15 files changed, 1314 insertions, 136 deletions

diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index a39e6cff86e..38319a69bd0 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -600,12 +600,14 @@ static const struct i2c_algorithm i2c_bit_algo = {
 /*
  * registering functions to load algorithms at runtime
  */
-static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
+static int __i2c_bit_add_bus(struct i2c_adapter *adap,
+			     int (*add_adapter)(struct i2c_adapter *))
 {
 	struct i2c_algo_bit_data *bit_adap = adap->algo_data;
+	int ret;
 
 	if (bit_test) {
-		int ret = test_bus(bit_adap, adap->name);
+		ret = test_bus(bit_adap, adap->name);
 		if (ret < 0)
 			return -ENODEV;
 	}
@@ -614,30 +616,27 @@ static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
 	adap->algo = &i2c_bit_algo;
 	adap->retries = 3;
 
+	ret = add_adapter(adap);
+	if (ret < 0)
+		return ret;
+
+	/* Complain if SCL can't be read */
+	if (bit_adap->getscl == NULL) {
+		dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n");
+		dev_warn(&adap->dev, "Bus may be unreliable\n");
+	}
 	return 0;
 }
 
 int i2c_bit_add_bus(struct i2c_adapter *adap)
 {
-	int err;
-
-	err = i2c_bit_prepare_bus(adap);
-	if (err)
-		return err;
-
-	return i2c_add_adapter(adap);
+	return __i2c_bit_add_bus(adap, i2c_add_adapter);
 }
 EXPORT_SYMBOL(i2c_bit_add_bus);
 
 int i2c_bit_add_numbered_bus(struct i2c_adapter *adap)
 {
-	int err;
-
-	err = i2c_bit_prepare_bus(adap);
-	if (err)
-		return err;
-
-	return i2c_add_numbered_adapter(adap);
+	return __i2c_bit_add_bus(adap, i2c_add_numbered_adapter);
 }
 EXPORT_SYMBOL(i2c_bit_add_numbered_bus);
 
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 3a6321cb803..113505a6434 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -638,6 +638,14 @@ config I2C_XILINX
 	  This driver can also be built as a module.  If so, the module
 	  will be called xilinx_i2c.
 
+config I2C_EG20T
+        tristate "PCH I2C of Intel EG20T"
+        depends on PCI
+        help
+          This driver is for PCH(Platform controller Hub) I2C of EG20T which
+          is an IOH(Input/Output Hub) for x86 embedded processor.
+          This driver can access PCH I2C bus device.
+
 comment "External I2C/SMBus adapter drivers"
 
 config I2C_PARPORT
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 84cb16ae6f9..9d2d0ec7fb2 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
 obj-$(CONFIG_I2C_VERSATILE)	+= i2c-versatile.o
 obj-$(CONFIG_I2C_OCTEON)	+= i2c-octeon.o
 obj-$(CONFIG_I2C_XILINX)	+= i2c-xiic.o
+obj-$(CONFIG_I2C_EG20T)         += i2c-eg20t.o
 
