xref: /openbmc/linux/drivers/i2c/i2c-core-acpi.c (revision 5d0e4d78)
1 /*
2  * Linux I2C core ACPI support code
3  *
4  * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the Free
8  * Software Foundation; either version 2 of the License, or (at your option)
9  * any later version.
10  */
11 
12 #include <linux/acpi.h>
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/i2c.h>
16 #include <linux/list.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 
20 #include "i2c-core.h"
21 
22 struct i2c_acpi_handler_data {
23 	struct acpi_connection_info info;
24 	struct i2c_adapter *adapter;
25 };
26 
27 struct gsb_buffer {
28 	u8	status;
29 	u8	len;
30 	union {
31 		u16	wdata;
32 		u8	bdata;
33 		u8	data[0];
34 	};
35 } __packed;
36 
37 struct i2c_acpi_lookup {
38 	struct i2c_board_info *info;
39 	acpi_handle adapter_handle;
40 	acpi_handle device_handle;
41 	acpi_handle search_handle;
42 	int n;
43 	int index;
44 	u32 speed;
45 	u32 min_speed;
46 };
47 
48 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
49 {
50 	struct i2c_acpi_lookup *lookup = data;
51 	struct i2c_board_info *info = lookup->info;
52 	struct acpi_resource_i2c_serialbus *sb;
53 	acpi_status status;
54 
55 	if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
56 		return 1;
57 
58 	sb = &ares->data.i2c_serial_bus;
59 	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
60 		return 1;
61 
62 	if (lookup->index != -1 && lookup->n++ != lookup->index)
63 		return 1;
64 
65 	status = acpi_get_handle(lookup->device_handle,
66 				 sb->resource_source.string_ptr,
67 				 &lookup->adapter_handle);
68 	if (!ACPI_SUCCESS(status))
69 		return 1;
70 
71 	info->addr = sb->slave_address;
72 	lookup->speed = sb->connection_speed;
73 	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
74 		info->flags |= I2C_CLIENT_TEN;
75 
76 	return 1;
77 }
78 
79 static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
80 	/*
81 	 * ACPI video acpi_devices, which are handled by the acpi-video driver
82 	 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
83 	 */
84 	{ ACPI_VIDEO_HID, 0 },
85 	{}
86 };
87 
88 static int i2c_acpi_do_lookup(struct acpi_device *adev,
89 			      struct i2c_acpi_lookup *lookup)
90 {
91 	struct i2c_board_info *info = lookup->info;
92 	struct list_head resource_list;
93 	int ret;
94 
95 	if (acpi_bus_get_status(adev) || !adev->status.present ||
96 	    acpi_device_enumerated(adev))
97 		return -EINVAL;
98 
99 	if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
100 		return -ENODEV;
101 
102 	memset(info, 0, sizeof(*info));
103 	lookup->device_handle = acpi_device_handle(adev);
104 
105 	/* Look up for I2cSerialBus resource */
106 	INIT_LIST_HEAD(&resource_list);
107 	ret = acpi_dev_get_resources(adev, &resource_list,
108 				     i2c_acpi_fill_info, lookup);
109 	acpi_dev_free_resource_list(&resource_list);
110 
111 	if (ret < 0 || !info->addr)
112 		return -EINVAL;
113 
114 	return 0;
115 }
116 
117 static int i2c_acpi_get_info(struct acpi_device *adev,
118 			     struct i2c_board_info *info,
119 			     struct i2c_adapter *adapter,
120 			     acpi_handle *adapter_handle)
121 {
122 	struct list_head resource_list;
123 	struct resource_entry *entry;
124 	struct i2c_acpi_lookup lookup;
125 	int ret;
126 
127 	memset(&lookup, 0, sizeof(lookup));
128 	lookup.info = info;
129 	lookup.index = -1;
130 
131 	ret = i2c_acpi_do_lookup(adev, &lookup);
132 	if (ret)
133 		return ret;
134 
135 	if (adapter) {
136 		/* The adapter must match the one in I2cSerialBus() connector */
