Loading...
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 DECLARE_FLEX_ARRAY(u8, data);
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_resource_count(struct acpi_resource *ares, void *data)
73{
74 struct acpi_resource_i2c_serialbus *sb;
75 int *count = data;
76
77 if (i2c_acpi_get_i2c_resource(ares, &sb))
78 *count = *count + 1;
79
80 return 1;
81}
82
83/**
84 * i2c_acpi_client_count - Count the number of I2cSerialBus resources
85 * @adev: ACPI device
86 *
87 * Returns the number of I2cSerialBus resources in the ACPI-device's
88 * resource-list; or a negative error code.
89 */
90int i2c_acpi_client_count(struct acpi_device *adev)
91{
92 int ret, count = 0;
93 LIST_HEAD(r);
94
95 ret = acpi_dev_get_resources(adev, &r, i2c_acpi_resource_count, &count);
96 if (ret < 0)
97 return ret;
98
99 acpi_dev_free_resource_list(&r);
100 return count;
101}
102EXPORT_SYMBOL_GPL(i2c_acpi_client_count);
103
104static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
105{
106 struct i2c_acpi_lookup *lookup = data;
107 struct i2c_board_info *info = lookup->info;
108 struct acpi_resource_i2c_serialbus *sb;
109 acpi_status status;
110
111 if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb))
112 return 1;
113
114 if (lookup->index != -1 && lookup->n++ != lookup->index)
115 return 1;
116
117 status = acpi_get_handle(lookup->device_handle,
118 sb->resource_source.string_ptr,
119 &lookup->adapter_handle);
120 if (ACPI_FAILURE(status))
121 return 1;
122
123 info->addr = sb->slave_address;
124 lookup->speed = sb->connection_speed;
125 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
126 info->flags |= I2C_CLIENT_TEN;
127
128 return 1;
129}
130
131static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
132 /*
133 * ACPI video acpi_devices, which are handled by the acpi-video driver
134 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
135 */
136 { ACPI_VIDEO_HID, 0 },
137 {}
138};
139
140struct i2c_acpi_irq_context {
141 int irq;
142 bool wake_capable;
143};
144
145static int i2c_acpi_do_lookup(struct acpi_device *adev,
146 struct i2c_acpi_lookup *lookup)
147{
148 struct i2c_board_info *info = lookup->info;
149 struct list_head resource_list;
150 int ret;
151
152 if (acpi_bus_get_status(adev))
153 return -EINVAL;
154
155 if (!acpi_dev_ready_for_enumeration(adev))
156 return -ENODEV;
157
158 if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
159 return -ENODEV;
160
161 memset(info, 0, sizeof(*info));
162 lookup->device_handle = acpi_device_handle(adev);
163
164 /* Look up for I2cSerialBus resource */
165 INIT_LIST_HEAD(&resource_list);
166 ret = acpi_dev_get_resources(adev, &resource_list,
167 i2c_acpi_fill_info, lookup);
168 acpi_dev_free_resource_list(&resource_list);
169
170 if (ret < 0 || !info->addr)
171 return -EINVAL;
172
173 return 0;
174}
175
176static int i2c_acpi_add_irq_resource(struct acpi_resource *ares, void *data)
177{
178 struct i2c_acpi_irq_context *irq_ctx = data;
179 struct resource r;
180
181 if (irq_ctx->irq > 0)
182 return 1;
183
184 if (!acpi_dev_resource_interrupt(ares, 0, &r))
185 return 1;
186
187 irq_ctx->irq = i2c_dev_irq_from_resources(&r, 1);
188 irq_ctx->wake_capable = r.flags & IORESOURCE_IRQ_WAKECAPABLE;
189
190 return 1; /* No need to add resource to the list */
191}
192
193/**
194 * i2c_acpi_get_irq - get device IRQ number from ACPI
195 * @client: Pointer to the I2C client device
196 * @wake_capable: Set to true if the IRQ is wake capable
197 *
198 * Find the IRQ number used by a specific client device.
199 *
200 * Return: The IRQ number or an error code.
