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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Linux I2C core ACPI support code
4 *
5 * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
6 */
7
8#include <linux/acpi.h>
9#include <linux/device.h>
10#include <linux/err.h>
11#include <linux/i2c.h>
12#include <linux/list.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15
16#include "i2c-core.h"
17
18struct i2c_acpi_handler_data {
19 struct acpi_connection_info info;
20 struct i2c_adapter *adapter;
21};
22
23struct gsb_buffer {
24 u8 status;
25 u8 len;
26 union {
27 u16 wdata;
28 u8 bdata;
29 u8 data[0];
30 };
31} __packed;
32
33struct i2c_acpi_lookup {
34 struct i2c_board_info *info;
35 acpi_handle adapter_handle;
36 acpi_handle device_handle;
37 acpi_handle search_handle;
38 int n;
39 int index;
40 u32 speed;
41 u32 min_speed;
42 u32 force_speed;
43};
44
45/**
46 * i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches
47 * @ares: ACPI resource
48 * @i2c: Pointer to I2cSerialBus resource will be returned here
49 *
50 * Checks if the given ACPI resource is of type I2cSerialBus.
51 * In this case, returns a pointer to it to the caller.
52 *
53 * Returns true if resource type is of I2cSerialBus, otherwise false.
54 */
55bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
56 struct acpi_resource_i2c_serialbus **i2c)
57{
58 struct acpi_resource_i2c_serialbus *sb;
59
60 if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
61 return false;
62
63 sb = &ares->data.i2c_serial_bus;
64 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
65 return false;
66
67 *i2c = sb;
68 return true;
69}
70EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
71
72static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
73{
74 struct i2c_acpi_lookup *lookup = data;
75 struct i2c_board_info *info = lookup->info;
76 struct acpi_resource_i2c_serialbus *sb;
77 acpi_status status;
78
79 if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb))
80 return 1;
81
82 if (lookup->index != -1 && lookup->n++ != lookup->index)
83 return 1;
84
85 status = acpi_get_handle(lookup->device_handle,
86 sb->resource_source.string_ptr,
87 &lookup->adapter_handle);
88 if (ACPI_FAILURE(status))
89 return 1;
90
91 info->addr = sb->slave_address;
92 lookup->speed = sb->connection_speed;
93 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
94 info->flags |= I2C_CLIENT_TEN;
95
96 return 1;
97}
98
99static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
100 /*
101 * ACPI video acpi_devices, which are handled by the acpi-video driver
102 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
103 */
104 { ACPI_VIDEO_HID, 0 },
105 {}
106};
107
108static int i2c_acpi_do_lookup(struct acpi_device *adev,
109 struct i2c_acpi_lookup *lookup)
110{
111 struct i2c_board_info *info = lookup->info;
112 struct list_head resource_list;
113 int ret;
114
115 if (acpi_bus_get_status(adev) || !adev->status.present)
116 return -EINVAL;
117
118 if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
119 return -ENODEV;
120
121 memset(info, 0, sizeof(*info));
122 lookup->device_handle = acpi_device_handle(adev);
123
124 /* Look up for I2cSerialBus resource */
125 INIT_LIST_HEAD(&resource_list);
126 ret = acpi_dev_get_resources(adev, &resource_list,
127 i2c_acpi_fill_info, lookup);
128 acpi_dev_free_resource_list(&resource_list);
129
130 if (ret < 0 || !info->addr)
131 return -EINVAL;
132
133 return 0;
134}
135
136static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
137{
138 int *irq = data;
139 struct resource r;
140
141 if (*irq <= 0 && acpi_dev_resource_interrupt(ares, 0, &r))
142 *irq = i2c_dev_irq_from_resources(&r, 1);
143
144 return 1; /* No need to add resource to the list */
145}
146
147/**
148 * i2c_acpi_get_irq - get device IRQ number from ACPI
149 * @client: Pointer to the I2C client device
150 *
151 * Find the IRQ number used by a specific client device.
