Staging: mid: Intel MID touch screen driver

Touchscreen driver used by intel mid devices. Some clean up by Alan Cox. This
driver is basically ready for upstreaming properly but is tied wrongly to the
SPI layer and needs firmware/SFI changes to fix that.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/Kconfig

@@ -143,5 +143,7 @@ source "drivers/staging/adis16255/Kconfig"
 
 source "drivers/staging/xgifb/Kconfig"
 
+source "drivers/staging/mrst-touchscreen/Kconfig"
+
 endif # !STAGING_EXCLUDE_BUILD
 endif # STAGING

drivers/staging/Makefile

@@ -52,3 +52,4 @@ obj-$(CONFIG_CXT1E1)		+= cxt1e1/
 obj-$(CONFIG_TI_ST)		+= ti-st/
 obj-$(CONFIG_ADIS16255)		+= adis16255/
 obj-$(CONFIG_FB_XGI)		+= xgifb/
+obj-$(CONFIG_TOUCHSCREEN_MRSTOUCH)	+= mrst-touchscreen/

drivers/staging/mrst-touchscreen/Kconfig

@@ -0,0 +1,7 @@
+config TOUCHSCREEN_INTEL_MID
+	tristate "Intel MID platform resistive touchscreen"
+	depends on INTEL_SCU_IPC
+	default y
+	help
+	  Say Y here if you have a Intel MID based touchscreen
+	  If unsure, say N.

drivers/staging/mrst-touchscreen/Makefile

@@ -0,0 +1,3 @@
+obj-$(CONFIG_TOUCHSCREEN_INTEL_MID) := intel_mid_touch.o
+
+

drivers/staging/mrst-touchscreen/TODO

@@ -0,0 +1,2 @@
+- Move the driver to not think it is SPI (requires fixing some of the SFI
+  and firmware side)

drivers/staging/mrst-touchscreen/intel-mid-touch.c

@@ -0,0 +1,864 @@
+/*
+ * intel_mid_touch.c - Intel MID Resistive Touch Screen Driver
+ *
+ * Copyright (C) 2008 Intel Corp
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * 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; ifnot, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Questions/Comments/Bug fixes to Sreedhara (sreedhara.ds@intel.com)
+ * 			    Ramesh Agarwal (ramesh.agarwal@intel.com)
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * TODO:
+ *	kill off mrstouch_debug eventually
+ *	review conversion of r/m/w sequences
+ *	Replace interrupt mutex abuse
+ *	Kill of mrstouchdevp pointer
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/param.h>
+#include <linux/spi/spi.h>
+#include <linux/irq.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <asm/intel_scu_ipc.h>
+
+
+#if defined(MRSTOUCH_DEBUG)
+#define mrstouch_debug(fmt, args...)\
+	do { \
+		printk(KERN_DEBUG "\n[MRSTOUCH(%d)] - ", __LINE__); \
+		printk(KERN_DEBUG fmt, ##args); \
+	} while (0);
+#else
+#define mrstouch_debug(fmt, args...)
