i2c: Add support for Ux500/Nomadik I2C controller

This adds support for ST-Ericsson's I2C block found
in Ux500 and Nomadik 8815 platforms.
Signed-off-by: srinidhi kasagar <srinidhi.kasagar@stericsson.com>
Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Reviewed-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

drivers/i2c/busses/Kconfig

@@ -440,6 +440,13 @@ config I2C_MV64XXX
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-mv64xxx.
 
+config I2C_NOMADIK
+	tristate "ST-Ericsson Nomadik/Ux500 I2C Controller"
+	depends on PLAT_NOMADIK
+	help
+	  If you say yes to this option, support will be included for the
+	  I2C interface from ST-Ericsson's Nomadik and Ux500 architectures.
+
 config I2C_OCORES
 	tristate "OpenCores I2C Controller"
 	depends on EXPERIMENTAL

drivers/i2c/busses/Makefile

@@ -42,6 +42,7 @@ obj-$(CONFIG_I2C_IOP3XX)	+= i2c-iop3xx.o
 obj-$(CONFIG_I2C_IXP2000)	+= i2c-ixp2000.o
 obj-$(CONFIG_I2C_MPC)		+= i2c-mpc.o
 obj-$(CONFIG_I2C_MV64XXX)	+= i2c-mv64xxx.o
+obj-$(CONFIG_I2C_NOMADIK)	+= i2c-nomadik.o
 obj-$(CONFIG_I2C_OCORES)	+= i2c-ocores.o
 obj-$(CONFIG_I2C_OMAP)		+= i2c-omap.o
 obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o

drivers/i2c/busses/i2c-nomadik.c

+/*
+ * Copyright (C) 2009 ST-Ericsson
+ * Copyright (C) 2009 STMicroelectronics
+ *
+ * I2C master mode controller driver, used in Nomadik 8815
+ * and Ux500 platforms.
+ *
+ * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
+ * Author: Sachin Verma <sachin.verma@st.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/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include <plat/i2c.h>
+
+#define DRIVER_NAME "nmk-i2c"
+
+/* I2C Controller register offsets */
+#define I2C_CR		(0x000)
+#define I2C_SCR		(0x004)
+#define I2C_HSMCR	(0x008)
+#define I2C_MCR		(0x00C)
+#define I2C_TFR		(0x010)
+#define I2C_SR		(0x014)
+#define I2C_RFR		(0x018)
+#define I2C_TFTR	(0x01C)
+#define I2C_RFTR	(0x020)
+#define I2C_DMAR	(0x024)
+#define I2C_BRCR	(0x028)
+#define I2C_IMSCR	(0x02C)
+#define I2C_RISR	(0x030)
+#define I2C_MISR	(0x034)
+#define I2C_ICR		(0x038)
+
+/* Control registers */
+#define I2C_CR_PE		(0x1 << 0)	/* Peripheral Enable */
+#define I2C_CR_OM		(0x3 << 1)	/* Operating mode */
+#define I2C_CR_SAM		(0x1 << 3)	/* Slave addressing mode */
+#define I2C_CR_SM		(0x3 << 4)	/* Speed mode */
+#define I2C_CR_SGCM		(0x1 << 6)	/* Slave general call mode */
+#define I2C_CR_FTX		(0x1 << 7)	/* Flush Transmit */
+#define I2C_CR_FRX		(0x1 << 8)	/* Flush Receive */
+#define I2C_CR_DMA_TX_EN	(0x1 << 9)	/* DMA Tx enable */
+#define I2C_CR_DMA_RX_EN	(0x1 << 10)	/* DMA Rx Enable */
+#define I2C_CR_DMA_SLE		(0x1 << 11)	/* DMA sync. logic enable */
+#define I2C_CR_LM		(0x1 << 12)	/* Loopback mode */
+#define I2C_CR_FON		(0x3 << 13)	/* Filtering on */
+#define I2C_CR_FS		(0x3 << 15)	/* Force stop enable */
+
+/* Master controller (MCR) register */
+#define I2C_MCR_OP		(0x1 << 0)	/* Operation */
+#define I2C_MCR_A7		(0x7f << 1)	/* 7-bit address */
+#define I2C_MCR_EA10		(0x7 << 8) 	/* 10-bit Extended address */
+#define I2C_MCR_SB		(0x1 << 11)	/* Extended address */
+#define I2C_MCR_AM		(0x3 << 12)	/* Address type */
+#define I2C_MCR_STOP		(0x1 << 14) 	/* Stop condition */
+#define I2C_MCR_LENGTH		(0x7ff << 15) 	/* Transaction length */
+
+/* Status register (SR) */
+#define I2C_SR_OP		(0x3 << 0)	/* Operation */
+#define I2C_SR_STATUS		(0x3 << 2)	/* controller status */
