1 /*
2 * Linux I2C core ACPI support code
3 *
4 * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 */
11
12 #include <linux/acpi.h>
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/i2c.h>
16 #include <linux/list.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19
20 #include "i2c-core.h"
21
22 struct i2c_acpi_handler_data {
23 struct acpi_connection_info info;
24 struct i2c_adapter *adapter;
25 };
26
27 struct gsb_buffer {
28 u8 status;
29 u8 len;
30 union {
31 u16 wdata;
32 u8 bdata;
33 u8 data[0];
34 };
35 } __packed;
36
37 struct i2c_acpi_lookup {
38 struct i2c_board_info *info;
39 acpi_handle adapter_handle;
40 acpi_handle device_handle;
41 acpi_handle search_handle;
42 int n;
43 int index;
44 u32 speed;
45 u32 min_speed;
46 };
47
i2c_acpi_fill_info(struct acpi_resource * ares,void * data)48 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
49 {
50 struct i2c_acpi_lookup *lookup = data;
51 struct i2c_board_info *info = lookup->info;
52 struct acpi_resource_i2c_serialbus *sb;
53 acpi_status status;
54
55 if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
56 return 1;
57
58 sb = &ares->data.i2c_serial_bus;
59 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
60 return 1;
61
62 if (lookup->index != -1 && lookup->n++ != lookup->index)
63 return 1;
64
65 status = acpi_get_handle(lookup->device_handle,
66 sb->resource_source.string_ptr,
67 &lookup->adapter_handle);
68 if (!ACPI_SUCCESS(status))
69 return 1;
70
71 info->addr = sb->slave_address;
72 lookup->speed = sb->connection_speed;
73 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
74 info->flags |= I2C_CLIENT_TEN;
75
76 return 1;
77 }
78
79 static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
80 /*
81 * ACPI video acpi_devices, which are handled by the acpi-video driver
82 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
83 */
84 { ACPI_VIDEO_HID, 0 },
85 {}
86 };
87
i2c_acpi_do_lookup(struct acpi_device * adev,struct i2c_acpi_lookup * lookup)88 static int i2c_acpi_do_lookup(struct acpi_device *adev,
89 struct i2c_acpi_lookup *lookup)
90 {
91 struct i2c_board_info *info = lookup->info;
92 struct list_head resource_list;
93 int ret;
94
95 if (acpi_bus_get_status(adev) || !adev->status.present ||
96 acpi_device_enumerated(adev))
97 return -EINVAL;
98
99 if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
100 return -ENODEV;
101
102 memset(info, 0, sizeof(*info));
103 lookup->device_handle = acpi_device_handle(adev);
104
105 /* Look up for I2cSerialBus resource */
106 INIT_LIST_HEAD(&resource_list);
107 ret = acpi_dev_get_resources(adev, &resource_list,
108 i2c_acpi_fill_info, lookup);
109 acpi_dev_free_resource_list(&resource_list);
110
111 if (ret < 0 || !info->addr)
112 return -EINVAL;
113
114 return 0;
115 }
116
i2c_acpi_get_info(struct acpi_device * adev,struct i2c_board_info * info,struct i2c_adapter * adapter,acpi_handle * adapter_handle)117 static int i2c_acpi_get_info(struct acpi_device *adev,
118 struct i2c_board_info *info,
119 struct i2c_adapter *adapter,
120 acpi_handle *adapter_handle)
121 {
122 struct list_head resource_list;
123 struct resource_entry *entry;
124 struct i2c_acpi_lookup lookup;
125 int ret;
126
127 memset(&lookup, 0, sizeof(lookup));
128 lookup.info = info;
129 lookup.index = -1;
130
131 ret = i2c_acpi_do_lookup(adev, &lookup);
132 if (ret)
133 return ret;
134
135 if (adapter) {
136 /* The adapter must match the one in I2cSerialBus() connector */
137 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
138 return -ENODEV;
139 } else {
140 struct acpi_device *adapter_adev;
141
142 /* The adapter must be present */
143 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
144 return -ENODEV;
