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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// 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 (!i2c_new_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
279const struct acpi_device_id *
280i2c_acpi_match_device(const struct acpi_device_id *matches,
281 struct i2c_client *client)
282{
283 if (!(client && matches))
284 return NULL;
285
286 return acpi_match_device(matches, &client->dev);
287}
288
289static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
290 /*
291 * These Silead touchscreen controllers only work at 400KHz, for
292 * some reason they do not work at 100KHz. On some devices the ACPI
293 * tables list another device at their bus as only being capable
294 * of 100KHz, testing has shown that these other devices work fine
295 * at 400KHz (as can be expected of any recent i2c hw) so we force
296 * the speed of the bus to 400 KHz if a Silead device is present.
297 */
298 { "MSSL1680", 0 },
299 {}
300};
301
302static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
303 void *data, void **return_value)
304{
305 struct i2c_acpi_lookup *lookup = data;
306 struct acpi_device *adev;
307
308 if (acpi_bus_get_device(handle, &adev))
309 return AE_OK;
310
311 if (i2c_acpi_do_lookup(adev, lookup))
312 return AE_OK;
313
314 if (lookup->search_handle != lookup->adapter_handle)
315 return AE_OK;
316
317 if (lookup->speed <= lookup->min_speed)
318 lookup->min_speed = lookup->speed;
319
320 if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
321 lookup->force_speed = 400000;
322
323 return AE_OK;
324}
325
326/**
327 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
328 * @dev: The device owning the bus
329 *
330 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
331 * devices connected to this bus and use the speed of slowest device.
332 *
333 * Returns the speed in Hz or zero
334 */
335u32 i2c_acpi_find_bus_speed(struct device *dev)
336{
337 struct i2c_acpi_lookup lookup;
338 struct i2c_board_info dummy;
339 acpi_status status;
340
341 if (!has_acpi_companion(dev))
342 return 0;
343
344 memset(&lookup, 0, sizeof(lookup));
345 lookup.search_handle = ACPI_HANDLE(dev);
346 lookup.min_speed = UINT_MAX;
347 lookup.info = &dummy;
348 lookup.index = -1;
349
350 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
351 I2C_ACPI_MAX_SCAN_DEPTH,
352 i2c_acpi_lookup_speed, NULL,
353 &lookup, NULL);
354
355 if (ACPI_FAILURE(status)) {
356 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
357 return 0;
358 }
359
360 if (lookup.force_speed) {
361 if (lookup.force_speed != lookup.min_speed)
362 dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
363 lookup.min_speed, lookup.force_speed);
364 return lookup.force_speed;
365 } else if (lookup.min_speed != UINT_MAX) {
366 return lookup.min_speed;
367 } else {
368 return 0;
369 }
370}
371EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
372
373static int i2c_acpi_find_match_adapter(struct device *dev, const void *data)
374{
375 struct i2c_adapter *adapter = i2c_verify_adapter(dev);
376
377 if (!adapter)
378 return 0;
379
380 return ACPI_HANDLE(dev) == (acpi_handle)data;
381}
382
383struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
384{
385 struct device *dev;
386
387 dev = bus_find_device(&i2c_bus_type, NULL, handle,
388 i2c_acpi_find_match_adapter);
389
390 return dev ? i2c_verify_adapter(dev) : NULL;
391}
392EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
393
394static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
395{
396 struct device *dev;
397
398 dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
399 return dev ? i2c_verify_client(dev) : NULL;
400}
401
402static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
403 void *arg)
404{
405 struct acpi_device *adev = arg;
406 struct i2c_board_info info;
407 acpi_handle adapter_handle;
408 struct i2c_adapter *adapter;
409 struct i2c_client *client;
410
411 switch (value) {
412 case ACPI_RECONFIG_DEVICE_ADD:
413 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
414 break;
415
416 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
417 if (!adapter)
418 break;
419
420 i2c_acpi_register_device(adapter, adev, &info);
421 break;
422 case ACPI_RECONFIG_DEVICE_REMOVE:
423 if (!acpi_device_enumerated(adev))
424 break;
425
426 client = i2c_acpi_find_client_by_adev(adev);
427 if (!client)
428 break;
429
430 i2c_unregister_device(client);
431 put_device(&client->dev);
432 break;
433 }
434
435 return NOTIFY_OK;
436}
437
438struct notifier_block i2c_acpi_notifier = {
439 .notifier_call = i2c_acpi_notify,
440};
441
442/**
443 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
444 * @dev: Device owning the ACPI resources to get the client from
445 * @index: Index of ACPI resource to get
446 * @info: describes the I2C device; note this is modified (addr gets set)
447 * Context: can sleep
448 *
449 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
450 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
451 * resources, in that case this function can be used to create an i2c-client
452 * for other I2cSerialBus resources in the Current Resource Settings table.
