xref: /openbmc/linux/drivers/i2c/i2c-core-acpi.c (revision 404e077a)
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 		DECLARE_FLEX_ARRAY(u8, data);
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 struct i2c_acpi_irq_context {
141 	int irq;
142 	bool wake_capable;
143 };
144 
145 static 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 
176 static 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  */
202 int 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 
232 static 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 
277 static 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 
295 static 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  */
320 void 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 
345 static 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 
358 static 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  */
388 u32 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 }
424 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
425 
426 struct 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 }
441 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
442 
443 static 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 
448 static 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 
485 struct 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  */
507 struct 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 }
542 EXPORT_SYMBOL_GPL(i2c_acpi_new_device_by_fwnode);
543 
544 bool 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 }
552 EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
553 
554 #ifdef CONFIG_ACPI_I2C_OPREGION
555 static 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 
598 static 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 
631 static acpi_status
632 i2c_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 
748 int 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 
789 void 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 */
814