145 if (acpi_bus_get_status(adapter_adev) ||
146 !adapter_adev->status.present)
147 return -ENODEV;
148 }
149
150 info->fwnode = acpi_fwnode_handle(adev);
151 if (adapter_handle)
152 *adapter_handle = lookup.adapter_handle;
153
154 /* Then fill IRQ number if any */
155 INIT_LIST_HEAD(&resource_list);
156 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
157 if (ret < 0)
158 return -EINVAL;
159
160 resource_list_for_each_entry(entry, &resource_list) {
161 if (resource_type(entry->res) == IORESOURCE_IRQ) {
162 info->irq = entry->res->start;
163 break;
164 }
165 }
166
167 acpi_dev_free_resource_list(&resource_list);
168
169 acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
170 sizeof(info->type));
171
172 return 0;
173 }
174
i2c_acpi_register_device(struct i2c_adapter * adapter,struct acpi_device * adev,struct i2c_board_info * info)175 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
176 struct acpi_device *adev,
177 struct i2c_board_info *info)
178 {
179 adev->power.flags.ignore_parent = true;
180 acpi_device_set_enumerated(adev);
181
182 if (!i2c_new_device(adapter, info)) {
183 adev->power.flags.ignore_parent = false;
184 dev_err(&adapter->dev,
185 "failed to add I2C device %s from ACPI\n",
186 dev_name(&adev->dev));
187 }
188 }
189
i2c_acpi_add_device(acpi_handle handle,u32 level,void * data,void ** return_value)190 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
191 void *data, void **return_value)
192 {
193 struct i2c_adapter *adapter = data;
194 struct acpi_device *adev;
195 struct i2c_board_info info;
196
197 if (acpi_bus_get_device(handle, &adev))
198 return AE_OK;
199
200 if (i2c_acpi_get_info(adev, &info, adapter, NULL))
201 return AE_OK;
202
203 i2c_acpi_register_device(adapter, adev, &info);
204
205 return AE_OK;
206 }
207
208 #define I2C_ACPI_MAX_SCAN_DEPTH 32
209
210 /**
211 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
212 * @adap: pointer to adapter
213 *
214 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
215 * namespace. When a device is found it will be added to the Linux device
216 * model and bound to the corresponding ACPI handle.
217 */
i2c_acpi_register_devices(struct i2c_adapter * adap)218 void i2c_acpi_register_devices(struct i2c_adapter *adap)
219 {
220 acpi_status status;
221
222 if (!has_acpi_companion(&adap->dev))
223 return;
224
225 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
226 I2C_ACPI_MAX_SCAN_DEPTH,
227 i2c_acpi_add_device, NULL,
228 adap, NULL);
229 if (ACPI_FAILURE(status))
230 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
231 }
232
233 const struct acpi_device_id *
i2c_acpi_match_device(const struct acpi_device_id * matches,struct i2c_client * client)234 i2c_acpi_match_device(const struct acpi_device_id *matches,
235 struct i2c_client *client)
236 {
237 if (!(client && matches))
238 return NULL;
239
240 return acpi_match_device(matches, &client->dev);
241 }
242
i2c_acpi_lookup_speed(acpi_handle handle,u32 level,void * data,void ** return_value)243 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
244 void *data, void **return_value)
245 {
246 struct i2c_acpi_lookup *lookup = data;
247 struct acpi_device *adev;
248
249 if (acpi_bus_get_device(handle, &adev))
250 return AE_OK;
251
252 if (i2c_acpi_do_lookup(adev, lookup))
253 return AE_OK;
254
255 if (lookup->search_handle != lookup->adapter_handle)
256 return AE_OK;
257
258 if (lookup->speed <= lookup->min_speed)
259 lookup->min_speed = lookup->speed;
260
261 return AE_OK;
262 }
263
264 /**
265 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
266 * @dev: The device owning the bus
267 *
268 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
269 * devices connected to this bus and use the speed of slowest device.