201 */
202int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable)
203{
204 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
205 struct list_head resource_list;
206 struct i2c_acpi_irq_context irq_ctx = {
207 .irq = -ENOENT,
208 };
209 int ret;
210
211 INIT_LIST_HEAD(&resource_list);
212
213 ret = acpi_dev_get_resources(adev, &resource_list,
214 i2c_acpi_add_irq_resource, &irq_ctx);
215 if (ret < 0)
216 return ret;
217
218 acpi_dev_free_resource_list(&resource_list);
219
220 if (irq_ctx.irq == -ENOENT)
221 irq_ctx.irq = acpi_dev_gpio_irq_wake_get(adev, 0, &irq_ctx.wake_capable);
222
223 if (irq_ctx.irq < 0)
224 return irq_ctx.irq;
225
226 if (wake_capable)
227 *wake_capable = irq_ctx.wake_capable;
228
229 return irq_ctx.irq;
230}
231
232static int i2c_acpi_get_info(struct acpi_device *adev,
233 struct i2c_board_info *info,
234 struct i2c_adapter *adapter,
235 acpi_handle *adapter_handle)
236{
237 struct i2c_acpi_lookup lookup;
238 int ret;
239
240 memset(&lookup, 0, sizeof(lookup));
241 lookup.info = info;
242 lookup.index = -1;
243
244 if (acpi_device_enumerated(adev))
245 return -EINVAL;
246
247 ret = i2c_acpi_do_lookup(adev, &lookup);
248 if (ret)
249 return ret;
250
251 if (adapter) {
252 /* The adapter must match the one in I2cSerialBus() connector */
253 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
254 return -ENODEV;
255 } else {
256 struct acpi_device *adapter_adev;
257
258 /* The adapter must be present */
259 adapter_adev = acpi_fetch_acpi_dev(lookup.adapter_handle);
260 if (!adapter_adev)
261 return -ENODEV;
262 if (acpi_bus_get_status(adapter_adev) ||
263 !adapter_adev->status.present)
264 return -ENODEV;
265 }
266
267 info->fwnode = acpi_fwnode_handle(adev);
268 if (adapter_handle)
269 *adapter_handle = lookup.adapter_handle;
270
271 acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
272 sizeof(info->type));
273
274 return 0;
275}
276
277static void i2c_acpi_register_device(struct i2c_adapter *adapter,
278 struct acpi_device *adev,
279 struct i2c_board_info *info)
280{
281 /*
282 * Skip registration on boards where the ACPI tables are
283 * known to contain bogus I2C devices.
284 */
285 if (acpi_quirk_skip_i2c_client_enumeration(adev))
286 return;
287
288 adev->power.flags.ignore_parent = true;
289 acpi_device_set_enumerated(adev);
290
291 if (IS_ERR(i2c_new_client_device(adapter, info)))
292 adev->power.flags.ignore_parent = false;
293}
294
295static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
296 void *data, void **return_value)
297{
298 struct i2c_adapter *adapter = data;
299 struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
300 struct i2c_board_info info;
301
302 if (!adev || i2c_acpi_get_info(adev, &info, adapter, NULL))
303 return AE_OK;
304
305 i2c_acpi_register_device(adapter, adev, &info);
306
307 return AE_OK;
308}
309
310#define I2C_ACPI_MAX_SCAN_DEPTH 32
311
312/**
313 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
314 * @adap: pointer to adapter
315 *
316 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
317 * namespace. When a device is found it will be added to the Linux device
318 * model and bound to the corresponding ACPI handle.
319 */
320void i2c_acpi_register_devices(struct i2c_adapter *adap)
321{
322 struct acpi_device *adev;
323 acpi_status status;
324
325 if (!has_acpi_companion(&adap->dev))
326 return;
327
328 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
329 I2C_ACPI_MAX_SCAN_DEPTH,
330 i2c_acpi_add_device, NULL,
331 adap, NULL);
332 if (ACPI_FAILURE(status))
333 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
334
335 if (!adap->dev.parent)
336 return;
337
338 adev = ACPI_COMPANION(adap->dev.parent);
339 if (!adev)
340 return;
341
342 acpi_dev_clear_dependencies(adev);
343}
344
345static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
346 /*
347 * These Silead touchscreen controllers only work at 400KHz, for
348 * some reason they do not work at 100KHz. On some devices the ACPI
349 * tables list another device at their bus as only being capable
350 * of 100KHz, testing has shown that these other devices work fine
351 * at 400KHz (as can be expected of any recent i2c hw) so we force
352 * the speed of the bus to 400 KHz if a Silead device is present.