152 *
153 * Return: The IRQ number or an error code.
154 */
155int i2c_acpi_get_irq(struct i2c_client *client)
156{
157 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
158 struct list_head resource_list;
159 int irq = -ENOENT;
160 int ret;
161
162 INIT_LIST_HEAD(&resource_list);
163
164 ret = acpi_dev_get_resources(adev, &resource_list,
165 i2c_acpi_add_resource, &irq);
166 if (ret < 0)
167 return ret;
168
169 acpi_dev_free_resource_list(&resource_list);
170
171 if (irq == -ENOENT)
172 irq = acpi_dev_gpio_irq_get(adev, 0);
173
174 return irq;
175}
176
177static int i2c_acpi_get_info(struct acpi_device *adev,
178 struct i2c_board_info *info,
179 struct i2c_adapter *adapter,
180 acpi_handle *adapter_handle)
181{
182 struct i2c_acpi_lookup lookup;
183 int ret;
184
185 memset(&lookup, 0, sizeof(lookup));
186 lookup.info = info;
187 lookup.index = -1;
188
189 if (acpi_device_enumerated(adev))
190 return -EINVAL;
191
192 ret = i2c_acpi_do_lookup(adev, &lookup);
193 if (ret)
194 return ret;
195
196 if (adapter) {
197 /* The adapter must match the one in I2cSerialBus() connector */
198 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
199 return -ENODEV;
200 } else {
201 struct acpi_device *adapter_adev;
202
203 /* The adapter must be present */
204 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
205 return -ENODEV;
206 if (acpi_bus_get_status(adapter_adev) ||
207 !adapter_adev->status.present)
208 return -ENODEV;
209 }
210
211 info->fwnode = acpi_fwnode_handle(adev);
212 if (adapter_handle)
213 *adapter_handle = lookup.adapter_handle;
214
215 acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
216 sizeof(info->type));
217
218 return 0;
219}
220
221static void i2c_acpi_register_device(struct i2c_adapter *adapter,
222 struct acpi_device *adev,
223 struct i2c_board_info *info)
224{
225 adev->power.flags.ignore_parent = true;
226 acpi_device_set_enumerated(adev);
227
228 if (IS_ERR(i2c_new_client_device(adapter, info))) {
229 adev->power.flags.ignore_parent = false;
230 dev_err(&adapter->dev,
231 "failed to add I2C device %s from ACPI\n",
232 dev_name(&adev->dev));
233 }
234}
235
236static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
237 void *data, void **return_value)
238{
239 struct i2c_adapter *adapter = data;
240 struct acpi_device *adev;
241 struct i2c_board_info info;
242
243 if (acpi_bus_get_device(handle, &adev))
244 return AE_OK;
245
246 if (i2c_acpi_get_info(adev, &info, adapter, NULL))
247 return AE_OK;
248
249 i2c_acpi_register_device(adapter, adev, &info);
250
251 return AE_OK;
252}
253
254#define I2C_ACPI_MAX_SCAN_DEPTH 32
255
256/**
257 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
258 * @adap: pointer to adapter
259 *
260 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
261 * namespace. When a device is found it will be added to the Linux device
262 * model and bound to the corresponding ACPI handle.
263 */
264void i2c_acpi_register_devices(struct i2c_adapter *adap)
265{
266 acpi_status status;
267
268 if (!has_acpi_companion(&adap->dev))
269 return;
270
271 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
272 I2C_ACPI_MAX_SCAN_DEPTH,
273 i2c_acpi_add_device, NULL,
274 adap, NULL);
275 if (ACPI_FAILURE(status))
276 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
277}
278
279static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
280 /*
281 * These Silead touchscreen controllers only work at 400KHz, for
282 * some reason they do not work at 100KHz. On some devices the ACPI
283 * tables list another device at their bus as only being capable
284 * of 100KHz, testing has shown that these other devices work fine
285 * at 400KHz (as can be expected of any recent i2c hw) so we force
286 * the speed of the bus to 400 KHz if a Silead device is present.
