xref: /linux/drivers/i2c/i2c-core-acpi.c (revision bba2c3615bd6cfee7456d1130f2e6b01b3f4e9ba)
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 static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
135 	/*
136 	 * ACPI video acpi_devices, which are handled by the acpi-video driver
137 	 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
138 	 */
139 	{ ACPI_VIDEO_HID, 0 },
140 	{}
141 };
142 
143 struct i2c_acpi_irq_context {
144 	int irq;
145 	bool wake_capable;
146 };
147 
148 static int i2c_acpi_do_lookup(struct acpi_device *adev,
149 			      struct i2c_acpi_lookup *lookup)
150 {
151 	struct i2c_board_info *info = lookup->info;
152 	struct list_head resource_list;
153 	int ret;
154 
155 	if (acpi_bus_get_status(adev))
156 		return -EINVAL;
157 
158 	if (!acpi_dev_ready_for_enumeration(adev))
159 		return -ENODEV;
160 
161 	if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
162 		return -ENODEV;
163 
164 	memset(info, 0, sizeof(*info));
165 	lookup->device_handle = acpi_device_handle(adev);
166 
167 	/* Look up for I2cSerialBus resource */
168 	INIT_LIST_HEAD(&resource_list);
169 	ret = acpi_dev_get_resources(adev, &resource_list,
170 				     i2c_acpi_fill_info, lookup);
171 	acpi_dev_free_resource_list(&resource_list);
172 
173 	if (ret < 0 || !info->addr)
174 		return -EINVAL;
175 
176 	return 0;
177 }
178 
179 static int i2c_acpi_add_irq_resource(struct acpi_resource *ares, void *data)
180 {
181 	struct i2c_acpi_irq_context *irq_ctx = data;
182 	struct resource r;
183 
184 	if (irq_ctx->irq > 0)
185 		return 1;
186 
187 	if (!acpi_dev_resource_interrupt(ares, 0, &r))
188 		return 1;
189 
190 	irq_ctx->irq = i2c_dev_irq_from_resources(&r, 1);
191 	irq_ctx->wake_capable = r.flags & IORESOURCE_IRQ_WAKECAPABLE;
192 
193 	return 1; /* No need to add resource to the list */
194 }
195 
196 /**
197  * i2c_acpi_get_irq - get device IRQ number from ACPI
198  * @client: Pointer to the I2C client device
199  * @wake_capable: Set to true if the IRQ is wake capable
200  *
201  * Find the IRQ number used by a specific client device.
202  *
203  * Return: The IRQ number or an error code.
204  */
205 int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable)
206 {
207 	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
208 	struct list_head resource_list;
209 	struct i2c_acpi_irq_context irq_ctx = {
210 		.irq = -ENOENT,
211 	};
212 	int ret;
213 
214 	INIT_LIST_HEAD(&resource_list);
215 
216 	ret = acpi_dev_get_resources(adev, &resource_list,
217 				     i2c_acpi_add_irq_resource, &irq_ctx);
218 	if (ret < 0)
219 		return ret;
220 
221 	acpi_dev_free_resource_list(&resource_list);
222 
223 	if (irq_ctx.irq == -ENOENT)
224 		irq_ctx.irq = acpi_dev_gpio_irq_wake_get(adev, 0, &irq_ctx.wake_capable);
225 
226 	if (irq_ctx.irq < 0)
227 		return irq_ctx.irq;
228 
229 	if (wake_capable)
230 		*wake_capable = irq_ctx.wake_capable;
231 
232 	return irq_ctx.irq;
233 }
234 
235 static int i2c_acpi_get_info(struct acpi_device *adev,
236 			     struct i2c_board_info *info,
237 			     struct i2c_adapter *adapter,
238 			     acpi_handle *adapter_handle)
239 {
240 	struct i2c_acpi_lookup lookup;
241 	int ret;
242 
243 	memset(&lookup, 0, sizeof(lookup));
244 	lookup.info = info;
245 	lookup.index = -1;
246 
247 	if (acpi_device_enumerated(adev))