+#define I2C_SR_CAUSE		(0x7 << 4)	/* Abort cause */
+#define I2C_SR_TYPE		(0x3 << 7)	/* Receive type */
+#define I2C_SR_LENGTH		(0x7ff << 9)	/* Transfer length */
+
+/* Interrupt mask set/clear (IMSCR) bits */
+#define I2C_IT_TXFE 		(0x1 << 0)
+#define I2C_IT_TXFNE		(0x1 << 1)
+#define I2C_IT_TXFF		(0x1 << 2)
+#define I2C_IT_TXFOVR		(0x1 << 3)
+#define I2C_IT_RXFE		(0x1 << 4)
+#define I2C_IT_RXFNF		(0x1 << 5)
+#define I2C_IT_RXFF		(0x1 << 6)
+#define I2C_IT_RFSR		(0x1 << 16)
+#define I2C_IT_RFSE		(0x1 << 17)
+#define I2C_IT_WTSR		(0x1 << 18)
+#define I2C_IT_MTD		(0x1 << 19)
+#define I2C_IT_STD		(0x1 << 20)
+#define I2C_IT_MAL		(0x1 << 24)
+#define I2C_IT_BERR		(0x1 << 25)
+#define I2C_IT_MTDWS		(0x1 << 28)
+
+#define GEN_MASK(val, mask, sb)  (((val) << (sb)) & (mask))
+
+/* some bits in ICR are reserved */
+#define I2C_CLEAR_ALL_INTS	0x131f007f
+
+/* first three msb bits are reserved */
+#define IRQ_MASK(mask)		(mask & 0x1fffffff)
+
+/* maximum threshold value */
+#define MAX_I2C_FIFO_THRESHOLD	15
+
+enum i2c_status {
+	I2C_NOP,
+	I2C_ON_GOING,
+	I2C_OK,
+	I2C_ABORT
+};
+
+/* operation */
+enum i2c_operation {
+	I2C_NO_OPERATION = 0xff,
+	I2C_WRITE = 0x00,
+	I2C_READ = 0x01
+};
+
+/* controller response timeout in ms */
+#define I2C_TIMEOUT_MS	500
+
+/**
+ * struct i2c_nmk_client - client specific data
+ * @slave_adr: 7-bit slave address
+ * @count: no. bytes to be transfered
+ * @buffer: client data buffer
+ * @xfer_bytes: bytes transfered till now
+ * @operation: current I2C operation
+ */
+struct i2c_nmk_client {
+	unsigned short		slave_adr;
+	unsigned long		count;
+	unsigned char		*buffer;
+	unsigned long		xfer_bytes;
+	enum i2c_operation	operation;
+};
+
+/**
+ * struct nmk_i2c_dev - private data structure of the controller
+ * @pdev: parent platform device
+ * @adap: corresponding I2C adapter
+ * @irq: interrupt line for the controller
+ * @virtbase: virtual io memory area
+ * @clk: hardware i2c block clock
+ * @cfg: machine provided controller configuration
+ * @cli: holder of client specific data
+ * @stop: stop condition
+ * @xfer_complete: acknowledge completion for a I2C message
+ * @result: controller propogated result
+ */
+struct nmk_i2c_dev {
+	struct platform_device		*pdev;
+	struct i2c_adapter 		adap;
+	int 				irq;
+	void __iomem			*virtbase;
+	struct clk			*clk;
+	struct nmk_i2c_controller	cfg;
+	struct i2c_nmk_client		cli;
+	int 				stop;
+	struct completion		xfer_complete;
+	int 				result;
+};
+
+/* controller's abort causes */
+static const char *abort_causes[] = {
+	"no ack received after address transmission",
+	"no ack received during data phase",
+	"ack received after xmission of master code",
+	"master lost arbitration",
+	"slave restarts",
+	"slave reset",
+	"overflow, maxsize is 2047 bytes",
+};
+
+static inline void i2c_set_bit(void __iomem *reg, u32 mask)
+{
+	writel(readl(reg) | mask, reg);
+}
+
+static inline void i2c_clr_bit(void __iomem *reg, u32 mask)
+{
+	writel(readl(reg) & ~mask, reg);
+}
+
+/**
+ * flush_i2c_fifo() - This function flushes the I2C FIFO
+ * @dev: private data of I2C Driver
+ *
+ * This function flushes the I2C Tx and Rx FIFOs. It returns
+ * 0 on successful flushing of FIFO
+ */
+static int flush_i2c_fifo(struct nmk_i2c_dev *dev)
+{
+#define LOOP_ATTEMPTS 10
+	int i;
+	unsigned long timeout;
+
+	/*
+	 * flush the transmit and receive FIFO. The flushing
+	 * operation takes several cycles before to be completed.