287 */
288 { "MSSL1680", 0 },
289 {}
290};
291
292static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
293 void *data, void **return_value)
294{
295 struct i2c_acpi_lookup *lookup = data;
296 struct acpi_device *adev;
297
298 if (acpi_bus_get_device(handle, &adev))
299 return AE_OK;
300
301 if (i2c_acpi_do_lookup(adev, lookup))
302 return AE_OK;
303
304 if (lookup->search_handle != lookup->adapter_handle)
305 return AE_OK;
306
307 if (lookup->speed <= lookup->min_speed)
308 lookup->min_speed = lookup->speed;
309
310 if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
311 lookup->force_speed = I2C_MAX_FAST_MODE_FREQ;
312
313 return AE_OK;
314}
315
316/**
317 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
318 * @dev: The device owning the bus
319 *
320 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
321 * devices connected to this bus and use the speed of slowest device.
322 *
323 * Returns the speed in Hz or zero
324 */
325u32 i2c_acpi_find_bus_speed(struct device *dev)
326{
327 struct i2c_acpi_lookup lookup;
328 struct i2c_board_info dummy;
329 acpi_status status;
330
331 if (!has_acpi_companion(dev))
332 return 0;
333
334 memset(&lookup, 0, sizeof(lookup));
335 lookup.search_handle = ACPI_HANDLE(dev);
336 lookup.min_speed = UINT_MAX;
337 lookup.info = &dummy;
338 lookup.index = -1;
339
340 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
341 I2C_ACPI_MAX_SCAN_DEPTH,
342 i2c_acpi_lookup_speed, NULL,
343 &lookup, NULL);
344
345 if (ACPI_FAILURE(status)) {
346 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
347 return 0;
348 }
349
350 if (lookup.force_speed) {
351 if (lookup.force_speed != lookup.min_speed)
352 dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
353 lookup.min_speed, lookup.force_speed);
354 return lookup.force_speed;
355 } else if (lookup.min_speed != UINT_MAX) {
356 return lookup.min_speed;
357 } else {
358 return 0;
359 }
360}
361EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
362
363static int i2c_acpi_find_match_adapter(struct device *dev, const void *data)
364{
365 struct i2c_adapter *adapter = i2c_verify_adapter(dev);
366
367 if (!adapter)
368 return 0;
369
370 return ACPI_HANDLE(dev) == (acpi_handle)data;
371}
372
373struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
374{
375 struct device *dev;
376
377 dev = bus_find_device(&i2c_bus_type, NULL, handle,
378 i2c_acpi_find_match_adapter);
379
380 return dev ? i2c_verify_adapter(dev) : NULL;
381}
382EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
383
384static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
385{
386 struct device *dev;
387 struct i2c_client *client;
388
389 dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
390 if (!dev)
391 return NULL;
392
393 client = i2c_verify_client(dev);
394 if (!client)
395 put_device(dev);
396
397 return client;
398}
399
400static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
401 void *arg)
402{
403 struct acpi_device *adev = arg;
404 struct i2c_board_info info;
405 acpi_handle adapter_handle;
406 struct i2c_adapter *adapter;
407 struct i2c_client *client;
408
409 switch (value) {
410 case ACPI_RECONFIG_DEVICE_ADD:
411 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
412 break;
413
414 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
415 if (!adapter)
416 break;
417
418 i2c_acpi_register_device(adapter, adev, &info);
419 break;
420 case ACPI_RECONFIG_DEVICE_REMOVE:
421 if (!acpi_device_enumerated(adev))
422 break;
423
424 client = i2c_acpi_find_client_by_adev(adev);
425 if (!client)
426 break;
427
428 i2c_unregister_device(client);
429 put_device(&client->dev);
430 break;
431 }
432
433 return NOTIFY_OK;
434}
435
436struct notifier_block i2c_acpi_notifier = {
437 .notifier_call = i2c_acpi_notify,
438};
439
440/**
441 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
442 * @dev: Device owning the ACPI resources to get the client from
443 * @index: Index of ACPI resource to get
444 * @info: describes the I2C device; note this is modified (addr gets set)
445 * Context: can sleep
446 *
447 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
448 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
449 * resources, in that case this function can be used to create an i2c-client
450 * for other I2cSerialBus resources in the Current Resource Settings table.