+#endif
+
+/* PMIC Interrupt registers */
+#define PMIC_REG_ID1   0x00 /*PMIC ID1 register */
+
+/* PMIC Interrupt registers */
+#define PMIC_REG_INT   0x04 /*PMIC interrupt register */
+#define PMIC_REG_MINT  0x05 /*PMIC interrupt mask register */
+
+/* ADC Interrupt registers */
+#define PMIC_REG_ADCINT   0x5F /*ADC interrupt register */
+#define PMIC_REG_MADCINT  0x60 /*ADC interrupt mask register */
+
+/* ADC Control registers */
+#define PMIC_REG_ADCCNTL1    0x61 /*ADC control register */
+
+/* ADC Channel Selection registers */
+#define PMICADDR0     0xA4
+#define END_OF_CHANNEL 0x1F
+
+/* ADC Result register */
+#define PMIC_REG_ADCSNS0H   0x64
+
+/* ADC channels for touch screen */
+#define MRST_TS_CHAN10   0xA /* Touch screen X+ connection */
+#define MRST_TS_CHAN11   0xB /* Touch screen X- connection */
+#define MRST_TS_CHAN12   0xC /* Touch screen Y+ connection */
+#define MRST_TS_CHAN13   0xD /* Touch screen Y- connection */
+
+/* Touch screen coordinate constants */
+#define TOUCH_PRESSURE   	50
+#define TOUCH_PRESSURE_FS	100
+
+#define XMOVE_LIMIT	5
+#define YMOVE_LIMIT	5
+#define XYMOVE_CNT	3
+
+#define MAX_10BIT	((1<<10)-1)
+
+/* Touch screen channel BIAS constants */
+#define XBIAS		0x20
+#define YBIAS		0x40
+#define ZBIAS		0x80
+
+/* Touch screen coordinates */
+#define MIN_X		10
+#define MAX_X		1024
+#define MIN_Y		10
+#define MAX_Y		1024
+#define WAIT_ADC_COMPLETION 10
+
+/* PMIC ADC round robin delays */
+#define ADC_LOOP_DELAY0 0x0 /* Continuous loop */
+#define ADC_LOOP_DELAY1 0x1 /* 4.5  ms approximate */
+
+/* PMIC Vendor Identifiers */
+#define PMIC_VENDOR_FS  0 /* PMIC vendor FreeScale */
+#define PMIC_VENDOR_MAXIM 1 /* PMIC vendor MAXIM */
+#define PMIC_VENDOR_NEC 2 /* PMIC vendor NEC */
+#define MRSTOUCH_MAX_CHANNELS 32 /* Maximum ADC channels */
+
+/* Touch screen device structure */
+struct mrstouch_dev {
+	struct spi_device *spi; /* SPI device associated with touch screen */
+	struct input_dev *input; /* input device for touchscreen*/
+	char 		phys[32]; /* Device name */
+	struct task_struct *pendet_thrd; /* PENDET interrupt handler */
+	struct mutex lock; /* Sync between interrupt and PENDET handler */
+	bool            busy; /* Busy flag */
+	u16             asr; /* Address selection register */
+	int             irq;    /* Touch screen IRQ # */
+	uint		vendor;  /* PMIC vendor */
+	uint		rev;  /* PMIC revision */
+	bool		suspended; /* Device suspended status */
+	bool		disabled;  /* Device disabled status */
+	u16		x;  /* X coordinate */
+	u16		y;  /* Y coordinate */
+	bool		pendown;  /* PEN position */
+} ;
+
+
+/* Global Pointer to Touch screen device */
+static struct mrstouch_dev *mrstouchdevp;
+
+/* Utility to read PMIC ID */
+static int mrstouch_pmic_id(uint *vendor, uint *rev)
+{
+	int err;
+	u8 r;
+
+	err = intel_scu_ipc_ioread8(PMIC_REG_ID1, &r);
+	if (err)
+		return err;
+
+	*vendor = r & 0x7;
+	*rev = (r >> 3) & 0x7;
+
+	return 0;
+}
+
+/*
+ * Parse ADC channels to find end of the channel configured by other ADC user
+ * NEC and MAXIM requires 4 channels and FreeScale needs 18 channels
+ */
+static int mrstouch_chan_parse(struct mrstouch_dev *tsdev)
+{
+	int err, i, j, found;
+	u32 r32;
+
+	found = -1;
+
+	for (i = 0; i < MRSTOUCH_MAX_CHANNELS; i++) {
+		if (found >= 0)
+			break;
+
+		err = intel_scu_ipc_ioread32(PMICADDR0, &r32);
+		if (err)
+			return err;
+
+		for (j = 0; j < 32; j+= 8) {
+			if (((r32 >> j) & 0xFF) == END_OF_CHANNEL) {
+				found = i;
+				break;
+			}
+		}
+	}
+	if (found < 0)
+		return 0;
+
+	if (tsdev->vendor == PMIC_VENDOR_FS) {
+		if (found && found > (MRSTOUCH_MAX_CHANNELS - 18))
+			return -ENOSPC;
+	} else {
+		if (found && found > (MRSTOUCH_MAX_CHANNELS - 4))
+			return -ENOSPC;
+	}
+	return found;
+}
+
+/* Utility to enable/disable pendet.
