xref: /openbmc/linux/drivers/i2c/i2c-core-acpi.c (revision 7671f967)
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 
18 struct i2c_acpi_handler_data {
19 	struct acpi_connection_info info;
20 	struct i2c_adapter *adapter;
21 };
22 
23 struct gsb_buffer {
24 	u8	status;
25 	u8	len;
26 	union {
27 		u16	wdata;
28 		u8	bdata;
29 		u8	data[0];
30 	};
31 } __packed;
32 
33 struct 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  */
55 bool 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 }
70 EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
71 
72 static 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  */
90 int 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 }
102 EXPORT_SYMBOL_GPL(i2c_acpi_client_count);
103 
104 static 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 
131 static 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 
140 static int i2c_acpi_do_lookup(struct acpi_device *adev,
141 			      struct i2c_acpi_lookup *lookup)
142 {
143 	struct i2c_board_info *info = lookup->info;
144 	struct list_head resource_list;
145 	int ret;
146 
147 	if (acpi_bus_get_status(adev))
148 		return -EINVAL;
149 
150 	if (!acpi_dev_ready_for_enumeration(adev))
151 		return -ENODEV;
152 
153 	if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
154 		return -ENODEV;
155 
156 	memset(info, 0, sizeof(*info));
157 	lookup->device_handle = acpi_device_handle(adev);
158 
159 	/* Look up for I2cSerialBus resource */
160 	INIT_LIST_HEAD(&resource_list);
161 	ret = acpi_dev_get_resources(adev, &resource_list,
162 				     i2c_acpi_fill_info, lookup);
163 	acpi_dev_free_resource_list(&resource_list);
164 
165 	if (ret < 0 || !info->addr)
166 		return -EINVAL;
167 
168 	return 0;
169 }
170 
171 static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
172 {
173 	int *irq = data;
174 	struct resource r;
175 
176 	if (*irq <= 0 && acpi_dev_resource_interrupt(ares, 0, &r))
177 		*irq = i2c_dev_irq_from_resources(&r, 1);
178 
179 	return 1; /* No need to add resource to the list */
180 }
181 
182 /**
183  * i2c_acpi_get_irq - get device IRQ number from ACPI
184  * @client: Pointer to the I2C client device
185  *
186  * Find the IRQ number used by a specific client device.
187  *
188  * Return: The IRQ number or an error code.
189  */
190 int i2c_acpi_get_irq(struct i2c_client *client)
191 {
192 	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
193 	struct list_head resource_list;
194 	int irq = -ENOENT;
195 	int ret;
196 
197 	INIT_LIST_HEAD(&resource_list);
198 
199 	ret = acpi_dev_get_resources(adev, &resource_list,
200 				     i2c_acpi_add_resource, &irq);
201 	if (ret < 0)
202 		return ret;
203 
204 	acpi_dev_free_resource_list(&resource_list);
205 
206 	if (irq == -ENOENT)
207 		irq = acpi_dev_gpio_irq_get(adev, 0);
208 
209 	return irq;
210 }
211 
212 static int i2c_acpi_get_info(struct acpi_device *adev,
213 			     struct i2c_board_info *info,
214 			     struct i2c_adapter *adapter,
215 			     acpi_handle *adapter_handle)
216 {
217 	struct i2c_acpi_lookup lookup;
218 	int ret;
219 
220 	memset(&lookup, 0, sizeof(lookup));
221 	lookup.info = info;
222 	lookup.index = -1;
223 
224 	if (acpi_device_enumerated(adev))
225 		return -EINVAL;
226 
227 	ret = i2c_acpi_do_lookup(adev, &lookup);
228 	if (ret)
229 		return ret;
230 
231 	if (adapter) {
232 		/* The adapter must match the one in I2cSerialBus() connector */
233 		if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
234 			return -ENODEV;
235 	} else {
236 		struct acpi_device *adapter_adev;
237 
238 		/* The adapter must be present */
239 		adapter_adev = acpi_fetch_acpi_dev(lookup.adapter_handle);
240 		if (!adapter_adev)
241 			return -ENODEV;
242 		if (acpi_bus_get_status(adapter_adev) ||
243 		    !adapter_adev->status.present)
244 			return -ENODEV;
245 	}
246 
247 	info->fwnode = acpi_fwnode_handle(adev);
248 	if (adapter_handle)
249 		*adapter_handle = lookup.adapter_handle;
250 
251 	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
252 			  sizeof(info->type));
253 
254 	return 0;
255 }
256 
257 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
258 				     struct acpi_device *adev,
259 				     struct i2c_board_info *info)
260 {
261 	/*
262 	 * Skip registration on boards where the ACPI tables are
263 	 * known to contain bogus I2C devices.