451 *
452 * Also see i2c_new_client_device, which this function calls to create the
453 * i2c-client.
454 *
455 * Returns a pointer to the new i2c-client, or error pointer in case of failure.
456 * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
457 */
458struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
459 struct i2c_board_info *info)
460{
461 struct acpi_device *adev = ACPI_COMPANION(dev);
462 struct i2c_acpi_lookup lookup;
463 struct i2c_adapter *adapter;
464 LIST_HEAD(resource_list);
465 int ret;
466
467 memset(&lookup, 0, sizeof(lookup));
468 lookup.info = info;
469 lookup.device_handle = acpi_device_handle(adev);
470 lookup.index = index;
471
472 ret = acpi_dev_get_resources(adev, &resource_list,
473 i2c_acpi_fill_info, &lookup);
474 if (ret < 0)
475 return ERR_PTR(ret);
476
477 acpi_dev_free_resource_list(&resource_list);
478
479 if (!info->addr)
480 return ERR_PTR(-EADDRNOTAVAIL);
481
482 adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
483 if (!adapter)
484 return ERR_PTR(-EPROBE_DEFER);
485
486 return i2c_new_client_device(adapter, info);
487}
488EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
489
490#ifdef CONFIG_ACPI_I2C_OPREGION
491static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
492 u8 cmd, u8 *data, u8 data_len)
493{
494
495 struct i2c_msg msgs[2];
496 int ret;
497 u8 *buffer;
498
499 buffer = kzalloc(data_len, GFP_KERNEL);
500 if (!buffer)
501 return AE_NO_MEMORY;
502
503 msgs[0].addr = client->addr;
504 msgs[0].flags = client->flags;
505 msgs[0].len = 1;
506 msgs[0].buf = &cmd;
507
508 msgs[1].addr = client->addr;
509 msgs[1].flags = client->flags | I2C_M_RD;
510 msgs[1].len = data_len;
511 msgs[1].buf = buffer;
512
513 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
514 if (ret < 0) {
515 /* Getting a NACK is unfortunately normal with some DSTDs */
516 if (ret == -EREMOTEIO)
517 dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
518 data_len, client->addr, cmd, ret);
519 else
520 dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
521 data_len, client->addr, cmd, ret);
522 /* 2 transfers must have completed successfully */
523 } else if (ret == 2) {
524 memcpy(data, buffer, data_len);
525 ret = 0;
526 } else {
527 ret = -EIO;
528 }
529
530 kfree(buffer);
531 return ret;
532}
533
534static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
535 u8 cmd, u8 *data, u8 data_len)
536{
537
538 struct i2c_msg msgs[1];
539 u8 *buffer;
540 int ret = AE_OK;
541
542 buffer = kzalloc(data_len + 1, GFP_KERNEL);
543 if (!buffer)
544 return AE_NO_MEMORY;
545
546 buffer[0] = cmd;
547 memcpy(buffer + 1, data, data_len);
548
549 msgs[0].addr = client->addr;
550 msgs[0].flags = client->flags;
551 msgs[0].len = data_len + 1;
552 msgs[0].buf = buffer;
553
554 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
555
556 kfree(buffer);
557
558 if (ret < 0) {
559 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
560 return ret;
561 }
562
563 /* 1 transfer must have completed successfully */
564 return (ret == 1) ? 0 : -EIO;
565}
566
567static acpi_status
568i2c_acpi_space_handler(u32 function, acpi_physical_address command,
569 u32 bits, u64 *value64,
570 void *handler_context, void *region_context)
571{
572 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
573 struct i2c_acpi_handler_data *data = handler_context;
574 struct acpi_connection_info *info = &data->info;
575 struct acpi_resource_i2c_serialbus *sb;
576 struct i2c_adapter *adapter = data->adapter;
577 struct i2c_client *client;
578 struct acpi_resource *ares;
579 u32 accessor_type = function >> 16;
580 u8 action = function & ACPI_IO_MASK;
581 acpi_status ret;
582 int status;
583
584 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