+	 * On the completion, the I2C internal logic clears these
+	 * bits, until then no one must access Tx, Rx FIFO and
+	 * should poll on these bits waiting for the completion.
+	 */
+	writel((I2C_CR_FTX | I2C_CR_FRX), dev->virtbase + I2C_CR);
+
+	for (i = 0; i < LOOP_ATTEMPTS; i++) {
+		timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT_MS);
+
+		while (!time_after(jiffies, timeout)) {
+			if ((readl(dev->virtbase + I2C_CR) &
+				(I2C_CR_FTX | I2C_CR_FRX)) == 0)
+					return 0;
+		}
+	}
+
+	dev_err(&dev->pdev->dev, "flushing operation timed out "
+		"giving up after %d attempts", LOOP_ATTEMPTS);
+
+	return -ETIMEDOUT;
+}
+
+/**
+ * disable_all_interrupts() - Disable all interrupts of this I2c Bus
+ * @dev: private data of I2C Driver
+ */
+static void disable_all_interrupts(struct nmk_i2c_dev *dev)
+{
+	u32 mask = IRQ_MASK(0);
+	writel(mask, dev->virtbase + I2C_IMSCR);
+}
+
+/**
+ * clear_all_interrupts() - Clear all interrupts of I2C Controller
+ * @dev: private data of I2C Driver
+ */
+static void clear_all_interrupts(struct nmk_i2c_dev *dev)
+{
+	u32 mask;
+	mask = IRQ_MASK(I2C_CLEAR_ALL_INTS);
+	writel(mask, dev->virtbase + I2C_ICR);
+}
+
+/**
+ * init_hw() - initialize the I2C hardware
+ * @dev: private data of I2C Driver
+ */
+static int init_hw(struct nmk_i2c_dev *dev)
+{
+	int stat;
+
+	stat = flush_i2c_fifo(dev);
+	if (stat)
+		return stat;
+
+	/* disable the controller */
+	i2c_clr_bit(dev->virtbase + I2C_CR , I2C_CR_PE);
+
+	disable_all_interrupts(dev);
+
+	clear_all_interrupts(dev);
+
+	dev->cli.operation = I2C_NO_OPERATION;
+
+	return 0;
+}
+
+/* enable peripheral, master mode operation */
+#define DEFAULT_I2C_REG_CR 	((1 << 1) | I2C_CR_PE)
+
+/**
+ * load_i2c_mcr_reg() - load the MCR register
+ * @dev: private data of controller
+ */
+static u32 load_i2c_mcr_reg(struct nmk_i2c_dev *dev)
+{
+	u32 mcr = 0;
+
+	/* 7-bit address transaction */
+	mcr |= GEN_MASK(1, I2C_MCR_AM, 12);
+	mcr |= GEN_MASK(dev->cli.slave_adr, I2C_MCR_A7, 1);
+
+	/* start byte procedure not applied */
+	mcr |= GEN_MASK(0, I2C_MCR_SB, 11);
+
+	/* check the operation, master read/write? */
+	if (dev->cli.operation == I2C_WRITE)
+		mcr |= GEN_MASK(I2C_WRITE, I2C_MCR_OP, 0);
+	else
+		mcr |= GEN_MASK(I2C_READ, I2C_MCR_OP, 0);
+
+	/* stop or repeated start? */
+	if (dev->stop)
+		mcr |= GEN_MASK(1, I2C_MCR_STOP, 14);
+	else
+		mcr &= ~(GEN_MASK(1, I2C_MCR_STOP, 14));
+
+	mcr |= GEN_MASK(dev->cli.count, I2C_MCR_LENGTH, 15);
+
+	return mcr;
+}
+
+/**
+ * setup_i2c_controller() - setup the controller
+ * @dev: private data of controller
+ */
+static void setup_i2c_controller(struct nmk_i2c_dev *dev)
+{
+	u32 brcr1, brcr2;
+	u32 i2c_clk, div;
+
+	writel(0x0, dev->virtbase + I2C_CR);
+	writel(0x0, dev->virtbase + I2C_HSMCR);
+	writel(0x0, dev->virtbase + I2C_TFTR);
+	writel(0x0, dev->virtbase + I2C_RFTR);
+	writel(0x0, dev->virtbase + I2C_DMAR);
+
+	/*
+	 * set the slsu:
+	 *
+	 * slsu defines the data setup time after SCL clock
+	 * stretching in terms of i2c clk cycles. The
+	 * needed setup time for the three modes are 250ns,
+	 * 100ns, 10ns repectively thus leading to the values
+	 * of 14, 6, 2 for a 48 MHz i2c clk.