137 		if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
138 			return -ENODEV;
139 	} else {
140 		struct acpi_device *adapter_adev;
141 
142 		/* The adapter must be present */
143 		if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
144 			return -ENODEV;
145 		if (acpi_bus_get_status(adapter_adev) ||
146 		    !adapter_adev->status.present)
147 			return -ENODEV;
148 	}
149 
150 	info->fwnode = acpi_fwnode_handle(adev);
151 	if (adapter_handle)
152 		*adapter_handle = lookup.adapter_handle;
153 
154 	/* Then fill IRQ number if any */
155 	INIT_LIST_HEAD(&resource_list);
156 	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
157 	if (ret < 0)
158 		return -EINVAL;
159 
160 	resource_list_for_each_entry(entry, &resource_list) {
161 		if (resource_type(entry->res) == IORESOURCE_IRQ) {
162 			info->irq = entry->res->start;
163 			break;
164 		}
165 	}
166 
167 	acpi_dev_free_resource_list(&resource_list);
168 
169 	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
170 			  sizeof(info->type));
171 
172 	return 0;
173 }
174 
175 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
176 				     struct acpi_device *adev,
177 				     struct i2c_board_info *info)
178 {
179 	adev->power.flags.ignore_parent = true;
180 	acpi_device_set_enumerated(adev);
181 
182 	if (!i2c_new_device(adapter, info)) {
183 		adev->power.flags.ignore_parent = false;
184 		dev_err(&adapter->dev,
185 			"failed to add I2C device %s from ACPI\n",
186 			dev_name(&adev->dev));
187 	}
188 }
189 
190 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
191 				       void *data, void **return_value)
192 {
193 	struct i2c_adapter *adapter = data;
194 	struct acpi_device *adev;
195 	struct i2c_board_info info;
196 
197 	if (acpi_bus_get_device(handle, &adev))
198 		return AE_OK;
199 
200 	if (i2c_acpi_get_info(adev, &info, adapter, NULL))
201 		return AE_OK;
202 
203 	i2c_acpi_register_device(adapter, adev, &info);
204 
205 	return AE_OK;
206 }
207 
208 #define I2C_ACPI_MAX_SCAN_DEPTH 32
209 
210 /**
211  * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
212  * @adap: pointer to adapter
213  *
214  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
215  * namespace. When a device is found it will be added to the Linux device
216  * model and bound to the corresponding ACPI handle.
217  */
218 void i2c_acpi_register_devices(struct i2c_adapter *adap)
219 {
220 	acpi_status status;
221 
222 	if (!has_acpi_companion(&adap->dev))
223 		return;
224 
225 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
226 				     I2C_ACPI_MAX_SCAN_DEPTH,
227 				     i2c_acpi_add_device, NULL,
228 				     adap, NULL);
229 	if (ACPI_FAILURE(status))
230 		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
231 }
232 
233 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
234 					   void *data, void **return_value)
235 {
236 	struct i2c_acpi_lookup *lookup = data;
237 	struct acpi_device *adev;
238 
239 	if (acpi_bus_get_device(handle, &adev))
240 		return AE_OK;
241 
242 	if (i2c_acpi_do_lookup(adev, lookup))
243 		return AE_OK;
244 
245 	if (lookup->search_handle != lookup->adapter_handle)
246 		return AE_OK;
247 
248 	if (lookup->speed <= lookup->min_speed)
249 		lookup->min_speed = lookup->speed;
250 
251 	return AE_OK;
252 }
253 
254 /**
255  * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
256  * @dev: The device owning the bus
257  *
258  * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
259  * devices connected to this bus and use the speed of slowest device.