+ * pendet set to true enables PENDET interrupt
+ * pendet set to false disables PENDET interrupt
+ * Also clears RND mask bit
+*/
+static int pendet_enable(struct mrstouch_dev *tsdev, bool pendet)
+{
+	u16 reg;
+	u8 r;
+	u8 pendet_enabled = 0;
+	int retry = 0;
+	int err;
+
+	err = intel_scu_ipc_ioread16(PMIC_REG_MADCINT, &reg);
+	if (err)
+		return err;
+
+	if (pendet) {
+		reg &= ~0x0005;
+		reg |= 0x2000; /* Enable pendet */
+	} else
+		reg &= 0xDFFF; /* Disable pendet */
+
+	/* Set MADCINT and update ADCCNTL1 (next reg byte) */
+	err = intel_scu_ipc_iowrite16(PMIC_REG_MADCINT, reg);
+	if (!pendet || err)
+		return err;
+
+	/*
+	 * Sometimes even after the register write succeeds
+	 * the PMIC register value is not updated. Retry few iterations
+	 * to enable pendet.
+	 */
+
+	err = intel_scu_ipc_ioread8(PMIC_REG_ADCCNTL1, &r);
+	pendet_enabled = (r >> 5) & 0x01;
+
+	retry = 0;
+	while (!err && !pendet_enabled) {
+		retry++;
+		msleep(10);
+		err = intel_scu_ipc_iowrite8(PMIC_REG_ADCCNTL1, reg >> 8);
+		if (err)
+			break;
+		err = intel_scu_ipc_ioread8(PMIC_REG_ADCCNTL1, &r);
+		if (err == 0)
+			pendet_enabled = (r >> 5) & 0x01;
+		if (retry >= 10) {
+			dev_err(&tsdev->spi->dev, "Touch screen disabled.\n");
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+/* To read PMIC ADC touch screen result
+ * Reads ADC storage registers for higher 7 and lower 3 bits
+ * converts the two readings to single value and turns off gain bit
+ */
+static int mrstouch_ts_chan_read(u16 offset, u16 chan, u16 *vp, u16 *vm)
+{
+	int err;
+	u16 result;
+	u32 res;
+
+	result = PMIC_REG_ADCSNS0H + offset;
+
+	if (chan == MRST_TS_CHAN12)
+		result += 4;
+
+	err = intel_scu_ipc_ioread32(result, &res);
+	if (err)
+		return err;
+
+	/* Mash the bits up */
+
+	*vp = (res & 0xFF) << 3;	/* Highest 7 bits */
+	*vp |= (res >> 8) & 0x07;	/* Lower 3 bits */
+	*vp &= 0x3FF;
+
+	res >>= 16;
+
+	*vm = (res & 0xFF) << 3;	/* Highest 7 bits */
+	*vm |= (res >> 8) & 0x07;	/* Lower 3 bits */
+	*vm &= 0x3FF;
+
+	return 0;
+}
+
+/* To configure touch screen channels
+ * Writes touch screen channels to ADC address selection registers
+ */
+static int mrstouch_ts_chan_set(uint offset)
+{
+	int count;
+	u16 chan;
+	u16 reg[5];
+	u8 data[5];
+
+	chan = PMICADDR0 + offset;
+	for (count = 0; count <= 3; count++) {
+		reg[count] = chan++;
+		data[count] = MRST_TS_CHAN10 + count;
+	}
+	reg[count] = chan;
+	data[count] = END_OF_CHANNEL;
+
+	return intel_scu_ipc_writev(reg, data, 5);
+}
+
+/* Initialize ADC */
+static int mrstouch_adc_init(struct mrstouch_dev *tsdev)
+{
+	int err, start;
+	u8 ra, rm;
+
+	err = mrstouch_pmic_id(&tsdev->vendor, &tsdev->rev);
+	if (err) {
+		dev_err(&tsdev->spi->dev, "Unable to read PMIC id\n");
+		return err;
+	}
+
+	start = mrstouch_chan_parse(tsdev);
+	if (start < 0) {
+		dev_err(&tsdev->spi->dev, "Unable to parse channels\n");
+		return start;
+	}
+
+	tsdev->asr = start;
+
+	mrstouch_debug("Channel offset(%d): 0x%X\n", tsdev->asr, tsdev->vendor);
+
+	/* ADC power on, start, enable PENDET and set loop delay
+	 * ADC loop delay is set to 4.5 ms approximately
+	 * Loop delay more than this results in jitter in adc readings
+	 * Setting loop delay to 0 (continous loop) in MAXIM stops PENDET
+	 * interrupt generation sometimes.