270 *
271 * Returns the speed in Hz or zero
272 */
i2c_acpi_find_bus_speed(struct device * dev)273 u32 i2c_acpi_find_bus_speed(struct device *dev)
274 {
275 struct i2c_acpi_lookup lookup;
276 struct i2c_board_info dummy;
277 acpi_status status;
278
279 if (!has_acpi_companion(dev))
280 return 0;
281
282 memset(&lookup, 0, sizeof(lookup));
283 lookup.search_handle = ACPI_HANDLE(dev);
284 lookup.min_speed = UINT_MAX;
285 lookup.info = &dummy;
286 lookup.index = -1;
287
288 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
289 I2C_ACPI_MAX_SCAN_DEPTH,
290 i2c_acpi_lookup_speed, NULL,
291 &lookup, NULL);
292
293 if (ACPI_FAILURE(status)) {
294 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
295 return 0;
296 }
297
298 return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
299 }
300 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
301
i2c_acpi_find_match_adapter(struct device * dev,void * data)302 static int i2c_acpi_find_match_adapter(struct device *dev, void *data)
303 {
304 struct i2c_adapter *adapter = i2c_verify_adapter(dev);
305
306 if (!adapter)
307 return 0;
308
309 return ACPI_HANDLE(dev) == (acpi_handle)data;
310 }
311
i2c_acpi_find_match_device(struct device * dev,void * data)312 static int i2c_acpi_find_match_device(struct device *dev, void *data)
313 {
314 return ACPI_COMPANION(dev) == data;
315 }
316
i2c_acpi_find_adapter_by_handle(acpi_handle handle)317 static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
318 {
319 struct device *dev;
320
321 dev = bus_find_device(&i2c_bus_type, NULL, handle,
322 i2c_acpi_find_match_adapter);
323 return dev ? i2c_verify_adapter(dev) : NULL;
324 }
325
i2c_acpi_find_client_by_adev(struct acpi_device * adev)326 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
327 {
328 struct device *dev;
329
330 dev = bus_find_device(&i2c_bus_type, NULL, adev,
331 i2c_acpi_find_match_device);
332 return dev ? i2c_verify_client(dev) : NULL;
333 }
334
i2c_acpi_notify(struct notifier_block * nb,unsigned long value,void * arg)335 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
336 void *arg)
337 {
338 struct acpi_device *adev = arg;
339 struct i2c_board_info info;
340 acpi_handle adapter_handle;
341 struct i2c_adapter *adapter;
342 struct i2c_client *client;
343
344 switch (value) {
345 case ACPI_RECONFIG_DEVICE_ADD:
346 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
347 break;
348
349 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
350 if (!adapter)
351 break;
352
353 i2c_acpi_register_device(adapter, adev, &info);
354 break;
355 case ACPI_RECONFIG_DEVICE_REMOVE:
356 if (!acpi_device_enumerated(adev))
357 break;
358
359 client = i2c_acpi_find_client_by_adev(adev);
360 if (!client)
361 break;
362
363 i2c_unregister_device(client);
364 put_device(&client->dev);
365 break;
366 }
367
368 return NOTIFY_OK;
369 }
370
371 struct notifier_block i2c_acpi_notifier = {
372 .notifier_call = i2c_acpi_notify,
373 };
374
375 /**
376 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
377 * @dev: Device owning the ACPI resources to get the client from
378 * @index: Index of ACPI resource to get
379 * @info: describes the I2C device; note this is modified (addr gets set)
380 * Context: can sleep
381 *
382 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
383 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
384 * resources, in that case this function can be used to create an i2c-client
385 * for other I2cSerialBus resources in the Current Resource Settings table.
386 *
387 * Also see i2c_new_device, which this function calls to create the i2c-client.
388 *
389 * Returns a pointer to the new i2c-client, or NULL if the adapter is not found.