 # External I2C/SMBus adapter drivers
 obj-$(CONFIG_I2C_PARPORT)	+= i2c-parport.o
diff --git a/drivers/i2c/busses/i2c-eg20t.c b/drivers/i2c/busses/i2c-eg20t.c
new file mode 100644
index 00000000000..2e067dd2ee5
--- /dev/null
+++ b/drivers/i2c/busses/i2c-eg20t.c
@@ -0,0 +1,900 @@
+/*
+ * Copyright (C) 2010 OKI SEMICONDUCTOR CO., LTD.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/pci.h>
+#include <linux/mutex.h>
+#include <linux/ktime.h>
+
+#define PCH_EVENT_SET	0	/* I2C Interrupt Event Set Status */
+#define PCH_EVENT_NONE	1	/* I2C Interrupt Event Clear Status */
+#define PCH_MAX_CLK		100000	/* Maximum Clock speed in MHz */
+#define PCH_BUFFER_MODE_ENABLE	0x0002	/* flag for Buffer mode enable */
+#define PCH_EEPROM_SW_RST_MODE_ENABLE	0x0008	/* EEPROM SW RST enable flag */
+
+#define PCH_I2CSADR	0x00	/* I2C slave address register */
+#define PCH_I2CCTL	0x04	/* I2C control register */
+#define PCH_I2CSR	0x08	/* I2C status register */
+#define PCH_I2CDR	0x0C	/* I2C data register */
+#define PCH_I2CMON	0x10	/* I2C bus monitor register */
+#define PCH_I2CBC	0x14	/* I2C bus transfer rate setup counter */
+#define PCH_I2CMOD	0x18	/* I2C mode register */
+#define PCH_I2CBUFSLV	0x1C	/* I2C buffer mode slave address register */
+#define PCH_I2CBUFSUB	0x20	/* I2C buffer mode subaddress register */
+#define PCH_I2CBUFFOR	0x24	/* I2C buffer mode format register */
+#define PCH_I2CBUFCTL	0x28	/* I2C buffer mode control register */
+#define PCH_I2CBUFMSK	0x2C	/* I2C buffer mode interrupt mask register */
+#define PCH_I2CBUFSTA	0x30	/* I2C buffer mode status register */
+#define PCH_I2CBUFLEV	0x34	/* I2C buffer mode level register */
+#define PCH_I2CESRFOR	0x38	/* EEPROM software reset mode format register */
+#define PCH_I2CESRCTL	0x3C	/* EEPROM software reset mode ctrl register */
+#define PCH_I2CESRMSK	0x40	/* EEPROM software reset mode */
+#define PCH_I2CESRSTA	0x44	/* EEPROM software reset mode status register */
+#define PCH_I2CTMR	0x48	/* I2C timer register */
+#define PCH_I2CSRST	0xFC	/* I2C reset register */
+#define PCH_I2CNF	0xF8	/* I2C noise filter register */
+
+#define BUS_IDLE_TIMEOUT	20
+#define PCH_I2CCTL_I2CMEN	0x0080
+#define TEN_BIT_ADDR_DEFAULT	0xF000
+#define TEN_BIT_ADDR_MASK	0xF0
+#define PCH_START		0x0020
+#define PCH_ESR_START		0x0001
+#define PCH_BUFF_START		0x1
+#define PCH_REPSTART		0x0004
+#define PCH_ACK			0x0008
+#define PCH_GETACK		0x0001
+#define CLR_REG			0x0
+#define I2C_RD			0x1
+#define I2CMCF_BIT		0x0080
+#define I2CMIF_BIT		0x0002
+#define I2CMAL_BIT		0x0010
+#define I2CBMFI_BIT		0x0001
+#define I2CBMAL_BIT		0x0002
+#define I2CBMNA_BIT		0x0004
+#define I2CBMTO_BIT		0x0008
+#define I2CBMIS_BIT		0x0010
+#define I2CESRFI_BIT		0X0001
+#define I2CESRTO_BIT		0x0002
+#define I2CESRFIIE_BIT		0x1
+#define I2CESRTOIE_BIT		0x2
+#define I2CBMDZ_BIT		0x0040
+#define I2CBMAG_BIT		0x0020
+#define I2CMBB_BIT		0x0020
+#define BUFFER_MODE_MASK	(I2CBMFI_BIT | I2CBMAL_BIT | I2CBMNA_BIT | \
+				I2CBMTO_BIT | I2CBMIS_BIT)
+#define I2C_ADDR_MSK		0xFF
+#define I2C_MSB_2B_MSK		0x300
+#define FAST_MODE_CLK		400
+#define FAST_MODE_EN		0x0001
+#define SUB_ADDR_LEN_MAX	4
+#define BUF_LEN_MAX		32
+#define PCH_BUFFER_MODE		0x1
+#define EEPROM_SW_RST_MODE	0x0002
+#define NORMAL_INTR_ENBL	0x0300
+#define EEPROM_RST_INTR_ENBL	(I2CESRFIIE_BIT | I2CESRTOIE_BIT)
+#define EEPROM_RST_INTR_DISBL	0x0
+#define BUFFER_MODE_INTR_ENBL	0x001F
+#define BUFFER_MODE_INTR_DISBL	0x0
+#define NORMAL_MODE		0x0
+#define BUFFER_MODE		0x1
+#define EEPROM_SR_MODE		0x2
+#define I2C_TX_MODE		0x0010
+#define PCH_BUF_TX		0xFFF7
+#define PCH_BUF_RD		0x0008
+#define I2C_ERROR_MASK	(I2CESRTO_EVENT | I2CBMIS_EVENT | I2CBMTO_EVENT | \
+			I2CBMNA_EVENT | I2CBMAL_EVENT | I2CMAL_EVENT)
+#define I2CMAL_EVENT		0x0001
+#define I2CMCF_EVENT		0x0002
+#define I2CBMFI_EVENT		0x0004
+#define I2CBMAL_EVENT		0x0008
+#define I2CBMNA_EVENT		0x0010
+#define I2CBMTO_EVENT		0x0020
+#define I2CBMIS_EVENT		0x0040
+#define I2CESRFI_EVENT		0x0080
+#define I2CESRTO_EVENT		0x0100
+#define PCI_DEVICE_ID_PCH_I2C	0x8817
+
+#define pch_dbg(adap, fmt, arg...)  \
+	dev_dbg(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
+
+#define pch_err(adap, fmt, arg...)  \
+	dev_err(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
+
+#define pch_pci_err(pdev, fmt, arg...)  \
+	dev_err(&pdev->dev, "%s :" fmt, __func__, ##arg)
+
+#define pch_pci_dbg(pdev, fmt, arg...)  \
+	dev_dbg(&pdev->dev, "%s :" fmt, __func__, ##arg)
+
+/**
+ * struct i2c_algo_pch_data - for I2C driver functionalities
+ * @pch_adapter:		stores the reference to i2c_adapter structure
+ * @p_adapter_info:		stores the reference to adapter_info structure
+ * @pch_base_address:		specifies the remapped base address
+ * @pch_buff_mode_en:		specifies if buffer mode is enabled
+ * @pch_event_flag:		specifies occurrence of interrupt events
+ * @pch_i2c_xfer_in_progress:	specifies whether the transfer is completed
+ */
+struct i2c_algo_pch_data {
+	struct i2c_adapter pch_adapter;
+	struct adapter_info *p_adapter_info;
+	void __iomem *pch_base_address;
+	int pch_buff_mode_en;
+	u32 pch_event_flag;
+	bool pch_i2c_xfer_in_progress;
+};
+
+/**
+ * struct adapter_info - This structure holds the adapter information for the
+			 PCH i2c controller
+ * @pch_data:		stores a list of i2c_algo_pch_data
+ * @pch_i2c_suspended:	specifies whether the system is suspended or not
+ *			perhaps with more lines and words.
+ *
+ * pch_data has as many elements as maximum I2C channels
+ */
+struct adapter_info {
+	struct i2c_algo_pch_data pch_data;
+	bool pch_i2c_suspended;
+};
+
+
+static int pch_i2c_speed = 100; /* I2C bus speed in Kbps */
+static int pch_clk = 50000;	/* specifies I2C clock speed in KHz */
+static wait_queue_head_t pch_event;
+static DEFINE_MUTEX(pch_mutex);
+
+static struct pci_device_id __devinitdata pch_pcidev_id[] = {
+	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_PCH_I2C)},
+	{0,}
+};
+
+static irqreturn_t pch_i2c_handler(int irq, void *pData);
+
+static inline void pch_setbit(void __iomem *addr, u32 offset, u32 bitmask)
+{
+	u32 val;
+	val = ioread32(addr + offset);
+	val |= bitmask;
+	iowrite32(val, addr + offset);
+}
+
+static inline void pch_clrbit(void __iomem *addr, u32 offset, u32 bitmask)
+{
+	u32 val;
+	val = ioread32(addr + offset);
+	val &= (~bitmask);
+	iowrite32(val, addr + offset);
+}
+
+/**
+ * pch_i2c_init() - hardware initialization of I2C module
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static void pch_i2c_init(struct i2c_algo_pch_data *adap)
+{
+	void __iomem *p = adap->pch_base_address;
+	u32 pch_i2cbc;
+	u32 pch_i2ctmr;
+	u32 reg_value;
+
+	/* reset I2C controller */
+	iowrite32(0x01, p + PCH_I2CSRST);
+	msleep(20);
+	iowrite32(0x0, p + PCH_I2CSRST);
+
+	/* Initialize I2C registers */
+	iowrite32(0x21, p + PCH_I2CNF);
+
+	pch_setbit(adap->pch_base_address, PCH_I2CCTL,
+			  PCH_I2CCTL_I2CMEN);
+
+	if (pch_i2c_speed != 400)
+		pch_i2c_speed = 100;
+
+	reg_value = PCH_I2CCTL_I2CMEN;
+	if (pch_i2c_speed == FAST_MODE_CLK) {
+		reg_value |= FAST_MODE_EN;
+		pch_dbg(adap, "Fast mode enabled\n");
+	}
+
+	if (pch_clk > PCH_MAX_CLK)
+		pch_clk = 62500;
+
+	pch_i2cbc = (pch_clk + (pch_i2c_speed * 4)) / pch_i2c_speed * 8;
+	/* Set transfer speed in I2CBC */
+	iowrite32(pch_i2cbc, p + PCH_I2CBC);
+
+	pch_i2ctmr = (pch_clk) / 8;
+	iowrite32(pch_i2ctmr, p + PCH_I2CTMR);
+
+	reg_value |= NORMAL_INTR_ENBL;	/* Enable interrupts in normal mode */
+	iowrite32(reg_value, p + PCH_I2CCTL);
+
+	pch_dbg(adap,
+		"I2CCTL=%x pch_i2cbc=%x pch_i2ctmr=%x Enable interrupts\n",
+		ioread32(p + PCH_I2CCTL), pch_i2cbc, pch_i2ctmr);
+
+	init_waitqueue_head(&pch_event);
+}
+
+static inline bool ktime_lt(const ktime_t cmp1, const ktime_t cmp2)
+{
+	return cmp1.tv64 < cmp2.tv64;
+}
+
+/**
+ * pch_i2c_wait_for_bus_idle() - check the status of bus.
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ * @timeout:	waiting time counter (us).
+ */
+static s32 pch_i2c_wait_for_bus_idle(struct i2c_algo_pch_data *adap,
+				 s32 timeout)
+{
+	void __iomem *p = adap->pch_base_address;
+
+	/* MAX timeout value is timeout*1000*1000nsec */
+	ktime_t ns_val = ktime_add_ns(ktime_get(), timeout*1000*1000);
+	do {
+		if ((ioread32(p + PCH_I2CSR) & I2CMBB_BIT) == 0)
+			break;
+		msleep(20);