585 if (ACPI_FAILURE(ret))
586 return ret;
587
588 client = kzalloc(sizeof(*client), GFP_KERNEL);
589 if (!client) {
590 ret = AE_NO_MEMORY;
591 goto err;
592 }
593
594 if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
595 ret = AE_BAD_PARAMETER;
596 goto err;
597 }
598
599 client->adapter = adapter;
600 client->addr = sb->slave_address;
601
602 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
603 client->flags |= I2C_CLIENT_TEN;
604
605 switch (accessor_type) {
606 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
607 if (action == ACPI_READ) {
608 status = i2c_smbus_read_byte(client);
609 if (status >= 0) {
610 gsb->bdata = status;
611 status = 0;
612 }
613 } else {
614 status = i2c_smbus_write_byte(client, gsb->bdata);
615 }
616 break;
617
618 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
619 if (action == ACPI_READ) {
620 status = i2c_smbus_read_byte_data(client, command);
621 if (status >= 0) {
622 gsb->bdata = status;
623 status = 0;
624 }
625 } else {
626 status = i2c_smbus_write_byte_data(client, command,
627 gsb->bdata);
628 }
629 break;
630
631 case ACPI_GSB_ACCESS_ATTRIB_WORD:
632 if (action == ACPI_READ) {
633 status = i2c_smbus_read_word_data(client, command);
634 if (status >= 0) {
635 gsb->wdata = status;
636 status = 0;
637 }
638 } else {
639 status = i2c_smbus_write_word_data(client, command,
640 gsb->wdata);
641 }
642 break;
643
644 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
645 if (action == ACPI_READ) {
646 status = i2c_smbus_read_block_data(client, command,
647 gsb->data);
648 if (status >= 0) {
649 gsb->len = status;
650 status = 0;
651 }
652 } else {
653 status = i2c_smbus_write_block_data(client, command,
654 gsb->len, gsb->data);
655 }
656 break;
657
658 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
659 if (action == ACPI_READ) {
660 status = acpi_gsb_i2c_read_bytes(client, command,
661 gsb->data, info->access_length);
662 } else {
663 status = acpi_gsb_i2c_write_bytes(client, command,
664 gsb->data, info->access_length);
665 }
666 break;
667
668 default:
669 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
670 accessor_type, client->addr);
671 ret = AE_BAD_PARAMETER;
672 goto err;
673 }
674
675 gsb->status = status;
676
677 err:
678 kfree(client);
679 ACPI_FREE(ares);
680 return ret;
681}
682
683
684int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
685{
686 acpi_handle handle;
687 struct i2c_acpi_handler_data *data;
688 acpi_status status;
689
690 if (!adapter->dev.parent)
691 return -ENODEV;
692
693 handle = ACPI_HANDLE(adapter->dev.parent);
694
695 if (!handle)
696 return -ENODEV;
697
698 data = kzalloc(sizeof(struct i2c_acpi_handler_data),
699 GFP_KERNEL);
700 if (!data)
701 return -ENOMEM;
702
703 data->adapter = adapter;
704 status = acpi_bus_attach_private_data(handle, (void *)data);
705 if (ACPI_FAILURE(status)) {
706 kfree(data);
707 return -ENOMEM;
708 }
709
710 status = acpi_install_address_space_handler(handle,
711 ACPI_ADR_SPACE_GSBUS,
712 &i2c_acpi_space_handler,
713 NULL,
714 data);
715 if (ACPI_FAILURE(status)) {
716 dev_err(&adapter->dev, "Error installing i2c space handler\n");
717 acpi_bus_detach_private_data(handle);
718 kfree(data);
719 return -ENOMEM;
720 }
721
722 acpi_walk_dep_device_list(handle);
723 return 0;
724}
725
726void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
727{
728 acpi_handle handle;
729 struct i2c_acpi_handler_data *data;
730 acpi_status status;
731
732 if (!adapter->dev.parent)
733 return;
734
735 handle = ACPI_HANDLE(adapter->dev.parent);
736
737 if (!handle)
738 return;
739
740 acpi_remove_address_space_handler(handle,
741 ACPI_ADR_SPACE_GSBUS,
742 &i2c_acpi_space_handler);
743