353 */
354 { "MSSL1680", 0 },
355 {}
356};
357
358static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
359 void *data, void **return_value)
360{
361 struct i2c_acpi_lookup *lookup = data;
362 struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
363
364 if (!adev || i2c_acpi_do_lookup(adev, lookup))
365 return AE_OK;
366
367 if (lookup->search_handle != lookup->adapter_handle)
368 return AE_OK;
369
370 if (lookup->speed <= lookup->min_speed)
371 lookup->min_speed = lookup->speed;
372
373 if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
374 lookup->force_speed = I2C_MAX_FAST_MODE_FREQ;
375
376 return AE_OK;
377}
378
379/**
380 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
381 * @dev: The device owning the bus
382 *
383 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
384 * devices connected to this bus and use the speed of slowest device.
385 *
386 * Returns the speed in Hz or zero
387 */
388u32 i2c_acpi_find_bus_speed(struct device *dev)
389{
390 struct i2c_acpi_lookup lookup;
391 struct i2c_board_info dummy;
392 acpi_status status;
393
394 if (!has_acpi_companion(dev))
395 return 0;
396
397 memset(&lookup, 0, sizeof(lookup));
398 lookup.search_handle = ACPI_HANDLE(dev);
399 lookup.min_speed = UINT_MAX;
400 lookup.info = &dummy;
401 lookup.index = -1;
402
403 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
404 I2C_ACPI_MAX_SCAN_DEPTH,
405 i2c_acpi_lookup_speed, NULL,
406 &lookup, NULL);
407
408 if (ACPI_FAILURE(status)) {
409 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
410 return 0;
411 }
412
413 if (lookup.force_speed) {
414 if (lookup.force_speed != lookup.min_speed)
415 dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
416 lookup.min_speed, lookup.force_speed);
417 return lookup.force_speed;
418 } else if (lookup.min_speed != UINT_MAX) {
419 return lookup.min_speed;
420 } else {
421 return 0;
422 }
423}
424EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
425
426struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
427{
428 struct i2c_adapter *adapter;
429 struct device *dev;
430
431 dev = bus_find_device(&i2c_bus_type, NULL, handle, device_match_acpi_handle);
432 if (!dev)
433 return NULL;
434
435 adapter = i2c_verify_adapter(dev);
436 if (!adapter)
437 put_device(dev);
438
439 return adapter;
440}
441EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
442
443static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
444{
445 return i2c_find_device_by_fwnode(acpi_fwnode_handle(adev));
446}
447
448static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
449 void *arg)
450{
451 struct acpi_device *adev = arg;
452 struct i2c_board_info info;
453 acpi_handle adapter_handle;
454 struct i2c_adapter *adapter;
455 struct i2c_client *client;
456
457 switch (value) {
458 case ACPI_RECONFIG_DEVICE_ADD:
459 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
460 break;
461
462 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
463 if (!adapter)
464 break;
465
466 i2c_acpi_register_device(adapter, adev, &info);
467 put_device(&adapter->dev);
468 break;
469 case ACPI_RECONFIG_DEVICE_REMOVE:
470 if (!acpi_device_enumerated(adev))
471 break;
472
473 client = i2c_acpi_find_client_by_adev(adev);
474 if (!client)
475 break;
476
477 i2c_unregister_device(client);
478 put_device(&client->dev);
479 break;
480 }
481
482 return NOTIFY_OK;
483}
484
485struct notifier_block i2c_acpi_notifier = {
486 .notifier_call = i2c_acpi_notify,
487};
488
489/**
490 * i2c_acpi_new_device_by_fwnode - Create i2c-client for the Nth I2cSerialBus resource
491 * @fwnode: fwnode with the ACPI resources to get the client from
492 * @index: Index of ACPI resource to get
493 * @info: describes the I2C device; note this is modified (addr gets set)
494 * Context: can sleep
495 *
496 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
497 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
498 * resources, in that case this function can be used to create an i2c-client
499 * for other I2cSerialBus resources in the Current Resource Settings table.
500 *
501 * Also see i2c_new_client_device, which this function calls to create the
502 * i2c-client.
503 *
504 * Returns a pointer to the new i2c-client, or error pointer in case of failure.