+	 */
+
+	if (tsdev->vendor == PMIC_VENDOR_FS) {
+		ra = 0xE0 | ADC_LOOP_DELAY0;
+		rm = 0x5;
+	} else {
+		/* NEC and MAXIm not consistent with loop delay 0 */
+		ra = 0xE0 | ADC_LOOP_DELAY1;
+		rm = 0x0;
+
+		/* configure touch screen channels */
+		err = mrstouch_ts_chan_set(tsdev->asr);
+		if (err)
+			return err;
+	}
+	err = intel_scu_ipc_update_register(PMIC_REG_ADCCNTL1, ra, 0xE7);
+	if (err == 0)
+		err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, rm, 0x03);
+	return err;
+}
+
+/* Reports x,y coordinates to event subsystem */
+static void mrstouch_report_xy(struct mrstouch_dev *tsdev, u16 x, u16 y, u16 z)
+{
+	int xdiff, ydiff;
+
+	if (tsdev->pendown && z <= TOUCH_PRESSURE) {
+		/* Pen removed, report button release */
+		mrstouch_debug("BTN REL(%d)", z);
+		input_report_key(tsdev->input, BTN_TOUCH, 0);
+		tsdev->pendown = false;
+	}
+
+	xdiff = abs(x - tsdev->x);
+	ydiff = abs(y - tsdev->y);
+
+	/*
+	if x and y values changes for XYMOVE_CNT readings it is considered
+	as stylus is moving. This is required to differentiate between stylus
+	movement and jitter
+	*/
+	if (x < MIN_X || x > MAX_X || y < MIN_Y || y > MAX_Y) {
+		/* Spurious values, release button if touched and return */
+		if (tsdev->pendown) {
+			mrstouch_debug("BTN REL(%d)", z);
+			input_report_key(tsdev->input, BTN_TOUCH, 0);
+			tsdev->pendown = false;
+		}
+		return;
+	} else if (xdiff >= XMOVE_LIMIT || ydiff >= YMOVE_LIMIT) {
+		tsdev->x = x;
+		tsdev->y = y;
+
+		input_report_abs(tsdev->input, ABS_X, x);
+		input_report_abs(tsdev->input, ABS_Y, y);
+		input_sync(tsdev->input);
+	}
+
+
+	if (!tsdev->pendown && z > TOUCH_PRESSURE) {
+		/* Pen touched, report button touch */
+		mrstouch_debug("BTN TCH(%d, %d, %d)", x, y, z);
+		input_report_key(tsdev->input, BTN_TOUCH, 1);
+		tsdev->pendown = true;
+	}
+}
+
+
+/* Utility to start ADC, used by freescale handler */
+static int pendet_mask(void)
+{
+	return 	intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0x02, 0x02);
+}
+
+/* Utility to stop ADC, used by freescale handler */
+static int pendet_umask(void)
+{
+	return 	intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0x00, 0x02);
+}
+
+/* Utility to read ADC, used by freescale handler */
+static int mrstouch_pmic_fs_adc_read(struct mrstouch_dev *tsdev)
+{
+	int err;
+	u16 x, y, z, result;
+	u16 reg[4];
+	u8 data[4];
+
+	result = PMIC_REG_ADCSNS0H + tsdev->asr;
+
+	reg[0] = result + 4;
+	reg[1] = result + 5;
+	reg[2] = result + 16;
+	reg[3] = result + 17;
+
+	err = intel_scu_ipc_readv(reg, data, 4);
+	if (err)
+		goto ipc_error;
+
+	x = data[0] << 3; /* Higher 7 bits */
