drivers/input/touchscreen/atmel_tsadcc.c - kernel/mindspeed - Git at Google

 /*
  *  Atmel Touch Screen Driver
  *
  *  Copyright (c) 2008 ATMEL
  *  Copyright (c) 2008 Dan Liang
  *  Copyright (c) 2008 TimeSys Corporation
  *  Copyright (c) 2008 Justin Waters
  *
  *  Based on touchscreen code from Atmel Corporation.
  *
  *  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/err.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/input.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/clk.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <mach/board.h>
 #include <mach/cpu.h>

 /* Register definitions based on AT91SAM9RL64 preliminary draft datasheet */

 #define ATMEL_TSADCC_CR		0x00	/* Control register */
 #define   ATMEL_TSADCC_SWRST	(1 << 0)	/* Software Reset*/
 #define	  ATMEL_TSADCC_START	(1 << 1)	/* Start conversion */

 #define ATMEL_TSADCC_MR		0x04	/* Mode register */
 #define	  ATMEL_TSADCC_TSAMOD	(3    <<  0)	/* ADC mode */
 #define	    ATMEL_TSADCC_TSAMOD_ADC_ONLY_MODE	(0x0)	/* ADC Mode */
 #define	    ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE	(0x1)	/* Touch Screen Only Mode */
 #define	  ATMEL_TSADCC_LOWRES	(1    <<  4)	/* Resolution selection */
 #define	  ATMEL_TSADCC_SLEEP	(1    <<  5)	/* Sleep mode */
 #define	  ATMEL_TSADCC_PENDET	(1    <<  6)	/* Pen Detect selection */
 #define	  ATMEL_TSADCC_PRES	(1    <<  7)	/* Pressure Measurement Selection */
 #define	  ATMEL_TSADCC_PRESCAL	(0x3f <<  8)	/* Prescalar Rate Selection */
 #define	  ATMEL_TSADCC_EPRESCAL	(0xff <<  8)	/* Prescalar Rate Selection (Extended) */
 #define	  ATMEL_TSADCC_STARTUP	(0x7f << 16)	/* Start Up time */
 #define	  ATMEL_TSADCC_SHTIM	(0xf  << 24)	/* Sample & Hold time */
 #define	  ATMEL_TSADCC_PENDBC	(0xf  << 28)	/* Pen Detect debouncing time */

 #define ATMEL_TSADCC_TRGR	0x08	/* Trigger register */
 #define	  ATMEL_TSADCC_TRGMOD	(7      <<  0)	/* Trigger mode */
 #define	    ATMEL_TSADCC_TRGMOD_NONE		(0 << 0)
 #define     ATMEL_TSADCC_TRGMOD_EXT_RISING	(1 << 0)
 #define     ATMEL_TSADCC_TRGMOD_EXT_FALLING	(2 << 0)
 #define     ATMEL_TSADCC_TRGMOD_EXT_ANY		(3 << 0)
 #define     ATMEL_TSADCC_TRGMOD_PENDET		(4 << 0)
 #define     ATMEL_TSADCC_TRGMOD_PERIOD		(5 << 0)
 #define     ATMEL_TSADCC_TRGMOD_CONTINUOUS	(6 << 0)
 #define   ATMEL_TSADCC_TRGPER	(0xffff << 16)	/* Trigger period */

 #define ATMEL_TSADCC_TSR	0x0C	/* Touch Screen register */
 #define	  ATMEL_TSADCC_TSFREQ	(0xf <<  0)	/* TS Frequency in Interleaved mode */
 #define	  ATMEL_TSADCC_TSSHTIM	(0xf << 24)	/* Sample & Hold time */

 #define ATMEL_TSADCC_CHER	0x10	/* Channel Enable register */
 #define ATMEL_TSADCC_CHDR	0x14	/* Channel Disable register */
 #define ATMEL_TSADCC_CHSR	0x18	/* Channel Status register */
 #define	  ATMEL_TSADCC_CH(n)	(1 << (n))	/* Channel number */

 #define ATMEL_TSADCC_SR		0x1C	/* Status register */
 #define	  ATMEL_TSADCC_EOC(n)	(1 << ((n)+0))	/* End of conversion for channel N */
 #define	  ATMEL_TSADCC_OVRE(n)	(1 << ((n)+8))	/* Overrun error for channel N */
 #define	  ATMEL_TSADCC_DRDY	(1 << 16)	/* Data Ready */
 #define	  ATMEL_TSADCC_GOVRE	(1 << 17)	/* General Overrun Error */
 #define	  ATMEL_TSADCC_ENDRX	(1 << 18)	/* End of RX Buffer */
 #define	  ATMEL_TSADCC_RXBUFF	(1 << 19)	/* TX Buffer full */
 #define	  ATMEL_TSADCC_PENCNT	(1 << 20)	/* Pen contact */
 #define	  ATMEL_TSADCC_NOCNT	(1 << 21)	/* No contact */

