1 files changed, 824 insertions, 0 deletions

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
new file mode 100644
index 000000000..4dd777cc0
--- /dev/null
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -0,0 +1,824 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux I2C core ACPI support code
+ *
+ * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
+ */
+
+#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;
+		DECLARE_FLEX_ARRAY(u8, data);
+	};
+} __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;
+	u32 force_speed;
+};
+
+/**
+ * i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches
+ * @ares:	ACPI resource
+ * @i2c:	Pointer to I2cSerialBus resource will be returned here
+ *
+ * Checks if the given ACPI resource is of type I2cSerialBus.
+ * In this case, returns a pointer to it to the caller.
+ *
+ * Returns true if resource type is of I2cSerialBus, otherwise false.
+ */
+bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
+			       struct acpi_resource_i2c_serialbus **i2c)
+{
+	struct acpi_resource_i2c_serialbus *sb;
+
+	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+		return false;
+
+	sb = &ares->data.i2c_serial_bus;
+	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
+		return false;
+
+	*i2c = sb;
+	return true;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
+
+static int i2c_acpi_resource_count(struct acpi_resource *ares, void *data)
+{
+	struct acpi_resource_i2c_serialbus *sb;
+	int *count = data;
+
+	if (i2c_acpi_get_i2c_resource(ares, &sb))
+		*count = *count + 1;
+
+	return 1;
+}
+
+/**
+ * i2c_acpi_client_count - Count the number of I2cSerialBus resources
+ * @adev:	ACPI device
+ *
+ * Returns the number of I2cSerialBus resources in the ACPI-device's
+ * resource-list; or a negative error code.
+ */
+int i2c_acpi_client_count(struct acpi_device *adev)
+{
+	int ret, count = 0;
+	LIST_HEAD(r);
+
+	ret = acpi_dev_get_resources(adev, &r, i2c_acpi_resource_count, &count);
+	if (ret < 0)
+		return ret;
+
+	acpi_dev_free_resource_list(&r);
+	return count;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_client_count);
+
+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 || !i2c_acpi_get_i2c_resource(ares, &sb))
+		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_FAILURE(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 },
+	{}
+};
+
+struct i2c_acpi_irq_context {
+	int irq;
+	bool wake_capable;
+};
+
+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))
+		return -EINVAL;
+
+	if (!acpi_dev_ready_for_enumeration(adev))
+		return -ENODEV;
+
+	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_add_irq_resource(struct acpi_resource *ares, void *data)
+{
+	struct i2c_acpi_irq_context *irq_ctx = data;
+	struct resource r;
+
+	if (irq_ctx->irq > 0)
+		return 1;
+
+	if (!acpi_dev_resource_interrupt(ares, 0, &r))
+		return 1;
+
+	irq_ctx->irq = i2c_dev_irq_from_resources(&r, 1);
+	irq_ctx->wake_capable = r.flags & IORESOURCE_IRQ_WAKECAPABLE;
+
+	return 1; /* No need to add resource to the list */
+}
+
+/**
+ * i2c_acpi_get_irq - get device IRQ number from ACPI
+ * @client: Pointer to the I2C client device
+ * @wake_capable: Set to true if the IRQ is wake capable
+ *
+ * Find the IRQ number used by a specific client device.
+ *
+ * Return: The IRQ number or an error code.
+ */
+int i2c_acpi_get_irq(struct i2c_client *client, bool *wake_capable)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
+	struct list_head resource_list;
+	struct i2c_acpi_irq_context irq_ctx = {
+		.irq = -ENOENT,
+	};
+	int ret;
+
+	INIT_LIST_HEAD(&resource_list);
+
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     i2c_acpi_add_irq_resource, &irq_ctx);
+	if (ret < 0)
+		return ret;
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	if (irq_ctx.irq == -ENOENT)
+		irq_ctx.irq = acpi_dev_gpio_irq_wake_get(adev, 0, &irq_ctx.wake_capable);
+
+	if (irq_ctx.irq < 0)
+		return irq_ctx.irq;
+
+	if (wake_capable)
+		*wake_capable = irq_ctx.wake_capable;
+
+	return irq_ctx.irq;
+}
+
+static int i2c_acpi_get_info(struct acpi_device *adev,
+			     struct i2c_board_info *info,
+			     struct i2c_adapter *adapter,
+			     acpi_handle *adapter_handle)
+{
+	struct i2c_acpi_lookup lookup;
+	int ret;
+
+	memset(&lookup, 0, sizeof(lookup));
+	lookup.info = info;
+	lookup.index = -1;
+
+	if (acpi_device_enumerated(adev))
+		return -EINVAL;
+
+	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 */
+		adapter_adev = acpi_fetch_acpi_dev(lookup.adapter_handle);
+		if (!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;
+
+	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)
+{
+	/*
+	 * Skip registration on boards where the ACPI tables are
+	 * known to contain bogus I2C devices.