+	} while (ktime_lt(ktime_get(), ns_val));
+
+	pch_dbg(adap, "I2CSR = %x\n", ioread32(p + PCH_I2CSR));
+
+	if (timeout == 0) {
+		pch_err(adap, "%s: Timeout Error.return%d\n", __func__, -ETIME);
+		return -ETIME;
+	}
+
+	return 0;
+}
+
+/**
+ * pch_i2c_start() - Generate I2C start condition in normal mode.
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ *
+ * Generate I2C start condition in normal mode by setting I2CCTL.I2CMSTA to 1.
+ */
+static void pch_i2c_start(struct i2c_algo_pch_data *adap)
+{
+	void __iomem *p = adap->pch_base_address;
+	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
+	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
+}
+
+/**
+ * pch_i2c_wait_for_xfer_complete() - initiates a wait for the tx complete event
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static s32 pch_i2c_wait_for_xfer_complete(struct i2c_algo_pch_data *adap)
+{
+	s32 ret;
+	ret = wait_event_timeout(pch_event,
+			(adap->pch_event_flag != 0), msecs_to_jiffies(50));
+	if (ret < 0) {
+		pch_err(adap, "timeout: %x\n", adap->pch_event_flag);
+		return ret;
+	}
+
+	if (ret == 0) {
+		pch_err(adap, "timeout: %x\n", adap->pch_event_flag);
+		return -ETIMEDOUT;
+	}
+
+	if (adap->pch_event_flag & I2C_ERROR_MASK) {
+		pch_err(adap, "error bits set: %x\n", adap->pch_event_flag);
+		return -EIO;
+	}
+
+	adap->pch_event_flag = 0;
+
+	return 0;
+}
+
+/**
+ * pch_i2c_getack() - to confirm ACK/NACK
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static s32 pch_i2c_getack(struct i2c_algo_pch_data *adap)
+{
+	u32 reg_val;
+	void __iomem *p = adap->pch_base_address;
+	reg_val = ioread32(p + PCH_I2CSR) & PCH_GETACK;
+
+	if (reg_val != 0) {
+		pch_err(adap, "return%d\n", -EPROTO);
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+/**
+ * pch_i2c_stop() - generate stop condition in normal mode.
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static void pch_i2c_stop(struct i2c_algo_pch_data *adap)
+{
+	void __iomem *p = adap->pch_base_address;
+	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
+	/* clear the start bit */
+	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
+}
+
+/**
+ * pch_i2c_repstart() - generate repeated start condition in normal mode
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static void pch_i2c_repstart(struct i2c_algo_pch_data *adap)
+{
+	void __iomem *p = adap->pch_base_address;
+	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
+	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_REPSTART);
+}
+
+/**
+ * pch_i2c_writebytes() - write data to I2C bus in normal mode
+ * @i2c_adap:	Pointer to the struct i2c_adapter.
+ * @last:	specifies whether last message or not.
+ *		In the case of compound mode it will be 1 for last message,
+ *		otherwise 0.
+ * @first:	specifies whether first message or not.
+ *		1 for first message otherwise 0.
+ */
+static s32 pch_i2c_writebytes(struct i2c_adapter *i2c_adap,
+			      struct i2c_msg *msgs, u32 last, u32 first)
+{
+	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
+	u8 *buf;
+	u32 length;
+	u32 addr;
+	u32 addr_2_msb;
+	u32 addr_8_lsb;
+	s32 wrcount;
+	void __iomem *p = adap->pch_base_address;
+
+	length = msgs->len;
+	buf = msgs->buf;
+	addr = msgs->addr;
+
+	/* enable master tx */
+	pch_setbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
+
+	pch_dbg(adap, "I2CCTL = %x msgs->len = %d\n", ioread32(p + PCH_I2CCTL),
+		length);
+
+	if (first) {
+		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
+			return -ETIME;
+	}
+
+	if (msgs->flags & I2C_M_TEN) {
+		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7);
+		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
+		if (first)
+			pch_i2c_start(adap);
+		if (pch_i2c_wait_for_xfer_complete(adap) == 0 &&
+		    pch_i2c_getack(adap) == 0) {
+			addr_8_lsb = (addr & I2C_ADDR_MSK);
+			iowrite32(addr_8_lsb, p + PCH_I2CDR);
+		} else {
+			pch_i2c_stop(adap);
+			return -ETIME;
+		}
+	} else {
+		/* set 7 bit slave address and R/W bit as 0 */
+		iowrite32(addr << 1, p + PCH_I2CDR);
+		if (first)
+			pch_i2c_start(adap);
+	}
+
+	if ((pch_i2c_wait_for_xfer_complete(adap) == 0) &&
+	    (pch_i2c_getack(adap) == 0)) {
+		for (wrcount = 0; wrcount < length; ++wrcount) {
+			/* write buffer value to I2C data register */
+			iowrite32(buf[wrcount], p + PCH_I2CDR);
+			pch_dbg(adap, "writing %x to Data register\n",
+				buf[wrcount]);
+
+			if (pch_i2c_wait_for_xfer_complete(adap) != 0)
+				return -ETIME;
+
+			if (pch_i2c_getack(adap))
+				return -EIO;
+		}
+
+		/* check if this is the last message */
+		if (last)
+			pch_i2c_stop(adap);
+		else
+			pch_i2c_repstart(adap);
+	} else {
+		pch_i2c_stop(adap);
+		return -EIO;
+	}
+
+	pch_dbg(adap, "return=%d\n", wrcount);
+
+	return wrcount;
+}
+
+/**
+ * pch_i2c_sendack() - send ACK
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static void pch_i2c_sendack(struct i2c_algo_pch_data *adap)
+{
+	void __iomem *p = adap->pch_base_address;
+	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
+	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
+}
+
+/**
+ * pch_i2c_sendnack() - send NACK
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static void pch_i2c_sendnack(struct i2c_algo_pch_data *adap)
+{
+	void __iomem *p = adap->pch_base_address;
+	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
+	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
+}
+
+/**
+ * pch_i2c_readbytes() - read data  from I2C bus in normal mode.
+ * @i2c_adap:	Pointer to the struct i2c_adapter.
+ * @msgs:	Pointer to i2c_msg structure.
+ * @last:	specifies whether last message or not.
+ * @first:	specifies whether first message or not.
+ */
+s32 pch_i2c_readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
+		  u32 last, u32 first)
+{
+	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
+
+	u8 *buf;
+	u32 count;
+	u32 length;
+	u32 addr;
+	u32 addr_2_msb;
+	void __iomem *p = adap->pch_base_address;
+
+	length = msgs->len;
+	buf = msgs->buf;
+	addr = msgs->addr;
+
+	/* enable master reception */
+	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
+
+	if (first) {
+		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
+			return -ETIME;
+	}
+
+	if (msgs->flags & I2C_M_TEN) {
+		addr_2_msb = (((addr & I2C_MSB_2B_MSK) >> 7) | (I2C_RD));
+		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
+
+	} else {
+		/* 7 address bits + R/W bit */
+		addr = (((addr) << 1) | (I2C_RD));
+		iowrite32(addr, p + PCH_I2CDR);
+	}
+
+	/* check if it is the first message */
+	if (first)
+		pch_i2c_start(adap);
+
+	if ((pch_i2c_wait_for_xfer_complete(adap) == 0) &&
+	    (pch_i2c_getack(adap) == 0)) {
+		pch_dbg(adap, "return %d\n", 0);
+
+		if (length == 0) {
+			pch_i2c_stop(adap);
+			ioread32(p + PCH_I2CDR); /* Dummy read needs */
+
+			count = length;
+		} else {
+			int read_index;
+			int loop;
+			pch_i2c_sendack(adap);
+
+			/* Dummy read */
+			for (loop = 1, read_index = 0; loop < length; loop++) {
+				buf[read_index] = ioread32(p + PCH_I2CDR);
+
+				if (loop != 1)
+					read_index++;
+
+				if (pch_i2c_wait_for_xfer_complete(adap) != 0) {
+					pch_i2c_stop(adap);
+					return -ETIME;
+				}
+			}	/* end for */
+
+			pch_i2c_sendnack(adap);
+
+			buf[read_index] = ioread32(p + PCH_I2CDR);
+
+			if (length != 1)
+				read_index++;
+
+			if (pch_i2c_wait_for_xfer_complete(adap) == 0) {
+				if (last)
+					pch_i2c_stop(adap);
+				else
+					pch_i2c_repstart(adap);
+
+				buf[read_index++] = ioread32(p + PCH_I2CDR);
+				count = read_index;
+			} else {
+				count = -ETIME;
+			}
+
+		}
+	} else {
+		count = -ETIME;
+		pch_i2c_stop(adap);
+	}
+
+	return count;
+}
+
+/**
+ * pch_i2c_cb_ch0() - Interrupt handler Call back function
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static void pch_i2c_cb_ch0(struct i2c_algo_pch_data *adap)
+{
+	u32 sts;
+	void __iomem *p = adap->pch_base_address;
+
+	sts = ioread32(p + PCH_I2CSR);
+	sts &= (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT);
+	if (sts & I2CMAL_BIT)
+		adap->pch_event_flag |= I2CMAL_EVENT;
+
+	if (sts & I2CMCF_BIT)
+		adap->pch_event_flag |= I2CMCF_EVENT;
+
+	/* clear the applicable bits */
+	pch_clrbit(adap->pch_base_address, PCH_I2CSR, sts);
+
+	pch_dbg(adap, "PCH_I2CSR = %x\n", ioread32(p + PCH_I2CSR));
+
+	wake_up(&pch_event);