260  *
261  * Returns the speed in Hz or zero
262  */
263 u32 i2c_acpi_find_bus_speed(struct device *dev)
264 {
265 	struct i2c_acpi_lookup lookup;
266 	struct i2c_board_info dummy;
267 	acpi_status status;
268 
269 	if (!has_acpi_companion(dev))
270 		return 0;
271 
272 	memset(&lookup, 0, sizeof(lookup));
273 	lookup.search_handle = ACPI_HANDLE(dev);
274 	lookup.min_speed = UINT_MAX;
275 	lookup.info = &dummy;
276 	lookup.index = -1;
277 
278 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
279 				     I2C_ACPI_MAX_SCAN_DEPTH,
280 				     i2c_acpi_lookup_speed, NULL,
281 				     &lookup, NULL);
282 
283 	if (ACPI_FAILURE(status)) {
284 		dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
285 		return 0;
286 	}
287 
288 	return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
289 }
290 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
291 
292 static int i2c_acpi_match_adapter(struct device *dev, void *data)
293 {
294 	struct i2c_adapter *adapter = i2c_verify_adapter(dev);
295 
296 	if (!adapter)
297 		return 0;
298 
299 	return ACPI_HANDLE(dev) == (acpi_handle)data;
300 }
301 
302 static int i2c_acpi_match_device(struct device *dev, void *data)
303 {
304 	return ACPI_COMPANION(dev) == data;
305 }
306 
307 static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
308 {
309 	struct device *dev;
310 
311 	dev = bus_find_device(&i2c_bus_type, NULL, handle,
312 			      i2c_acpi_match_adapter);
313 	return dev ? i2c_verify_adapter(dev) : NULL;
314 }
315 
316 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
317 {
318 	struct device *dev;
319 
320 	dev = bus_find_device(&i2c_bus_type, NULL, adev, i2c_acpi_match_device);
321 	return dev ? i2c_verify_client(dev) : NULL;
322 }
323 
324 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
325 			   void *arg)
326 {
327 	struct acpi_device *adev = arg;
328 	struct i2c_board_info info;
329 	acpi_handle adapter_handle;
330 	struct i2c_adapter *adapter;
331 	struct i2c_client *client;
332 
333 	switch (value) {
334 	case ACPI_RECONFIG_DEVICE_ADD:
335 		if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
336 			break;
337 
338 		adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
339 		if (!adapter)
340 			break;
341 
342 		i2c_acpi_register_device(adapter, adev, &info);
343 		break;
344 	case ACPI_RECONFIG_DEVICE_REMOVE:
345 		if (!acpi_device_enumerated(adev))
346 			break;
347 
348 		client = i2c_acpi_find_client_by_adev(adev);
349 		if (!client)
350 			break;
351 
352 		i2c_unregister_device(client);
353 		put_device(&client->dev);
354 		break;
355 	}
356 
357 	return NOTIFY_OK;
358 }
359 
360 struct notifier_block i2c_acpi_notifier = {
361 	.notifier_call = i2c_acpi_notify,
362 };
363 
364 /**
365  * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
366  * @dev:     Device owning the ACPI resources to get the client from
367  * @index:   Index of ACPI resource to get
368  * @info:    describes the I2C device; note this is modified (addr gets set)
369  * Context: can sleep
370  *
371  * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
372  * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
373  * resources, in that case this function can be used to create an i2c-client
374  * for other I2cSerialBus resources in the Current Resource Settings table.
375  *
376  * Also see i2c_new_device, which this function calls to create the i2c-client.
377  *
378  * Returns a pointer to the new i2c-client, or NULL if the adapter is not found.