453 *
454 * Also see i2c_new_device, which this function calls to create the i2c-client.
455 *
456 * Returns a pointer to the new i2c-client, or error pointer in case of failure.
457 * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
458 */
459struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
460 struct i2c_board_info *info)
461{
462 struct i2c_acpi_lookup lookup;
463 struct i2c_adapter *adapter;
464 struct i2c_client *client;
465 struct acpi_device *adev;
466 LIST_HEAD(resource_list);
467 int ret;
468
469 adev = ACPI_COMPANION(dev);
470 if (!adev)
471 return ERR_PTR(-EINVAL);
472
473 memset(&lookup, 0, sizeof(lookup));
474 lookup.info = info;
475 lookup.device_handle = acpi_device_handle(adev);
476 lookup.index = index;
477
478 ret = acpi_dev_get_resources(adev, &resource_list,
479 i2c_acpi_fill_info, &lookup);
480 if (ret < 0)
481 return ERR_PTR(ret);
482
483 acpi_dev_free_resource_list(&resource_list);
484
485 if (!info->addr)
486 return ERR_PTR(-EADDRNOTAVAIL);
487
488 adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
489 if (!adapter)
490 return ERR_PTR(-EPROBE_DEFER);
491
492 client = i2c_new_device(adapter, info);
493 if (!client)
494 return ERR_PTR(-ENODEV);
495
496 return client;
497}
498EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
499
500#ifdef CONFIG_ACPI_I2C_OPREGION
501static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
502 u8 cmd, u8 *data, u8 data_len)
503{
504
505 struct i2c_msg msgs[2];
506 int ret;
507 u8 *buffer;
508
509 buffer = kzalloc(data_len, GFP_KERNEL);
510 if (!buffer)
511 return AE_NO_MEMORY;
512
513 msgs[0].addr = client->addr;
514 msgs[0].flags = client->flags;
515 msgs[0].len = 1;
516 msgs[0].buf = &cmd;
517
518 msgs[1].addr = client->addr;
519 msgs[1].flags = client->flags | I2C_M_RD;
520 msgs[1].len = data_len;
521 msgs[1].buf = buffer;
522
523 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
524 if (ret < 0) {
525 /* Getting a NACK is unfortunately normal with some DSTDs */
526 if (ret == -EREMOTEIO)
527 dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
528 data_len, client->addr, cmd, ret);
529 else
530 dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
531 data_len, client->addr, cmd, ret);
532 /* 2 transfers must have completed successfully */
533 } else if (ret == 2) {
534 memcpy(data, buffer, data_len);
535 ret = 0;
536 } else {
537 ret = -EIO;
538 }
539
540 kfree(buffer);
541 return ret;
542}
543
544static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
545 u8 cmd, u8 *data, u8 data_len)
546{
547
548 struct i2c_msg msgs[1];
549 u8 *buffer;
550 int ret = AE_OK;
551
552 buffer = kzalloc(data_len + 1, GFP_KERNEL);
553 if (!buffer)
554 return AE_NO_MEMORY;
555
556 buffer[0] = cmd;
557 memcpy(buffer + 1, data, data_len);
558
559 msgs[0].addr = client->addr;
560 msgs[0].flags = client->flags;
561 msgs[0].len = data_len + 1;
562 msgs[0].buf = buffer;
563
564 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
565
566 kfree(buffer);
567
568 if (ret < 0) {
569 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
570 return ret;
571 }
572
573 /* 1 transfer must have completed successfully */
574 return (ret == 1) ? 0 : -EIO;
575}
576
577static acpi_status
578i2c_acpi_space_handler(u32 function, acpi_physical_address command,
579 u32 bits, u64 *value64,
580 void *handler_context, void *region_context)
581{
582 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
583 struct i2c_acpi_handler_data *data = handler_context;
584 struct acpi_connection_info *info = &data->info;
585 struct acpi_resource_i2c_serialbus *sb;
586 struct i2c_adapter *adapter = data->adapter;
587 struct i2c_client *client;
588 struct acpi_resource *ares;
589 u32 accessor_type = function >> 16;
590 u8 action = function & ACPI_IO_MASK;
591 acpi_status ret;
592 int status;
593
594 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