744 status = acpi_bus_get_private_data(handle, (void **)&data);
745 if (ACPI_SUCCESS(status))
746 kfree(data);
747
748 acpi_bus_detach_private_data(handle);
749}
750#endif /* CONFIG_ACPI_I2C_OPREGION */
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
22struct i2c_acpi_handler_data {
23 struct acpi_connection_info info;
24 struct i2c_adapter *adapter;
25};
26
27struct gsb_buffer {
28 u8 status;
29 u8 len;
30 union {
31 u16 wdata;
32 u8 bdata;
33 u8 data[0];
34 };
35} __packed;
36
37struct 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
48static 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
79static 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
88static 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
117static 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
175static 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
190static 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 */
218void 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
233const struct acpi_device_id *
234i2c_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
243static 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 */
273u32 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}
300EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
301
302static 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
312static int i2c_acpi_find_match_device(struct device *dev, void *data)
313{
314 return ACPI_COMPANION(dev) == data;
315}
316
317static 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
326static 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
335static 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
371struct 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 */
391struct 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}
422EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
423
424#ifdef CONFIG_ACPI_I2C_OPREGION
425static 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 } else {
457 memcpy(data, buffer, data_len);
458 }
459
460 kfree(buffer);
461 return ret;
462}
463
464static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
465 u8 cmd, u8 *data, u8 data_len)
466{
467
468 struct i2c_msg msgs[1];
469 u8 *buffer;
470 int ret = AE_OK;
471
472 buffer = kzalloc(data_len + 1, GFP_KERNEL);
473 if (!buffer)
474 return AE_NO_MEMORY;
475
476 buffer[0] = cmd;
477 memcpy(buffer + 1, data, data_len);
478
479 msgs[0].addr = client->addr;
480 msgs[0].flags = client->flags;
481 msgs[0].len = data_len + 1;
482 msgs[0].buf = buffer;
483
484 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
485 if (ret < 0)
486 dev_err(&client->adapter->dev, "i2c write failed\n");
487
488 kfree(buffer);
489 return ret;
490}
491
492static acpi_status
493i2c_acpi_space_handler(u32 function, acpi_physical_address command,
494 u32 bits, u64 *value64,
495 void *handler_context, void *region_context)
496{
497 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
498 struct i2c_acpi_handler_data *data = handler_context;
499 struct acpi_connection_info *info = &data->info;
500 struct acpi_resource_i2c_serialbus *sb;
501 struct i2c_adapter *adapter = data->adapter;
502 struct i2c_client *client;
503 struct acpi_resource *ares;
504 u32 accessor_type = function >> 16;
505 u8 action = function & ACPI_IO_MASK;
506 acpi_status ret;
507 int status;
508
509 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
510 if (ACPI_FAILURE(ret))
511 return ret;
512
513 client = kzalloc(sizeof(*client), GFP_KERNEL);
514 if (!client) {
515 ret = AE_NO_MEMORY;
516 goto err;
517 }
518
519 if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
520 ret = AE_BAD_PARAMETER;
521 goto err;
522 }
523
524 sb = &ares->data.i2c_serial_bus;
525 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
