd, ret);
		else
			dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
				data_len, client->addr, cmd, ret);
	} else {
		memcpy(data, buffer, data_len);
	}

	kfree(buffer);
	return ret;
}

static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
		u8 cmd, u8 *data, u8 data_len)
{

	struct i2c_msg msgs[1];
	u8 *buffer;
	int ret = AE_OK;

	buffer = kzalloc(data_len + 1, GFP_KERNEL);
	if (!buffer)
		return AE_NO_MEMORY;

	buffer[0] = cmd;
	memcpy(buffer + 1, data, data_len);

	msgs[0].addr = client->addr;
	msgs[0].flags = client->flags;
	msgs[0].len = data_len + 1;
	msgs[0].buf = buffer;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0)
		dev_err(&client->adapter->dev, "i2c write failed\n");

	kfree(buffer);
	return ret;
}

static acpi_status
i2c_acpi_space_handler(u32 function, acpi_physical_address command,
			u32 bits, u64 *value64,
			void *handler_context, void *region_context)
{
	struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
	struct i2c_acpi_handler_data *data = handler_context;
	struct acpi_connection_info *info = &data->info;
	struct acpi_resource_i2c_serialbus *sb;
	struct i2c_adapter *adapter = data->adapter;
	struct i2c_client *client;
	struct acpi_resource *ares;
	u32 accessor_type = function >> 16;
	u8 action = function & ACPI_IO_MASK;
	acpi_status ret;
	int status;

	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
	if (ACPI_FAILURE(ret))
		return ret;

	client = kzalloc(sizeof(*client), GFP_KERNEL);
	if (!client) {
		ret = AE_NO_MEMORY;
		goto err;
	}

	if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	sb = &ares->data.i2c_serial_bus;
	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	client->adapter = adapter;
	client->addr = sb->slave_address;

	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
		client->flags |= I2C_CLIENT_TEN;

	switch (accessor_type) {
	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
		if (action == ACPI_READ) {
			status = i2c_smbus_read_byte(client);
			if (status >= 0) {
				gsb->bdata = status;
				status = 0;
			}
		} else {
			status = i2c_smbus_write_byte(client, gsb->bdata);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_BYTE:
		if (action == ACPI_READ) {
			status = i2c_smbus_read_byte_data(client, command);
			if (status >= 0) {
				gsb->bdata = status;
				status = 0;
			}
		} else {
			status = i2c_smbus_write_byte_data(client, command,
					gsb->bdata);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_WORD:
		if (action == ACPI_READ) {
			status = i2c_smbus_read_word_data(client, command);
			if (status >= 0) {
				gsb->wdata = status;
				status = 0;
			}
		} else {
			status = i2c_smbus_write_word_data(client, command,
					gsb->wdata);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
		if (action == ACPI_READ) {
			status = i2c_smbus_read_block_data(client, command,
					gsb->data);
			if (status >= 0) {
				gsb->len = status;
				status = 0;
			}
		} else {
			status = i2c_smbus_write_block_data(client, command,
					gsb->len, gsb->data);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
		if (action == ACPI_READ) {
			status = acpi_gsb_i2c_read_bytes(client, command,
					gsb->data, info->access_length);
			if (status > 0)
				status = 0;
		} else {
			status = acpi_gsb_i2c_write_bytes(client, command,
					gsb->data, info->access_length);
		}
		break;

	default:
		dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
			 accessor_type, client->addr);
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	gsb->status = status;

 err:
	kfree(client);
	ACPI_FREE(ares);
	return ret;
}


int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
{
	acpi_handle handle;
	struct i2c_acpi_handler_data *data;
	acpi_status status;

	if (!adapter->dev.parent)
		return -ENODEV;

	handle = ACPI_HANDLE(adapter->dev.parent);

	if (!handle)
		return -ENODEV;

	data = kzalloc(sizeof(struct i2c_acpi_handler_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->adapter = adapter;
	status = acpi_bus_attach_private_data(handle, (void *)data);
	if (ACPI_FAILURE(status)) {
		kfree(data);
		return -ENOMEM;
	}

	status = acpi_install_address_space_handler(handle,
				ACPI_ADR_SPACE_GSBUS,
				&i2c_acpi_space_handler,
				NULL,
				data);
	if (ACPI_FAILURE(status)) {
		dev_err(&adapter->dev, "Error installing i2c space handler\n");
		acpi_bus_detach_private_data(handle);
		kfree(data);
		return -ENOMEM;
	}

	acpi_walk_dep_device_list(handle);
	return 0;
}

void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
{
	acpi_handle handle;
	struct i2c_acpi_handler_data *data;
	acpi_status status;

	if (!adapter->dev.parent)
		return;

	handle = ACPI_HANDLE(adapter->dev.parent);

	if (!handle)
		return;

	acpi_remove_address_space_handler(handle,
				ACPI_ADR_SPACE_GSBUS,
				&i2c_acpi_space_handler);

	status = acpi_bus_get_private_data(handle, (void **)&data);
	if (ACPI_SUCCESS(status))
		kfree(data);

	acpi_bus_detach_private_data(handle);
}
#endif /* CONFIG_ACPI_I2C_OPREGION */