+	x |= data[1] & 0x7; /* Lower 3 bits */
+	x &= 0x3FF;
+
+	y = data[2] << 3; /* Higher 7 bits */
+	y |= data[3] & 0x7; /* Lower 3 bits */
+	y &= 0x3FF;
+
+	/* Read Z value */
+	reg[0] = result + 28;
+	reg[1] = result + 29;
+
+	err = intel_scu_ipc_readv(reg, data, 4);
+	if (err)
+		goto ipc_error;
+
+	z = data[0] << 3; /* Higher 7 bits */
+	z |= data[1] & 0x7; /* Lower 3 bits */
+	z &= 0x3FF;
+
+#if defined(MRSTOUCH_PRINT_XYZP)
+	mrstouch_debug("X: %d, Y: %d, Z: %d", x, y, z);
+#endif
+
+	if (z >= TOUCH_PRESSURE_FS) {
+		mrstouch_report_xy(tsdev, x, y, TOUCH_PRESSURE - 1); /* Pen Removed */
+		return TOUCH_PRESSURE - 1;
+	} else {
+		mrstouch_report_xy(tsdev, x, y, TOUCH_PRESSURE + 1); /* Pen Touched */
+		return TOUCH_PRESSURE + 1;
+	}
+
+	return 0;
+
+ipc_error:
+	dev_err(&tsdev->spi->dev, "ipc error during fs_adc read\n");
+	return err;
+}
+
+/* To handle free scale pmic pendet interrupt */
+static int pmic0_pendet(void *dev_id)
+{
+	int err, count;
+	u16 chan;
+	unsigned int touched;
+	struct mrstouch_dev *tsdev = (struct mrstouch_dev *)dev_id;
+	u16 reg[5];
+	u8 data[5];
+
+	chan = PMICADDR0 + tsdev->asr;
+
+	/* Set X BIAS */
+	for (count = 0; count <= 3; count++) {
+		reg[count] = chan++;
+		data[count] = 0x2A;
+	}
+	reg[count] =  chan++; /* Dummy */
+	data[count] = 0;
+
+	err = intel_scu_ipc_writev(reg, data, 5);
+	if (err)
+		goto ipc_error;
+
+	msleep(WAIT_ADC_COMPLETION);
+
+	/* Set Y BIAS */
+	for (count = 0; count <= 3; count++) {
+		reg[count] = chan++;
+		data[count] = 0x4A;
+	}
+	reg[count] = chan++; /* Dummy */
+	data[count] = 0;
+
+	err = intel_scu_ipc_writev(reg, data, 5);
+	if (err)
+		goto ipc_error;
+
+	msleep(WAIT_ADC_COMPLETION);
+
+	/* Set Z BIAS */
+	err = intel_scu_ipc_iowrite32(chan + 2, 0x8A8A8A8A);
+	if (err)
+		goto ipc_error;
+
+	msleep(WAIT_ADC_COMPLETION);
+
+	/*Read touch screen channels till pen removed
+	 * Freescale reports constant value of z for all points
+	 * z is high when screen is not touched and low when touched
+	 * Map high z value to not touched and low z value to pen touched
+	 */
+	touched = mrstouch_pmic_fs_adc_read(tsdev);
+	while (touched > TOUCH_PRESSURE) {
+		touched = mrstouch_pmic_fs_adc_read(tsdev);
+		msleep(WAIT_ADC_COMPLETION);
+	}
+
+	/* Clear all TS channels */
+	chan = PMICADDR0 + tsdev->asr;
+	for (count = 0; count <= 4; count++) {
+		reg[count] = chan++;
+		data[count] = 0;
+	}
+	err = intel_scu_ipc_writev(reg, data, 5);
+	if (err)
+		goto ipc_error;
+
+	for (count = 0; count <= 4; count++) {
+		reg[count] = chan++;
+		data[count] = 0;
+	}
+	err = intel_scu_ipc_writev(reg, data, 5);
+	if (err)
+		goto ipc_error;
+
