1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Linux I2C core ACPI support code
5 * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
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>
18 struct i2c_acpi_handler_data {
19 struct acpi_connection_info info;
20 struct i2c_adapter *adapter;
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;
45 * i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches
46 * @ares: ACPI resource
47 * @i2c: Pointer to I2cSerialBus resource will be returned here
49 * Checks if the given ACPI resource is of type I2cSerialBus.
50 * In this case, returns a pointer to it to the caller.
52 * Returns true if resource type is of I2cSerialBus, otherwise false.
54 bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
55 struct acpi_resource_i2c_serialbus **i2c)
57 struct acpi_resource_i2c_serialbus *sb;
59 if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
62 sb = &ares->data.i2c_serial_bus;
63 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
69 EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
71 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
73 struct i2c_acpi_lookup *lookup = data;
74 struct i2c_board_info *info = lookup->info;
75 struct acpi_resource_i2c_serialbus *sb;
78 if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb))
81 if (lookup->index != -1 && lookup->n++ != lookup->index)
84 status = acpi_get_handle(lookup->device_handle,
85 sb->resource_source.string_ptr,
86 &lookup->adapter_handle);
87 if (ACPI_FAILURE(status))
90 info->addr = sb->slave_address;
91 lookup->speed = sb->connection_speed;
92 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
93 info->flags |= I2C_CLIENT_TEN;
98 static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
100 * ACPI video acpi_devices, which are handled by the acpi-video driver
101 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
103 { ACPI_VIDEO_HID, 0 },
107 static int i2c_acpi_do_lookup(struct acpi_device *adev,
108 struct i2c_acpi_lookup *lookup)
110 struct i2c_board_info *info = lookup->info;
111 struct list_head resource_list;
114 if (acpi_bus_get_status(adev) || !adev->status.present)
117 if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
120 memset(info, 0, sizeof(*info));
121 lookup->device_handle = acpi_device_handle(adev);
123 /* Look up for I2cSerialBus resource */
124 INIT_LIST_HEAD(&resource_list);
125 ret = acpi_dev_get_resources(adev, &resource_list,
126 i2c_acpi_fill_info, lookup);
127 acpi_dev_free_resource_list(&resource_list);
129 if (ret < 0 || !info->addr)
135 static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
140 if (*irq <= 0 && acpi_dev_resource_interrupt(ares, 0, &r))
141 *irq = i2c_dev_irq_from_resources(&r, 1);
143 return 1; /* No need to add resource to the list */
147 * i2c_acpi_get_irq - get device IRQ number from ACPI
148 * @client: Pointer to the I2C client device
150 * Find the IRQ number used by a specific client device.
152 * Return: The IRQ number or an error code.
154 int i2c_acpi_get_irq(struct i2c_client *client)
156 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
157 struct list_head resource_list;
161 INIT_LIST_HEAD(&resource_list);
163 ret = acpi_dev_get_resources(adev, &resource_list,
164 i2c_acpi_add_resource, &irq);
168 acpi_dev_free_resource_list(&resource_list);
171 irq = acpi_dev_gpio_irq_get(adev, 0);
176 static int i2c_acpi_get_info(struct acpi_device *adev,
177 struct i2c_board_info *info,
178 struct i2c_adapter *adapter,
179 acpi_handle *adapter_handle)
181 struct i2c_acpi_lookup lookup;
184 memset(&lookup, 0, sizeof(lookup));
188 if (acpi_device_enumerated(adev))
191 ret = i2c_acpi_do_lookup(adev, &lookup);
196 /* The adapter must match the one in I2cSerialBus() connector */
197 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
200 struct acpi_device *adapter_adev;
202 /* The adapter must be present */
203 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
205 if (acpi_bus_get_status(adapter_adev) ||
206 !adapter_adev->status.present)
210 info->fwnode = acpi_fwnode_handle(adev);
212 *adapter_handle = lookup.adapter_handle;
214 acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
220 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
221 struct acpi_device *adev,
222 struct i2c_board_info *info)
224 adev->power.flags.ignore_parent = true;
225 acpi_device_set_enumerated(adev);
227 if (!i2c_new_device(adapter, info)) {
228 adev->power.flags.ignore_parent = false;
229 dev_err(&adapter->dev,
230 "failed to add I2C device %s from ACPI\n",
231 dev_name(&adev->dev));
235 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
236 void *data, void **return_value)
238 struct i2c_adapter *adapter = data;
239 struct acpi_device *adev;
240 struct i2c_board_info info;
242 if (acpi_bus_get_device(handle, &adev))
245 if (i2c_acpi_get_info(adev, &info, adapter, NULL))
248 i2c_acpi_register_device(adapter, adev, &info);
253 #define I2C_ACPI_MAX_SCAN_DEPTH 32
256 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
257 * @adap: pointer to adapter
259 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
260 * namespace. When a device is found it will be added to the Linux device
261 * model and bound to the corresponding ACPI handle.
