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Release 4.14 drivers/i2c/i2c-core-acpi.c

Directory: drivers/i2c
/*
 * Linux I2C core ACPI support code
 *
 * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "i2c-core.h"


struct i2c_acpi_handler_data {
	
struct acpi_connection_info info;
	
struct i2c_adapter *adapter;
};


struct gsb_buffer {
	
u8	status;
	
u8	len;
	union {
		
u16	wdata;
		
u8	bdata;
		
u8	data[0];
	};

} __packed;


struct i2c_acpi_lookup {
	
struct i2c_board_info *info;
	
acpi_handle adapter_handle;
	
acpi_handle device_handle;
	
acpi_handle search_handle;
	
int n;
	
int index;
	
u32 speed;
	
u32 min_speed;
};


static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data) { struct i2c_acpi_lookup *lookup = data; struct i2c_board_info *info = lookup->info; struct acpi_resource_i2c_serialbus *sb; acpi_status status; if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) return 1; sb = &ares->data.i2c_serial_bus; if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) return 1; if (lookup->index != -1 && lookup->n++ != lookup->index) return 1; status = acpi_get_handle(lookup->device_handle, sb->resource_source.string_ptr, &lookup->adapter_handle); if (!ACPI_SUCCESS(status)) return 1; info->addr = sb->slave_address; lookup->speed = sb->connection_speed; if (sb->access_mode == ACPI_I2C_10BIT_MODE) info->flags |= I2C_CLIENT_TEN; return 1; }

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static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = { /* * ACPI video acpi_devices, which are handled by the acpi-video driver * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these. */ { ACPI_VIDEO_HID, 0 }, {} };
static int i2c_acpi_do_lookup(struct acpi_device *adev, struct i2c_acpi_lookup *lookup) { struct i2c_board_info *info = lookup->info; struct list_head resource_list; int ret; if (acpi_bus_get_status(adev) || !adev->status.present || acpi_device_enumerated(adev)) return -EINVAL; if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0) return -ENODEV; memset(info, 0, sizeof(*info)); lookup->device_handle = acpi_device_handle(adev); /* Look up for I2cSerialBus resource */ INIT_LIST_HEAD(&resource_list); ret = acpi_dev_get_resources(adev, &resource_list, i2c_acpi_fill_info, lookup); acpi_dev_free_resource_list(&resource_list); if (ret < 0 || !info->addr) return -EINVAL; return 0; }

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static int i2c_acpi_get_info(struct acpi_device *adev, struct i2c_board_info *info, struct i2c_adapter *adapter, acpi_handle *adapter_handle) { struct list_head resource_list; struct resource_entry *entry; struct i2c_acpi_lookup lookup; int ret; memset(&lookup, 0, sizeof(lookup)); lookup.info = info; lookup.index = -1; ret = i2c_acpi_do_lookup(adev, &lookup); if (ret) return ret; if (adapter) { /* The adapter must match the one in I2cSerialBus() connector */ if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle) return -ENODEV; } else { struct acpi_device *adapter_adev; /* The adapter must be present */ if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev)) return -ENODEV; if (acpi_bus_get_status(adapter_adev) || !adapter_adev->status.present) return -ENODEV; } info->fwnode = acpi_fwnode_handle(adev); if (adapter_handle) *adapter_handle = lookup.adapter_handle; /* Then fill IRQ number if any */ INIT_LIST_HEAD(&resource_list); ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL); if (ret < 0) return -EINVAL; resource_list_for_each_entry(entry, &resource_list) { if (resource_type(entry->res) == IORESOURCE_IRQ) { info->irq = entry->res->start; break; } } acpi_dev_free_resource_list(&resource_list); acpi_set_modalias(adev, dev_name(&adev->dev), info->type, sizeof(info->type)); return 0; }