505 * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
506 */
507struct i2c_client *i2c_acpi_new_device_by_fwnode(struct fwnode_handle *fwnode,
508 int index,
509 struct i2c_board_info *info)
510{
511 struct i2c_acpi_lookup lookup;
512 struct i2c_adapter *adapter;
513 struct acpi_device *adev;
514 LIST_HEAD(resource_list);
515 int ret;
516
517 adev = to_acpi_device_node(fwnode);
518 if (!adev)
519 return ERR_PTR(-ENODEV);
520
521 memset(&lookup, 0, sizeof(lookup));
522 lookup.info = info;
523 lookup.device_handle = acpi_device_handle(adev);
524 lookup.index = index;
525
526 ret = acpi_dev_get_resources(adev, &resource_list,
527 i2c_acpi_fill_info, &lookup);
528 if (ret < 0)
529 return ERR_PTR(ret);
530
531 acpi_dev_free_resource_list(&resource_list);
532
533 if (!info->addr)
534 return ERR_PTR(-EADDRNOTAVAIL);
535
536 adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
537 if (!adapter)
538 return ERR_PTR(-EPROBE_DEFER);
539
540 return i2c_new_client_device(adapter, info);
541}
542EXPORT_SYMBOL_GPL(i2c_acpi_new_device_by_fwnode);
543
544bool i2c_acpi_waive_d0_probe(struct device *dev)
545{
546 struct i2c_driver *driver = to_i2c_driver(dev->driver);
547 struct acpi_device *adev = ACPI_COMPANION(dev);
548
549 return driver->flags & I2C_DRV_ACPI_WAIVE_D0_PROBE &&
550 adev && adev->power.state_for_enumeration >= adev->power.state;
551}
552EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
553
554#ifdef CONFIG_ACPI_I2C_OPREGION
555static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
556 u8 cmd, u8 *data, u8 data_len)
557{
558
559 struct i2c_msg msgs[2];
560 int ret;
561 u8 *buffer;
562
563 buffer = kzalloc(data_len, GFP_KERNEL);
564 if (!buffer)
565 return AE_NO_MEMORY;
566
567 msgs[0].addr = client->addr;
568 msgs[0].flags = client->flags;
569 msgs[0].len = 1;
570 msgs[0].buf = &cmd;
571
572 msgs[1].addr = client->addr;
573 msgs[1].flags = client->flags | I2C_M_RD;
574 msgs[1].len = data_len;
575 msgs[1].buf = buffer;
576
577 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
578 if (ret < 0) {
579 /* Getting a NACK is unfortunately normal with some DSTDs */
580 if (ret == -EREMOTEIO)
581 dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
582 data_len, client->addr, cmd, ret);
583 else
584 dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
585 data_len, client->addr, cmd, ret);
586 /* 2 transfers must have completed successfully */
587 } else if (ret == 2) {
588 memcpy(data, buffer, data_len);
589 ret = 0;
590 } else {
591 ret = -EIO;
592 }
593
594 kfree(buffer);
595 return ret;
596}
597
598static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
599 u8 cmd, u8 *data, u8 data_len)
600{
601
602 struct i2c_msg msgs[1];
603 u8 *buffer;
604 int ret = AE_OK;
605
606 buffer = kzalloc(data_len + 1, GFP_KERNEL);
607 if (!buffer)
608 return AE_NO_MEMORY;
609
610 buffer[0] = cmd;
611 memcpy(buffer + 1, data, data_len);
612
613 msgs[0].addr = client->addr;
614 msgs[0].flags = client->flags;
615 msgs[0].len = data_len + 1;
616 msgs[0].buf = buffer;
617
618 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
619
620 kfree(buffer);
621
622 if (ret < 0) {
623 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
624 return ret;
625 }
626
627 /* 1 transfer must have completed successfully */
628 return (ret == 1) ? 0 : -EIO;
629}
630
631static acpi_status
632i2c_acpi_space_handler(u32 function, acpi_physical_address command,
633 u32 bits, u64 *value64,
634 void *handler_context, void *region_context)
635{
636 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
637 struct i2c_acpi_handler_data *data = handler_context;
638 struct acpi_connection_info *info = &data->info;
639 struct acpi_resource_i2c_serialbus *sb;
640 struct i2c_adapter *adapter = data->adapter;
641 struct i2c_client *client;
642 struct acpi_resource *ares;
643 u32 accessor_type = function >> 16;
644 u8 action = function & ACPI_IO_MASK;
645 acpi_status ret;
646 int status;