+	 */
+	writel(dev->cfg.slsu << 16, dev->virtbase + I2C_SCR);
+
+	i2c_clk = clk_get_rate(dev->clk);
+
+	/* fallback to std. mode if machine has not provided it */
+	if (dev->cfg.clk_freq == 0)
+		dev->cfg.clk_freq = 100000;
+
+	/*
+	 * The spec says, in case of std. mode the divider is
+	 * 2 whereas it is 3 for fast and fastplus mode of
+	 * operation. TODO - high speed support.
+	 */
+	div = (dev->cfg.clk_freq > 100000) ? 3 : 2;
+
+	/*
+	 * generate the mask for baud rate counters. The controller
+	 * has two baud rate counters. One is used for High speed
+	 * operation, and the other is for std, fast mode, fast mode
+	 * plus operation. Currently we do not supprt high speed mode
+	 * so set brcr1 to 0.
+	 */
+	brcr1 = 0 << 16;
+	brcr2 = (i2c_clk/(dev->cfg.clk_freq * div)) & 0xffff;
+
+	/* set the baud rate counter register */
+	writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR);
+
+	/*
+	 * set the speed mode. Currently we support
+	 * only standard and fast mode of operation
+	 * TODO - support for fast mode plus (upto 1Mb/s)
+	 * and high speed (up to 3.4 Mb/s)
+	 */
+	if (dev->cfg.sm > I2C_FREQ_MODE_FAST) {
+		dev_err(&dev->pdev->dev, "do not support this mode "
+			"defaulting to std. mode\n");
+		brcr2 = i2c_clk/(100000 * 2) & 0xffff;
+		writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR);
+		writel(I2C_FREQ_MODE_STANDARD << 4,
+				dev->virtbase + I2C_CR);
+	}
+	writel(dev->cfg.sm << 4, dev->virtbase + I2C_CR);
+
+	/* set the Tx and Rx FIFO threshold */
+	writel(dev->cfg.tft, dev->virtbase + I2C_TFTR);
+	writel(dev->cfg.rft, dev->virtbase + I2C_RFTR);
+}
+
+/**
+ * read_i2c() - Read from I2C client device
+ * @dev: private data of I2C Driver
+ *
+ * This function reads from i2c client device when controller is in
+ * master mode. There is a completion timeout. If there is no transfer
+ * before timeout error is returned.
+ */
+static int read_i2c(struct nmk_i2c_dev *dev)
+{
+	u32 status = 0;
+	u32 mcr;
+	u32 irq_mask = 0;
+	int timeout;
+
+	mcr = load_i2c_mcr_reg(dev);
+	writel(mcr, dev->virtbase + I2C_MCR);
+
+	/* load the current CR value */
+	writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR,
+			dev->virtbase + I2C_CR);
+
+	/* enable the controller */
+	i2c_set_bit(dev->virtbase + I2C_CR, I2C_CR_PE);
+
+	init_completion(&dev->xfer_complete);
+
+	/* enable interrupts by setting the mask */
+	irq_mask = (I2C_IT_RXFNF | I2C_IT_RXFF |
+			I2C_IT_MAL | I2C_IT_BERR);
+
+	if (dev->stop)
+		irq_mask |= I2C_IT_MTD;
+	else
+		irq_mask |= I2C_IT_MTDWS;
+
+	irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask);
+
+	writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask,
+			dev->virtbase + I2C_IMSCR);
+
+	timeout = wait_for_completion_interruptible_timeout(
+		&dev->xfer_complete, msecs_to_jiffies(I2C_TIMEOUT_MS));
+
+	if (timeout < 0) {
+		dev_err(&dev->pdev->dev,
+			"wait_for_completion_interruptible_timeout"
+			"returned %d waiting for event\n", timeout);
+		status = timeout;
+	}
+
+	if (timeout == 0) {
+		/* controler has timedout, re-init the h/w */
+		dev_err(&dev->pdev->dev, "controller timed out, re-init h/w\n");
+		(void) init_hw(dev);
+		status = -ETIMEDOUT;
+	}
+
+	return status;
+}
+
+/**
+ * write_i2c() - Write data to I2C client.