+	err = intel_scu_ipc_iowrite32(chan + 2, 0x00000000);
+	if (err)
+		goto ipc_error;
+
+	return 0;
+
+ipc_error:
+	dev_err(&tsdev->spi->dev, "ipc error during pendet\n");
+	return err;
+}
+
+
+/* To enable X, Y and Z bias values
+ * Enables YPYM for X channels and XPXM for Y channels
+ */
+static int mrstouch_ts_bias_set(uint offset, uint bias)
+{
+	int count;
+	u16 chan, start;
+	u16 reg[4];
+	u8 data[4];
+
+	chan = PMICADDR0 + offset;
+	start = MRST_TS_CHAN10;
+
+	for (count = 0; count <= 3; count++) {
+		reg[count] = chan++;
+		data[count] = bias | (start + count);
+	}
+	return intel_scu_ipc_writev(reg, data, 4);
+}
+
+/* To read touch screen channel values */
+static int mrstouch_adc_read(struct mrstouch_dev *tsdev)
+{
+	int err;
+	u16 xp, xm, yp, ym, zp, zm;
+
+	/* configure Y bias for X channels */
+	err = mrstouch_ts_bias_set(tsdev->asr, YBIAS);
+	if (err)
+		goto ipc_error;
+
+	msleep(WAIT_ADC_COMPLETION);
+
+	/* read x+ and x- channels */
+	err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN10, &xp, &xm);
+	if (err)
+		goto ipc_error;
+
+	/* configure x bias for y channels */
+	err = mrstouch_ts_bias_set(tsdev->asr, XBIAS);
+	if (err)
+		goto ipc_error;
+
+	msleep(WAIT_ADC_COMPLETION);
+
+	/* read y+ and y- channels */
+	err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN12, &yp, &ym);
+	if (err)
+		goto ipc_error;
+
+	/* configure z bias for x and y channels */
+	err = mrstouch_ts_bias_set(tsdev->asr, ZBIAS);
+	if (err)
+		goto ipc_error;
+
+	msleep(WAIT_ADC_COMPLETION);
+
+	/* read z+ and z- channels */
+	err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN10, &zp, &zm);
+	if (err)
+		goto ipc_error;
+
+#if defined(MRSTOUCH_PRINT_XYZP)
+	printk(KERN_INFO "X+: %d, Y+: %d, Z+: %d\n", xp, yp, zp);
+#endif
+
+#if defined(MRSTOUCH_PRINT_XYZM)
+	printk(KERN_INFO "X-: %d, Y-: %d, Z-: %d\n", xm, ym, zm);
+#endif
+
+	mrstouch_report_xy(tsdev, xp, yp, zp); /* report x and y to eventX */
+
+	return zp;
+
+ipc_error:
+	dev_err(&tsdev->spi->dev, "ipc error during adc read\n");
+	return err;
+}
+
+/* PENDET interrupt handler function for NEC and MAXIM */
+static void pmic12_pendet(void *data)
+{
+	unsigned int touched;
+	struct mrstouch_dev *tsdev = (struct mrstouch_dev *)data;
+
+	/* read touch screen channels till pen removed */
+	do {
+		touched = mrstouch_adc_read(tsdev);
+	} while (touched > TOUCH_PRESSURE);
+}
+
+/* Handler to process PENDET interrupt */
+int mrstouch_pendet(void *data)
+{
+	struct mrstouch_dev *tsdev = (struct mrstouch_dev *)data;
+	while (1) {
+		/* Wait for PENDET interrupt */
+		if (mutex_lock_interruptible(&tsdev->lock)) {
+			msleep(WAIT_ADC_COMPLETION);