+}
+
+/**
+ * pch_i2c_handler() - interrupt handler for the PCH I2C controller
+ * @irq:	irq number.
+ * @pData:	cookie passed back to the handler function.
+ */
+static irqreturn_t pch_i2c_handler(int irq, void *pData)
+{
+	s32 reg_val;
+
+	struct i2c_algo_pch_data *adap_data = (struct i2c_algo_pch_data *)pData;
+	void __iomem *p = adap_data->pch_base_address;
+	u32 mode = ioread32(p + PCH_I2CMOD) & (BUFFER_MODE | EEPROM_SR_MODE);
+
+	if (mode != NORMAL_MODE) {
+		pch_err(adap_data, "I2C mode is not supported\n");
+		return IRQ_NONE;
+	}
+
+	reg_val = ioread32(p + PCH_I2CSR);
+	if (reg_val & (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT))
+		pch_i2c_cb_ch0(adap_data);
+	else
+		return IRQ_NONE;
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * pch_i2c_xfer() - Reading adnd writing data through I2C bus
+ * @i2c_adap:	Pointer to the struct i2c_adapter.
+ * @msgs:	Pointer to i2c_msg structure.
+ * @num:	number of messages.
+ */
+static s32 pch_i2c_xfer(struct i2c_adapter *i2c_adap,
+		    struct i2c_msg *msgs, s32 num)
+{
+	struct i2c_msg *pmsg;
+	u32 i = 0;
+	u32 status;
+	u32 msglen;
+	u32 subaddrlen;
+	s32 ret;
+
+	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
+
+	ret = mutex_lock_interruptible(&pch_mutex);
+	if (ret)
+		return -ERESTARTSYS;
+
+	if (adap->p_adapter_info->pch_i2c_suspended) {
+		mutex_unlock(&pch_mutex);
+		return -EBUSY;
+	}
+
+	pch_dbg(adap, "adap->p_adapter_info->pch_i2c_suspended is %d\n",
+		adap->p_adapter_info->pch_i2c_suspended);
+	/* transfer not completed */
+	adap->pch_i2c_xfer_in_progress = true;
+
+	pmsg = &msgs[0];
+	pmsg->flags |= adap->pch_buff_mode_en;
+	status = pmsg->flags;
+	pch_dbg(adap,
+		"After invoking I2C_MODE_SEL :flag= 0x%x\n", status);
+	/* calculate sub address length and message length */
+	/* these are applicable only for buffer mode */
+	subaddrlen = pmsg->buf[0];
+	/* calculate actual message length excluding
+	 * the sub address fields */
+	msglen = (pmsg->len) - (subaddrlen + 1);
+	if (status & (I2C_M_RD)) {
+		pch_dbg(adap, "invoking pch_i2c_readbytes\n");
+		ret = pch_i2c_readbytes(i2c_adap, pmsg, (i + 1 == num),
+				   (i == 0));
+	} else {
+		pch_dbg(adap, "invoking pch_i2c_writebytes\n");
+		ret = pch_i2c_writebytes(i2c_adap, pmsg, (i + 1 == num),
+				    (i == 0));
+	}
+
+	adap->pch_i2c_xfer_in_progress = false;	/* transfer completed */
+
+	mutex_unlock(&pch_mutex);
+
+	return ret;
+}
+
+/**
+ * pch_i2c_func() - return the functionality of the I2C driver
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static u32 pch_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
+}
+
+static struct i2c_algorithm pch_algorithm = {
+	.master_xfer = pch_i2c_xfer,
+	.functionality = pch_i2c_func
+};
+
+/**
+ * pch_i2c_disbl_int() - Disable PCH I2C interrupts
+ * @adap:	Pointer to struct i2c_algo_pch_data.
+ */
+static void pch_i2c_disbl_int(struct i2c_algo_pch_data *adap)
+{
+	void __iomem *p = adap->pch_base_address;
+
+	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, NORMAL_INTR_ENBL);
+
+	iowrite32(EEPROM_RST_INTR_DISBL, p + PCH_I2CESRMSK);
+
+	iowrite32(BUFFER_MODE_INTR_DISBL, p + PCH_I2CBUFMSK);
+}
+
+static int __devinit pch_i2c_probe(struct pci_dev *pdev,
+			       const struct pci_device_id *id)
+{
+	void __iomem *base_addr;
+	s32 ret;
+	struct adapter_info *adap_info;
+
+	pch_pci_dbg(pdev, "Entered.\n");
+
+	adap_info = kzalloc((sizeof(struct adapter_info)), GFP_KERNEL);
+	if (adap_info == NULL) {
+		pch_pci_err(pdev, "Memory allocation FAILED\n");
+		return -ENOMEM;
+	}
+
+	ret = pci_enable_device(pdev);
+	if (ret) {
+		pch_pci_err(pdev, "pci_enable_device FAILED\n");
+		goto err_pci_enable;
+	}
+
+	ret = pci_request_regions(pdev, KBUILD_MODNAME);
+	if (ret) {
+		pch_pci_err(pdev, "pci_request_regions FAILED\n");
+		goto err_pci_req;
+	}
+
+	base_addr = pci_iomap(pdev, 1, 0);
+
+	if (base_addr == NULL) {
+		pch_pci_err(pdev, "pci_iomap FAILED\n");
+		ret = -ENOMEM;
+		goto err_pci_iomap;
+	}
+
+	adap_info->pch_i2c_suspended = false;
+
+	adap_info->pch_data.p_adapter_info = adap_info;
+
+	adap_info->pch_data.pch_adapter.owner = THIS_MODULE;
+	adap_info->pch_data.pch_adapter.class = I2C_CLASS_HWMON;
+	strcpy(adap_info->pch_data.pch_adapter.name, KBUILD_MODNAME);
+	adap_info->pch_data.pch_adapter.algo = &pch_algorithm;
+	adap_info->pch_data.pch_adapter.algo_data =
+						&adap_info->pch_data;
+
+	/* (i * 0x80) + base_addr; */
+	adap_info->pch_data.pch_base_address = base_addr;
+
+	adap_info->pch_data.pch_adapter.dev.parent = &pdev->dev;
+
+	ret = i2c_add_adapter(&(adap_info->pch_data.pch_adapter));
+
+	if (ret) {
+		pch_pci_err(pdev, "i2c_add_adapter FAILED\n");
+		goto err_i2c_add_adapter;
+	}
+
+	pch_i2c_init(&adap_info->pch_data);
+	ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED,
+		  KBUILD_MODNAME, &adap_info->pch_data);
+	if (ret) {
+		pch_pci_err(pdev, "request_irq FAILED\n");
+		goto err_request_irq;
+	}
+
+	pci_set_drvdata(pdev, adap_info);
+	pch_pci_dbg(pdev, "returns %d.\n", ret);
+	return 0;
+
+err_request_irq:
+	i2c_del_adapter(&(adap_info->pch_data.pch_adapter));
+err_i2c_add_adapter:
+	pci_iounmap(pdev, base_addr);
+err_pci_iomap:
+	pci_release_regions(pdev);
+err_pci_req:
+	pci_disable_device(pdev);
+err_pci_enable:
+	kfree(adap_info);
+	return ret;
+}
+
+static void __devexit pch_i2c_remove(struct pci_dev *pdev)
+{
+	struct adapter_info *adap_info = pci_get_drvdata(pdev);
+
+	pch_i2c_disbl_int(&adap_info->pch_data);
+	free_irq(pdev->irq, &adap_info->pch_data);
+	i2c_del_adapter(&(adap_info->pch_data.pch_adapter));
+
+	if (adap_info->pch_data.pch_base_address) {
+		pci_iounmap(pdev, adap_info->pch_data.pch_base_address);
+		adap_info->pch_data.pch_base_address = 0;
+	}
+
+	pci_set_drvdata(pdev, NULL);
+
+	pci_release_regions(pdev);
+
+	pci_disable_device(pdev);
+	kfree(adap_info);
+}
+
+#ifdef CONFIG_PM
+static int pch_i2c_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+	int ret;
+	struct adapter_info *adap_info = pci_get_drvdata(pdev);
+	void __iomem *p = adap_info->pch_data.pch_base_address;
+
+	adap_info->pch_i2c_suspended = true;
+
+	while ((adap_info->pch_data.pch_i2c_xfer_in_progress)) {
+		/* Wait until all channel transfers are completed */
+		msleep(20);
+	}
+	/* Disable the i2c interrupts */
+	pch_i2c_disbl_int(&adap_info->pch_data);
+
+	pch_pci_dbg(pdev, "I2CSR = %x I2CBUFSTA = %x I2CESRSTA = %x "
+		"invoked function pch_i2c_disbl_int successfully\n",
+		ioread32(p + PCH_I2CSR), ioread32(p + PCH_I2CBUFSTA),
+		ioread32(p + PCH_I2CESRSTA));
+
+	ret = pci_save_state(pdev);
+
+	if (ret) {
+		pch_pci_err(pdev, "pci_save_state\n");
+		return ret;
+	}
+
+	pci_enable_wake(pdev, PCI_D3hot, 0);
+	pci_disable_device(pdev);
+	pci_set_power_state(pdev, pci_choose_state(pdev, state));
+
+	return 0;
+}
+
+static int pch_i2c_resume(struct pci_dev *pdev)
+{
+	struct adapter_info *adap_info = pci_get_drvdata(pdev);
+
+	pci_set_power_state(pdev, PCI_D0);
+	pci_restore_state(pdev);
+
+	if (pci_enable_device(pdev) < 0) {
+		pch_pci_err(pdev, "pch_i2c_resume:pci_enable_device FAILED\n");
+		return -EIO;
+	}
+
+	pci_enable_wake(pdev, PCI_D3hot, 0);
+
+	pch_i2c_init(&adap_info->pch_data);
+
+	adap_info->pch_i2c_suspended = false;
+
+	return 0;
+}
+#else
+#define pch_i2c_suspend NULL
+#define pch_i2c_resume NULL
+#endif
+
+static struct pci_driver pch_pcidriver = {
+	.name = KBUILD_MODNAME,
+	.id_table = pch_pcidev_id,
+	.probe = pch_i2c_probe,
+	.remove = __devexit_p(pch_i2c_remove),
+	.suspend = pch_i2c_suspend,
+	.resume = pch_i2c_resume
+};
+
+static int __init pch_pci_init(void)
+{
+	return pci_register_driver(&pch_pcidriver);
+}
+module_init(pch_pci_init);
+
+static void __exit pch_pci_exit(void)
+{
+	pci_unregister_driver(&pch_pcidriver);
+}
+module_exit(pch_pci_exit);
+
+MODULE_DESCRIPTION("PCH I2C PCI Driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tomoya MORINAGA. <tomoya-linux@dsn.okisemi.com>");
+module_param(pch_i2c_speed, int, (S_IRUSR | S_IWUSR));
+module_param(pch_clk, int, (S_IRUSR | S_IWUSR));
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 02835ce7ff4..7979aef7ee7 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -72,6 +72,7 @@
 #include <linux/acpi.h>
 #include <linux/io.h>
 #include <linux/dmi.h>
+#include <linux/slab.h>
 