248 		return -EINVAL;
249 
250 	ret = i2c_acpi_do_lookup(adev, &lookup);
251 	if (ret)
252 		return ret;
253 
254 	if (adapter) {
255 		/* The adapter must match the one in I2cSerialBus() connector */
256 		if (!device_match_acpi_handle(&adapter->dev, lookup.adapter_handle))
257 			return -ENODEV;
258 	} else {
259 		struct acpi_device *adapter_adev;
260 
261 		/* The adapter must be present */
262 		adapter_adev = acpi_fetch_acpi_dev(lookup.adapter_handle);
263 		if (!adapter_adev)
264 			return -ENODEV;
265 		if (acpi_bus_get_status(adapter_adev) ||
266 		    !adapter_adev->status.present)
267 			return -ENODEV;
268 	}
269 
270 	info->fwnode = acpi_fwnode_handle(adev);
271 	if (adapter_handle)
272 		*adapter_handle = lookup.adapter_handle;
273 
274 	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
275 			  sizeof(info->type));
276 
277 	return 0;
278 }
279 
280 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
281 				     struct acpi_device *adev,
282 				     struct i2c_board_info *info)
283 {
284 	/*
285 	 * Skip registration on boards where the ACPI tables are
286 	 * known to contain bogus I2C devices.
287 	 */
288 	if (acpi_quirk_skip_i2c_client_enumeration(adev))
289 		return;
290 
291 	adev->power.flags.ignore_parent = true;
292 	acpi_device_set_enumerated(adev);
293 
294 	if (IS_ERR(i2c_new_client_device(adapter, info)))
295 		adev->power.flags.ignore_parent = false;
296 }
297 
298 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
299 				       void *data, void **return_value)
300 {
301 	struct i2c_adapter *adapter = data;
302 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
303 	struct i2c_board_info info;
304 
305 	if (!adev || i2c_acpi_get_info(adev, &info, adapter, NULL))
306 		return AE_OK;
307 
308 	i2c_acpi_register_device(adapter, adev, &info);
309 
310 	return AE_OK;
311 }
312 
313 #define I2C_ACPI_MAX_SCAN_DEPTH 32
314 
315 /**
316  * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
317  * @adap: pointer to adapter
318  *
319  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
320  * namespace. When a device is found it will be added to the Linux device
321  * model and bound to the corresponding ACPI handle.
322  */
323 void i2c_acpi_register_devices(struct i2c_adapter *adap)
324 {
325 	struct acpi_device *adev;
326 	acpi_status status;
327 
328 	if (!has_acpi_companion(&adap->dev))
329 		return;
330 
331 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
332 				     I2C_ACPI_MAX_SCAN_DEPTH,
333 				     i2c_acpi_add_device, NULL,
334 				     adap, NULL);
335 	if (ACPI_FAILURE(status))
336 		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
337 
338 	if (!adap->dev.parent)
339 		return;
340 
341 	adev = ACPI_COMPANION(adap->dev.parent);
342 	if (!adev)
343 		return;
344 
345 	acpi_dev_clear_dependencies(adev);
346 }
347 
348 static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
349 	/*
350 	 * These Silead touchscreen controllers only work at 400KHz, for
351 	 * some reason they do not work at 100KHz. On some devices the ACPI
352 	 * tables list another device at their bus as only being capable
353 	 * of 100KHz, testing has shown that these other devices work fine
354 	 * at 400KHz (as can be expected of any recent i2c hw) so we force
355 	 * the speed of the bus to 400 KHz if a Silead device is present.
