Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c fixes from Wolfram Sang:
 "This is probably not the kind of pull request you want to see that
  late in the cycle.  Yet, the ACPI refactorization was problematic
  again and caused another two issues which need fixing.  My holidays
  with limited internet (plus travelling) and the developer's illness
  didn't help either :(

  The details:

   - ACPI code was refactored out into a seperate file and as a
     side-effect, the i2c-core module got renamed.  Jean Delvare
     rightfully complained about the rename being problematic for
     distributions.  So, Mika and I thought the least problematic way to
     deal with it is to move all the code back into the main i2c core
     source file.  This is mainly a huge code move with some #ifdeffery
     applied.  No functional code changes.  Our personal tests and the
     testbots did not find problems.  (I was thinking about reverting,
     too, yet that would also have ~800 lines changed)

   - The new ACPI code also had a NULL pointer exception, thanks to
     Peter for finding and fixing it.

   - Mikko fixed a locking problem by decoupling clock_prepare and
     clock_enable.

   - Addy learnt that the datasheet was wrong and reimplemented the
     frequency setup according to the new algorithm.

  - Fan fixed an off-by-one error when copying data

  - Janusz fixed a copy'n'paste bug which gave a wrong error message

  - Sergei made sure that "don't touch" bits are not accessed"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: acpi: Fix NULL Pointer dereference
  i2c: move acpi code back into the core
  i2c: rk3x: fix divisor calculation for SCL frequency
  i2c: mxs: fix error message in pio transfer
  i2c: ismt: use correct length when copy buffer
  i2c: rcar: fix RCAR_IRQ_ACK_{RECV|SEND}
  i2c: tegra: Move clk_prepare/clk_set_rate to probe

8 files changed, 420 insertions, 391 deletions

diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index e0228b228256..1722f50f2473 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -2,11 +2,8 @@
 # Makefile for the i2c core.
 #
 
-i2ccore-y := i2c-core.o
-i2ccore-$(CONFIG_ACPI)	 	+= i2c-acpi.o
-
 obj-$(CONFIG_I2C_BOARDINFO)	+= i2c-boardinfo.o
-obj-$(CONFIG_I2C)		+= i2ccore.o
+obj-$(CONFIG_I2C)		+= i2c-core.o
 obj-$(CONFIG_I2C_SMBUS)		+= i2c-smbus.o
 obj-$(CONFIG_I2C_CHARDEV)	+= i2c-dev.o
 obj-$(CONFIG_I2C_MUX)		+= i2c-mux.o
diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c
index 984492553e95..d9ee43c80cde 100644
--- a/drivers/i2c/busses/i2c-ismt.c
+++ b/drivers/i2c/busses/i2c-ismt.c
@@ -497,7 +497,7 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
 			desc->wr_len_cmd = dma_size;
 			desc->control |= ISMT_DESC_BLK;
 			priv->dma_buffer[0] = command;
-			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size);
+			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size - 1);
 		} else {
 			/* Block Read */
 			dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA:  READ\n");
@@ -525,7 +525,7 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
 			desc->wr_len_cmd = dma_size;
 			desc->control |= ISMT_DESC_I2C;
 			priv->dma_buffer[0] = command;
-			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size);
+			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size - 1);
 		} else {
 			/* i2c Block Read */
 			dev_dbg(dev, "I2C_SMBUS_I2C_BLOCK_DATA:  READ\n");
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 7170fc892829..65a21fed08b5 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -429,7 +429,7 @@ static int mxs_i2c_pio_setup_xfer(struct i2c_adapter *adap,
 		ret = mxs_i2c_pio_wait_xfer_end(i2c);
 		if (ret) {
 			dev_err(i2c->dev,
-				"PIO: Failed to send SELECT command!\n");
+				"PIO: Failed to send READ command!\n");
 			goto cleanup;
 		}
 
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 1cc146cfc1f3..e506fcd3ca04 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -76,8 +76,8 @@
 #define RCAR_IRQ_RECV	(MNR | MAL | MST | MAT | MDR)
 #define RCAR_IRQ_STOP	(MST)
 
-#define RCAR_IRQ_ACK_SEND	(~(MAT | MDE))
-#define RCAR_IRQ_ACK_RECV	(~(MAT | MDR))
+#define RCAR_IRQ_ACK_SEND	(~(MAT | MDE) & 0xFF)
+#define RCAR_IRQ_ACK_RECV	(~(MAT | MDR) & 0xFF)
 