 /* I801 SMBus address offsets */
 #define SMBHSTSTS(p)	(0 + (p)->smba)
diff --git a/drivers/i2c/busses/i2c-iop3xx.c b/drivers/i2c/busses/i2c-iop3xx.c
index 112c61f7b8c..f09c9319a2b 100644
--- a/drivers/i2c/busses/i2c-iop3xx.c
+++ b/drivers/i2c/busses/i2c-iop3xx.c
@@ -409,7 +409,7 @@ iop3xx_i2c_remove(struct platform_device *pdev)
 		IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE);
 	__raw_writel(cr, adapter_data->ioaddr + CR_OFFSET);
 
-	iounmap((void __iomem*)adapter_data->ioaddr);
+	iounmap(adapter_data->ioaddr);
 	release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 	kfree(adapter_data);
 	kfree(padapter);
@@ -453,7 +453,7 @@ iop3xx_i2c_probe(struct platform_device *pdev)
 	/* set the adapter enumeration # */
 	adapter_data->id = i2c_id++;
 
-	adapter_data->ioaddr = (u32)ioremap(res->start, IOP3XX_I2C_IO_SIZE);
+	adapter_data->ioaddr = ioremap(res->start, IOP3XX_I2C_IO_SIZE);
 	if (!adapter_data->ioaddr) {
 		ret = -ENOMEM;
 		goto release_region;
@@ -498,7 +498,7 @@ iop3xx_i2c_probe(struct platform_device *pdev)
 	return 0;
 
 unmap:
-	iounmap((void __iomem*)adapter_data->ioaddr);
+	iounmap(adapter_data->ioaddr);
 
 release_region:
 	release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
diff --git a/drivers/i2c/busses/i2c-iop3xx.h b/drivers/i2c/busses/i2c-iop3xx.h
index 8485861f6a3..097e270955d 100644
--- a/drivers/i2c/busses/i2c-iop3xx.h
+++ b/drivers/i2c/busses/i2c-iop3xx.h
@@ -97,7 +97,7 @@
 #define	IOP3XX_I2C_IO_SIZE	0x18
 
 struct i2c_algo_iop3xx_data {
-	u32 ioaddr;
+	void __iomem *ioaddr;
 	wait_queue_head_t waitq;
 	spinlock_t lock;
 	u32 SR_enabled, SR_received;
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 16242063144..a9941c65f22 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -59,6 +59,7 @@ enum {
 	MV64XXX_I2C_STATE_INVALID,
 	MV64XXX_I2C_STATE_IDLE,
 	MV64XXX_I2C_STATE_WAITING_FOR_START_COND,
+	MV64XXX_I2C_STATE_WAITING_FOR_RESTART,
 	MV64XXX_I2C_STATE_WAITING_FOR_ADDR_1_ACK,
 	MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK,
 	MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK,
@@ -70,6 +71,7 @@ enum {
 	MV64XXX_I2C_ACTION_INVALID,
 	MV64XXX_I2C_ACTION_CONTINUE,
 	MV64XXX_I2C_ACTION_SEND_START,
+	MV64XXX_I2C_ACTION_SEND_RESTART,
 	MV64XXX_I2C_ACTION_SEND_ADDR_1,
 	MV64XXX_I2C_ACTION_SEND_ADDR_2,
 	MV64XXX_I2C_ACTION_SEND_DATA,
@@ -91,6 +93,7 @@ struct mv64xxx_i2c_data {
 	u32			addr2;
 	u32			bytes_left;
 	u32			byte_posn;
+	u32			send_stop;
 	u32			block;
 	int			rc;
 	u32			freq_m;
@@ -159,8 +162,15 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
 		if ((drv_data->bytes_left == 0)
 				|| (drv_data->aborting
 					&& (drv_data->byte_posn != 0))) {
-			drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
-			drv_data->state = MV64XXX_I2C_STATE_IDLE;
+			if (drv_data->send_stop) {
+				drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
+				drv_data->state = MV64XXX_I2C_STATE_IDLE;
+			} else {
+				drv_data->action =
+					MV64XXX_I2C_ACTION_SEND_RESTART;
+				drv_data->state =
+					MV64XXX_I2C_STATE_WAITING_FOR_RESTART;
+			}
 		} else {
 			drv_data->action = MV64XXX_I2C_ACTION_SEND_DATA;
 			drv_data->state =
@@ -228,6 +238,15 @@ static void
 mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
 {
 	switch(drv_data->action) {
+	case MV64XXX_I2C_ACTION_SEND_RESTART:
+		drv_data->cntl_bits |= MV64XXX_I2C_REG_CONTROL_START;
+		drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
+		writel(drv_data->cntl_bits,
+			drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
+		drv_data->block = 0;
+		wake_up_interruptible(&drv_data->waitq);
+		break;
+
 	case MV64XXX_I2C_ACTION_CONTINUE:
 		writel(drv_data->cntl_bits,
 			drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
@@ -386,7 +405,8 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
 }
 
 static int
-mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg)
+mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg,
+				int is_first, int is_last)
 {
 	unsigned long	flags;
 
@@ -406,10 +426,18 @@ mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg)
 			drv_data->bytes_left--;
 		}
 	} else {
-		drv_data->action = MV64XXX_I2C_ACTION_SEND_START;
-		drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_START_COND;
+		if (is_first) {
+			drv_data->action = MV64XXX_I2C_ACTION_SEND_START;
+			drv_data->state =
+				MV64XXX_I2C_STATE_WAITING_FOR_START_COND;
+		} else {
+			drv_data->action = MV64XXX_I2C_ACTION_SEND_ADDR_1;
+			drv_data->state =
+				MV64XXX_I2C_STATE_WAITING_FOR_ADDR_1_ACK;
+		}
 	}
 
+	drv_data->send_stop = is_last;
 	drv_data->block = 1;
 	mv64xxx_i2c_do_action(drv_data);
 	spin_unlock_irqrestore(&drv_data->lock, flags);
@@ -437,9 +465,12 @@ mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
 	int	i, rc;
 
-	for (i=0; i<num; i++)
-		if ((rc = mv64xxx_i2c_execute_msg(drv_data, &msgs[i])) < 0)
+	for (i = 0; i < num; i++) {
+		rc = mv64xxx_i2c_execute_msg(drv_data, &msgs[i],
+						i == 0, i + 1 == num);
+		if (rc < 0)
 			return rc;
+	}
 
 	return num;
 }
diff --git a/drivers/i2c/busses/i2c-nforce2.c b/drivers/i2c/busses/i2c-nforce2.c
index a605a5029cf..ff1e127dfea 100644
--- a/drivers/i2c/busses/i2c-nforce2.c
+++ b/drivers/i2c/busses/i2c-nforce2.c
@@ -432,7 +432,7 @@ static int __devinit nforce2_probe(struct pci_dev *dev, const struct pci_device_
 
 static void __devexit nforce2_remove(struct pci_dev *dev)
 {
-	struct nforce2_smbus *smbuses = (void*) pci_get_drvdata(dev);
+	struct nforce2_smbus *smbuses = pci_get_drvdata(dev);
 
 	nforce2_set_reference(NULL);
 	if (smbuses[0].base) {
diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index 0070371b29f..ef3bcb1ce86 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -9,6 +9,41 @@
  * kind, whether express or implied.
  */
 
