xref: /linux/drivers/i2c/i2c-core-acpi.c (revision 570f7e331f5febb30f1384817463c7e42b65ca7d)
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  * Return:
88  * The number of I2cSerialBus resources in the ACPI-device's
89  * resource-list; or a negative error code.
90  *
91  * Specifically returns -ENOENT when no resources found.
92  */
93 int i2c_acpi_client_count(struct acpi_device *adev)
94 {
95 	int ret, count = 0;
96 	LIST_HEAD(r);
97 
98 	ret = acpi_dev_get_resources(adev, &r, i2c_acpi_resource_count, &count);
99 	if (ret < 0)
100 		return ret;
101 
102 	acpi_dev_free_resource_list(&r);
103 	return count ?: -ENOENT;
104 }
105 EXPORT_SYMBOL_GPL(i2c_acpi_client_count);
106 
107 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
108 {
109 	struct i2c_acpi_lookup *lookup = data;
110 	struct i2c_board_info *info = lookup->info;
111 	struct acpi_resource_i2c_serialbus *sb;
112 	acpi_status status;
113 
114 	if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb))
115 		return 1;
116 
117 	if (lookup->index != -1 && lookup->n++ != lookup->index)
118 		return 1;
119 
120 	status = acpi_get_handle(lookup->device_handle,
121 				 sb->resource_source.string_ptr,
122 				 &lookup->adapter_handle);
123 	if (ACPI_FAILURE(status))
124 		return 1;
125 
126 	info->addr = sb->slave_address;
127 	lookup->speed = sb->connection_speed;
128 	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
129 		info->flags |= I2C_CLIENT_TEN;
130 
131 	return 1;
132 }
133 
134 struct i2c_acpi_irq_context {
135 	int irq;
136 	bool wake_capable;
137 };
138 
139 static int i2c_acpi_do_lookup(struct acpi_device *adev,
140 			      struct i2c_acpi_lookup *lookup)
141 {
142 	struct i2c_board_info *info = lookup->info;
143 	struct list_head resource_list;
144 	int ret;
145 
146 	if (acpi_bus_get_status(adev))
147 		return -EINVAL;
148 
149 	if (!acpi_dev_ready_for_enumeration(adev))
150 		return -ENODEV;
151 
152 	/*
153 	 * ACPI video devices, which are handled by the acpi-video driver,
154 	 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
155 	 */
156 	if (acpi_dev_is_video_device(adev))
157 		return -ENODEV;
158 
159 	memset(info, 0, sizeof(*info));
160 	lookup->device_handle = acpi_device_handle(adev);
161 
162 	/* Look up for I2cSerialBus resource */
163 	INIT_LIST_HEAD(&resource_list);
164 	ret = acpi_dev_get_resources(adev, &resource_list,
165 				     i2c_acpi_fill_info, lookup);
166 	if (ret < 0)
167 		return ret;
168 
169 	acpi_dev_free_resource_list(&resource_list);
170 
171 	if (!info->addr)
172 		return -EINVAL;
173 
174 	return 0;
175 }
176 
177 static int i2c_acpi_add_irq_resource(struct acpi_resource *ares, void *data)
178 {
179 	struct i2c_acpi_irq_context *irq_ctx = data;
180 	struct resource r;
181 
182 	if (irq_ctx->irq > 0)
183 		return 1;
184 
185 	if (!acpi_dev_resource_interrupt(ares, 0, &r))
186 		return 1;
187 
188 	irq_ctx->irq = i2c_dev_irq_from_resources(&r, 1);
189 	irq_ctx->wake_capable = r.flags & IORESOURCE_IRQ_WAKECAPABLE;
190 
191 	return 1; /* No need to add resource to the list */
192 }
193 
194 /**
195  * i2c_acpi_get_irq - get device IRQ number from ACPI
196  * @client: Pointer to the I2C client device
197  * @wake_capable: Set to true if the IRQ is wake capable
198  *
199  * Find the IRQ number used by a specific client device.
200  *
201  * Return: The IRQ number or an error code.