 #define ID_LAST_MSG	(1 << 0)
 #define ID_IOERROR	(1 << 1)
diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index e637c32ae517..93cfc837200b 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -433,12 +433,11 @@ static void rk3x_i2c_set_scl_rate(struct rk3x_i2c *i2c, unsigned long scl_rate)
 	unsigned long i2c_rate = clk_get_rate(i2c->clk);
 	unsigned int div;
 
-	/* SCL rate = (clk rate) / (8 * DIV) */
-	div = DIV_ROUND_UP(i2c_rate, scl_rate * 8);
-
-	/* The lower and upper half of the CLKDIV reg describe the length of
-	 * SCL low & high periods. */
-	div = DIV_ROUND_UP(div, 2);
+	/* set DIV = DIVH = DIVL
+	 * SCL rate = (clk rate) / (8 * (DIVH + 1 + DIVL + 1))
+	 *          = (clk rate) / (16 * (DIV + 1))
+	 */
+	div = DIV_ROUND_UP(i2c_rate, scl_rate * 16) - 1;
 
 	i2c_writel(i2c, (div << 16) | (div & 0xffff), REG_CLKDIV);
 }
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 87d0371cebb7..efba1ebe16ba 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -380,34 +380,33 @@ static inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev)
 {
 	int ret;
 	if (!i2c_dev->hw->has_single_clk_source) {
-		ret = clk_prepare_enable(i2c_dev->fast_clk);
+		ret = clk_enable(i2c_dev->fast_clk);
 		if (ret < 0) {
 			dev_err(i2c_dev->dev,
 				"Enabling fast clk failed, err %d\n", ret);
 			return ret;
 		}
 	}
-	ret = clk_prepare_enable(i2c_dev->div_clk);
+	ret = clk_enable(i2c_dev->div_clk);
 	if (ret < 0) {
 		dev_err(i2c_dev->dev,
 			"Enabling div clk failed, err %d\n", ret);
-		clk_disable_unprepare(i2c_dev->fast_clk);
+		clk_disable(i2c_dev->fast_clk);
 	}
 	return ret;
 }
 
 static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev)
 {
-	clk_disable_unprepare(i2c_dev->div_clk);
+	clk_disable(i2c_dev->div_clk);
 	if (!i2c_dev->hw->has_single_clk_source)
-		clk_disable_unprepare(i2c_dev->fast_clk);
+		clk_disable(i2c_dev->fast_clk);
 }
 
 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 {
 	u32 val;
 	int err = 0;
-	int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE;
 	u32 clk_divisor;
 
 	err = tegra_i2c_clock_enable(i2c_dev);
@@ -428,9 +427,6 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	i2c_writel(i2c_dev, val, I2C_CNFG);
 	i2c_writel(i2c_dev, 0, I2C_INT_MASK);
 
-	clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1);
-	clk_set_rate(i2c_dev->div_clk, i2c_dev->bus_clk_rate * clk_multiplier);
-
 	/* Make sure clock divisor programmed correctly */
 	clk_divisor = i2c_dev->hw->clk_divisor_hs_mode;
 	clk_divisor |= i2c_dev->hw->clk_divisor_std_fast_mode <<
@@ -712,6 +708,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	void __iomem *base;
 	int irq;
 	int ret = 0;
+	int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(&pdev->dev, res);
@@ -777,17 +774,39 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, i2c_dev);
 
+	if (!i2c_dev->hw->has_single_clk_source) {
+		ret = clk_prepare(i2c_dev->fast_clk);
+		if (ret < 0) {
+			dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
+			return ret;
+		}
+	}
+
+	clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1);
+	ret = clk_set_rate(i2c_dev->div_clk,
+			   i2c_dev->bus_clk_rate * clk_multiplier);
+	if (ret) {
+		dev_err(i2c_dev->dev, "Clock rate change failed %d\n", ret);
+		goto unprepare_fast_clk;
+	}
+
+	ret = clk_prepare(i2c_dev->div_clk);
+	if (ret < 0) {
+		dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
+		goto unprepare_fast_clk;
+	}
+
 	ret = tegra_i2c_init(i2c_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to initialize i2c controller");
-		return ret;
+		goto unprepare_div_clk;
 	}
 
 	ret = devm_request_irq(&pdev->dev, i2c_dev->irq,
 			tegra_i2c_isr, 0, dev_name(&pdev->dev), i2c_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
-		return ret;
+		goto unprepare_div_clk;
 	}
 