+ * @dev: private data of I2C Driver
+ *
+ * This function writes data to I2C client
+ */
+static int write_i2c(struct nmk_i2c_dev *dev)
+{
+	u32 status = 0;
+	u32 mcr;
+	u32 irq_mask = 0;
+	int timeout;
+
+	mcr = load_i2c_mcr_reg(dev);
+
+	writel(mcr, dev->virtbase + I2C_MCR);
+
+	/* load the current CR value */
+	writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR,
+			dev->virtbase + I2C_CR);
+
+	/* enable the controller */
+	i2c_set_bit(dev->virtbase + I2C_CR , I2C_CR_PE);
+
+	init_completion(&dev->xfer_complete);
+
+	/* enable interrupts by settings the masks */
+	irq_mask = (I2C_IT_TXFNE | I2C_IT_TXFOVR |
+			I2C_IT_MAL | I2C_IT_BERR);
+
+	/*
+	 * check if we want to transfer a single or multiple bytes, if so
+	 * set the MTDWS bit (Master Transaction Done Without Stop)
+	 * to start repeated start operation
+	 */
+	if (dev->stop)
+		irq_mask |= I2C_IT_MTD;
+	else
+		irq_mask |= I2C_IT_MTDWS;
+
+	irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask);
+
+	writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask,
+			dev->virtbase + I2C_IMSCR);
+
+	timeout = wait_for_completion_interruptible_timeout(
+		&dev->xfer_complete, msecs_to_jiffies(I2C_TIMEOUT_MS));
+
+	if (timeout < 0) {
+		dev_err(&dev->pdev->dev,
+			"wait_for_completion_interruptible_timeout"
+			"returned %d waiting for event\n", timeout);
+		status = timeout;
+	}
+
+	if (timeout == 0) {
+		/* controler has timedout, re-init the h/w */
+		dev_err(&dev->pdev->dev, "controller timed out, re-init h/w\n");
+		(void) init_hw(dev);
+		status = -ETIMEDOUT;
+	}
+
+	return status;
+}
+
+/**
+ * nmk_i2c_xfer() - I2C transfer function used by kernel framework
+ * @i2c_adap 	- Adapter pointer to the controller
+ * @msgs[] - Pointer to data to be written.
+ * @num_msgs - Number of messages to be executed
+ *
+ * This is the function called by the generic kernel i2c_transfer()
+ * or i2c_smbus...() API calls. Note that this code is protected by the
+ * semaphore set in the kernel i2c_transfer() function.
+ *
+ * NOTE:
+ * READ TRANSFER : We impose a restriction of the first message to be the
+ * 		index message for any read transaction.
+ * 		- a no index is coded as '0',
+ * 		- 2byte big endian index is coded as '3'
+ * 		!!! msg[0].buf holds the actual index.
+ * 		This is compatible with generic messages of smbus emulator
+ * 		that send a one byte index.
+ * 		eg. a I2C transation to read 2 bytes from index 0
+ *			idx = 0;
+ *			msg[0].addr = client->addr;
+ *			msg[0].flags = 0x0;
+ *			msg[0].len = 1;
+ *			msg[0].buf = &idx;
+ *
+ *			msg[1].addr = client->addr;
+ *			msg[1].flags = I2C_M_RD;
+ *			msg[1].len = 2;
+ *			msg[1].buf = rd_buff
+ *			i2c_transfer(adap, msg, 2);
+ *
+ * WRITE TRANSFER : The I2C standard interface interprets all data as payload.
+ *		If you want to emulate an SMBUS write transaction put the
+ *		index as first byte(or first and second) in the payload.