 #define ATMEL_TSADCC_LCDR	0x20	/* Last Converted Data register */
 #define	  ATMEL_TSADCC_DATA	(0x3ff << 0)	/* Channel data */

 #define ATMEL_TSADCC_IER	0x24	/* Interrupt Enable register */
 #define ATMEL_TSADCC_IDR	0x28	/* Interrupt Disable register */
 #define ATMEL_TSADCC_IMR	0x2C	/* Interrupt Mask register */
 #define ATMEL_TSADCC_CDR0	0x30	/* Channel Data 0 */
 #define ATMEL_TSADCC_CDR1	0x34	/* Channel Data 1 */
 #define ATMEL_TSADCC_CDR2	0x38	/* Channel Data 2 */
 #define ATMEL_TSADCC_CDR3	0x3C	/* Channel Data 3 */
 #define ATMEL_TSADCC_CDR4	0x40	/* Channel Data 4 */
 #define ATMEL_TSADCC_CDR5	0x44	/* Channel Data 5 */

 #define ATMEL_TSADCC_XPOS	0x50
 #define ATMEL_TSADCC_Z1DAT	0x54
 #define ATMEL_TSADCC_Z2DAT	0x58

 #define PRESCALER_VAL(x)	((x) >> 8)

 #define ADC_DEFAULT_CLOCK	100000

 struct atmel_tsadcc {
 	struct input_dev	*input;
 	char			phys[32];
 	struct clk		*clk;
 	int			irq;
 	unsigned int		prev_absx;
 	unsigned int		prev_absy;
 	unsigned char		bufferedmeasure;
 };

 static void __iomem		*tsc_base;

 #define atmel_tsadcc_read(reg)		__raw_readl(tsc_base + (reg))
 #define atmel_tsadcc_write(reg, val)	__raw_writel((val), tsc_base + (reg))

 static irqreturn_t atmel_tsadcc_interrupt(int irq, void *dev)
 {
 	struct atmel_tsadcc	*ts_dev = (struct atmel_tsadcc *)dev;
 	struct input_dev	*input_dev = ts_dev->input;

 	unsigned int status;
 	unsigned int reg;

 	status = atmel_tsadcc_read(ATMEL_TSADCC_SR);
 	status &= atmel_tsadcc_read(ATMEL_TSADCC_IMR);

 	if (status & ATMEL_TSADCC_NOCNT) {
 		/* Contact lost */
 		reg = atmel_tsadcc_read(ATMEL_TSADCC_MR) | ATMEL_TSADCC_PENDBC;

 		atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
 		atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
 		atmel_tsadcc_write(ATMEL_TSADCC_IDR,
 				   ATMEL_TSADCC_EOC(3) | ATMEL_TSADCC_NOCNT);
 		atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);

 		input_report_key(input_dev, BTN_TOUCH, 0);
 		ts_dev->bufferedmeasure = 0;
 		input_sync(input_dev);

 	} else if (status & ATMEL_TSADCC_PENCNT) {
 		/* Pen detected */
 		reg = atmel_tsadcc_read(ATMEL_TSADCC_MR);
 		reg &= ~ATMEL_TSADCC_PENDBC;

 		atmel_tsadcc_write(ATMEL_TSADCC_IDR, ATMEL_TSADCC_PENCNT);
 		atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
 		atmel_tsadcc_write(ATMEL_TSADCC_IER,
 				   ATMEL_TSADCC_EOC(3) | ATMEL_TSADCC_NOCNT);
 		atmel_tsadcc_write(ATMEL_TSADCC_TRGR,
 				   ATMEL_TSADCC_TRGMOD_PERIOD | (0x0FFF << 16));

 	} else if (status & ATMEL_TSADCC_EOC(3)) {
 		/* Conversion finished */

 		if (ts_dev->bufferedmeasure) {
 			/* Last measurement is always discarded, since it can
 			 * be erroneous.
 			 * Always report previous measurement */
 			input_report_abs(input_dev, ABS_X, ts_dev->prev_absx);
 			input_report_abs(input_dev, ABS_Y, ts_dev->prev_absy);
 			input_report_key(input_dev, BTN_TOUCH, 1);
 			input_sync(input_dev);
 		} else
 			ts_dev->bufferedmeasure = 1;