 	i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
@@ -803,16 +822,30 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to add I2C adapter\n");
-		return ret;
+		goto unprepare_div_clk;
 	}
 
 	return 0;
+
+unprepare_div_clk:
+	clk_unprepare(i2c_dev->div_clk);
+
+unprepare_fast_clk:
+	if (!i2c_dev->hw->has_single_clk_source)
+		clk_unprepare(i2c_dev->fast_clk);
+
+	return ret;
 }
 
 static int tegra_i2c_remove(struct platform_device *pdev)
 {
 	struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 	i2c_del_adapter(&i2c_dev->adapter);
+
+	clk_unprepare(i2c_dev->div_clk);
+	if (!i2c_dev->hw->has_single_clk_source)
+		clk_unprepare(i2c_dev->fast_clk);
+
 	return 0;
 }
 
diff --git a/drivers/i2c/i2c-acpi.c b/drivers/i2c/i2c-acpi.c
deleted file mode 100644
index 0dbc18c15c43..000000000000
--- a/drivers/i2c/i2c-acpi.c
+++ /dev/null
@@ -1,364 +0,0 @@
-/*
- * I2C ACPI 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 version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * for more details.
- */
-#define pr_fmt(fmt) "I2C/ACPI : " fmt
-
-#include <linux/kernel.h>
-#include <linux/errno.h>
-#include <linux/err.h>
-#include <linux/i2c.h>
-#include <linux/acpi.h>
-
-struct acpi_i2c_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;
-
-static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
-{
-	struct i2c_board_info *info = data;
-
-	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
-		struct acpi_resource_i2c_serialbus *sb;
-
-		sb = &ares->data.i2c_serial_bus;
-		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
-			info->addr = sb->slave_address;
-			if (sb->access_mode == ACPI_I2C_10BIT_MODE)
-				info->flags |= I2C_CLIENT_TEN;
-		}
-	} else if (info->irq < 0) {
-		struct resource r;
-
-		if (acpi_dev_resource_interrupt(ares, 0, &r))
-			info->irq = r.start;
-	}
-
-	/* Tell the ACPI core to skip this resource */
-	return 1;
-}
-
-static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
-				       void *data, void **return_value)
-{
-	struct i2c_adapter *adapter = data;
-	struct list_head resource_list;
-	struct i2c_board_info info;
-	struct acpi_device *adev;
-	int ret;
-
-	if (acpi_bus_get_device(handle, &adev))
-		return AE_OK;
-	if (acpi_bus_get_status(adev) || !adev->status.present)
-		return AE_OK;
-
-	memset(&info, 0, sizeof(info));
-	info.acpi_node.companion = adev;
-	info.irq = -1;
-
-	INIT_LIST_HEAD(&resource_list);
-	ret = acpi_dev_get_resources(adev, &resource_list,
-				     acpi_i2c_add_resource, &info);
-	acpi_dev_free_resource_list(&resource_list);
-
-	if (ret < 0 || !info.addr)
-		return AE_OK;
-
-	adev->power.flags.ignore_parent = true;
-	strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
-	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));
-	}
-
-	return AE_OK;
-}
-
-/**
- * acpi_i2c_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 acpi_i2c_register_devices(struct i2c_adapter *adap)
-{
-	acpi_handle handle;
-	acpi_status status;
-
-	if (!adap->dev.parent)
-		return;
-
-	handle = ACPI_HANDLE(adap->dev.parent);
-	if (!handle)
-		return;
-
-	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
-				     acpi_i2c_add_device, NULL,
-				     adap, NULL);
-	if (ACPI_FAILURE(status))
-		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
-}
-
-#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
-acpi_i2c_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 acpi_i2c_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 = AE_OK;
-	int status;
-
-	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
-	if (ACPI_FAILURE(ret))
-		return ret;
-
-	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;
-	}
-
-	memset(&client, 0, sizeof(client));
-	client.adapter = adapter;
-	client.addr = sb->slave_address;
-	client.flags = 0;
-
-	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:
-		pr_info("protocol(0x%02x) is not supported.\n", accessor_type);
-		ret = AE_BAD_PARAMETER;
-		goto err;
-	}
-
-	gsb->status = status;
-
- err:
-	ACPI_FREE(ares);
-	return ret;
-}
-
-
-int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
-{
-	acpi_handle handle = ACPI_HANDLE(adapter->dev.parent);
-	struct acpi_i2c_handler_data *data;
-	acpi_status status;
-
-	if (!handle)
-		return -ENODEV;
-
-	data = kzalloc(sizeof(struct acpi_i2c_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,
-				&acpi_i2c_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 acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
-{
-	acpi_handle handle = ACPI_HANDLE(adapter->dev.parent);
-	struct acpi_i2c_handler_data *data;
-	acpi_status status;
-
-	if (!handle)
-		return;
-
-	acpi_remove_address_space_handler(handle,
-				ACPI_ADR_SPACE_GSBUS,
-				&acpi_i2c_space_handler);
-
-	status = acpi_bus_get_private_data(handle, (void **)&data);
-	if (ACPI_SUCCESS(status))
-		kfree(data);
-
-	acpi_bus_detach_private_data(handle);
-}
-#endif
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 632057a44615..ccfbbab82a15 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -27,6 +27,8 @@
    OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
    (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
    (c) 2013  Wolfram Sang <wsa@the-dreams.de>
+   I2C ACPI code Copyright (C) 2014 Intel Corp
+   Author: Lan Tianyu <tianyu.lan@intel.com>
  */
 