264 	 */
265 	if (acpi_quirk_skip_i2c_client_enumeration(adev))
266 		return;
267 
268 	adev->power.flags.ignore_parent = true;
269 	acpi_device_set_enumerated(adev);
270 
271 	if (IS_ERR(i2c_new_client_device(adapter, info)))
272 		adev->power.flags.ignore_parent = false;
273 }
274 
275 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
276 				       void *data, void **return_value)
277 {
278 	struct i2c_adapter *adapter = data;
279 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
280 	struct i2c_board_info info;
281 
282 	if (!adev || i2c_acpi_get_info(adev, &info, adapter, NULL))
283 		return AE_OK;
284 
285 	i2c_acpi_register_device(adapter, adev, &info);
286 
287 	return AE_OK;
288 }
289 
290 #define I2C_ACPI_MAX_SCAN_DEPTH 32
291 
292 /**
293  * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
294  * @adap: pointer to adapter
295  *
296  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
297  * namespace. When a device is found it will be added to the Linux device
298  * model and bound to the corresponding ACPI handle.
299  */
300 void i2c_acpi_register_devices(struct i2c_adapter *adap)
301 {
302 	struct acpi_device *adev;
303 	acpi_status status;
304 
305 	if (!has_acpi_companion(&adap->dev))
306 		return;
307 
308 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
309 				     I2C_ACPI_MAX_SCAN_DEPTH,
310 				     i2c_acpi_add_device, NULL,
311 				     adap, NULL);
312 	if (ACPI_FAILURE(status))
313 		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
314 
315 	if (!adap->dev.parent)
316 		return;
317 
318 	adev = ACPI_COMPANION(adap->dev.parent);
319 	if (!adev)
320 		return;
321 
322 	acpi_dev_clear_dependencies(adev);
323 }
324 
325 static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
326 	/*
327 	 * These Silead touchscreen controllers only work at 400KHz, for
328 	 * some reason they do not work at 100KHz. On some devices the ACPI
329 	 * tables list another device at their bus as only being capable
330 	 * of 100KHz, testing has shown that these other devices work fine
331 	 * at 400KHz (as can be expected of any recent i2c hw) so we force
332 	 * the speed of the bus to 400 KHz if a Silead device is present.
333 	 */
334 	{ "MSSL1680", 0 },
335 	{}
336 };
337 
338 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
339 					   void *data, void **return_value)
340 {
341 	struct i2c_acpi_lookup *lookup = data;
342 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
343 
344 	if (!adev || i2c_acpi_do_lookup(adev, lookup))
345 		return AE_OK;
346 
347 	if (lookup->search_handle != lookup->adapter_handle)
348 		return AE_OK;
349 
350 	if (lookup->speed <= lookup->min_speed)
351 		lookup->min_speed = lookup->speed;
352 
353 	if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
354 		lookup->force_speed = I2C_MAX_FAST_MODE_FREQ;
355 
356 	return AE_OK;
357 }
358 
359 /**
360  * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
361  * @dev: The device owning the bus
362  *
363  * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
364  * devices connected to this bus and use the speed of slowest device.