379  */
380 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
381 				       struct i2c_board_info *info)
382 {
383 	struct i2c_acpi_lookup lookup;
384 	struct i2c_adapter *adapter;
385 	struct acpi_device *adev;
386 	LIST_HEAD(resource_list);
387 	int ret;
388 
389 	adev = ACPI_COMPANION(dev);
390 	if (!adev)
391 		return NULL;
392 
393 	memset(&lookup, 0, sizeof(lookup));
394 	lookup.info = info;
395 	lookup.device_handle = acpi_device_handle(adev);
396 	lookup.index = index;
397 
398 	ret = acpi_dev_get_resources(adev, &resource_list,
399 				     i2c_acpi_fill_info, &lookup);
400 	acpi_dev_free_resource_list(&resource_list);
401 
402 	if (ret < 0 || !info->addr)
403 		return NULL;
404 
405 	adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
406 	if (!adapter)
407 		return NULL;
408 
409 	return i2c_new_device(adapter, info);
410 }
411 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
412 
413 #ifdef CONFIG_ACPI_I2C_OPREGION
414 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
415 		u8 cmd, u8 *data, u8 data_len)
416 {
417 
418 	struct i2c_msg msgs[2];
419 	int ret;
420 	u8 *buffer;
421 
422 	buffer = kzalloc(data_len, GFP_KERNEL);
423 	if (!buffer)
424 		return AE_NO_MEMORY;
425 
426 	msgs[0].addr = client->addr;
427 	msgs[0].flags = client->flags;
428 	msgs[0].len = 1;
429 	msgs[0].buf = &cmd;
430 
431 	msgs[1].addr = client->addr;
432 	msgs[1].flags = client->flags | I2C_M_RD;
433 	msgs[1].len = data_len;
434 	msgs[1].buf = buffer;
435 
436 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
437 	if (ret < 0)
438 		dev_err(&client->adapter->dev, "i2c read failed\n");
439 	else
440 		memcpy(data, buffer, data_len);
441 
442 	kfree(buffer);
443 	return ret;
444 }
445 
446 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
447 		u8 cmd, u8 *data, u8 data_len)
448 {
449 
450 	struct i2c_msg msgs[1];
451 	u8 *buffer;
452 	int ret = AE_OK;
453 
454 	buffer = kzalloc(data_len + 1, GFP_KERNEL);
455 	if (!buffer)
456 		return AE_NO_MEMORY;
457 
458 	buffer[0] = cmd;
459 	memcpy(buffer + 1, data, data_len);
460 
461 	msgs[0].addr = client->addr;
462 	msgs[0].flags = client->flags;
463 	msgs[0].len = data_len + 1;
464 	msgs[0].buf = buffer;
465 
466 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
467 	if (ret < 0)
468 		dev_err(&client->adapter->dev, "i2c write failed\n");
469 
470 	kfree(buffer);
471 	return ret;
472 }
473 
474 static acpi_status
475 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
476 			u32 bits, u64 *value64,
477 			void *handler_context, void *region_context)
478 {
479 	struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
480 	struct i2c_acpi_handler_data *data = handler_context;
481 	struct acpi_connection_info *info = &data->info;
482 	struct acpi_resource_i2c_serialbus *sb;
483 	struct i2c_adapter *adapter = data->adapter;
484 	struct i2c_client *client;
485 	struct acpi_resource *ares;
486 	u32 accessor_type = function >> 16;
487 	u8 action = function & ACPI_IO_MASK;
488 	acpi_status ret;
489 	int status;
490 
491 	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
492 	if (ACPI_FAILURE(ret))
493 		return ret;
494 
495 	client = kzalloc(sizeof(*client), GFP_KERNEL);
496 	if (!client) {
497 		ret = AE_NO_MEMORY;
498 		goto err;
499 	}
500 
501 	if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
502 		ret = AE_BAD_PARAMETER;
503 		goto err;
504 	}
505 
506 	sb = &ares->data.i2c_serial_bus;
507 	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
508 		ret = AE_BAD_PARAMETER;
509 		goto err;
510 	}
511 
512 	client->adapter = adapter;
513 	client->addr = sb->slave_address;
514 
515 	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
516 		client->flags |= I2C_CLIENT_TEN;
517 
