i2c-eg20t: add driver for Intel EG20T

I2C driver for Intel EG20T PCH

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Reviewed-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Qi Wang <qi.wang@intel.com>
[ben-linux@fluff.org: reworded commit message]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

3 files changed, 909 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 3a6321cb8030..113505a6434e 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 84cb16ae6f9e..9d2d0ec7fb23 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 000000000000..2e067dd2ee51
--- /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));