 #include <linux/module.h>
@@ -78,6 +80,368 @@ void i2c_transfer_trace_unreg(void)
 	static_key_slow_dec(&i2c_trace_msg);
 }
 
+#if defined(CONFIG_ACPI)
+struct acpi_i2c_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;
+
+static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
+{
+	struct i2c_board_info *info = data;
+
+	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
+		struct acpi_resource_i2c_serialbus *sb;
+
+		sb = &ares->data.i2c_serial_bus;
+		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
+			info->addr = sb->slave_address;
+			if (sb->access_mode == ACPI_I2C_10BIT_MODE)
+				info->flags |= I2C_CLIENT_TEN;
+		}
+	} else if (info->irq < 0) {
+		struct resource r;
+
+		if (acpi_dev_resource_interrupt(ares, 0, &r))
+			info->irq = r.start;
+	}
+
+	/* Tell the ACPI core to skip this resource */
+	return 1;
+}
+
+static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
+				       void *data, void **return_value)
+{
+	struct i2c_adapter *adapter = data;
+	struct list_head resource_list;
+	struct i2c_board_info info;
+	struct acpi_device *adev;
+	int ret;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return AE_OK;
+	if (acpi_bus_get_status(adev) || !adev->status.present)
+		return AE_OK;
+
+	memset(&info, 0, sizeof(info));
+	info.acpi_node.companion = adev;
+	info.irq = -1;
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     acpi_i2c_add_resource, &info);
+	acpi_dev_free_resource_list(&resource_list);
+
+	if (ret < 0 || !info.addr)
+		return AE_OK;
+
+	adev->power.flags.ignore_parent = true;
+	strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
+	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));
+	}
+
+	return AE_OK;
+}
+
+/**
+ * acpi_i2c_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 acpi_i2c_register_devices(struct i2c_adapter *adap)
+{
+	acpi_handle handle;
+	acpi_status status;
+
+	if (!adap->dev.parent)
+		return;
+
+	handle = ACPI_HANDLE(adap->dev.parent);
+	if (!handle)
+		return;
+
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+				     acpi_i2c_add_device, NULL,
+				     adap, NULL);
+	if (ACPI_FAILURE(status))
+		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
+}
+
+#else /* CONFIG_ACPI */
+static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) { }
+#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
+acpi_i2c_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 acpi_i2c_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 = AE_OK;
+	int status;
+
+	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
+	if (ACPI_FAILURE(ret))
+		return ret;
+
+	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;
+	}
+
+	memset(&client, 0, sizeof(client));
+	client.adapter = adapter;
+	client.addr = sb->slave_address;
+	client.flags = 0;
+
+	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:
+		pr_info("protocol(0x%02x) is not supported.\n", accessor_type);
+		ret = AE_BAD_PARAMETER;
+		goto err;
+	}
+
+	gsb->status = status;
+
+ err:
+	ACPI_FREE(ares);
+	return ret;
+}
+
+
+static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
+{
+	acpi_handle handle;
+	struct acpi_i2c_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 acpi_i2c_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,
+				&acpi_i2c_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;
+}
+
+static void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
+{
+	acpi_handle handle;
+	struct acpi_i2c_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,
+				&acpi_i2c_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 acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
+{ }
+
+static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
+{ return 0; }
+#endif /* CONFIG_ACPI_I2C_OPREGION */
+
 /* ------------------------------------------------------------------------- */
 
 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,