518 	switch (accessor_type) {
519 	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
520 		if (action == ACPI_READ) {
521 			status = i2c_smbus_read_byte(client);
522 			if (status >= 0) {
523 				gsb->bdata = status;
524 				status = 0;
525 			}
526 		} else {
527 			status = i2c_smbus_write_byte(client, gsb->bdata);
528 		}
529 		break;
530 
531 	case ACPI_GSB_ACCESS_ATTRIB_BYTE:
532 		if (action == ACPI_READ) {
533 			status = i2c_smbus_read_byte_data(client, command);
534 			if (status >= 0) {
535 				gsb->bdata = status;
536 				status = 0;
537 			}
538 		} else {
539 			status = i2c_smbus_write_byte_data(client, command,
540 					gsb->bdata);
541 		}
542 		break;
543 
544 	case ACPI_GSB_ACCESS_ATTRIB_WORD:
545 		if (action == ACPI_READ) {
546 			status = i2c_smbus_read_word_data(client, command);
547 			if (status >= 0) {
548 				gsb->wdata = status;
549 				status = 0;
550 			}
551 		} else {
552 			status = i2c_smbus_write_word_data(client, command,
553 					gsb->wdata);
554 		}
555 		break;
556 
557 	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
558 		if (action == ACPI_READ) {
559 			status = i2c_smbus_read_block_data(client, command,
560 					gsb->data);
561 			if (status >= 0) {
562 				gsb->len = status;
563 				status = 0;
564 			}
565 		} else {
566 			status = i2c_smbus_write_block_data(client, command,
567 					gsb->len, gsb->data);
568 		}
569 		break;
570 
571 	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
572 		if (action == ACPI_READ) {
573 			status = acpi_gsb_i2c_read_bytes(client, command,
574 					gsb->data, info->access_length);
575 			if (status > 0)
576 				status = 0;
577 		} else {
578 			status = acpi_gsb_i2c_write_bytes(client, command,
579 					gsb->data, info->access_length);
580 		}
581 		break;
582 
583 	default:
584 		dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
585 			 accessor_type, client->addr);
586 		ret = AE_BAD_PARAMETER;
587 		goto err;
588 	}
589 
590 	gsb->status = status;
591 
592  err:
593 	kfree(client);
594 	ACPI_FREE(ares);
595 	return ret;
596 }
597 
598 
599 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
600 {
601 	acpi_handle handle;
602 	struct i2c_acpi_handler_data *data;
603 	acpi_status status;
604 
605 	if (!adapter->dev.parent)
606 		return -ENODEV;
607 
608 	handle = ACPI_HANDLE(adapter->dev.parent);
609 
610 	if (!handle)
611 		return -ENODEV;
612 
613 	data = kzalloc(sizeof(struct i2c_acpi_handler_data),
614 			    GFP_KERNEL);
615 	if (!data)
616 		return -ENOMEM;
617 
618 	data->adapter = adapter;
619 	status = acpi_bus_attach_private_data(handle, (void *)data);
620 	if (ACPI_FAILURE(status)) {
621 		kfree(data);
622 		return -ENOMEM;
623 	}
624 
625 	status = acpi_install_address_space_handler(handle,
626 				ACPI_ADR_SPACE_GSBUS,
627 				&i2c_acpi_space_handler,
628 				NULL,
629 				data);
630 	if (ACPI_FAILURE(status)) {
631 		dev_err(&adapter->dev, "Error installing i2c space handler\n");
632 		acpi_bus_detach_private_data(handle);
633 		kfree(data);
634 		return -ENOMEM;
635 	}
636 
637 	acpi_walk_dep_device_list(handle);
638 	return 0;
639 }
640 
641 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
642 {
643 	acpi_handle handle;
644 	struct i2c_acpi_handler_data *data;
645 	acpi_status status;
646 
647 	if (!adapter->dev.parent)
648 		return;
649 
650 	handle = ACPI_HANDLE(adapter->dev.parent);
651 
652 	if (!handle)
653 		return;
654 
655 	acpi_remove_address_space_handler(handle,
656 				ACPI_ADR_SPACE_GSBUS,
657 				&i2c_acpi_space_handler);
658 
659 	status = acpi_bus_get_private_data(handle, (void **)&data);
660 	if (ACPI_SUCCESS(status))
661 		kfree(data);
662 
663 	acpi_bus_detach_private_data(handle);
664 }
665 #endif /* CONFIG_ACPI_I2C_OPREGION */
666