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path: root/drivers/i2c/i2c-core-acpi.c
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Diffstat (limited to 'drivers/i2c/i2c-core-acpi.c')
-rw-r--r--drivers/i2c/i2c-core-acpi.c665
1 files changed, 665 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
new file mode 100644
index 000000000000..4842ec3a5451
--- /dev/null
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -0,0 +1,665 @@
+/*
+ * 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;
+}
+
+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;
+}
+
+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;
+}
+
+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));
+ }
+}
+
+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;
+}
+
+#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");
+}
+
+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;
+}
+
+/**
+ * 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;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
+
+static int i2c_acpi_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;
+}
+
+static int i2c_acpi_match_device(struct device *dev, void *data)
+{
+ return ACPI_COMPANION(dev) == data;
+}
+
+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_match_adapter);
+ return dev ? i2c_verify_adapter(dev) : NULL;
+}
+
+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_match_device);
+ return dev ? i2c_verify_client(dev) : NULL;
+}
+
+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;
+}
+
+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);
+}
+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;
+}
+
+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;
+}
+
+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;
+}
+
+
+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;
+}
+
+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);
+}
+#endif /* CONFIG_ACPI_I2C_OPREGION */