+	 */
+	if (acpi_quirk_skip_i2c_client_enumeration(adev))
+		return;
+
+	adev->power.flags.ignore_parent = true;
+	acpi_device_set_enumerated(adev);
+
+	if (IS_ERR(i2c_new_client_device(adapter, info)))
+		adev->power.flags.ignore_parent = false;
+}
+
+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 = acpi_fetch_acpi_dev(handle);
+	struct i2c_board_info info;
+
+	if (!adev || 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)
+{
+	struct acpi_device *adev;
+	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");
+
+	if (!adap->dev.parent)
+		return;
+
+	adev = ACPI_COMPANION(adap->dev.parent);
+	if (!adev)
+		return;
+
+	acpi_dev_clear_dependencies(adev);
+}
+
+static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
+	/*
+	 * These Silead touchscreen controllers only work at 400KHz, for
+	 * some reason they do not work at 100KHz. On some devices the ACPI
+	 * tables list another device at their bus as only being capable
+	 * of 100KHz, testing has shown that these other devices work fine
+	 * at 400KHz (as can be expected of any recent i2c hw) so we force
+	 * the speed of the bus to 400 KHz if a Silead device is present.
+	 */
+	{ "MSSL1680", 0 },
+	{}
+};
+
+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 = acpi_fetch_acpi_dev(handle);
+
+	if (!adev || 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;
+
+	if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
+		lookup->force_speed = I2C_MAX_FAST_MODE_FREQ;
+
+	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;
+	}
+
+	if (lookup.force_speed) {
+		if (lookup.force_speed != lookup.min_speed)
+			dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
+				 lookup.min_speed, lookup.force_speed);
+		return lookup.force_speed;
+	} else if (lookup.min_speed != UINT_MAX) {
+		return lookup.min_speed;
+	} else {
+		return 0;
+	}
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
+
+struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
+{
+	struct i2c_adapter *adapter;
+	struct device *dev;
+
+	dev = bus_find_device(&i2c_bus_type, NULL, handle, device_match_acpi_handle);
+	if (!dev)
+		return NULL;
+
+	adapter = i2c_verify_adapter(dev);
+	if (!adapter)
+		put_device(dev);
+
+	return adapter;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
+
+static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
+{
+	struct device *dev;
+	struct i2c_client *client;
+
+	dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
+	if (!dev)
+		return NULL;
+
+	client = i2c_verify_client(dev);
+	if (!client)
+		put_device(dev);
+
+	return client;
+}
+
+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);
+		put_device(&adapter->dev);
+		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_by_fwnode - Create i2c-client for the Nth I2cSerialBus resource
+ * @fwnode:  fwnode with 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_client_device, which this function calls to create the
+ * i2c-client.
+ *
+ * Returns a pointer to the new i2c-client, or error pointer in case of failure.
+ * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
+ */
+struct i2c_client *i2c_acpi_new_device_by_fwnode(struct fwnode_handle *fwnode,
+						 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 = to_acpi_device_node(fwnode);
+	if (!adev)
+		return ERR_PTR(-ENODEV);
+
+	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);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	if (!info->addr)
+		return ERR_PTR(-EADDRNOTAVAIL);
+
+	adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
+	if (!adapter)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	return i2c_new_client_device(adapter, info);
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_new_device_by_fwnode);
+
+bool i2c_acpi_waive_d0_probe(struct device *dev)
+{
+	struct i2c_driver *driver = to_i2c_driver(dev->driver);
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	return driver->flags & I2C_DRV_ACPI_WAIVE_D0_PROBE &&
+		adev && adev->power.state_for_enumeration >= adev->power.state;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
+
+#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) {
+		/* Getting a NACK is unfortunately normal with some DSTDs */
+		if (ret == -EREMOTEIO)
+			dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
+				data_len, client->addr, cmd, ret);
+		else
+			dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
+				data_len, client->addr, cmd, ret);
+	/* 2 transfers must have completed successfully */
+	} else if (ret == 2) {
+		memcpy(data, buffer, data_len);
+		ret = 0;
+	} else {
+		ret = -EIO;
+	}
+
+	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));
+
+	kfree(buffer);
+
+	if (ret < 0) {
+		dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
+		return ret;
+	}
+
+	/* 1 transfer must have completed successfully */
+	return (ret == 1) ? 0 : -EIO;
+}
+
+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 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
+		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);
+		} 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;
+	}
+
+	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 */