+ *		eg. a I2C transation to write 2 bytes from index 1
+ *			wr_buff[0] = 0x1;
+ *			wr_buff[1] = 0x23;
+ *			wr_buff[2] = 0x46;
+ *			msg[0].flags = 0x0;
+ *			msg[0].len = 3;
+ *			msg[0].buf = wr_buff;
+ *			i2c_transfer(adap, msg, 1);
+ *
+ * To read or write a block of data (multiple bytes) using SMBUS emulation
+ * please use the i2c_smbus_read_i2c_block_data()
+ * or i2c_smbus_write_i2c_block_data() API
+ */
+static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
+		struct i2c_msg msgs[], int num_msgs)
+{
+	int status;
+	int i;
+	u32 cause;
+	struct nmk_i2c_dev *dev = i2c_get_adapdata(i2c_adap);
+
+	status = init_hw(dev);
+	if (status)
+		return status;
+
+	/* setup the i2c controller */
+	setup_i2c_controller(dev);
+
+	for (i = 0; i < num_msgs; i++) {
+		if (unlikely(msgs[i].flags & I2C_M_TEN)) {
+			dev_err(&dev->pdev->dev, "10 bit addressing"
+					"not supported\n");
+			return -EINVAL;
+		}
+		dev->cli.slave_adr	= msgs[i].addr;
+		dev->cli.buffer		= msgs[i].buf;
+		dev->cli.count		= msgs[i].len;
+		dev->stop = (i < (num_msgs - 1)) ? 0 : 1;
+		dev->result = 0;
+
+		if (msgs[i].flags & I2C_M_RD) {
+			/* it is a read operation */
+			dev->cli.operation = I2C_READ;
+			status = read_i2c(dev);
+		} else {
+			/* write operation */
+			dev->cli.operation = I2C_WRITE;
+			status = write_i2c(dev);
+		}
+		if (status || (dev->result)) {
+			/* get the abort cause */
+			cause =	(readl(dev->virtbase + I2C_SR) >> 4) & 0x7;
+			dev_err(&dev->pdev->dev, "error during I2C"
+					"message xfer: %d\n", cause);
+			dev_err(&dev->pdev->dev, "%s\n",
+				cause >= ARRAY_SIZE(abort_causes)
+				? "unknown reason" : abort_causes[cause]);
+			return status;
+		}
+		mdelay(1);
+	}
+	/* return the no. messages processed */
+	if (status)
+		return status;
+	else
+		return num_msgs;
+}
+
+/**
+ * disable_interrupts() - disable the interrupts
+ * @dev: private data of controller
+ */
+static int disable_interrupts(struct nmk_i2c_dev *dev, u32 irq)
+{
+	irq = IRQ_MASK(irq);
+	writel(readl(dev->virtbase + I2C_IMSCR) & ~(I2C_CLEAR_ALL_INTS & irq),
+			dev->virtbase + I2C_IMSCR);
+	return 0;
+}
+
+/**
+ * i2c_irq_handler() - interrupt routine
+ * @irq: interrupt number
+ * @arg: data passed to the handler
+ *
+ * This is the interrupt handler for the i2c driver. Currently
+ * it handles the major interrupts like Rx & Tx FIFO management
+ * interrupts, master transaction interrupts, arbitration and
+ * bus error interrupts. The rest of the interrupts are treated as
+ * unhandled.
+ */
+static irqreturn_t i2c_irq_handler(int irq, void *arg)
+{
+	struct nmk_i2c_dev *dev = arg;
+	u32 tft, rft;
+	u32 count;
+	u32 misr;
+	u32 src = 0;
+
+	/* load Tx FIFO and Rx FIFO threshold values */
+	tft = readl(dev->virtbase + I2C_TFTR);
+	rft = readl(dev->virtbase + I2C_RFTR);
+
+	/* read interrupt status register */
+	misr = readl(dev->virtbase + I2C_MISR);
+
+	src = __ffs(misr);
+	switch ((1 << src)) {
+
+	/* Transmit FIFO nearly empty interrupt */
+	case I2C_IT_TXFNE:
+	{
+		if (dev->cli.operation == I2C_READ) {
+			/*
+			 * in read operation why do we care for writing?
+			 * so disable the Transmit FIFO interrupt
+			 */
+			disable_interrupts(dev, I2C_IT_TXFNE);
+		} else {
+			for (count = (MAX_I2C_FIFO_THRESHOLD - tft - 2);
+					(count > 0) &&
+					(dev->cli.count != 0);
+					count--) {
+				/* write to the Tx FIFO */
+				writeb(*dev->cli.buffer,
+					dev->virtbase + I2C_TFR);
+				dev->cli.buffer++;
+				dev->cli.count--;
+				dev->cli.xfer_bytes++;
+			}
+			/*
+			 * if done, close the transfer by disabling the
+			 * corresponding TXFNE interrupt
+			 */
+			if (dev->cli.count == 0)
+				disable_interrupts(dev,	I2C_IT_TXFNE);
+		}
+	}
+	break;
+
+	/*
+	 * Rx FIFO nearly full interrupt.