356 	 */
357 	{ "MSSL1680", 0 },
358 	{}
359 };
360 
361 static const struct acpi_device_id i2c_acpi_force_100khz_device_ids[] = {
362 	/*
363 	 * When a 400KHz freq is used on this model of ELAN touchpad in Linux,
364 	 * excessive smoothing (similar to when the touchpad's firmware detects
365 	 * a noisy signal) is sometimes applied. As some devices' (e.g, Lenovo
366 	 * V15 G4) ACPI tables specify a 400KHz frequency for this device and
367 	 * some I2C busses (e.g, Designware I2C) default to a 400KHz freq,
368 	 * force the speed to 100KHz as a workaround.
369 	 *
370 	 * For future investigation: This problem may be related to the default
371 	 * HCNT/LCNT values given by some busses' drivers, because they are not
372 	 * specified in the aforementioned devices' ACPI tables, and because
373 	 * the device works without issues on Windows at what is expected to be
374 	 * a 400KHz frequency. The root cause of the issue is not known.
375 	 */
376 	{ "DLL0945", 0 },
377 	{ "ELAN0678", 0 },
378 	{ "ELAN06FA", 0 },
379 	{}
380 };
381 
382 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
383 					   void *data, void **return_value)
384 {
385 	struct i2c_acpi_lookup *lookup = data;
386 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
387 
388 	if (!adev || i2c_acpi_do_lookup(adev, lookup))
389 		return AE_OK;
390 
391 	if (lookup->search_handle != lookup->adapter_handle)
392 		return AE_OK;
393 
394 	if (lookup->speed <= lookup->min_speed)
395 		lookup->min_speed = lookup->speed;
396 
397 	if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
398 		lookup->force_speed = I2C_MAX_FAST_MODE_FREQ;
399 
400 	if (acpi_match_device_ids(adev, i2c_acpi_force_100khz_device_ids) == 0)
401 		lookup->force_speed = I2C_MAX_STANDARD_MODE_FREQ;
402 
403 	return AE_OK;
404 }
405 
406 /**
407  * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
408  * @dev: The device owning the bus
409  *
410  * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
411  * devices connected to this bus and use the speed of slowest device.
412  *
413  * Returns the speed in Hz or zero
414  */
415 u32 i2c_acpi_find_bus_speed(struct device *dev)
416 {
417 	struct i2c_acpi_lookup lookup;
418 	struct i2c_board_info dummy;
419 	acpi_status status;
420 
421 	if (!has_acpi_companion(dev))
422 		return 0;
423 
424 	memset(&lookup, 0, sizeof(lookup));
425 	lookup.search_handle = ACPI_HANDLE(dev);
426 	lookup.min_speed = UINT_MAX;
427 	lookup.info = &dummy;
428 	lookup.index = -1;
429 
430 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
431 				     I2C_ACPI_MAX_SCAN_DEPTH,
432 				     i2c_acpi_lookup_speed, NULL,
433 				     &lookup, NULL);
434 
435 	if (ACPI_FAILURE(status)) {
436 		dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
437 		return 0;
438 	}
439 
440 	if (lookup.force_speed) {
441 		if (lookup.force_speed != lookup.min_speed)
442 			dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
443 				 lookup.min_speed, lookup.force_speed);
444 		return lookup.force_speed;
445 	} else if (lookup.min_speed != UINT_MAX) {
446 		return lookup.min_speed;
447 	} else {
448 		return 0;
449 	}
450 }
451 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
452 
453 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
454 {
455 	struct i2c_adapter *adapter;
456 	struct device *dev;
457 
458 	dev = bus_find_device(&i2c_bus_type, NULL, handle, device_match_acpi_handle);
459 	if (!dev)
460 		return NULL;
461 
462 	adapter = i2c_verify_adapter(dev);
463 	if (!adapter)
464 		put_device(dev);
465 