263 void i2c_acpi_register_devices(struct i2c_adapter *adap)
267 if (!has_acpi_companion(&adap->dev))
270 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
271 I2C_ACPI_MAX_SCAN_DEPTH,
272 i2c_acpi_add_device, NULL,
274 if (ACPI_FAILURE(status))
275 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
278 const struct acpi_device_id *
279 i2c_acpi_match_device(const struct acpi_device_id *matches,
280 struct i2c_client *client)
282 if (!(client && matches))
285 return acpi_match_device(matches, &client->dev);
288 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
289 void *data, void **return_value)
291 struct i2c_acpi_lookup *lookup = data;
292 struct acpi_device *adev;
294 if (acpi_bus_get_device(handle, &adev))
297 if (i2c_acpi_do_lookup(adev, lookup))
300 if (lookup->search_handle != lookup->adapter_handle)
303 if (lookup->speed <= lookup->min_speed)
304 lookup->min_speed = lookup->speed;
310 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
311 * @dev: The device owning the bus
313 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
314 * devices connected to this bus and use the speed of slowest device.
316 * Returns the speed in Hz or zero
318 u32 i2c_acpi_find_bus_speed(struct device *dev)
320 struct i2c_acpi_lookup lookup;
321 struct i2c_board_info dummy;
324 if (!has_acpi_companion(dev))
327 memset(&lookup, 0, sizeof(lookup));
328 lookup.search_handle = ACPI_HANDLE(dev);
329 lookup.min_speed = UINT_MAX;
330 lookup.info = &dummy;
333 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
334 I2C_ACPI_MAX_SCAN_DEPTH,
335 i2c_acpi_lookup_speed, NULL,
338 if (ACPI_FAILURE(status)) {
339 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
343 return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
345 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
347 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
349 struct device *dev = bus_find_device_by_acpi_dev(&i2c_bus_type, handle);
351 return dev ? i2c_verify_adapter(dev) : NULL;
353 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
355 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
359 dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
360 return dev ? i2c_verify_client(dev) : NULL;
363 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
366 struct acpi_device *adev = arg;
367 struct i2c_board_info info;
368 acpi_handle adapter_handle;
369 struct i2c_adapter *adapter;
370 struct i2c_client *client;
373 case ACPI_RECONFIG_DEVICE_ADD:
374 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
377 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
381 i2c_acpi_register_device(adapter, adev, &info);
383 case ACPI_RECONFIG_DEVICE_REMOVE:
384 if (!acpi_device_enumerated(adev))
387 client = i2c_acpi_find_client_by_adev(adev);
391 i2c_unregister_device(client);
392 put_device(&client->dev);
399 struct notifier_block i2c_acpi_notifier = {
400 .notifier_call = i2c_acpi_notify,
404 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
405 * @dev: Device owning the ACPI resources to get the client from
406 * @index: Index of ACPI resource to get
407 * @info: describes the I2C device; note this is modified (addr gets set)
410 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
411 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
412 * resources, in that case this function can be used to create an i2c-client
413 * for other I2cSerialBus resources in the Current Resource Settings table.
415 * Also see i2c_new_device, which this function calls to create the i2c-client.
417 * Returns a pointer to the new i2c-client, or error pointer in case of failure.