+	 * This is set when the numer of entries in Rx FIFO is
+	 * greater or equal than the threshold value programmed
+	 * in RFT
+	 */
+	case I2C_IT_RXFNF:
+		for (count = rft; count > 0; count--) {
+			/* Read the Rx FIFO */
+			*dev->cli.buffer = readb(dev->virtbase + I2C_RFR);
+			dev->cli.buffer++;
+		}
+		dev->cli.count -= rft;
+		dev->cli.xfer_bytes += rft;
+		break;
+
+	/* Rx FIFO full */
+	case I2C_IT_RXFF:
+		for (count = MAX_I2C_FIFO_THRESHOLD; count > 0; count--) {
+			*dev->cli.buffer = readb(dev->virtbase + I2C_RFR);
+			dev->cli.buffer++;
+		}
+		dev->cli.count -= MAX_I2C_FIFO_THRESHOLD;
+		dev->cli.xfer_bytes += MAX_I2C_FIFO_THRESHOLD;
+		break;
+
+	/* Master Transaction Done with/without stop */
+	case I2C_IT_MTD:
+	case I2C_IT_MTDWS:
+		if (dev->cli.operation == I2C_READ) {
+			while (!readl(dev->virtbase + I2C_RISR) & I2C_IT_RXFE) {
+				if (dev->cli.count == 0)
+					break;
+				*dev->cli.buffer =
+					readb(dev->virtbase + I2C_RFR);
+				dev->cli.buffer++;
+				dev->cli.count--;
+				dev->cli.xfer_bytes++;
+			}
+		}
+
+		i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MTD);
+		i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MTDWS);
+
+		disable_interrupts(dev,
+				(I2C_IT_TXFNE | I2C_IT_TXFE | I2C_IT_TXFF
+					| I2C_IT_TXFOVR | I2C_IT_RXFNF
+					| I2C_IT_RXFF | I2C_IT_RXFE));
+
+		if (dev->cli.count) {
+			dev->result = -1;
+			dev_err(&dev->pdev->dev, "%lu bytes still remain to be"
+					"xfered\n", dev->cli.count);
+			(void) init_hw(dev);
+		}
+		complete(&dev->xfer_complete);
+
+		break;
+
+	/* Master Arbitration lost interrupt */
+	case I2C_IT_MAL:
+		dev->result = -1;
+		(void) init_hw(dev);
+
+		i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MAL);
+		complete(&dev->xfer_complete);
+
+		break;
+
+	/*
+	 * Bus Error interrupt.
+	 * This happens when an unexpected start/stop condition occurs
+	 * during the transaction.
+	 */
+	case I2C_IT_BERR:
+		dev->result = -1;
+		/* get the status */
+		if (((readl(dev->virtbase + I2C_SR) >> 2) & 0x3) == I2C_ABORT)
+			(void) init_hw(dev);
+
+		i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_BERR);
+		complete(&dev->xfer_complete);
+
+		break;
+
+	/*
+	 * Tx FIFO overrun interrupt.
+	 * This is set when a write operation in Tx FIFO is performed and
+	 * the Tx FIFO is full.
+	 */
+	case I2C_IT_TXFOVR:
+		dev->result = -1;
+		(void) init_hw(dev);
+
+		dev_err(&dev->pdev->dev, "Tx Fifo Over run\n");
+		complete(&dev->xfer_complete);
+
+		break;
+
+	/* unhandled interrupts by this driver - TODO*/
+	case I2C_IT_TXFE:
+	case I2C_IT_TXFF:
+	case I2C_IT_RXFE:
+	case I2C_IT_RFSR:
+	case I2C_IT_RFSE:
+	case I2C_IT_WTSR:
+	case I2C_IT_STD:
+		dev_err(&dev->pdev->dev, "unhandled Interrupt\n");
+		break;
+	default:
+		dev_err(&dev->pdev->dev, "spurious Interrupt..\n");
+		break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C
+		| I2C_FUNC_SMBUS_BYTE_DATA
+		| I2C_FUNC_SMBUS_WORD_DATA
+		| I2C_FUNC_SMBUS_I2C_BLOCK;
+}
+
+static const struct i2c_algorithm nmk_i2c_algo = {
+	.master_xfer	= nmk_i2c_xfer,
+	.functionality	= nmk_i2c_functionality
+};
+
+static int __devinit nmk_i2c_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct resource *res;
+	struct nmk_i2c_controller *pdata =
+			pdev->dev.platform_data;
+	struct nmk_i2c_dev	*dev;
+	struct i2c_adapter *adap;
+