+/*
+ * Device tree configuration:
+ *
+ * Required properties:
+ * - compatible      : "opencores,i2c-ocores"
+ * - reg             : bus address start and address range size of device
+ * - interrupts      : interrupt number
+ * - regstep         : size of device registers in bytes
+ * - clock-frequency : frequency of bus clock in Hz
+ * 
+ * Example:
+ *
+ *  i2c0: ocores@a0000000 {
+ *              compatible = "opencores,i2c-ocores";
+ *              reg = <0xa0000000 0x8>;
+ *              interrupts = <10>;
+ *
+ *              regstep = <1>;
+ *              clock-frequency = <20000000>;
+ *
+ * -- Devices connected on this I2C bus get
+ * -- defined here; address- and size-cells
+ * -- apply to these child devices
+ *
+ *              #address-cells = <1>;
+ *              #size-cells = <0>;
+ *
+ *              dummy@60 {
+ *                     compatible = "dummy";
+ *                     reg = <60>;
+ *              };
+ *  };
+ *
+ */
+
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -210,6 +245,32 @@ static struct i2c_adapter ocores_adapter = {
 	.algo		= &ocores_algorithm,
 };
 
+#ifdef CONFIG_OF
+static int ocores_i2c_of_probe(struct platform_device* pdev,
+				struct ocores_i2c* i2c)
+{
+	__be32* val;
+
+	val = of_get_property(pdev->dev.of_node, "regstep", NULL);
+	if (!val) {
+		dev_err(&pdev->dev, "Missing required parameter 'regstep'");
+		return -ENODEV;
+	}
+	i2c->regstep = be32_to_cpup(val);
+
+	val = of_get_property(pdev->dev.of_node, "clock-frequency", NULL);
+	if (!val) {
+		dev_err(&pdev->dev,
+			"Missing required parameter 'clock-frequency'");
+		return -ENODEV;
+	}
+	i2c->clock_khz = be32_to_cpup(val) / 1000;
+
+	return 0;
+}
+#else
+#define ocores_i2c_of_probe(pdev,i2c) -ENODEV
+#endif
 
 static int __devinit ocores_i2c_probe(struct platform_device *pdev)
 {
@@ -227,37 +288,41 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
 	if (!res2)
 		return -ENODEV;
 
-	pdata = (struct ocores_i2c_platform_data*) pdev->dev.platform_data;
-	if (!pdata)
-		return -ENODEV;
-
-	i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
+	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
 	if (!i2c)
 		return -ENOMEM;
 
-	if (!request_mem_region(res->start, resource_size(res),
-				pdev->name)) {
+	if (!devm_request_mem_region(&pdev->dev, res->start,
+				     resource_size(res), pdev->name)) {
 		dev_err(&pdev->dev, "Memory region busy\n");
-		ret = -EBUSY;
-		goto request_mem_failed;
+		return -EBUSY;
 	}
 
-	i2c->base = ioremap(res->start, resource_size(res));
+	i2c->base = devm_ioremap_nocache(&pdev->dev, res->start,
+					 resource_size(res));
 	if (!i2c->base) {
 		dev_err(&pdev->dev, "Unable to map registers\n");
-		ret = -EIO;
-		goto map_failed;
+		return -EIO;
+	}
+
+	pdata = pdev->dev.platform_data;
+	if (pdata) {
+		i2c->regstep = pdata->regstep;
+		i2c->clock_khz = pdata->clock_khz;
+	} else {
+		ret = ocores_i2c_of_probe(pdev, i2c);
+		if (ret)
+			return ret;
 	}
 
-	i2c->regstep = pdata->regstep;
-	i2c->clock_khz = pdata->clock_khz;
 	ocores_init(i2c);
 
 	init_waitqueue_head(&i2c->wait);
-	ret = request_irq(res2->start, ocores_isr, 0, pdev->name, i2c);
+	ret = devm_request_irq(&pdev->dev, res2->start, ocores_isr, 0,
+			       pdev->name, i2c);
 	if (ret) {
 		dev_err(&pdev->dev, "Cannot claim IRQ\n");
-		goto request_irq_failed;
+		return ret;
 	}
 
 	/* hook up driver to tree */
@@ -265,36 +330,29 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
 	i2c->adap = ocores_adapter;
 	i2c_set_adapdata(&i2c->adap, i2c);
 	i2c->adap.dev.parent = &pdev->dev;
+#ifdef CONFIG_OF
+	i2c->adap.dev.of_node = pdev->dev.of_node;
+#endif
 
 	/* add i2c adapter to i2c tree */
 	ret = i2c_add_adapter(&i2c->adap);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to add adapter\n");
-		goto add_adapter_failed;
+		return ret;
 	}
 
 	/* add in known devices to the bus */
-	for (i = 0; i < pdata->num_devices; i++)
-		i2c_new_device(&i2c->adap, pdata->devices + i);
+	if (pdata) {
+		for (i = 0; i < pdata->num_devices; i++)
+			i2c_new_device(&i2c->adap, pdata->devices + i);
+	}
 
 	return 0;
-
-add_adapter_failed:
-	free_irq(res2->start, i2c);
-request_irq_failed:
-	iounmap(i2c->base);
-map_failed:
-	release_mem_region(res->start, resource_size(res));
-request_mem_failed:
-	kfree(i2c);
-
-	return ret;
 }
 
 static int __devexit ocores_i2c_remove(struct platform_device* pdev)
 {
 	struct ocores_i2c *i2c = platform_get_drvdata(pdev);
-	struct resource *res;
 
 	/* disable i2c logic */
 	oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
@@ -304,18 +362,6 @@ static int __devexit ocores_i2c_remove(struct platform_device* pdev)
 	i2c_del_adapter(&i2c->adap);
 	platform_set_drvdata(pdev, NULL);
 
-	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (res)
-		free_irq(res->start, i2c);
-
-	iounmap(i2c->base);
-
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (res)
-		release_mem_region(res->start, resource_size(res));
-
-	kfree(i2c);
-
 	return 0;
 }
 
@@ -344,6 +390,16 @@ static int ocores_i2c_resume(struct platform_device *pdev)
 #define ocores_i2c_resume	NULL
 #endif
 
+#ifdef CONFIG_OF
+static struct of_device_id ocores_i2c_match[] = {
+        {
+                .compatible = "opencores,i2c-ocores",
+        },
+        {},
+};
+MODULE_DEVICE_TABLE(of, ocores_i2c_match);
+#endif
+
 /* work with hotplug and coldplug */
 MODULE_ALIAS("platform:ocores-i2c");
 
@@ -355,6 +411,9 @@ static struct platform_driver ocores_i2c_driver = {
 	.driver  = {
 		.owner = THIS_MODULE,
 		.name = "ocores-i2c",
+#ifdef CONFIG_OF
+                .of_match_table = ocores_i2c_match,
+#endif
 	},
 };
 
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index b33c78586bf..b605ff3a1fa 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -39,6 +39,7 @@
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/i2c-omap.h>
+#include <linux/pm_runtime.h>
 
 /* I2C controller revisions */
 #define OMAP_I2C_REV_2			0x20
@@ -175,8 +176,6 @@ struct omap_i2c_dev {
 	void __iomem		*base;		/* virtual */
 	int			irq;
 	int			reg_shift;      /* bit shift for I2C register addresses */
-	struct clk		*iclk;		/* Interface clock */
-	struct clk		*fclk;		/* Functional clock */
 	struct completion	cmd_complete;
 	struct resource		*ioarea;
 	u32			latency;	/* maximum mpu wkup latency */
@@ -265,45 +264,18 @@ static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
 				(i2c_dev->regs[reg] << i2c_dev->reg_shift));
 }
 
-static int __init omap_i2c_get_clocks(struct omap_i2c_dev *dev)
+static void omap_i2c_unidle(struct omap_i2c_dev *dev)
 {
-	int ret;
-
-	dev->iclk = clk_get(dev->dev, "ick");
-	if (IS_ERR(dev->iclk)) {
-		ret = PTR_ERR(dev->iclk);
-		dev->iclk = NULL;
-		return ret;
-	}
+	struct platform_device *pdev;
+	struct omap_i2c_bus_platform_data *pdata;
 