365  *
366  * Returns the speed in Hz or zero
367  */
368 u32 i2c_acpi_find_bus_speed(struct device *dev)
369 {
370 	struct i2c_acpi_lookup lookup;
371 	struct i2c_board_info dummy;
372 	acpi_status status;
373 
374 	if (!has_acpi_companion(dev))
375 		return 0;
376 
377 	memset(&lookup, 0, sizeof(lookup));
378 	lookup.search_handle = ACPI_HANDLE(dev);
379 	lookup.min_speed = UINT_MAX;
380 	lookup.info = &dummy;
381 	lookup.index = -1;
382 
383 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
384 				     I2C_ACPI_MAX_SCAN_DEPTH,
385 				     i2c_acpi_lookup_speed, NULL,
386 				     &lookup, NULL);
387 
388 	if (ACPI_FAILURE(status)) {
389 		dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
390 		return 0;
391 	}
392 
393 	if (lookup.force_speed) {
394 		if (lookup.force_speed != lookup.min_speed)
395 			dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
396 				 lookup.min_speed, lookup.force_speed);
397 		return lookup.force_speed;
398 	} else if (lookup.min_speed != UINT_MAX) {
399 		return lookup.min_speed;
400 	} else {
401 		return 0;
402 	}
403 }
404 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
405 
406 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
407 {
408 	struct i2c_adapter *adapter;
409 	struct device *dev;
410 
411 	dev = bus_find_device(&i2c_bus_type, NULL, handle, device_match_acpi_handle);
412 	if (!dev)
413 		return NULL;
414 
415 	adapter = i2c_verify_adapter(dev);
416 	if (!adapter)
417 		put_device(dev);
418 
419 	return adapter;
420 }
421 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
422 
423 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
424 {
425 	struct device *dev;
426 	struct i2c_client *client;
427 
428 	dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
429 	if (!dev)
430 		return NULL;
431 
432 	client = i2c_verify_client(dev);
433 	if (!client)
434 		put_device(dev);
435 
436 	return client;
437 }
438 
439 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
440 			   void *arg)
441 {
442 	struct acpi_device *adev = arg;
443 	struct i2c_board_info info;
444 	acpi_handle adapter_handle;
445 	struct i2c_adapter *adapter;
446 	struct i2c_client *client;
447 
448 	switch (value) {
449 	case ACPI_RECONFIG_DEVICE_ADD:
450 		if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
451 			break;
452 
453 		adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
454 		if (!adapter)
455 			break;
456 
457 		i2c_acpi_register_device(adapter, adev, &info);
458 		put_device(&adapter->dev);
459 		break;
460 	case ACPI_RECONFIG_DEVICE_REMOVE:
461 		if (!acpi_device_enumerated(adev))
462 			break;
463 
464 		client = i2c_acpi_find_client_by_adev(adev);
465 		if (!client)
466 			break;
467 
468 		i2c_unregister_device(client);
469 		put_device(&client->dev);
470 		break;
471 	}
472 
473 	return NOTIFY_OK;
474 }
475 
476 struct notifier_block i2c_acpi_notifier = {
477 	.notifier_call = i2c_acpi_notify,
478 };
479 
480 /**
481  * i2c_acpi_new_device_by_fwnode - Create i2c-client for the Nth I2cSerialBus resource
482  * @fwnode:  fwnode with the ACPI resources to get the client from
483  * @index:   Index of ACPI resource to get
484  * @info:    describes the I2C device; note this is modified (addr gets set)
485  * Context: can sleep
486  *
487  * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
488  * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
489  * resources, in that case this function can be used to create an i2c-client
490  * for other I2cSerialBus resources in the Current Resource Settings table.
491  *
492  * Also see i2c_new_client_device, which this function calls to create the
493  * i2c-client.
494  *
495  * Returns a pointer to the new i2c-client, or error pointer in case of failure.