202  */
203 int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable)
204 {
205 	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
206 	struct list_head resource_list;
207 	struct i2c_acpi_irq_context irq_ctx = {
208 		.irq = -ENOENT,
209 	};
210 	int ret;
211 
212 	INIT_LIST_HEAD(&resource_list);
213 
214 	ret = acpi_dev_get_resources(adev, &resource_list,
215 				     i2c_acpi_add_irq_resource, &irq_ctx);
216 	if (ret < 0)
217 		return ret;
218 
219 	acpi_dev_free_resource_list(&resource_list);
220 
221 	if (irq_ctx.irq == -ENOENT)
222 		irq_ctx.irq = acpi_dev_gpio_irq_wake_get(adev, 0, &irq_ctx.wake_capable);
223 
224 	if (irq_ctx.irq < 0)
225 		return irq_ctx.irq;
226 
227 	if (wake_capable)
228 		*wake_capable = irq_ctx.wake_capable;
229 
230 	return irq_ctx.irq;
231 }
232 
233 static int i2c_acpi_get_info(struct acpi_device *adev,
234 			     struct i2c_board_info *info,
235 			     struct i2c_adapter *adapter,
236 			     acpi_handle *adapter_handle)
237 {
238 	struct i2c_acpi_lookup lookup;
239 	int ret;
240 
241 	memset(&lookup, 0, sizeof(lookup));
242 	lookup.info = info;
243 	lookup.index = -1;
244 
245 	if (acpi_device_enumerated(adev))
246 		return -EINVAL;
247 
248 	ret = i2c_acpi_do_lookup(adev, &lookup);
249 	if (ret)
250 		return ret;
251 
252 	if (adapter) {
253 		/* The adapter must match the one in I2cSerialBus() connector */
254 		if (!device_match_acpi_handle(&adapter->dev, lookup.adapter_handle))
255 			return -ENODEV;
256 	} else {
257 		struct acpi_device *adapter_adev;
258 
259 		/* The adapter must be present */
260 		adapter_adev = acpi_fetch_acpi_dev(lookup.adapter_handle);
261 		if (!adapter_adev)
262 			return -ENODEV;
263 		if (acpi_bus_get_status(adapter_adev) ||
264 		    !adapter_adev->status.present)
265 			return -ENODEV;
266 	}
267 
268 	info->fwnode = acpi_fwnode_handle(adev);
269 	if (adapter_handle)
270 		*adapter_handle = lookup.adapter_handle;
271 
272 	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
273 			  sizeof(info->type));
274 
275 	return 0;
276 }
277 
278 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
279 				     struct acpi_device *adev,
280 				     struct i2c_board_info *info)
281 {
282 	/*
283 	 * Skip registration on boards where the ACPI tables are
284 	 * known to contain bogus I2C devices.
285 	 */
286 	if (acpi_quirk_skip_i2c_client_enumeration(adev))
287 		return;
288 
289 	adev->power.flags.ignore_parent = true;
290 	acpi_device_set_enumerated(adev);
291 
292 	if (IS_ERR(i2c_new_client_device(adapter, info)))
293 		adev->power.flags.ignore_parent = false;
294 }
295 
296 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
297 				       void *data, void **return_value)
298 {
299 	struct i2c_adapter *adapter = data;
300 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
301 	struct i2c_board_info info;
302 
303 	if (!adev || i2c_acpi_get_info(adev, &info, adapter, NULL))
304 		return AE_OK;
305 
306 	i2c_acpi_register_device(adapter, adev, &info);
307 
308 	return AE_OK;
309 }
310 
311 #define I2C_ACPI_MAX_SCAN_DEPTH 32
312 
313 /**
314  * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
315  * @adap: pointer to adapter
316  *
317  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
318  * namespace. When a device is found it will be added to the Linux device
319  * model and bound to the corresponding ACPI handle.