+			continue;
+		}
+
+		if (tsdev->busy)
+			return 0;
+
+		tsdev->busy = true;
+
+		if (tsdev->vendor == PMIC_VENDOR_NEC ||
+			tsdev->vendor == PMIC_VENDOR_MAXIM) {
+			/* PENDET must be disabled in NEC before reading ADC */
+			pendet_enable(tsdev,false); /* Disbale PENDET */
+			pmic12_pendet(tsdev);
+			pendet_enable(tsdev, true); /*Enable PENDET */
+		} else if (tsdev->vendor == PMIC_VENDOR_FS) {
+			pendet_umask(); /* Stop ADC */
+			pmic0_pendet(tsdev);
+			pendet_mask(); /* Stop ADC */
+		} else
+		dev_err(&tsdev->spi->dev, "Unsupported touchscreen: %d\n",
+				tsdev->vendor);
+
+		tsdev->busy = false;
+
+	}
+	return 0;
+}
+
+/* PENDET interrupt handler */
+static irqreturn_t pendet_intr_handler(int irq, void *handle)
+{
+	struct mrstouch_dev *tsdev = (struct mrstouch_dev *)handle;
+
+	mutex_unlock(&tsdev->lock);
+	return IRQ_HANDLED;
+}
+
+/* Intializes input device and registers with input subsystem */
+static int ts_input_dev_init(struct mrstouch_dev *tsdev, struct spi_device *spi)
+{
+	int err = 0;
+
+	mrstouch_debug("%s", __func__);
+
+	tsdev->input = input_allocate_device();
+	if (!tsdev->input) {
+		dev_err(&tsdev->spi->dev, "Unable to allocate input device.\n");
+		return -EINVAL;
+	}
+
+	tsdev->input->name = "mrst_touchscreen";
+	snprintf(tsdev->phys, sizeof(tsdev->phys),
+			"%s/input0", dev_name(&spi->dev));
+	tsdev->input->phys = tsdev->phys;
+	tsdev->input->dev.parent = &spi->dev;
+
+	tsdev->input->id.vendor = tsdev->vendor;
+	tsdev->input->id.version = tsdev->rev;
+
+	tsdev->input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	tsdev->input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+
+	input_set_abs_params(tsdev->input, ABS_X, MIN_X, MIN_Y, 0, 0);
+	input_set_abs_params(tsdev->input, ABS_Y, MIN_X, MIN_Y, 0, 0);
+
+	err = input_register_device(tsdev->input);
+	if (err) {
+		dev_err(&tsdev->spi->dev, "unable to register input device\n");
+		input_free_device(tsdev->input);
+		return err;
+	}
+
+	mrstouch_debug("%s", "mrstouch initialized");
+
+	return 0;
+
+}
+
+/* Probe function for touch screen driver */
+static int __devinit mrstouch_probe(struct spi_device *mrstouch_spi)
+{
+	int err;
+	unsigned int myirq;
+	struct mrstouch_dev *tsdev;
+
+	mrstouch_debug("%s(%p)", __func__, mrstouch_spi);
+
+	mrstouchdevp = NULL;
+	myirq = mrstouch_spi->irq;
+
+	if (!mrstouch_spi->irq) {
+		dev_err(&mrstouch_spi->dev, "no interrupt assigned\n");
+		return -EINVAL;
+	}
+
+	tsdev = kzalloc(sizeof(struct mrstouch_dev), GFP_KERNEL);
+	if (!tsdev) {
+		dev_err(&mrstouch_spi->dev, "unable to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	tsdev->irq = myirq;