496  * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
497  */
498 struct i2c_client *i2c_acpi_new_device_by_fwnode(struct fwnode_handle *fwnode,
499 						 int index,
500 						 struct i2c_board_info *info)
501 {
502 	struct i2c_acpi_lookup lookup;
503 	struct i2c_adapter *adapter;
504 	struct acpi_device *adev;
505 	LIST_HEAD(resource_list);
506 	int ret;
507 
508 	adev = to_acpi_device_node(fwnode);
509 	if (!adev)
510 		return ERR_PTR(-ENODEV);
511 
512 	memset(&lookup, 0, sizeof(lookup));
513 	lookup.info = info;
514 	lookup.device_handle = acpi_device_handle(adev);
515 	lookup.index = index;
516 
517 	ret = acpi_dev_get_resources(adev, &resource_list,
518 				     i2c_acpi_fill_info, &lookup);
519 	if (ret < 0)
520 		return ERR_PTR(ret);
521 
522 	acpi_dev_free_resource_list(&resource_list);
523 
524 	if (!info->addr)
525 		return ERR_PTR(-EADDRNOTAVAIL);
526 
527 	adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
528 	if (!adapter)
529 		return ERR_PTR(-EPROBE_DEFER);
530 
531 	return i2c_new_client_device(adapter, info);
532 }
533 EXPORT_SYMBOL_GPL(i2c_acpi_new_device_by_fwnode);
534 
535 bool i2c_acpi_waive_d0_probe(struct device *dev)
536 {
537 	struct i2c_driver *driver = to_i2c_driver(dev->driver);
538 	struct acpi_device *adev = ACPI_COMPANION(dev);
539 
540 	return driver->flags & I2C_DRV_ACPI_WAIVE_D0_PROBE &&
541 		adev && adev->power.state_for_enumeration >= adev->power.state;
542 }
543 EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
544 
545 #ifdef CONFIG_ACPI_I2C_OPREGION
546 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
547 		u8 cmd, u8 *data, u8 data_len)
548 {
549 
550 	struct i2c_msg msgs[2];
551 	int ret;
552 	u8 *buffer;
553 
554 	buffer = kzalloc(data_len, GFP_KERNEL);
555 	if (!buffer)
556 		return AE_NO_MEMORY;
557 
558 	msgs[0].addr = client->addr;
559 	msgs[0].flags = client->flags;
560 	msgs[0].len = 1;
561 	msgs[0].buf = &cmd;
562 
563 	msgs[1].addr = client->addr;
564 	msgs[1].flags = client->flags | I2C_M_RD;
565 	msgs[1].len = data_len;
566 	msgs[1].buf = buffer;
567 
568 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
569 	if (ret < 0) {
570 		/* Getting a NACK is unfortunately normal with some DSTDs */
571 		if (ret == -EREMOTEIO)
572 			dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
573 				data_len, client->addr, cmd, ret);
574 		else
575 			dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
576 				data_len, client->addr, cmd, ret);
577 	/* 2 transfers must have completed successfully */
578 	} else if (ret == 2) {
579 		memcpy(data, buffer, data_len);
580 		ret = 0;
581 	} else {
582 		ret = -EIO;
583 	}
584 
585 	kfree(buffer);
586 	return ret;
587 }
588 
589 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
590 		u8 cmd, u8 *data, u8 data_len)
591 {
592 
593 	struct i2c_msg msgs[1];
594 	u8 *buffer;
595 	int ret = AE_OK;
596 
597 	buffer = kzalloc(data_len + 1, GFP_KERNEL);
598 	if (!buffer)
599 		return AE_NO_MEMORY;
600 
601 	buffer[0] = cmd;
602 	memcpy(buffer + 1, data, data_len);
603 
604 	msgs[0].addr = client->addr;
605 	msgs[0].flags = client->flags;
606 	msgs[0].len = data_len + 1;
607 	msgs[0].buf = buffer;
608 
609 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
610 
611 	kfree(buffer);
612 
613 	if (ret < 0) {
614 		dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
615 		return ret;
616 	}
617 
618 	/* 1 transfer must have completed successfully */
619 	return (ret == 1) ? 0 : -EIO;
620 }
621 
622 static acpi_status
623 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
624 			u32 bits, u64 *value64,
625 			void *handler_context, void *region_context)
626 {
627 	struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
628 	struct i2c_acpi_handler_data *data = handler_context;
629 	struct acpi_connection_info *info = &data->info;
630 	struct acpi_resource_i2c_serialbus *sb;
631 	struct i2c_adapter *adapter = data->adapter;
632 	struct i2c_client *client;
633 	struct acpi_resource *ares;
634 	u32 accessor_type = function >> 16;
635 	u8 action = function & ACPI_IO_MASK;
636 	acpi_status ret;
637 	int status;
638 
639 	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