320  */
321 void i2c_acpi_register_devices(struct i2c_adapter *adap)
322 {
323 	struct acpi_device *adev;
324 	acpi_status status;
325 
326 	if (!has_acpi_companion(&adap->dev))
327 		return;
328 
329 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
330 				     I2C_ACPI_MAX_SCAN_DEPTH,
331 				     i2c_acpi_add_device, NULL,
332 				     adap, NULL);
333 	if (ACPI_FAILURE(status))
334 		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
335 
336 	if (!adap->dev.parent)
337 		return;
338 
339 	adev = ACPI_COMPANION(adap->dev.parent);
340 	if (!adev)
341 		return;
342 
343 	acpi_dev_clear_dependencies(adev);
344 }
345 
346 static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
347 	/*
348 	 * These Silead touchscreen controllers only work at 400KHz, for
349 	 * some reason they do not work at 100KHz. On some devices the ACPI
350 	 * tables list another device at their bus as only being capable
351 	 * of 100KHz, testing has shown that these other devices work fine
352 	 * at 400KHz (as can be expected of any recent i2c hw) so we force
353 	 * the speed of the bus to 400 KHz if a Silead device is present.
354 	 */
355 	{ "MSSL1680", 0 },
356 	{}
357 };
358 
359 static const struct acpi_device_id i2c_acpi_force_100khz_device_ids[] = {
360 	/*
361 	 * When a 400KHz freq is used on this model of ELAN touchpad in Linux,
362 	 * excessive smoothing (similar to when the touchpad's firmware detects
363 	 * a noisy signal) is sometimes applied. As some devices' (e.g, Lenovo
364 	 * V15 G4) ACPI tables specify a 400KHz frequency for this device and
365 	 * some I2C busses (e.g, Designware I2C) default to a 400KHz freq,
366 	 * force the speed to 100KHz as a workaround.
367 	 *
368 	 * For future investigation: This problem may be related to the default
369 	 * HCNT/LCNT values given by some busses' drivers, because they are not
370 	 * specified in the aforementioned devices' ACPI tables, and because
371 	 * the device works without issues on Windows at what is expected to be
372 	 * a 400KHz frequency. The root cause of the issue is not known.
373 	 */
374 	{ "DLL0945", 0 },
375 	{ "ELAN0678", 0 },
376 	{ "ELAN06FA", 0 },
377 	{ "ELAN1300", 0 },
378 	{}
379 };
380 
381 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
382 					   void *data, void **return_value)
383 {
384 	struct i2c_acpi_lookup *lookup = data;
385 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
386 
387 	if (!adev || i2c_acpi_do_lookup(adev, lookup))
388 		return AE_OK;
389 
390 	if (lookup->search_handle != lookup->adapter_handle)
391 		return AE_OK;
392 
393 	if (lookup->speed <= lookup->min_speed)
394 		lookup->min_speed = lookup->speed;
395 
396 	if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
397 		lookup->force_speed = I2C_MAX_FAST_MODE_FREQ;
398 
399 	if (acpi_match_device_ids(adev, i2c_acpi_force_100khz_device_ids) == 0)
400 		lookup->force_speed = I2C_MAX_STANDARD_MODE_FREQ;
401 
402 	return AE_OK;
403 }
404 
405 /**
406  * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
407  * @dev: The device owning the bus
408  *
409  * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
410  * devices connected to this bus and use the speed of slowest device.
411  *
412  * Returns the speed in Hz or zero
413  */
414 u32 i2c_acpi_find_bus_speed(struct device *dev)
415 {
416 	struct i2c_acpi_lookup lookup;
417 	struct i2c_board_info dummy;
418 	acpi_status status;
419 
420 	if (!has_acpi_companion(dev))
421 		return 0;
422 
423 	memset(&lookup, 0, sizeof(lookup));
424 	lookup.search_handle = ACPI_HANDLE(dev);
425 	lookup.min_speed = UINT_MAX;
426 	lookup.info = &dummy;
427 	lookup.index = -1;
428 
429 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
430 				     I2C_ACPI_MAX_SCAN_DEPTH,
431 				     i2c_acpi_lookup_speed, NULL,
432 				     &lookup, NULL);
433 