466 	return adapter;
467 }
468 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
469 
470 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
471 {
472 	return i2c_find_device_by_fwnode(acpi_fwnode_handle(adev));
473 }
474 
475 static struct i2c_adapter *i2c_acpi_find_adapter_by_adev(struct acpi_device *adev)
476 {
477 	return i2c_find_adapter_by_fwnode(acpi_fwnode_handle(adev));
478 }
479 
480 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
481 			   void *arg)
482 {
483 	struct acpi_device *adev = arg;
484 	struct i2c_board_info info;
485 	acpi_handle adapter_handle;
486 	struct i2c_adapter *adapter;
487 	struct i2c_client *client;
488 
489 	switch (value) {
490 	case ACPI_RECONFIG_DEVICE_ADD:
491 		if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
492 			break;
493 
494 		adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
495 		if (!adapter)
496 			break;
497 
498 		i2c_acpi_register_device(adapter, adev, &info);
499 		put_device(&adapter->dev);
500 		break;
501 	case ACPI_RECONFIG_DEVICE_REMOVE:
502 		if (!acpi_device_enumerated(adev))
503 			break;
504 
505 		client = i2c_acpi_find_client_by_adev(adev);
506 		if (client) {
507 			i2c_unregister_device(client);
508 			put_device(&client->dev);
509 		}
510 
511 		adapter = i2c_acpi_find_adapter_by_adev(adev);
512 		if (adapter) {
513 			acpi_unbind_one(&adapter->dev);
514 			put_device(&adapter->dev);
515 		}
516 
517 		break;
518 	}
519 
520 	return NOTIFY_OK;
521 }
522 
523 struct notifier_block i2c_acpi_notifier = {
524 	.notifier_call = i2c_acpi_notify,
525 };
526 
527 /**
528  * i2c_acpi_new_device_by_fwnode - Create i2c-client for the Nth I2cSerialBus resource
529  * @fwnode:  fwnode with the ACPI resources to get the client from
530  * @index:   Index of ACPI resource to get
531  * @info:    describes the I2C device; note this is modified (addr gets set)
532  * Context: can sleep
533  *
534  * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
535  * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
536  * resources, in that case this function can be used to create an i2c-client
537  * for other I2cSerialBus resources in the Current Resource Settings table.
538  *
539  * Also see i2c_new_client_device, which this function calls to create the
540  * i2c-client.
541  *
542  * Returns a pointer to the new i2c-client, or error pointer in case of failure.
543  * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
544  */
545 struct i2c_client *i2c_acpi_new_device_by_fwnode(struct fwnode_handle *fwnode,
546 						 int index,
547 						 struct i2c_board_info *info)
548 {
549 	struct i2c_acpi_lookup lookup;
550 	struct i2c_adapter *adapter;
551 	struct acpi_device *adev;
552 	LIST_HEAD(resource_list);
553 	int ret;
554 
555 	adev = to_acpi_device_node(fwnode);
556 	if (!adev)
557 		return ERR_PTR(-ENODEV);
558 
559 	memset(&lookup, 0, sizeof(lookup));
560 	lookup.info = info;
561 	lookup.device_handle = acpi_device_handle(adev);
562 	lookup.index = index;
563 
564 	ret = acpi_dev_get_resources(adev, &resource_list,
565 				     i2c_acpi_fill_info, &lookup);
566 	if (ret < 0)
567 		return ERR_PTR(ret);
568 
569 	acpi_dev_free_resource_list(&resource_list);
570 
571 	if (!info->addr)
572 		return ERR_PTR(-EADDRNOTAVAIL);
573 
574 	adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
575 	if (!adapter)
576 		return ERR_PTR(-EPROBE_DEFER);
577 
578 	return i2c_new_client_device(adapter, info);
579 }
580 EXPORT_SYMBOL_GPL(i2c_acpi_new_device_by_fwnode);
581 
582 bool i2c_acpi_waive_d0_probe(struct device *dev)