390 */
i2c_acpi_new_device(struct device * dev,int index,struct i2c_board_info * info)391 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
392 struct i2c_board_info *info)
393 {
394 struct i2c_acpi_lookup lookup;
395 struct i2c_adapter *adapter;
396 struct acpi_device *adev;
397 LIST_HEAD(resource_list);
398 int ret;
399
400 adev = ACPI_COMPANION(dev);
401 if (!adev)
402 return NULL;
403
404 memset(&lookup, 0, sizeof(lookup));
405 lookup.info = info;
406 lookup.device_handle = acpi_device_handle(adev);
407 lookup.index = index;
408
409 ret = acpi_dev_get_resources(adev, &resource_list,
410 i2c_acpi_fill_info, &lookup);
411 acpi_dev_free_resource_list(&resource_list);
412
413 if (ret < 0 || !info->addr)
414 return NULL;
415
416 adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
417 if (!adapter)
418 return NULL;
419
420 return i2c_new_device(adapter, info);
421 }
422 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
423
424 #ifdef CONFIG_ACPI_I2C_OPREGION
acpi_gsb_i2c_read_bytes(struct i2c_client * client,u8 cmd,u8 * data,u8 data_len)425 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
426 u8 cmd, u8 *data, u8 data_len)
427 {
428
429 struct i2c_msg msgs[2];
430 int ret;
431 u8 *buffer;
432
433 buffer = kzalloc(data_len, GFP_KERNEL);
434 if (!buffer)
435 return AE_NO_MEMORY;
436
437 msgs[0].addr = client->addr;
438 msgs[0].flags = client->flags;
439 msgs[0].len = 1;
440 msgs[0].buf = &cmd;
441
442 msgs[1].addr = client->addr;
443 msgs[1].flags = client->flags | I2C_M_RD;
444 msgs[1].len = data_len;
445 msgs[1].buf = buffer;
446
447 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
448 if (ret < 0) {
449 /* Getting a NACK is unfortunately normal with some DSTDs */
450 if (ret == -EREMOTEIO)
451 dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
452 data_len, client->addr, cmd, ret);
453 else
454 dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
455 data_len, client->addr, cmd, ret);
456 /* 2 transfers must have completed successfully */
457 } else if (ret == 2) {
458 memcpy(data, buffer, data_len);
459 ret = 0;
460 } else {
461 ret = -EIO;
462 }
463
464 kfree(buffer);
465 return ret;
466 }
467
acpi_gsb_i2c_write_bytes(struct i2c_client * client,u8 cmd,u8 * data,u8 data_len)468 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
469 u8 cmd, u8 *data, u8 data_len)
470 {
471
472 struct i2c_msg msgs[1];
473 u8 *buffer;
474 int ret = AE_OK;
475
476 buffer = kzalloc(data_len + 1, GFP_KERNEL);
477 if (!buffer)
478 return AE_NO_MEMORY;
479
480 buffer[0] = cmd;
481 memcpy(buffer + 1, data, data_len);
482
483 msgs[0].addr = client->addr;
484 msgs[0].flags = client->flags;
485 msgs[0].len = data_len + 1;
486 msgs[0].buf = buffer;
487
488 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
489
490 kfree(buffer);
491
492 if (ret < 0) {
493 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
494 return ret;
495 }
496
497 /* 1 transfer must have completed successfully */
498 return (ret == 1) ? 0 : -EIO;
499 }
500
501 static acpi_status
i2c_acpi_space_handler(u32 function,acpi_physical_address command,u32 bits,u64 * value64,void * handler_context,void * region_context)502 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
503 u32 bits, u64 *value64,
504 void *handler_context, void *region_context)
505 {
506 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
507 struct i2c_acpi_handler_data *data = handler_context;
508 struct acpi_connection_info *info = &data->info;
509 struct acpi_resource_i2c_serialbus *sb;
510 struct i2c_adapter *adapter = data->adapter;
511 struct i2c_client *client;
512 struct acpi_resource *ares;
513 u32 accessor_type = function >> 16;
514 u8 action = function & ACPI_IO_MASK;
515 acpi_status ret;
516 int status;
517
518 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
519 if (ACPI_FAILURE(ret))
520 return ret;
521
522 client = kzalloc(sizeof(*client), GFP_KERNEL);
523 if (!client) {
524 ret = AE_NO_MEMORY;
525 goto err;
526 }
527