434 	if (ACPI_FAILURE(status)) {
435 		dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
436 		return 0;
437 	}
438 
439 	if (lookup.force_speed) {
440 		if (lookup.force_speed != lookup.min_speed)
441 			dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
442 				 lookup.min_speed, lookup.force_speed);
443 		return lookup.force_speed;
444 	} else if (lookup.min_speed != UINT_MAX) {
445 		return lookup.min_speed;
446 	} else {
447 		return 0;
448 	}
449 }
450 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
451 
452 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
453 {
454 	struct i2c_adapter *adapter;
455 	struct device *dev;
456 
457 	dev = bus_find_device(&i2c_bus_type, NULL, handle, device_match_acpi_handle);
458 	if (!dev)
459 		return NULL;
460 
461 	adapter = i2c_verify_adapter(dev);
462 	if (!adapter)
463 		put_device(dev);
464 
465 	return adapter;
466 }
467 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
468 
469 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
470 {
471 	return i2c_find_device_by_fwnode(acpi_fwnode_handle(adev));
472 }
473 
474 static struct i2c_adapter *i2c_acpi_find_adapter_by_adev(struct acpi_device *adev)
475 {
476 	return i2c_find_adapter_by_fwnode(acpi_fwnode_handle(adev));
477 }
478 
479 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
480 			   void *arg)
481 {
482 	struct acpi_device *adev = arg;
483 	struct i2c_board_info info;
484 	acpi_handle adapter_handle;
485 	struct i2c_adapter *adapter;
486 	struct i2c_client *client;
487 
488 	switch (value) {
489 	case ACPI_RECONFIG_DEVICE_ADD:
490 		if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
491 			break;
492 
493 		adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
494 		if (!adapter)
495 			break;
496 
497 		i2c_acpi_register_device(adapter, adev, &info);
498 		put_device(&adapter->dev);
499 		break;
500 	case ACPI_RECONFIG_DEVICE_REMOVE:
501 		if (!acpi_device_enumerated(adev))
502 			break;
503 
504 		client = i2c_acpi_find_client_by_adev(adev);
505 		if (client) {
506 			i2c_unregister_device(client);
507 			put_device(&client->dev);
508 		}
509 
510 		adapter = i2c_acpi_find_adapter_by_adev(adev);
511 		if (adapter) {
512 			acpi_unbind_one(&adapter->dev);
513 			put_device(&adapter->dev);
514 		}
515 
516 		break;
517 	}
518 
519 	return NOTIFY_OK;
520 }
521 
522 struct notifier_block i2c_acpi_notifier = {
523 	.notifier_call = i2c_acpi_notify,
524 };
525 
526 /**
527  * i2c_acpi_new_device_by_fwnode - Create i2c-client for the Nth I2cSerialBus resource
528  * @fwnode:  fwnode with the ACPI resources to get the client from
529  * @index:   Index of ACPI resource to get
530  * @info:    describes the I2C device; note this is modified (addr gets set)
531  * Context: can sleep
532  *
533  * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
534  * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
535  * resources, in that case this function can be used to create an i2c-client
536  * for other I2cSerialBus resources in the Current Resource Settings table.
537  *
538  * Also see i2c_new_client_device, which this function calls to create the
539  * i2c-client.
540  *
541  * Returns a pointer to the new i2c-client, or error pointer in case of failure.
542  * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
543  */
544 struct i2c_client *i2c_acpi_new_device_by_fwnode(struct fwnode_handle *fwnode,
545 						 int index,
546 						 struct i2c_board_info *info)
547 {
548 	struct i2c_acpi_lookup lookup;
549 	struct i2c_adapter *adapter;
550 	struct acpi_device *adev;
551 	LIST_HEAD(resource_list);
552 	int ret;
553 
554 	adev = to_acpi_device_node(fwnode);
555 	if (!adev)
556 		return ERR_PTR(-ENODEV);
557 
558 	memset(&lookup, 0, sizeof(lookup));
559 	lookup.info = info;
560 	lookup.device_handle = acpi_device_handle(adev);