595 if (ACPI_FAILURE(ret))
596 return ret;
597
598 client = kzalloc(sizeof(*client), GFP_KERNEL);
599 if (!client) {
600 ret = AE_NO_MEMORY;
601 goto err;
602 }
603
604 if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
605 ret = AE_BAD_PARAMETER;
606 goto err;
607 }
608
609 client->adapter = adapter;
610 client->addr = sb->slave_address;
611
612 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
613 client->flags |= I2C_CLIENT_TEN;
614
615 switch (accessor_type) {
616 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
617 if (action == ACPI_READ) {
618 status = i2c_smbus_read_byte(client);
619 if (status >= 0) {
620 gsb->bdata = status;
621 status = 0;
622 }
623 } else {
624 status = i2c_smbus_write_byte(client, gsb->bdata);
625 }
626 break;
627
628 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
629 if (action == ACPI_READ) {
630 status = i2c_smbus_read_byte_data(client, command);
631 if (status >= 0) {
632 gsb->bdata = status;
633 status = 0;
634 }
635 } else {
636 status = i2c_smbus_write_byte_data(client, command,
637 gsb->bdata);
638 }
639 break;
640
641 case ACPI_GSB_ACCESS_ATTRIB_WORD:
642 if (action == ACPI_READ) {
643 status = i2c_smbus_read_word_data(client, command);
644 if (status >= 0) {
645 gsb->wdata = status;
646 status = 0;
647 }
648 } else {
649 status = i2c_smbus_write_word_data(client, command,
650 gsb->wdata);
651 }
652 break;
653
654 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
655 if (action == ACPI_READ) {
656 status = i2c_smbus_read_block_data(client, command,
657 gsb->data);
658 if (status >= 0) {
659 gsb->len = status;
660 status = 0;
661 }
662 } else {
663 status = i2c_smbus_write_block_data(client, command,
664 gsb->len, gsb->data);
665 }
666 break;
667
668 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
669 if (action == ACPI_READ) {
670 status = acpi_gsb_i2c_read_bytes(client, command,
671 gsb->data, info->access_length);
672 } else {
673 status = acpi_gsb_i2c_write_bytes(client, command,
674 gsb->data, info->access_length);
675 }
676 break;
677
678 default:
679 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
680 accessor_type, client->addr);
681 ret = AE_BAD_PARAMETER;
682 goto err;
683 }
684
685 gsb->status = status;
686
687 err:
688 kfree(client);
689 ACPI_FREE(ares);
690 return ret;
691}
692
693
694int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
695{
696 acpi_handle handle;
697 struct i2c_acpi_handler_data *data;
698 acpi_status status;
699
700 if (!adapter->dev.parent)
701 return -ENODEV;
702
703 handle = ACPI_HANDLE(adapter->dev.parent);
704
705 if (!handle)
706 return -ENODEV;
707
708 data = kzalloc(sizeof(struct i2c_acpi_handler_data),
709 GFP_KERNEL);
710 if (!data)
711 return -ENOMEM;
712
713 data->adapter = adapter;
714 status = acpi_bus_attach_private_data(handle, (void *)data);
715 if (ACPI_FAILURE(status)) {
716 kfree(data);
717 return -ENOMEM;
718 }
719
720 status = acpi_install_address_space_handler(handle,
721 ACPI_ADR_SPACE_GSBUS,
722 &i2c_acpi_space_handler,
723 NULL,
724 data);
725 if (ACPI_FAILURE(status)) {
726 dev_err(&adapter->dev, "Error installing i2c space handler\n");
727 acpi_bus_detach_private_data(handle);
728 kfree(data);
729 return -ENOMEM;
730 }
731
732 acpi_walk_dep_device_list(handle);
733 return 0;
734}
735
736void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
737{
738 acpi_handle handle;
739 struct i2c_acpi_handler_data *data;
740 acpi_status status;
741
742 if (!adapter->dev.parent)
743 return;
744
745 handle = ACPI_HANDLE(adapter->dev.parent);
746
747 if (!handle)
748 return;
749
750 acpi_remove_address_space_handler(handle,
751 ACPI_ADR_SPACE_GSBUS,
752 &i2c_acpi_space_handler);
753
754 status = acpi_bus_get_private_data(handle, (void **)&data);
755 if (ACPI_SUCCESS(status))
756 kfree(data);
757
758 acpi_bus_detach_private_data(handle);
759}
760#endif /* CONFIG_ACPI_I2C_OPREGION */