528 if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
529 ret = AE_BAD_PARAMETER;
530 goto err;
531 }
532
533 sb = &ares->data.i2c_serial_bus;
534 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
535 ret = AE_BAD_PARAMETER;
536 goto err;
537 }
538
539 client->adapter = adapter;
540 client->addr = sb->slave_address;
541
542 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
543 client->flags |= I2C_CLIENT_TEN;
544
545 switch (accessor_type) {
546 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
547 if (action == ACPI_READ) {
548 status = i2c_smbus_read_byte(client);
549 if (status >= 0) {
550 gsb->bdata = status;
551 status = 0;
552 }
553 } else {
554 status = i2c_smbus_write_byte(client, gsb->bdata);
555 }
556 break;
557
558 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
559 if (action == ACPI_READ) {
560 status = i2c_smbus_read_byte_data(client, command);
561 if (status >= 0) {
562 gsb->bdata = status;
563 status = 0;
564 }
565 } else {
566 status = i2c_smbus_write_byte_data(client, command,
567 gsb->bdata);
568 }
569 break;
570
571 case ACPI_GSB_ACCESS_ATTRIB_WORD:
572 if (action == ACPI_READ) {
573 status = i2c_smbus_read_word_data(client, command);
574 if (status >= 0) {
575 gsb->wdata = status;
576 status = 0;
577 }
578 } else {
579 status = i2c_smbus_write_word_data(client, command,
580 gsb->wdata);
581 }
582 break;
583
584 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
585 if (action == ACPI_READ) {
586 status = i2c_smbus_read_block_data(client, command,
587 gsb->data);
588 if (status >= 0) {
589 gsb->len = status;
590 status = 0;
591 }
592 } else {
593 status = i2c_smbus_write_block_data(client, command,
594 gsb->len, gsb->data);
595 }
596 break;
597
598 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
599 if (action == ACPI_READ) {
600 status = acpi_gsb_i2c_read_bytes(client, command,
601 gsb->data, info->access_length);
602 } else {
603 status = acpi_gsb_i2c_write_bytes(client, command,
604 gsb->data, info->access_length);
605 }
606 break;
607
608 default:
609 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
610 accessor_type, client->addr);
611 ret = AE_BAD_PARAMETER;
612 goto err;
613 }
614
615 gsb->status = status;
616
617 err:
618 kfree(client);
619 ACPI_FREE(ares);
620 return ret;
621 }
622
623
i2c_acpi_install_space_handler(struct i2c_adapter * adapter)624 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
625 {
626 acpi_handle handle;
627 struct i2c_acpi_handler_data *data;
628 acpi_status status;
629
630 if (!adapter->dev.parent)
631 return -ENODEV;
632
633 handle = ACPI_HANDLE(adapter->dev.parent);
634
635 if (!handle)
636 return -ENODEV;
637
638 data = kzalloc(sizeof(struct i2c_acpi_handler_data),
639 GFP_KERNEL);
640 if (!data)
641 return -ENOMEM;
642
643 data->adapter = adapter;
644 status = acpi_bus_attach_private_data(handle, (void *)data);
645 if (ACPI_FAILURE(status)) {
646 kfree(data);
647 return -ENOMEM;
648 }
649
650 status = acpi_install_address_space_handler(handle,
651 ACPI_ADR_SPACE_GSBUS,
652 &i2c_acpi_space_handler,
653 NULL,
654 data);
655 if (ACPI_FAILURE(status)) {
656 dev_err(&adapter->dev, "Error installing i2c space handler\n");
657 acpi_bus_detach_private_data(handle);
658 kfree(data);
659 return -ENOMEM;
660 }
661
662 acpi_walk_dep_device_list(handle);
663 return 0;
664 }
665
i2c_acpi_remove_space_handler(struct i2c_adapter * adapter)666 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
667 {
668 acpi_handle handle;
669 struct i2c_acpi_handler_data *data;
670 acpi_status status;
671
672 if (!adapter->dev.parent)
673 return;
674
675 handle = ACPI_HANDLE(adapter->dev.parent);
676
677 if (!handle)
678 return;
679
680 acpi_remove_address_space_handler(handle,
681 ACPI_ADR_SPACE_GSBUS,
682 &i2c_acpi_space_handler);
683
684 status = acpi_bus_get_private_data(handle, (void **)&data);
685 if (ACPI_SUCCESS(status))
686 kfree(data);
687
688 acpi_bus_detach_private_data(handle);
689 }
690 #endif /* CONFIG_ACPI_I2C_OPREGION */
691