561 	lookup.index = index;
562 
563 	ret = acpi_dev_get_resources(adev, &resource_list,
564 				     i2c_acpi_fill_info, &lookup);
565 	if (ret < 0)
566 		return ERR_PTR(ret);
567 
568 	acpi_dev_free_resource_list(&resource_list);
569 
570 	if (!info->addr)
571 		return ERR_PTR(-EADDRNOTAVAIL);
572 
573 	adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
574 	if (!adapter)
575 		return ERR_PTR(-EPROBE_DEFER);
576 
577 	return i2c_new_client_device(adapter, info);
578 }
579 EXPORT_SYMBOL_GPL(i2c_acpi_new_device_by_fwnode);
580 
581 bool i2c_acpi_waive_d0_probe(struct device *dev)
582 {
583 	struct i2c_driver *driver = to_i2c_driver(dev->driver);
584 	struct acpi_device *adev = ACPI_COMPANION(dev);
585 
586 	return driver->flags & I2C_DRV_ACPI_WAIVE_D0_PROBE &&
587 		adev && adev->power.state_for_enumeration >= adev->power.state;
588 }
589 EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
590 
591 #ifdef CONFIG_ACPI_I2C_OPREGION
592 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
593 		u8 cmd, u8 *data, u8 data_len)
594 {
595 
596 	struct i2c_msg msgs[2];
597 	int ret;
598 	u8 *buffer;
599 
600 	buffer = kzalloc(data_len, GFP_KERNEL);
601 	if (!buffer)
602 		return AE_NO_MEMORY;
603 
604 	msgs[0].addr = client->addr;
605 	msgs[0].flags = client->flags;
606 	msgs[0].len = 1;
607 	msgs[0].buf = &cmd;
608 
609 	msgs[1].addr = client->addr;
610 	msgs[1].flags = client->flags | I2C_M_RD;
611 	msgs[1].len = data_len;
612 	msgs[1].buf = buffer;
613 
614 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
615 	if (ret < 0) {
616 		/* Getting a NACK is unfortunately normal with some DSTDs */
617 		if (ret == -EREMOTEIO)
618 			dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
619 				data_len, client->addr, cmd, ret);
620 		else
621 			dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
622 				data_len, client->addr, cmd, ret);
623 	/* 2 transfers must have completed successfully */
624 	} else if (ret == 2) {
625 		memcpy(data, buffer, data_len);
626 		ret = 0;
627 	} else {
628 		ret = -EIO;
629 	}
630 
631 	kfree(buffer);
632 	return ret;
633 }
634 
635 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
636 		u8 cmd, u8 *data, u8 data_len)
637 {
638 
639 	struct i2c_msg msgs[1];
640 	u8 *buffer;
641 	int ret = AE_OK;
642 
643 	buffer = kzalloc(data_len + 1, GFP_KERNEL);
644 	if (!buffer)
645 		return AE_NO_MEMORY;
646 
647 	buffer[0] = cmd;
648 	memcpy(buffer + 1, data, data_len);
649 
650 	msgs[0].addr = client->addr;
651 	msgs[0].flags = client->flags;
652 	msgs[0].len = data_len + 1;
653 	msgs[0].buf = buffer;
654 
655 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
656 
657 	kfree(buffer);
658 
659 	if (ret < 0) {
660 		dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
661 		return ret;
662 	}
663 
664 	/* 1 transfer must have completed successfully */
665 	return (ret == 1) ? 0 : -EIO;
666 }
667 
668 static acpi_status
669 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
670 			u32 bits, u64 *value64,
671 			void *handler_context, void *region_context)
672 {
673 	struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
674 	struct i2c_acpi_handler_data *data = handler_context;
675 	struct acpi_connection_info *info = &data->info;
676 	struct acpi_resource_i2c_serialbus *sb;
677 	struct i2c_adapter *adapter = data->adapter;
678 	struct i2c_client *client;
679 	struct acpi_resource *ares;
680 	u32 accessor_type = function >> 16;
681 	u8 action = function & ACPI_IO_MASK;
682 	acpi_status ret;
683 	int status;
684 
685 	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
686 	if (ACPI_FAILURE(ret))
687 		return ret;
688 
689 	client = kzalloc_obj(*client);
690 	if (!client) {
691 		ret = AE_NO_MEMORY;
692 		goto err;
693 	}
694 
695 	if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
696 		ret = AE_BAD_PARAMETER;
