i2c: break out ACPI support into separate file

Removes some ifdeffery. Also add the new file to the relevant
MAINTAINERS section.

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

4 files changed, 669 insertions, 648 deletions

diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 189e0e6476f0..7bb65a4369e1 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -5,6 +5,7 @@
 obj-$(CONFIG_I2C_BOARDINFO)	+= i2c-boardinfo.o
 obj-$(CONFIG_I2C)		+= i2c-core.o
 i2c-core-objs 			:= i2c-core-base.o i2c-core-smbus.o
+i2c-core-$(CONFIG_ACPI)		+= i2c-core-acpi.o
 i2c-core-$(CONFIG_I2C_SLAVE) 	+= i2c-core-slave.o
 i2c-core-$(CONFIG_OF) 		+= i2c-core-of.o
 
diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
new file mode 100644
index 000000000000..052005579ed6
--- /dev/null
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -0,0 +1,653 @@
+/*
+ * 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 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;
+
+	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 */
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 461451da1065..ac7b95e4cda7 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -16,8 +16,6 @@
 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
    Mux support by Rodolfo Giometti <giometti@enneenne.com> and
    Michael Lawnick <michael.lawnick.ext@nsn.com>
-   I2C ACPI code Copyright (C) 2014 Intel Corp
-   Author: Lan Tianyu <tianyu.lan@intel.com>
  */
 
 #define pr_fmt(fmt) "i2c-core: " fmt
@@ -83,652 +81,6 @@ void i2c_transfer_trace_unreg(void)
 	static_key_slow_dec(&i2c_trace_msg);
 }
 
-#if defined(CONFIG_ACPI)
-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 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;
-
-	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.
- */
-static 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;
-}
-
-static 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);
-#else /* CONFIG_ACPI */
-static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
-extern struct notifier_block i2c_acpi_notifier;
-#endif /* CONFIG_ACPI */
-
-#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;
-}
-
-
-static 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;
-}
-
-static 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);
-}
-#else /* CONFIG_ACPI_I2C_OPREGION */
-static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
-{ }
-
-static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
-{ return 0; }
-#endif /* CONFIG_ACPI_I2C_OPREGION */
-
-/* ------------------------------------------------------------------------- */
-
 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
 						const struct i2c_client *client)
 {
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
index 22151c88e885..3b63f5e5b89c 100644
--- a/drivers/i2c/i2c-core.h
+++ b/drivers/i2c/i2c-core.h
@@ -30,6 +30,21 @@ extern int		__i2c_first_dynamic_bus_num;
 int i2c_check_addr_validity(unsigned addr, unsigned short flags);
 int i2c_check_7bit_addr_validity_strict(unsigned short addr);
 
+#ifdef CONFIG_ACPI
+void i2c_acpi_register_devices(struct i2c_adapter *adap);
+#else /* CONFIG_ACPI */
+static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
+#endif /* CONFIG_ACPI */
+extern struct notifier_block i2c_acpi_notifier;
+
+#ifdef CONFIG_ACPI_I2C_OPREGION
+int i2c_acpi_install_space_handler(struct i2c_adapter *adapter);
+void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter);
+#else /* CONFIG_ACPI_I2C_OPREGION */
+static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { return 0; }
+static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { }
+#endif /* CONFIG_ACPI_I2C_OPREGION */
+
 #ifdef CONFIG_OF
 void of_i2c_register_devices(struct i2c_adapter *adap);
 #else