418 * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
420 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
421 struct i2c_board_info *info)
423 struct i2c_acpi_lookup lookup;
424 struct i2c_adapter *adapter;
425 struct i2c_client *client;
426 struct acpi_device *adev;
427 LIST_HEAD(resource_list);
430 adev = ACPI_COMPANION(dev);
432 return ERR_PTR(-EINVAL);
434 memset(&lookup, 0, sizeof(lookup));
436 lookup.device_handle = acpi_device_handle(adev);
437 lookup.index = index;
439 ret = acpi_dev_get_resources(adev, &resource_list,
440 i2c_acpi_fill_info, &lookup);
444 acpi_dev_free_resource_list(&resource_list);
447 return ERR_PTR(-EADDRNOTAVAIL);
449 adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
451 return ERR_PTR(-EPROBE_DEFER);
453 client = i2c_new_device(adapter, info);
455 return ERR_PTR(-ENODEV);
459 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
461 #ifdef CONFIG_ACPI_I2C_OPREGION
462 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
463 u8 cmd, u8 *data, u8 data_len)
466 struct i2c_msg msgs[2];
470 buffer = kzalloc(data_len, GFP_KERNEL);
474 msgs[0].addr = client->addr;
475 msgs[0].flags = client->flags;
479 msgs[1].addr = client->addr;
480 msgs[1].flags = client->flags | I2C_M_RD;
481 msgs[1].len = data_len;
482 msgs[1].buf = buffer;
484 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
486 /* Getting a NACK is unfortunately normal with some DSTDs */
487 if (ret == -EREMOTEIO)
488 dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
489 data_len, client->addr, cmd, ret);
491 dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
492 data_len, client->addr, cmd, ret);
493 /* 2 transfers must have completed successfully */
494 } else if (ret == 2) {
495 memcpy(data, buffer, data_len);
505 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
506 u8 cmd, u8 *data, u8 data_len)
509 struct i2c_msg msgs[1];
513 buffer = kzalloc(data_len + 1, GFP_KERNEL);
518 memcpy(buffer + 1, data, data_len);
520 msgs[0].addr = client->addr;
521 msgs[0].flags = client->flags;
522 msgs[0].len = data_len + 1;
523 msgs[0].buf = buffer;
525 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
530 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
534 /* 1 transfer must have completed successfully */
535 return (ret == 1) ? 0 : -EIO;
539 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
540 u32 bits, u64 *value64,
541 void *handler_context, void *region_context)
543 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
544 struct i2c_acpi_handler_data *data = handler_context;
545 struct acpi_connection_info *info = &data->info;
546 struct acpi_resource_i2c_serialbus *sb;
547 struct i2c_adapter *adapter = data->adapter;
548 struct i2c_client *client;
549 struct acpi_resource *ares;
550 u32 accessor_type = function >> 16;
551 u8 action = function & ACPI_IO_MASK;
555 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
556 if (ACPI_FAILURE(ret))
559 client = kzalloc(sizeof(*client), GFP_KERNEL);
565 if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
566 ret = AE_BAD_PARAMETER;
570 client->adapter = adapter;
571 client->addr = sb->slave_address;
573 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
574 client->flags |= I2C_CLIENT_TEN;
576 switch (accessor_type) {
577 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
578 if (action == ACPI_READ) {
579 status = i2c_smbus_read_byte(client);
585 status = i2c_smbus_write_byte(client, gsb->bdata);
589 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
590 if (action == ACPI_READ) {
591 status = i2c_smbus_read_byte_data(client, command);
597 status = i2c_smbus_write_byte_data(client, command,
602 case ACPI_GSB_ACCESS_ATTRIB_WORD:
603 if (action == ACPI_READ) {
604 status = i2c_smbus_read_word_data(client, command);
610 status = i2c_smbus_write_word_data(client, command,
615 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
616 if (action == ACPI_READ) {
617 status = i2c_smbus_read_block_data(client, command,
624 status = i2c_smbus_write_block_data(client, command,
625 gsb->len, gsb->data);
629 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
630 if (action == ACPI_READ) {
631 status = acpi_gsb_i2c_read_bytes(client, command,
632 gsb->data, info->access_length);
634 status = acpi_gsb_i2c_write_bytes(client, command,
635 gsb->data, info->access_length);
640 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
641 accessor_type, client->addr);
642 ret = AE_BAD_PARAMETER;
646 gsb->status = status;
655 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
658 struct i2c_acpi_handler_data *data;
661 if (!adapter->dev.parent)
664 handle = ACPI_HANDLE(adapter->dev.parent);
669 data = kzalloc(sizeof(struct i2c_acpi_handler_data),
674 data->adapter = adapter;
675 status = acpi_bus_attach_private_data(handle, (void *)data);
676 if (ACPI_FAILURE(status)) {
681 status = acpi_install_address_space_handler(handle,
682 ACPI_ADR_SPACE_GSBUS,
683 &i2c_acpi_space_handler,
686 if (ACPI_FAILURE(status)) {
687 dev_err(&adapter->dev, "Error installing i2c space handler\n");
688 acpi_bus_detach_private_data(handle);
693 acpi_walk_dep_device_list(handle);
697 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
700 struct i2c_acpi_handler_data *data;
703 if (!adapter->dev.parent)
706 handle = ACPI_HANDLE(adapter->dev.parent);
711 acpi_remove_address_space_handler(handle,
712 ACPI_ADR_SPACE_GSBUS,
713 &i2c_acpi_space_handler);
715 status = acpi_bus_get_private_data(handle, (void **)&data);
716 if (ACPI_SUCCESS(status))
719 acpi_bus_detach_private_data(handle);
721 #endif /* CONFIG_ACPI_I2C_OPREGION */