647
648 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
649 if (ACPI_FAILURE(ret))
650 return ret;
651
652 client = kzalloc(sizeof(*client), GFP_KERNEL);
653 if (!client) {
654 ret = AE_NO_MEMORY;
655 goto err;
656 }
657
658 if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
659 ret = AE_BAD_PARAMETER;
660 goto err;
661 }
662
663 client->adapter = adapter;
664 client->addr = sb->slave_address;
665
666 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
667 client->flags |= I2C_CLIENT_TEN;
668
669 switch (accessor_type) {
670 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
671 if (action == ACPI_READ) {
672 status = i2c_smbus_read_byte(client);
673 if (status >= 0) {
674 gsb->bdata = status;
675 status = 0;
676 }
677 } else {
678 status = i2c_smbus_write_byte(client, gsb->bdata);
679 }
680 break;
681
682 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
683 if (action == ACPI_READ) {
684 status = i2c_smbus_read_byte_data(client, command);
685 if (status >= 0) {
686 gsb->bdata = status;
687 status = 0;
688 }
689 } else {
690 status = i2c_smbus_write_byte_data(client, command,
691 gsb->bdata);
692 }
693 break;
694
695 case ACPI_GSB_ACCESS_ATTRIB_WORD:
696 if (action == ACPI_READ) {
697 status = i2c_smbus_read_word_data(client, command);
698 if (status >= 0) {
699 gsb->wdata = status;
700 status = 0;
701 }
702 } else {
703 status = i2c_smbus_write_word_data(client, command,
704 gsb->wdata);
705 }
706 break;
707
708 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
709 if (action == ACPI_READ) {
710 status = i2c_smbus_read_block_data(client, command,
711 gsb->data);
712 if (status >= 0) {
713 gsb->len = status;
714 status = 0;
715 }
716 } else {
717 status = i2c_smbus_write_block_data(client, command,
718 gsb->len, gsb->data);
719 }
720 break;
721
722 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
723 if (action == ACPI_READ) {
724 status = acpi_gsb_i2c_read_bytes(client, command,
725 gsb->data, info->access_length);
726 } else {
727 status = acpi_gsb_i2c_write_bytes(client, command,
728 gsb->data, info->access_length);
729 }
730 break;
731
732 default:
733 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
734 accessor_type, client->addr);
735 ret = AE_BAD_PARAMETER;
736 goto err;
737 }
738
739 gsb->status = status;
740
741 err:
742 kfree(client);
743 ACPI_FREE(ares);
744 return ret;
745}
746
747
748int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
749{
750 acpi_handle handle;
751 struct i2c_acpi_handler_data *data;
752 acpi_status status;
753
754 if (!adapter->dev.parent)
755 return -ENODEV;
756
757 handle = ACPI_HANDLE(adapter->dev.parent);
758
759 if (!handle)
760 return -ENODEV;
761
762 data = kzalloc(sizeof(struct i2c_acpi_handler_data),
763 GFP_KERNEL);
764 if (!data)
765 return -ENOMEM;
766
767 data->adapter = adapter;
768 status = acpi_bus_attach_private_data(handle, (void *)data);
769 if (ACPI_FAILURE(status)) {
770 kfree(data);
771 return -ENOMEM;
772 }
773
774 status = acpi_install_address_space_handler(handle,
775 ACPI_ADR_SPACE_GSBUS,
776 &i2c_acpi_space_handler,
777 NULL,
778 data);
779 if (ACPI_FAILURE(status)) {
780 dev_err(&adapter->dev, "Error installing i2c space handler\n");
781 acpi_bus_detach_private_data(handle);
782 kfree(data);
783 return -ENOMEM;
784 }
785
786 return 0;
787}
788
789void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
790{
791 acpi_handle handle;
792 struct i2c_acpi_handler_data *data;
793 acpi_status status;
794
795 if (!adapter->dev.parent)
796 return;
797
798 handle = ACPI_HANDLE(adapter->dev.parent);
799
800 if (!handle)
801 return;
802
803 acpi_remove_address_space_handler(handle,
804 ACPI_ADR_SPACE_GSBUS,
805 &i2c_acpi_space_handler);
806
807 status = acpi_bus_get_private_data(handle, (void **)&data);
808 if (ACPI_SUCCESS(status))
809 kfree(data);
810
811 acpi_bus_detach_private_data(handle);
812}
813#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 */