-	dev->fclk = clk_get(dev->dev, "fck");
-	if (IS_ERR(dev->fclk)) {
-		ret = PTR_ERR(dev->fclk);
-		if (dev->iclk != NULL) {
-			clk_put(dev->iclk);
-			dev->iclk = NULL;
-		}
-		dev->fclk = NULL;
-		return ret;
-	}
-
-	return 0;
-}
+	WARN_ON(!dev->idle);
 
-static void omap_i2c_put_clocks(struct omap_i2c_dev *dev)
-{
-	clk_put(dev->fclk);
-	dev->fclk = NULL;
-	clk_put(dev->iclk);
-	dev->iclk = NULL;
-}
+	pdev = to_platform_device(dev->dev);
+	pdata = pdev->dev.platform_data;
 
-static void omap_i2c_unidle(struct omap_i2c_dev *dev)
-{
-	WARN_ON(!dev->idle);
+	pm_runtime_get_sync(&pdev->dev);
 
-	clk_enable(dev->iclk);
-	clk_enable(dev->fclk);
 	if (cpu_is_omap34xx()) {
 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 		omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, dev->pscstate);
@@ -326,10 +298,15 @@ static void omap_i2c_unidle(struct omap_i2c_dev *dev)
 
 static void omap_i2c_idle(struct omap_i2c_dev *dev)
 {
+	struct platform_device *pdev;
+	struct omap_i2c_bus_platform_data *pdata;
 	u16 iv;
 
 	WARN_ON(dev->idle);
 
+	pdev = to_platform_device(dev->dev);
+	pdata = pdev->dev.platform_data;
+
 	dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
 	if (dev->rev >= OMAP_I2C_REV_ON_4430)
 		omap_i2c_write_reg(dev, OMAP_I2C_IRQENABLE_CLR, 1);
@@ -345,8 +322,8 @@ static void omap_i2c_idle(struct omap_i2c_dev *dev)
 		omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
 	}
 	dev->idle = 1;
-	clk_disable(dev->fclk);
-	clk_disable(dev->iclk);
+
+	pm_runtime_put_sync(&pdev->dev);
 }
 
 static int omap_i2c_init(struct omap_i2c_dev *dev)
@@ -356,6 +333,7 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
 	unsigned long fclk_rate = 12000000;
 	unsigned long timeout;
 	unsigned long internal_clk = 0;
+	struct clk *fclk;
 
 	if (dev->rev >= OMAP_I2C_REV_2) {
 		/* Disable I2C controller before soft reset */
@@ -414,7 +392,9 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
 		 * always returns 12MHz for the functional clock, we can
 		 * do this bit unconditionally.
 		 */
-		fclk_rate = clk_get_rate(dev->fclk);
+		fclk = clk_get(dev->dev, "fck");
+		fclk_rate = clk_get_rate(fclk);
+		clk_put(fclk);
 
 		/* TRM for 5912 says the I2C clock must be prescaled to be
 		 * between 7 - 12 MHz. The XOR input clock is typically
@@ -443,7 +423,9 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
 			internal_clk = 9600;
 		else
 			internal_clk = 4000;
-		fclk_rate = clk_get_rate(dev->fclk) / 1000;
+		fclk = clk_get(dev->dev, "fck");
+		fclk_rate = clk_get_rate(fclk) / 1000;
+		clk_put(fclk);
 
 		/* Compute prescaler divisor */
 		psc = fclk_rate / internal_clk;
@@ -616,12 +598,8 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 	 * REVISIT: We should abort the transfer on signals, but the bus goes
 	 * into arbitration and we're currently unable to recover from it.
 	 */
-	if (dev->set_mpu_wkup_lat != NULL)
-		dev->set_mpu_wkup_lat(dev->dev, dev->latency);
 	r = wait_for_completion_timeout(&dev->cmd_complete,
 					OMAP_I2C_TIMEOUT);
-	if (dev->set_mpu_wkup_lat != NULL)
-		dev->set_mpu_wkup_lat(dev->dev, -1);
 	dev->buf_len = 0;
 	if (r < 0)
 		return r;
@@ -672,12 +650,18 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	if (r < 0)
 		goto out;
 
+	if (dev->set_mpu_wkup_lat != NULL)
+		dev->set_mpu_wkup_lat(dev->dev, dev->latency);
+
 	for (i = 0; i < num; i++) {
 		r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
 		if (r != 0)
 			break;
 	}
 
+	if (dev->set_mpu_wkup_lat != NULL)
+		dev->set_mpu_wkup_lat(dev->dev, -1);
+
 	if (r == 0)
 		r = num;
 
@@ -1048,14 +1032,12 @@ omap_i2c_probe(struct platform_device *pdev)
 	else
 		dev->reg_shift = 2;
 
-	if ((r = omap_i2c_get_clocks(dev)) != 0)
-		goto err_iounmap;
-
 	if (cpu_is_omap44xx())
 		dev->regs = (u8 *) omap4_reg_map;
 	else
 		dev->regs = (u8 *) reg_map;
 
+	pm_runtime_enable(&pdev->dev);
 	omap_i2c_unidle(dev);
 
 	dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
@@ -1127,8 +1109,6 @@ err_free_irq:
 err_unuse_clocks:
 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 	omap_i2c_idle(dev);
-	omap_i2c_put_clocks(dev);
-err_iounmap:
 	iounmap(dev->base);
 err_free_mem:
 	platform_set_drvdata(pdev, NULL);
@@ -1150,7 +1130,6 @@ omap_i2c_remove(struct platform_device *pdev)
 	free_irq(dev->irq, dev);
 	i2c_del_adapter(&dev->adapter);
 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
-	omap_i2c_put_clocks(dev);
 	iounmap(dev->base);
 	kfree(dev);
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1162,7 +1141,7 @@ static struct platform_driver omap_i2c_driver = {
 	.probe		= omap_i2c_probe,
 	.remove		= omap_i2c_remove,
 	.driver		= {
-		.name	= "i2c_omap",
+		.name	= "omap_i2c",
 		.owner	= THIS_MODULE,
 	},
 };
@@ -1184,4 +1163,4 @@ module_exit(omap_i2c_exit_driver);
 MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
 MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:i2c_omap");
+MODULE_ALIAS("platform:omap_i2c");
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 6b4cc567645..c7db6980e3a 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1362,7 +1362,7 @@ EXPORT_SYMBOL(i2c_transfer);
  *
  * Returns negative errno, or else the number of bytes written.
  */
-int i2c_master_send(struct i2c_client *client, const char *buf, int count)
+int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
 {
 	int ret;
 	struct i2c_adapter *adap = client->adapter;
@@ -1389,7 +1389,7 @@ EXPORT_SYMBOL(i2c_master_send);
  *
  * Returns negative errno, or else the number of bytes read.
  */
-int i2c_master_recv(struct i2c_client *client, char *buf, int count)
+int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
 {
 	struct i2c_adapter *adap = client->adapter;
 	struct i2c_msg msg;
@@ -1679,7 +1679,7 @@ static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
  * This executes the SMBus "receive byte" protocol, returning negative errno
  * else the byte received from the device.
  */
-s32 i2c_smbus_read_byte(struct i2c_client *client)
+s32 i2c_smbus_read_byte(const struct i2c_client *client)
 {
 	union i2c_smbus_data data;
 	int status;
@@ -1699,7 +1699,7 @@ EXPORT_SYMBOL(i2c_smbus_read_byte);
  * This executes the SMBus "send byte" protocol, returning negative errno
  * else zero on success.
  */
-s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
+s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
 {
 	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
 	                      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
@@ -1714,7 +1714,7 @@ EXPORT_SYMBOL(i2c_smbus_write_byte);
  * This executes the SMBus "read byte" protocol, returning negative errno
  * else a data byte received from the device.
  */
-s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
+s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
 {
 	union i2c_smbus_data data;
 	int status;
@@ -1735,7 +1735,8 @@ EXPORT_SYMBOL(i2c_smbus_read_byte_data);
  * This executes the SMBus "write byte" protocol, returning negative errno
  * else zero on success.
  */
-s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
+s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
+			      u8 value)
 {
 	union i2c_smbus_data data;
 	data.byte = value;
@@ -1753,7 +1754,7 @@ EXPORT_SYMBOL(i2c_smbus_write_byte_data);
  * This executes the SMBus "read word" protocol, returning negative errno
  * else a 16-bit unsigned "word" received from the device.
  */
-s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
+s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
 {
 	union i2c_smbus_data data;
 	int status;
@@ -1774,7 +1775,8 @@ EXPORT_SYMBOL(i2c_smbus_read_word_data);
  * This executes the SMBus "write word" protocol, returning negative errno
  * else zero on success.
  */
-s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
+s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
+			      u16 value)
 {
 	union i2c_smbus_data data;
 	data.word = value;
@@ -1793,7 +1795,8 @@ EXPORT_SYMBOL(i2c_smbus_write_word_data);
  * This executes the SMBus "process call" protocol, returning negative errno
  * else a 16-bit unsigned "word" received from the device.
  */
-s32 i2c_smbus_process_call(struct i2c_client *client, u8 command, u16 value)
+s32 i2c_smbus_process_call(const struct i2c_client *client, u8 command,
+			   u16 value)
 {
 	union i2c_smbus_data data;
 	int status;
@@ -1821,7 +1824,7 @@ EXPORT_SYMBOL(i2c_smbus_process_call);
  * support this; its emulation through I2C messaging relies on a specific
  * mechanism (I2C_M_RECV_LEN) which may not be implemented.
  */
-s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command,
+s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
 			      u8 *values)
 {
 	union i2c_smbus_data data;
@@ -1848,7 +1851,7 @@ EXPORT_SYMBOL(i2c_smbus_read_block_data);
  * This executes the SMBus "block write" protocol, returning negative errno
  * else zero on success.
  */
-s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
+s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
 			       u8 length, const u8 *values)
 {
 	union i2c_smbus_data data;
@@ -1864,7 +1867,7 @@ s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
 EXPORT_SYMBOL(i2c_smbus_write_block_data);
 