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static void i2c_acpi_register_device(struct i2c_adapter *adapter, struct acpi_device *adev, struct i2c_board_info *info) { adev->power.flags.ignore_parent = true; acpi_device_set_enumerated(adev); if (!i2c_new_device(adapter, info)) { adev->power.flags.ignore_parent = false; dev_err(&adapter->dev, "failed to add I2C device %s from ACPI\n", dev_name(&adev->dev)); } }

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static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level, void *data, void **return_value) { struct i2c_adapter *adapter = data; struct acpi_device *adev; struct i2c_board_info info; if (acpi_bus_get_device(handle, &adev)) return AE_OK; if (i2c_acpi_get_info(adev, &info, adapter, NULL)) return AE_OK; i2c_acpi_register_device(adapter, adev, &info); return AE_OK; }

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#define I2C_ACPI_MAX_SCAN_DEPTH 32 /** * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter * @adap: pointer to adapter * * Enumerate all I2C slave devices behind this adapter by walking the ACPI * namespace. When a device is found it will be added to the Linux device * model and bound to the corresponding ACPI handle. */
void i2c_acpi_register_devices(struct i2c_adapter *adap) { acpi_status status; if (!has_acpi_companion(&adap->dev)) return; status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, I2C_ACPI_MAX_SCAN_DEPTH, i2c_acpi_add_device, NULL, adap, NULL); if (ACPI_FAILURE(status)) dev_warn(&adap->dev, "failed to enumerate I2C slaves\n"); }

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const struct acpi_device_id * i2c_acpi_match_device(const struct acpi_device_id *matches, struct i2c_client *client) { if (!(client && matches)) return NULL; return acpi_match_device(matches, &client->dev); }

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static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level, void *data, void **return_value) { struct i2c_acpi_lookup *lookup = data; struct acpi_device *adev; if (acpi_bus_get_device(handle, &adev)) return AE_OK; if (i2c_acpi_do_lookup(adev, lookup)) return AE_OK; if (lookup->search_handle != lookup->adapter_handle) return AE_OK; if (lookup->speed <= lookup->min_speed) lookup->min_speed = lookup->speed; return AE_OK; }

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/** * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI * @dev: The device owning the bus * * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves * devices connected to this bus and use the speed of slowest device. * * Returns the speed in Hz or zero */
u32 i2c_acpi_find_bus_speed(struct device *dev) { struct i2c_acpi_lookup lookup; struct i2c_board_info dummy; acpi_status status; if (!has_acpi_companion(dev)) return 0; memset(&lookup, 0, sizeof(lookup)); lookup.search_handle = ACPI_HANDLE(dev); lookup.min_speed = UINT_MAX; lookup.info = &dummy; lookup.index = -1; status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, I2C_ACPI_MAX_SCAN_DEPTH, i2c_acpi_lookup_speed, NULL, &lookup, NULL); if (ACPI_FAILURE(status)) { dev_warn(dev, "unable to find I2C bus speed from ACPI\n"); return 0; } return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0; }

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EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
static int i2c_acpi_find_match_adapter(struct device *dev, void *data) { struct i2c_adapter *adapter = i2c_verify_adapter(dev); if (!adapter) return 0; return ACPI_HANDLE(dev) == (acpi_handle)data; }

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static int i2c_acpi_find_match_device(struct device *dev, void *data) { return ACPI_COMPANION(dev) == data; }

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static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle) { struct device *dev; dev = bus_find_device(&i2c_bus_type, NULL, handle, i2c_acpi_find_match_adapter); return dev ? i2c_verify_adapter(dev) : NULL; }

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static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev) { struct device *dev; dev = bus_find_device(&i2c_bus_type, NULL, adev, i2c_acpi_find_match_device); return dev ? i2c_verify_client(dev) : NULL; }

