Re: [PATCH] mid: Intel MID touch screen driver

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Alan,

On Tue, Jun 01, 2010 at 12:50:06PM +0100, Alan Cox wrote:
> From: Sreedhara DS <sreedhara.ds@intel.com>
> 
> 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>
> ---
> 
>  drivers/staging/Kconfig                            |    2 
>  drivers/staging/Makefile                           |    1 
>  drivers/staging/mrst-touchscreen/Kconfig           |    7 
>  drivers/staging/mrst-touchscreen/Makefile          |    3 
>  drivers/staging/mrst-touchscreen/TODO              |    2 
>  drivers/staging/mrst-touchscreen/intel-mid-touch.c |  864 ++++++++++++++++++++
>  6 files changed, 879 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/staging/mrst-touchscreen/Kconfig
>  create mode 100644 drivers/staging/mrst-touchscreen/Makefile
>  create mode 100644 drivers/staging/mrst-touchscreen/TODO
>  create mode 100644 drivers/staging/mrst-touchscreen/intel-mid-touch.c
> 
> 
> diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
> index b5c3b30..4828515 100644
> --- a/drivers/staging/Kconfig
> +++ b/drivers/staging/Kconfig
> @@ -141,5 +141,7 @@ source "drivers/staging/ti-st/Kconfig"
>  
>  source "drivers/staging/adis16255/Kconfig"
>  
> +source "drivers/staging/mrst-touchscreen/Kconfig"
> +
>  endif # !STAGING_EXCLUDE_BUILD
>  endif # STAGING
> diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
> index e330dd5..9e19849 100644
> --- a/drivers/staging/Makefile
> +++ b/drivers/staging/Makefile
> @@ -51,3 +51,4 @@ obj-$(CONFIG_CRYSTALHD)		+= crystalhd/
>  obj-$(CONFIG_CXT1E1)		+= cxt1e1/
>  obj-$(CONFIG_TI_ST)		+= ti-st/
>  obj-$(CONFIG_ADIS16255)		+= adis16255/
> +obj-$(CONFIG_TOUCHSCREEN_MRSTOUCH) += mrst-touchscreen/
> diff --git a/drivers/staging/mrst-touchscreen/Kconfig b/drivers/staging/mrst-touchscreen/Kconfig
> new file mode 100644
> index 0000000..c2af492
> --- /dev/null
> +++ b/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.

To compile this driver as amodule...

> diff --git a/drivers/staging/mrst-touchscreen/Makefile b/drivers/staging/mrst-touchscreen/Makefile
> new file mode 100644
> index 0000000..2d638b0
> --- /dev/null
> +++ b/drivers/staging/mrst-touchscreen/Makefile
> @@ -0,0 +1,3 @@
> +obj-$(CONFIG_TOUCHSCREEN_INTEL_MID) := intel_mid_touch.o
> +
> +
> diff --git a/drivers/staging/mrst-touchscreen/TODO b/drivers/staging/mrst-touchscreen/TODO
> new file mode 100644
> index 0000000..7157028
> --- /dev/null
> +++ b/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)
> diff --git a/drivers/staging/mrst-touchscreen/intel-mid-touch.c b/drivers/staging/mrst-touchscreen/intel-mid-touch.c
> new file mode 100644
> index 0000000..3c15ee5
> --- /dev/null
> +++ b/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 */

Does not seem to be used.

> +	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;
> +	}

Why does it muck with pressure here?

> +
> +	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);

I do not believe this is even allowed.

> +	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;

-ENOMEM

> +	}
> +
> +	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);
> +

The device apperas to provide true pressure readings, report it as well.

> +	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");


Here you are leakign input device.

> +		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);

Here you are leakign input devicei again.

> +		goto mrstouch_err_free_mem;

Switch to threaded IRQ?

> +	}
> +	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;

Very useful...

> +	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);

Shall not call free after unregister.

> +	kfree(mrstouchdevp);
> +	if (mrstouchdevp->pendet_thrd)
> +		kthread_stop(mrstouchdevp->pendet_thrd);

Surely too late.

> +	return 0;
> +}
> +
> +static struct spi_driver mrstouch_driver = {
> +	.driver = {
> +		.name   = "pmic_touch",
> +		.bus    = &spi_bus_type,

Should it do this?

> +		.owner  = THIS_MODULE,
> +	},
> +	.probe          = mrstouch_probe,
> +	.suspend        = mrstouch_suspend,
> +	.resume         = mrstouch_resume,
> +	.remove         = mrstouch_remove,

__devexit_p()

> +};
> +
> +static int __init mrstouch_module_init(void)
> +{
> +	int err;
> +
> +	mrstouch_debug("%s", __func__);

Kill.

> +	err = spi_register_driver(&mrstouch_driver);
> +	if (err) {
> +		mrstouch_debug("%s(%d)", "SPI PENDET failed", err);

pr_err.

> +		return -1;

return err;

> +	}
> +
> +	return 0;
> +}
> +
> +static void __exit mrstouch_module_exit(void)
> +{
> +	mrstouch_debug("%s", __func__);

Kill.

> +	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");
> 

-- 
Dmitry