697 		goto err;
698 	}
699 
700 	client->adapter = adapter;
701 	client->addr = sb->slave_address;
702 
703 	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
704 		client->flags |= I2C_CLIENT_TEN;
705 
706 	switch (accessor_type) {
707 	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
708 		if (action == ACPI_READ) {
709 			status = i2c_smbus_read_byte(client);
710 			if (status >= 0) {
711 				gsb->bdata = status;
712 				status = 0;
713 			}
714 		} else {
715 			status = i2c_smbus_write_byte(client, gsb->bdata);
716 		}
717 		break;
718 
719 	case ACPI_GSB_ACCESS_ATTRIB_BYTE:
720 		if (action == ACPI_READ) {
721 			status = i2c_smbus_read_byte_data(client, command);
722 			if (status >= 0) {
723 				gsb->bdata = status;
724 				status = 0;
725 			}
726 		} else {
727 			status = i2c_smbus_write_byte_data(client, command,
728 					gsb->bdata);
729 		}
730 		break;
731 
732 	case ACPI_GSB_ACCESS_ATTRIB_WORD:
733 		if (action == ACPI_READ) {
734 			status = i2c_smbus_read_word_data(client, command);
735 			if (status >= 0) {
736 				gsb->wdata = status;
737 				status = 0;
738 			}
739 		} else {
740 			status = i2c_smbus_write_word_data(client, command,
741 					gsb->wdata);
742 		}
743 		break;
744 
745 	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
746 		if (action == ACPI_READ) {
747 			status = i2c_smbus_read_block_data(client, command,
748 					gsb->data);
749 			if (status >= 0) {
750 				gsb->len = status;
751 				status = 0;
752 			}
753 		} else {
754 			status = i2c_smbus_write_block_data(client, command,
755 					gsb->len, gsb->data);
756 		}
757 		break;
758 
759 	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
760 		if (action == ACPI_READ) {
761 			status = acpi_gsb_i2c_read_bytes(client, command,
762 					gsb->data, info->access_length);
763 		} else {
764 			status = acpi_gsb_i2c_write_bytes(client, command,
765 					gsb->data, info->access_length);
766 		}
767 		break;
768 
769 	default:
770 		dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
771 			 accessor_type, client->addr);
772 		ret = AE_BAD_PARAMETER;
773 		goto err;
774 	}
775 
776 	gsb->status = status;
777 
778  err:
779 	kfree(client);
780 	ACPI_FREE(ares);
781 	return ret;
782 }
783 
784 
785 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
786 {
787 	acpi_handle handle;
788 	struct i2c_acpi_handler_data *data;
789 	acpi_status status;
790 
791 	if (!adapter->dev.parent)
792 		return -ENODEV;
793 
794 	handle = ACPI_HANDLE(adapter->dev.parent);
795 
796 	if (!handle)
797 		return -ENODEV;
798 
799 	data = kzalloc_obj(struct i2c_acpi_handler_data);
800 	if (!data)
801 		return -ENOMEM;
802 
803 	data->adapter = adapter;
804 	status = acpi_bus_attach_private_data(handle, (void *)data);
805 	if (ACPI_FAILURE(status)) {
806 		kfree(data);
807 		return -ENOMEM;
808 	}
809 
810 	status = acpi_install_address_space_handler(handle,
811 				ACPI_ADR_SPACE_GSBUS,
812 				&i2c_acpi_space_handler,
813 				NULL,
814 				data);
815 	if (ACPI_FAILURE(status)) {
816 		dev_err(&adapter->dev, "Error installing i2c space handler\n");
817 		acpi_bus_detach_private_data(handle);
818 		kfree(data);
819 		return -ENOMEM;
820 	}
821 
822 	return 0;
823 }
824 
825 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
826 {
827 	acpi_handle handle;
828 	struct i2c_acpi_handler_data *data;
829 	acpi_status status;
830 
831 	if (!adapter->dev.parent)
832 		return;
833 
834 	handle = ACPI_HANDLE(adapter->dev.parent);
835 
836 	if (!handle)
837 		return;
838 
839 	acpi_remove_address_space_handler(handle,
840 				ACPI_ADR_SPACE_GSBUS,
841 				&i2c_acpi_space_handler);
842 
843 	status = acpi_bus_get_private_data(handle, (void **)&data);
844 	if (ACPI_SUCCESS(status))
845 		kfree(data);
846 
847 	acpi_bus_detach_private_data(handle);
848 }
849 #endif /* CONFIG_ACPI_I2C_OPREGION */
850