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static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value, void *arg) { struct acpi_device *adev = arg; struct i2c_board_info info; acpi_handle adapter_handle; struct i2c_adapter *adapter; struct i2c_client *client; switch (value) { case ACPI_RECONFIG_DEVICE_ADD: if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle)) break; adapter = i2c_acpi_find_adapter_by_handle(adapter_handle); if (!adapter) break; i2c_acpi_register_device(adapter, adev, &info); break; case ACPI_RECONFIG_DEVICE_REMOVE: if (!acpi_device_enumerated(adev)) break; client = i2c_acpi_find_client_by_adev(adev); if (!client) break; i2c_unregister_device(client); put_device(&client->dev); break; } return NOTIFY_OK; }

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struct notifier_block i2c_acpi_notifier = { .notifier_call = i2c_acpi_notify, }; /** * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource * @dev: Device owning the ACPI resources to get the client from * @index: Index of ACPI resource to get * @info: describes the I2C device; note this is modified (addr gets set) * Context: can sleep * * By default the i2c subsys creates an i2c-client for the first I2cSerialBus * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus * resources, in that case this function can be used to create an i2c-client * for other I2cSerialBus resources in the Current Resource Settings table. * * Also see i2c_new_device, which this function calls to create the i2c-client. * * Returns a pointer to the new i2c-client, or NULL if the adapter is not found. */
struct i2c_client *i2c_acpi_new_device(struct device *dev, int index, struct i2c_board_info *info) { struct i2c_acpi_lookup lookup; struct i2c_adapter *adapter; struct acpi_device *adev; LIST_HEAD(resource_list); int ret; adev = ACPI_COMPANION(dev); if (!adev) return NULL; memset(&lookup, 0, sizeof(lookup)); lookup.info = info; lookup.device_handle = acpi_device_handle(adev); lookup.index = index; ret = acpi_dev_get_resources(adev, &resource_list, i2c_acpi_fill_info, &lookup); acpi_dev_free_resource_list(&resource_list); if (ret < 0 || !info->addr) return NULL; adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle); if (!adapter) return NULL; return i2c_new_device(adapter, info); }

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EXPORT_SYMBOL_GPL(i2c_acpi_new_device); #ifdef CONFIG_ACPI_I2C_OPREGION
static int acpi_gsb_i2c_read_bytes(struct i2c_client *client, u8 cmd, u8 *data, u8 data_len) { struct i2c_msg msgs[2]; int ret; u8 *buffer; buffer = kzalloc(data_len, GFP_KERNEL); if (!buffer) return AE_NO_MEMORY; msgs[0].addr = client->addr; msgs[0].flags = client->flags; msgs[0].len = 1; msgs[0].buf = &cmd; msgs[1].addr = client->addr; msgs[1].flags = client->flags | I2C_M_RD; msgs[1].len = data_len; msgs[1].buf = buffer; ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); if (ret < 0) dev_err(&client->adapter->dev, "i2c read failed\n"); else memcpy(data, buffer, data_len); kfree(buffer); return ret; }

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static int acpi_gsb_i2c_write_bytes(struct i2c_client *client, u8 cmd, u8 *data, u8 data_len) { struct i2c_msg msgs[1]; u8 *buffer; int ret = AE_OK; buffer = kzalloc(data_len + 1, GFP_KERNEL); if (!buffer) return AE_NO_MEMORY; buffer[0] = cmd; memcpy(buffer + 1, data, data_len); msgs[0].addr = client->addr; msgs[0].flags = client->flags; msgs[0].len = data_len + 1; msgs[0].buf = buffer; ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); if (ret < 0) dev_err(&client->adapter->dev, "i2c write failed\n"); kfree(buffer); return ret; }