 /* Returns the number of read bytes */
-s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
+s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
 				  u8 length, u8 *values)
 {
 	union i2c_smbus_data data;
@@ -1884,7 +1887,7 @@ s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
 }
 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
 
-s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client, u8 command,
+s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
 				   u8 length, const u8 *values)
 {
 	union i2c_smbus_data data;
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index 4d91d80bfd2..90b7a016389 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -5,6 +5,18 @@
 menu "Multiplexer I2C Chip support"
 	depends on I2C_MUX
 
+config I2C_MUX_GPIO
+	tristate "GPIO-based I2C multiplexer"
+	depends on GENERIC_GPIO
+	help
+	  If you say yes to this option, support will be included for a
+	  GPIO based I2C multiplexer. This driver provides access to
+	  I2C busses connected through a MUX, which is controlled
+	  through GPIO pins.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called gpio-i2cmux.
+
 config I2C_MUX_PCA9541
 	tristate "NXP PCA9541 I2C Master Selector"
 	depends on EXPERIMENTAL
diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
index d743806d9b4..4640436ea61 100644
--- a/drivers/i2c/muxes/Makefile
+++ b/drivers/i2c/muxes/Makefile
@@ -1,6 +1,7 @@
 #
 # Makefile for multiplexer I2C chip drivers.
 
+obj-$(CONFIG_I2C_MUX_GPIO)	+= gpio-i2cmux.o
 obj-$(CONFIG_I2C_MUX_PCA9541)	+= pca9541.o
 obj-$(CONFIG_I2C_MUX_PCA954x)	+= pca954x.o
 
diff --git a/drivers/i2c/muxes/gpio-i2cmux.c b/drivers/i2c/muxes/gpio-i2cmux.c
new file mode 100644
index 00000000000..7b6ce624cd6
--- /dev/null
+++ b/drivers/i2c/muxes/gpio-i2cmux.c
@@ -0,0 +1,184 @@
+/*
+ * I2C multiplexer using GPIO API
+ *
+ * Peter Korsgaard <peter.korsgaard@barco.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.
+ */
+
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/gpio-i2cmux.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+
+struct gpiomux {
+	struct i2c_adapter *parent;
+	struct i2c_adapter **adap; /* child busses */
+	struct gpio_i2cmux_platform_data data;
+};
+
+static void gpiomux_set(const struct gpiomux *mux, unsigned val)
+{
+	int i;
+
+	for (i = 0; i < mux->data.n_gpios; i++)
+		gpio_set_value(mux->data.gpios[i], val & (1 << i));
+}
+
+static int gpiomux_select(struct i2c_adapter *adap, void *data, u32 chan)
+{
+	struct gpiomux *mux = data;
+
+	gpiomux_set(mux, mux->data.values[chan]);
+
+	return 0;
+}
+
+static int gpiomux_deselect(struct i2c_adapter *adap, void *data, u32 chan)
+{
+	struct gpiomux *mux = data;
+
+	gpiomux_set(mux, mux->data.idle);
+
+	return 0;
+}
+
+static int __devinit gpiomux_probe(struct platform_device *pdev)
+{
+	struct gpiomux *mux;
+	struct gpio_i2cmux_platform_data *pdata;
+	struct i2c_adapter *parent;
+	int (*deselect) (struct i2c_adapter *, void *, u32);
+	unsigned initial_state;
+	int i, ret;
+
+	pdata = pdev->dev.platform_data;
+	if (!pdata) {
+		dev_err(&pdev->dev, "Missing platform data\n");
+		return -ENODEV;
+	}
+
+	parent = i2c_get_adapter(pdata->parent);
+	if (!parent) {
+		dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
+			pdata->parent);
+		return -ENODEV;
+	}
+
+	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
+	if (!mux) {
+		ret = -ENOMEM;
+		goto alloc_failed;
+	}
+
+	mux->parent = parent;
+	mux->data = *pdata;
+	mux->adap = kzalloc(sizeof(struct i2c_adapter *) * pdata->n_values,
+			    GFP_KERNEL);
+	if (!mux->adap) {
+		ret = -ENOMEM;
+		goto alloc_failed2;
+	}
+
+	if (pdata->idle != GPIO_I2CMUX_NO_IDLE) {
+		initial_state = pdata->idle;
+		deselect = gpiomux_deselect;
+	} else {
+		initial_state = pdata->values[0];
+		deselect = NULL;
+	}
+
+	for (i = 0; i < pdata->n_gpios; i++) {
+		ret = gpio_request(pdata->gpios[i], "gpio-i2cmux");
+		if (ret)
+			goto err_request_gpio;
+		gpio_direction_output(pdata->gpios[i],
+				      initial_state & (1 << i));
+	}
+
+	for (i = 0; i < pdata->n_values; i++) {
+		u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;
+
+		mux->adap[i] = i2c_add_mux_adapter(parent, mux, nr, i,
+						   gpiomux_select, deselect);
+		if (!mux->adap[i]) {
+			ret = -ENODEV;
+			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
+			goto add_adapter_failed;
+		}
+	}
+
+	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
+		 pdata->n_values, parent->name);
+
+	platform_set_drvdata(pdev, mux);
+
+	return 0;
+
+add_adapter_failed:
+	for (; i > 0; i--)
+		i2c_del_mux_adapter(mux->adap[i - 1]);
+	i = pdata->n_gpios;
+err_request_gpio:
+	for (; i > 0; i--)
+		gpio_free(pdata->gpios[i - 1]);
+	kfree(mux->adap);
+alloc_failed2:
+	kfree(mux);
+alloc_failed:
+	i2c_put_adapter(parent);
+
+	return ret;
+}
+
+static int __devexit gpiomux_remove(struct platform_device *pdev)
+{
+	struct gpiomux *mux = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < mux->data.n_values; i++)
+		i2c_del_mux_adapter(mux->adap[i]);
+
+	for (i = 0; i < mux->data.n_gpios; i++)
+		gpio_free(mux->data.gpios[i]);
+
+	platform_set_drvdata(pdev, NULL);
+	i2c_put_adapter(mux->parent);
+	kfree(mux->adap);
+	kfree(mux);
+
+	return 0;
+}
+
+static struct platform_driver gpiomux_driver = {
+	.probe	= gpiomux_probe,
+	.remove	= __devexit_p(gpiomux_remove),
+	.driver	= {
+		.owner	= THIS_MODULE,
+		.name	= "gpio-i2cmux",
+	},
+};
+
+static int __init gpiomux_init(void)
+{
+	return platform_driver_register(&gpiomux_driver);
+}
+
+static void __exit gpiomux_exit(void)
+{
+	platform_driver_unregister(&gpiomux_driver);
+}
+
+module_init(gpiomux_init);
+module_exit(gpiomux_exit);
+
+MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
+MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpio-i2cmux");