583 {
584 	struct i2c_driver *driver = to_i2c_driver(dev->driver);
585 	struct acpi_device *adev = ACPI_COMPANION(dev);
586 
587 	return driver->flags & I2C_DRV_ACPI_WAIVE_D0_PROBE &&
588 		adev && adev->power.state_for_enumeration >= adev->power.state;
589 }
590 EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
591 
592 #ifdef CONFIG_ACPI_I2C_OPREGION
593 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
594 		u8 cmd, u8 *data, u8 data_len)
595 {
596 
597 	struct i2c_msg msgs[2];
598 	int ret;
599 	u8 *buffer;
600 
601 	buffer = kzalloc(data_len, GFP_KERNEL);
602 	if (!buffer)
603 		return AE_NO_MEMORY;
604 
605 	msgs[0].addr = client->addr;
606 	msgs[0].flags = client->flags;
607 	msgs[0].len = 1;
608 	msgs[0].buf = &cmd;
609 
610 	msgs[1].addr = client->addr;
611 	msgs[1].flags = client->flags | I2C_M_RD;
612 	msgs[1].len = data_len;
613 	msgs[1].buf = buffer;
614 
615 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
616 	if (ret < 0) {
617 		/* Getting a NACK is unfortunately normal with some DSTDs */
618 		if (ret == -EREMOTEIO)
619 			dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
620 				data_len, client->addr, cmd, ret);
621 		else
622 			dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
623 				data_len, client->addr, cmd, ret);
624 	/* 2 transfers must have completed successfully */
625 	} else if (ret == 2) {
626 		memcpy(data, buffer, data_len);
627 		ret = 0;
628 	} else {
629 		ret = -EIO;
630 	}
631 
632 	kfree(buffer);
633 	return ret;
634 }
635 
636 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
637 		u8 cmd, u8 *data, u8 data_len)
638 {
639 
640 	struct i2c_msg msgs[1];
641 	u8 *buffer;
642 	int ret = AE_OK;
643 
644 	buffer = kzalloc(data_len + 1, GFP_KERNEL);
645 	if (!buffer)
646 		return AE_NO_MEMORY;
647 
648 	buffer[0] = cmd;
649 	memcpy(buffer + 1, data, data_len);
650 
651 	msgs[0].addr = client->addr;
652 	msgs[0].flags = client->flags;
653 	msgs[0].len = data_len + 1;
654 	msgs[0].buf = buffer;
655 
656 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
657 
658 	kfree(buffer);
659 
660 	if (ret < 0) {
661 		dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
662 		return ret;
663 	}
664 
665 	/* 1 transfer must have completed successfully */
666 	return (ret == 1) ? 0 : -EIO;
667 }
668 
669 static acpi_status
670 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
671 			u32 bits, u64 *value64,
672 			void *handler_context, void *region_context)
673 {
674 	struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
675 	struct i2c_acpi_handler_data *data = handler_context;
676 	struct acpi_connection_info *info = &data->info;
677 	struct acpi_resource_i2c_serialbus *sb;
678 	struct i2c_adapter *adapter = data->adapter;
679 	struct i2c_client *client;
680 	struct acpi_resource *ares;
681 	u32 accessor_type = function >> 16;
682 	u8 action = function & ACPI_IO_MASK;
683 	acpi_status ret;
684 	int status;
685 
686 	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
687 	if (ACPI_FAILURE(ret))
688 		return ret;
689 
690 	client = kzalloc_obj(*client);
691 	if (!client) {
692 		ret = AE_NO_MEMORY;
693 		goto err;
694 	}
695 
696 	if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
697 		ret = AE_BAD_PARAMETER;
698 		goto err;
699 	}
700 
701 	client->adapter = adapter;
702 	client->addr = sb->slave_address;
703 
704 	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
705 		client->flags |= I2C_CLIENT_TEN;
706 
707 	switch (accessor_type) {
708 	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