+	mrstouchdevp = tsdev;
+
+	err = mrstouch_adc_init(tsdev);
+	if (err) {
+		dev_err(&mrstouch_spi->dev, "ADC init failed\n");
+		goto mrstouch_err_free_mem;
+	}
+
+	dev_set_drvdata(&mrstouch_spi->dev, tsdev);
+	tsdev->spi = mrstouch_spi;
+
+	err = ts_input_dev_init(tsdev, mrstouch_spi);
+	if (err) {
+		dev_err(&tsdev->spi->dev, "ts_input_dev_init failed");
+		goto mrstouch_err_free_mem;
+	}
+
+	mutex_init(&tsdev->lock);
+	mutex_lock(&tsdev->lock)
+
+	mrstouch_debug("Requesting IRQ-%d", myirq);
+	err = request_irq(myirq, pendet_intr_handler,
+				0, "mrstouch", tsdev);
+	if (err) {
+		dev_err(&tsdev->spi->dev, "unable to allocate irq\n");
+		goto mrstouch_err_free_mem;
+	}
+
+	tsdev->pendet_thrd = kthread_run(mrstouch_pendet,
+				(void *)tsdev, "pendet handler");
+	if (IS_ERR(tsdev->pendet_thrd)) {
+		dev_err(&tsdev->spi->dev, "kthread_run failed\n");
+		err = PTR_ERR(tsdev->pendet_thrd);
+		goto mrstouch_err_free_mem;
+	}
+	mrstouch_debug("%s", "Driver initialized");
+	return 0;
+
+mrstouch_err_free_mem:
+	kfree(tsdev);
+	return err;
+}
+
+static int mrstouch_suspend(struct spi_device *spi, pm_message_t msg)
+{
+	mrstouch_debug("%s", __func__);
+	mrstouchdevp->suspended = 1;
+	return 0;
+}
+
+static int mrstouch_resume(struct spi_device *spi)
+{
+	mrstouch_debug("%s", __func__);
+	mrstouchdevp->suspended = 0;
+	return 0;
+}
+
+static int mrstouch_remove(struct spi_device *spi)
+{
+	mrstouch_debug("%s", __func__);
+	free_irq(mrstouchdevp->irq, mrstouchdevp);
+	input_unregister_device(mrstouchdevp->input);
+	input_free_device(mrstouchdevp->input);
+	kfree(mrstouchdevp);
+	if (mrstouchdevp->pendet_thrd)
+		kthread_stop(mrstouchdevp->pendet_thrd);
+	return 0;
+}
+
+static struct spi_driver mrstouch_driver = {
+	.driver = {
+		.name   = "pmic_touch",
+		.bus    = &spi_bus_type,
+		.owner  = THIS_MODULE,
+	},
+	.probe          = mrstouch_probe,
+	.suspend        = mrstouch_suspend,
+	.resume         = mrstouch_resume,
+	.remove         = mrstouch_remove,
+};
+
+static int __init mrstouch_module_init(void)
+{
+	int err;
+
+	mrstouch_debug("%s", __func__);
+	err = spi_register_driver(&mrstouch_driver);
+	if (err) {
+		mrstouch_debug("%s(%d)", "SPI PENDET failed", err);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void __exit mrstouch_module_exit(void)
+{
+	mrstouch_debug("%s", __func__);
+	spi_unregister_driver(&mrstouch_driver);
+	return;
+}
+
+module_init(mrstouch_module_init);
+module_exit(mrstouch_module_exit);
+
+MODULE_AUTHOR("Sreedhara Murthy. D.S, sreedhara.ds@intel.com");
+MODULE_DESCRIPTION("Intel Moorestown Resistive Touch Screen Driver");
+MODULE_LICENSE("GPL");