+	dev = kzalloc(sizeof(struct nmk_i2c_dev), GFP_KERNEL);
+	if (!dev) {
+		dev_err(&pdev->dev, "cannot allocate memory\n");
+		ret = -ENOMEM;
+		goto err_no_mem;
+	}
+
+	dev->pdev = pdev;
+	platform_set_drvdata(pdev, dev);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENOENT;
+		goto err_no_resource;
+	}
+
+	if (request_mem_region(res->start, resource_size(res),
+		DRIVER_NAME "I/O region") == 	NULL)	{
+		ret = -EBUSY;
+		goto err_no_region;
+	}
+
+	dev->virtbase = ioremap(res->start, resource_size(res));
+	if (!dev->virtbase) {
+		ret = -ENOMEM;
+		goto err_no_ioremap;
+	}
+
+	dev->irq = platform_get_irq(pdev, 0);
+	ret = request_irq(dev->irq, i2c_irq_handler, IRQF_DISABLED,
+				DRIVER_NAME, dev);
+	if (ret) {
+		dev_err(&pdev->dev, "cannot claim the irq %d\n", dev->irq);
+		goto err_irq;
+	}
+
+	dev->clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dev->clk)) {
+		dev_err(&pdev->dev, "could not get i2c clock\n");
+		ret = PTR_ERR(dev->clk);
+		goto err_no_clk;
+	}
+
+	clk_enable(dev->clk);
+
+	adap = &dev->adap;
+	adap->dev.parent = &pdev->dev;
+	adap->owner	= THIS_MODULE;
+	adap->class	= I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	adap->algo	= &nmk_i2c_algo;
+
+	/* fetch the controller id */
+	adap->nr	= pdev->id;
+
+	/* fetch the controller configuration from machine */
+	dev->cfg.clk_freq = pdata->clk_freq;
+	dev->cfg.slsu	= pdata->slsu;
+	dev->cfg.tft	= pdata->tft;
+	dev->cfg.rft	= pdata->rft;
+	dev->cfg.sm	= pdata->sm;
+
+	i2c_set_adapdata(adap, dev);
+
+	ret = init_hw(dev);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "error in initializing i2c hardware\n");
+		goto err_init_hw;
+	}
+
+	dev_dbg(&pdev->dev, "initialize I2C%d bus on virtual "
+		"base %p\n", pdev->id, dev->virtbase);
+
+	ret = i2c_add_numbered_adapter(adap);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to add adapter\n");
+		goto err_add_adap;
+	}
+
+	return 0;
+
+ err_init_hw:
+	clk_disable(dev->clk);
+ err_add_adap:
+	clk_put(dev->clk);
+ err_no_clk:
+	free_irq(dev->irq, dev);
+ err_irq:
+	iounmap(dev->virtbase);
+ err_no_ioremap:
+	release_mem_region(res->start, resource_size(res));
+ err_no_region:
+	platform_set_drvdata(pdev, NULL);
+ err_no_resource:
+	kfree(dev);
+ err_no_mem:
+
+	return ret;
+}
+
+static int __devexit nmk_i2c_remove(struct platform_device *pdev)
+{
+	struct nmk_i2c_dev *dev = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&dev->adap);
+	flush_i2c_fifo(dev);
+	disable_all_interrupts(dev);
+	clear_all_interrupts(dev);
+	/* disable the controller */
+	i2c_clr_bit(dev->virtbase + I2C_CR, I2C_CR_PE);
+	free_irq(dev->irq, dev);
+	iounmap(dev->virtbase);
+	clk_disable(dev->clk);
+	clk_put(dev->clk);
+	platform_set_drvdata(pdev, NULL);
+	kfree(dev);
+
+	return 0;
+}
+
+static struct platform_driver nmk_i2c_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = DRIVER_NAME,
+	},
+	.probe = nmk_i2c_probe,
+	.remove = __devexit_p(nmk_i2c_remove),
+};
+
+static int __init nmk_i2c_init(void)
+{
+	return platform_driver_register(&nmk_i2c_driver);
+}
+
+static void __exit nmk_i2c_exit(void)
+{
+	platform_driver_unregister(&nmk_i2c_driver);
+}
+
+subsys_initcall(nmk_i2c_init);
+module_exit(nmk_i2c_exit);
+
+MODULE_AUTHOR("Sachin Verma, Srinidhi KASAGAR");
+MODULE_DESCRIPTION("Nomadik/Ux500 I2C driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);