709 		if (action == ACPI_READ) {
710 			status = i2c_smbus_read_byte(client);
711 			if (status >= 0) {
712 				gsb->bdata = status;
713 				status = 0;
714 			}
715 		} else {
716 			status = i2c_smbus_write_byte(client, gsb->bdata);
717 		}
718 		break;
719 
720 	case ACPI_GSB_ACCESS_ATTRIB_BYTE:
721 		if (action == ACPI_READ) {
722 			status = i2c_smbus_read_byte_data(client, command);
723 			if (status >= 0) {
724 				gsb->bdata = status;
725 				status = 0;
726 			}
727 		} else {
728 			status = i2c_smbus_write_byte_data(client, command,
729 					gsb->bdata);
730 		}
731 		break;
732 
733 	case ACPI_GSB_ACCESS_ATTRIB_WORD:
734 		if (action == ACPI_READ) {
735 			status = i2c_smbus_read_word_data(client, command);
736 			if (status >= 0) {
737 				gsb->wdata = status;
738 				status = 0;
739 			}
740 		} else {
741 			status = i2c_smbus_write_word_data(client, command,
742 					gsb->wdata);
743 		}
744 		break;
745 
746 	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
747 		if (action == ACPI_READ) {
748 			status = i2c_smbus_read_block_data(client, command,
749 					gsb->data);
750 			if (status >= 0) {
751 				gsb->len = status;
752 				status = 0;
753 			}
754 		} else {
755 			status = i2c_smbus_write_block_data(client, command,
756 					gsb->len, gsb->data);
757 		}
758 		break;
759 
760 	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
761 		if (action == ACPI_READ) {
762 			status = acpi_gsb_i2c_read_bytes(client, command,
763 					gsb->data, info->access_length);
764 		} else {
765 			status = acpi_gsb_i2c_write_bytes(client, command,
766 					gsb->data, info->access_length);
767 		}
768 		break;
769 
770 	default:
771 		dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
772 			 accessor_type, client->addr);
773 		ret = AE_BAD_PARAMETER;
774 		goto err;
775 	}
776 
777 	gsb->status = status;
778 
779  err:
780 	kfree(client);
781 	ACPI_FREE(ares);
782 	return ret;
783 }
784 
785 
786 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
787 {
788 	acpi_handle handle;
789 	struct i2c_acpi_handler_data *data;
790 	acpi_status status;
791 
792 	if (!adapter->dev.parent)
793 		return -ENODEV;
794 
795 	handle = ACPI_HANDLE(adapter->dev.parent);
796 
797 	if (!handle)
798 		return -ENODEV;
799 
800 	data = kzalloc_obj(struct i2c_acpi_handler_data);
801 	if (!data)
802 		return -ENOMEM;
803 
804 	data->adapter = adapter;
805 	status = acpi_bus_attach_private_data(handle, (void *)data);
806 	if (ACPI_FAILURE(status)) {
807 		kfree(data);
808 		return -ENOMEM;
809 	}
810 
811 	status = acpi_install_address_space_handler(handle,
812 				ACPI_ADR_SPACE_GSBUS,
813 				&i2c_acpi_space_handler,
814 				NULL,
815 				data);
816 	if (ACPI_FAILURE(status)) {
817 		dev_err(&adapter->dev, "Error installing i2c space handler\n");
818 		acpi_bus_detach_private_data(handle);
819 		kfree(data);
820 		return -ENOMEM;
821 	}
822 
823 	return 0;
824 }
825 
826 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
827 {
828 	acpi_handle handle;
829 	struct i2c_acpi_handler_data *data;
830 	acpi_status status;
831 
832 	if (!adapter->dev.parent)
833 		return;
834 
835 	handle = ACPI_HANDLE(adapter->dev.parent);
836 
837 	if (!handle)
838 		return;
839 
840 	acpi_remove_address_space_handler(handle,
841 				ACPI_ADR_SPACE_GSBUS,
842 				&i2c_acpi_space_handler);
843 
844 	status = acpi_bus_get_private_data(handle, (void **)&data);
845 	if (ACPI_SUCCESS(status))
846 		kfree(data);
847 
848 	acpi_bus_detach_private_data(handle);
849 }
850 #endif /* CONFIG_ACPI_I2C_OPREGION */
851