526 ret = AE_BAD_PARAMETER;
527 goto err;
528 }
529
530 client->adapter = adapter;
531 client->addr = sb->slave_address;
532
533 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
534 client->flags |= I2C_CLIENT_TEN;
535
536 switch (accessor_type) {
537 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
538 if (action == ACPI_READ) {
539 status = i2c_smbus_read_byte(client);
540 if (status >= 0) {
541 gsb->bdata = status;
542 status = 0;
543 }
544 } else {
545 status = i2c_smbus_write_byte(client, gsb->bdata);
546 }
547 break;
548
549 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
550 if (action == ACPI_READ) {
551 status = i2c_smbus_read_byte_data(client, command);
552 if (status >= 0) {
553 gsb->bdata = status;
554 status = 0;
555 }
556 } else {
557 status = i2c_smbus_write_byte_data(client, command,
558 gsb->bdata);
559 }
560 break;
561
562 case ACPI_GSB_ACCESS_ATTRIB_WORD:
563 if (action == ACPI_READ) {
564 status = i2c_smbus_read_word_data(client, command);
565 if (status >= 0) {
566 gsb->wdata = status;
567 status = 0;
568 }
569 } else {
570 status = i2c_smbus_write_word_data(client, command,
571 gsb->wdata);
572 }
573 break;
574
575 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
576 if (action == ACPI_READ) {
577 status = i2c_smbus_read_block_data(client, command,
578 gsb->data);
579 if (status >= 0) {
580 gsb->len = status;
581 status = 0;
582 }
583 } else {
584 status = i2c_smbus_write_block_data(client, command,
585 gsb->len, gsb->data);
586 }
587 break;
588
589 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
590 if (action == ACPI_READ) {
591 status = acpi_gsb_i2c_read_bytes(client, command,
592 gsb->data, info->access_length);
593 if (status > 0)
594 status = 0;
595 } else {
596 status = acpi_gsb_i2c_write_bytes(client, command,
597 gsb->data, info->access_length);
598 }
599 break;
600
601 default:
602 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
603 accessor_type, client->addr);
604 ret = AE_BAD_PARAMETER;
605 goto err;
606 }
607
608 gsb->status = status;
609
610 err:
611 kfree(client);
612 ACPI_FREE(ares);
613 return ret;
614}
615
616
617int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
618{
619 acpi_handle handle;
620 struct i2c_acpi_handler_data *data;
621 acpi_status status;
622
623 if (!adapter->dev.parent)
624 return -ENODEV;
625
626 handle = ACPI_HANDLE(adapter->dev.parent);
627
628 if (!handle)
629 return -ENODEV;
630
631 data = kzalloc(sizeof(struct i2c_acpi_handler_data),
632 GFP_KERNEL);
633 if (!data)
634 return -ENOMEM;
635
636 data->adapter = adapter;
637 status = acpi_bus_attach_private_data(handle, (void *)data);
638 if (ACPI_FAILURE(status)) {
639 kfree(data);
640 return -ENOMEM;
641 }
642
643 status = acpi_install_address_space_handler(handle,
644 ACPI_ADR_SPACE_GSBUS,
645 &i2c_acpi_space_handler,
646 NULL,
647 data);
648 if (ACPI_FAILURE(status)) {
649 dev_err(&adapter->dev, "Error installing i2c space handler\n");
650 acpi_bus_detach_private_data(handle);
651 kfree(data);
652 return -ENOMEM;
653 }
654
655 acpi_walk_dep_device_list(handle);
656 return 0;
657}
658
659void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
660{
661 acpi_handle handle;
662 struct i2c_acpi_handler_data *data;
663 acpi_status status;
664
665 if (!adapter->dev.parent)
666 return;
667
668 handle = ACPI_HANDLE(adapter->dev.parent);
669
670 if (!handle)
671 return;
672
673 acpi_remove_address_space_handler(handle,
674 ACPI_ADR_SPACE_GSBUS,
675 &i2c_acpi_space_handler);
676
677 status = acpi_bus_get_private_data(handle, (void **)&data);
678 if (ACPI_SUCCESS(status))
679 kfree(data);
680
681 acpi_bus_detach_private_data(handle);
682}
683#endif /* CONFIG_ACPI_I2C_OPREGION */