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static acpi_status i2c_acpi_space_handler(u32 function, acpi_physical_address command, u32 bits, u64 *value64, void *handler_context, void *region_context) { struct gsb_buffer *gsb = (struct gsb_buffer *)value64; struct i2c_acpi_handler_data *data = handler_context; struct acpi_connection_info *info = &data->info; struct acpi_resource_i2c_serialbus *sb; struct i2c_adapter *adapter = data->adapter; struct i2c_client *client; struct acpi_resource *ares; u32 accessor_type = function >> 16; u8 action = function & ACPI_IO_MASK; acpi_status ret; int status; ret = acpi_buffer_to_resource(info->connection, info->length, &ares); if (ACPI_FAILURE(ret)) return ret; client = kzalloc(sizeof(*client), GFP_KERNEL); if (!client) { ret = AE_NO_MEMORY; goto err; } if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) { ret = AE_BAD_PARAMETER; goto err; } sb = &ares->data.i2c_serial_bus; if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) { ret = AE_BAD_PARAMETER; goto err; } client->adapter = adapter; client->addr = sb->slave_address; if (sb->access_mode == ACPI_I2C_10BIT_MODE) client->flags |= I2C_CLIENT_TEN; switch (accessor_type) { case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV: if (action == ACPI_READ) { status = i2c_smbus_read_byte(client); if (status >= 0) { gsb->bdata = status; status = 0; } } else { status = i2c_smbus_write_byte(client, gsb->bdata); } break; case ACPI_GSB_ACCESS_ATTRIB_BYTE: if (action == ACPI_READ) { status = i2c_smbus_read_byte_data(client, command); if (status >= 0) { gsb->bdata = status; status = 0; } } else { status = i2c_smbus_write_byte_data(client, command, gsb->bdata); } break; case ACPI_GSB_ACCESS_ATTRIB_WORD: if (action == ACPI_READ) { status = i2c_smbus_read_word_data(client, command); if (status >= 0) { gsb->wdata = status; status = 0; } } else { status = i2c_smbus_write_word_data(client, command, gsb->wdata); } break; case ACPI_GSB_ACCESS_ATTRIB_BLOCK: if (action == ACPI_READ) { status = i2c_smbus_read_block_data(client, command, gsb->data); if (status >= 0) { gsb->len = status; status = 0; } } else { status = i2c_smbus_write_block_data(client, command, gsb->len, gsb->data); } break; case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE: if (action == ACPI_READ) { status = acpi_gsb_i2c_read_bytes(client, command, gsb->data, info->access_length); if (status > 0) status = 0; } else { status = acpi_gsb_i2c_write_bytes(client, command, gsb->data, info->access_length); } break; default: dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n", accessor_type, client->addr); ret = AE_BAD_PARAMETER; goto err; } gsb->status = status; err: kfree(client); ACPI_FREE(ares); return ret; }

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int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { acpi_handle handle; struct i2c_acpi_handler_data *data; acpi_status status; if (!adapter->dev.parent) return -ENODEV; handle = ACPI_HANDLE(adapter->dev.parent); if (!handle) return -ENODEV; data = kzalloc(sizeof(struct i2c_acpi_handler_data), GFP_KERNEL); if (!data) return -ENOMEM; data->adapter = adapter; status = acpi_bus_attach_private_data(handle, (void *)data); if (ACPI_FAILURE(status)) { kfree(data); return -ENOMEM; } status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GSBUS, &i2c_acpi_space_handler, NULL, data); if (ACPI_FAILURE(status)) { dev_err(&adapter->dev, "Error installing i2c space handler\n"); acpi_bus_detach_private_data(handle); kfree(data); return -ENOMEM; } acpi_walk_dep_device_list(handle); return 0; }

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void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { acpi_handle handle; struct i2c_acpi_handler_data *data; acpi_status status; if (!adapter->dev.parent) return; handle = ACPI_HANDLE(adapter->dev.parent); if (!handle) return; acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GSBUS, &i2c_acpi_space_handler); status = acpi_bus_get_private_data(handle, (void **)&data); if (ACPI_SUCCESS(status)) kfree(data); acpi_bus_detach_private_data(handle); }

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#endif /* CONFIG_ACPI_I2C_OPREGION */

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Directory: drivers/i2c
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