640 	if (ACPI_FAILURE(ret))
641 		return ret;
642 
643 	client = kzalloc(sizeof(*client), GFP_KERNEL);
644 	if (!client) {
645 		ret = AE_NO_MEMORY;
646 		goto err;
647 	}
648 
649 	if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
650 		ret = AE_BAD_PARAMETER;
651 		goto err;
652 	}
653 
654 	client->adapter = adapter;
655 	client->addr = sb->slave_address;
656 
657 	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
658 		client->flags |= I2C_CLIENT_TEN;
659 
660 	switch (accessor_type) {
661 	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
662 		if (action == ACPI_READ) {
663 			status = i2c_smbus_read_byte(client);
664 			if (status >= 0) {
665 				gsb->bdata = status;
666 				status = 0;
667 			}
668 		} else {
669 			status = i2c_smbus_write_byte(client, gsb->bdata);
670 		}
671 		break;
672 
673 	case ACPI_GSB_ACCESS_ATTRIB_BYTE:
674 		if (action == ACPI_READ) {
675 			status = i2c_smbus_read_byte_data(client, command);
676 			if (status >= 0) {
677 				gsb->bdata = status;
678 				status = 0;
679 			}
680 		} else {
681 			status = i2c_smbus_write_byte_data(client, command,
682 					gsb->bdata);
683 		}
684 		break;
685 
686 	case ACPI_GSB_ACCESS_ATTRIB_WORD:
687 		if (action == ACPI_READ) {
688 			status = i2c_smbus_read_word_data(client, command);
689 			if (status >= 0) {
690 				gsb->wdata = status;
691 				status = 0;
692 			}
693 		} else {
694 			status = i2c_smbus_write_word_data(client, command,
695 					gsb->wdata);
696 		}
697 		break;
698 
699 	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
700 		if (action == ACPI_READ) {
701 			status = i2c_smbus_read_block_data(client, command,
702 					gsb->data);
703 			if (status >= 0) {
704 				gsb->len = status;
705 				status = 0;
706 			}
707 		} else {
708 			status = i2c_smbus_write_block_data(client, command,
709 					gsb->len, gsb->data);
710 		}
711 		break;
712 
713 	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
714 		if (action == ACPI_READ) {
715 			status = acpi_gsb_i2c_read_bytes(client, command,
716 					gsb->data, info->access_length);
717 		} else {
718 			status = acpi_gsb_i2c_write_bytes(client, command,
719 					gsb->data, info->access_length);
720 		}
721 		break;
722 
723 	default:
724 		dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
725 			 accessor_type, client->addr);
726 		ret = AE_BAD_PARAMETER;
727 		goto err;
728 	}
729 
730 	gsb->status = status;
731 
732  err:
733 	kfree(client);
734 	ACPI_FREE(ares);
735 	return ret;
736 }
737 
738 
739 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
740 {
741 	acpi_handle handle;
742 	struct i2c_acpi_handler_data *data;
743 	acpi_status status;
744 
745 	if (!adapter->dev.parent)
746 		return -ENODEV;
747 
748 	handle = ACPI_HANDLE(adapter->dev.parent);
749 
750 	if (!handle)
751 		return -ENODEV;
752 
753 	data = kzalloc(sizeof(struct i2c_acpi_handler_data),
754 			    GFP_KERNEL);
755 	if (!data)
756 		return -ENOMEM;
757 
758 	data->adapter = adapter;
759 	status = acpi_bus_attach_private_data(handle, (void *)data);
760 	if (ACPI_FAILURE(status)) {
761 		kfree(data);
762 		return -ENOMEM;
763 	}
764 
765 	status = acpi_install_address_space_handler(handle,
766 				ACPI_ADR_SPACE_GSBUS,
767 				&i2c_acpi_space_handler,
768 				NULL,
769 				data);
770 	if (ACPI_FAILURE(status)) {
771 		dev_err(&adapter->dev, "Error installing i2c space handler\n");
772 		acpi_bus_detach_private_data(handle);
773 		kfree(data);
774 		return -ENOMEM;
775 	}
776 
777 	return 0;
778 }
779 
780 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
781 {
782 	acpi_handle handle;
783 	struct i2c_acpi_handler_data *data;
784 	acpi_status status;
785 
786 	if (!adapter->dev.parent)
787 		return;
788 
789 	handle = ACPI_HANDLE(adapter->dev.parent);
790 
791 	if (!handle)
792 		return;
793 
794 	acpi_remove_address_space_handler(handle,
795 				ACPI_ADR_SPACE_GSBUS,
796 				&i2c_acpi_space_handler);
797 
798 	status = acpi_bus_get_private_data(handle, (void **)&data);
799 	if (ACPI_SUCCESS(status))
800 		kfree(data);
801 
802 	acpi_bus_detach_private_data(handle);
803 }
804 #endif /* CONFIG_ACPI_I2C_OPREGION */
805