 		/* Now make new measurement */
 		ts_dev->prev_absx = atmel_tsadcc_read(ATMEL_TSADCC_CDR3) << 10;
 		ts_dev->prev_absx /= atmel_tsadcc_read(ATMEL_TSADCC_CDR2);

 		ts_dev->prev_absy = atmel_tsadcc_read(ATMEL_TSADCC_CDR1) << 10;
 		ts_dev->prev_absy /= atmel_tsadcc_read(ATMEL_TSADCC_CDR0);
 	}

 	return IRQ_HANDLED;
 }

 /*
  * The functions for inserting/removing us as a module.
  */

 static int __devinit atmel_tsadcc_probe(struct platform_device *pdev)
 {
 	struct atmel_tsadcc	*ts_dev;
 	struct input_dev	*input_dev;
 	struct resource		*res;
 	struct at91_tsadcc_data *pdata = pdev->dev.platform_data;
 	int		err = 0;
 	unsigned int	prsc;
 	unsigned int	reg;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
 		dev_err(&pdev->dev, "no mmio resource defined.\n");
 		return -ENXIO;
 	}

 	/* Allocate memory for device */
 	ts_dev = kzalloc(sizeof(struct atmel_tsadcc), GFP_KERNEL);
 	if (!ts_dev) {
 		dev_err(&pdev->dev, "failed to allocate memory.\n");
 		return -ENOMEM;
 	}
 	platform_set_drvdata(pdev, ts_dev);

 	input_dev = input_allocate_device();
 	if (!input_dev) {
 		dev_err(&pdev->dev, "failed to allocate input device.\n");
 		err = -EBUSY;
 		goto err_free_mem;
 	}

 	ts_dev->irq = platform_get_irq(pdev, 0);
 	if (ts_dev->irq < 0) {
 		dev_err(&pdev->dev, "no irq ID is designated.\n");
 		err = -ENODEV;
 		goto err_free_dev;
 	}

 	if (!request_mem_region(res->start, resource_size(res),
 				"atmel tsadcc regs")) {
 		dev_err(&pdev->dev, "resources is unavailable.\n");
 		err = -EBUSY;
 		goto err_free_dev;
 	}

 	tsc_base = ioremap(res->start, resource_size(res));
 	if (!tsc_base) {
 		dev_err(&pdev->dev, "failed to map registers.\n");
 		err = -ENOMEM;
 		goto err_release_mem;
 	}

 	err = request_irq(ts_dev->irq, atmel_tsadcc_interrupt, 0,
 			pdev->dev.driver->name, ts_dev);
 	if (err) {
 		dev_err(&pdev->dev, "failed to allocate irq.\n");
 		goto err_unmap_regs;
 	}

 	ts_dev->clk = clk_get(&pdev->dev, "tsc_clk");
 	if (IS_ERR(ts_dev->clk)) {
 		dev_err(&pdev->dev, "failed to get ts_clk\n");
 		err = PTR_ERR(ts_dev->clk);
 		goto err_free_irq;
 	}

 	ts_dev->input = input_dev;
 	ts_dev->bufferedmeasure = 0;

 	snprintf(ts_dev->phys, sizeof(ts_dev->phys),
 		 "%s/input0", dev_name(&pdev->dev));

 	input_dev->name = "atmel touch screen controller";
 	input_dev->phys = ts_dev->phys;
 	input_dev->dev.parent = &pdev->dev;

 	__set_bit(EV_ABS, input_dev->evbit);
 	input_set_abs_params(input_dev, ABS_X, 0, 0x3FF, 0, 0);
 	input_set_abs_params(input_dev, ABS_Y, 0, 0x3FF, 0, 0);

 	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);

 	/* clk_enable() always returns 0, no need to check it */
 	clk_enable(ts_dev->clk);

 	prsc = clk_get_rate(ts_dev->clk);
 	dev_info(&pdev->dev, "Master clock is set at: %d Hz\n", prsc);

 	if (!pdata)
 		goto err_fail;

 	if (!pdata->adc_clock)
 		pdata->adc_clock = ADC_DEFAULT_CLOCK;

 	prsc = (prsc / (2 * pdata->adc_clock)) - 1;

 	/* saturate if this value is too high */
 	if (cpu_is_at91sam9rl()) {
 		if (prsc > PRESCALER_VAL(ATMEL_TSADCC_PRESCAL))
 			prsc = PRESCALER_VAL(ATMEL_TSADCC_PRESCAL);
 	} else {
 		if (prsc > PRESCALER_VAL(ATMEL_TSADCC_EPRESCAL))
 			prsc = PRESCALER_VAL(ATMEL_TSADCC_EPRESCAL);
 	}

 	dev_info(&pdev->dev, "Prescaler is set at: %d\n", prsc);

 	reg = ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE		|
 		((0x00 << 5) & ATMEL_TSADCC_SLEEP)	|	/* Normal Mode */
 		((0x01 << 6) & ATMEL_TSADCC_PENDET)	|	/* Enable Pen Detect */
 		(prsc << 8)				|
 		((0x26 << 16) & ATMEL_TSADCC_STARTUP)	|
 		((pdata->pendet_debounce << 28) & ATMEL_TSADCC_PENDBC);

 	atmel_tsadcc_write(ATMEL_TSADCC_CR, ATMEL_TSADCC_SWRST);
 	atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
 	atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
 	atmel_tsadcc_write(ATMEL_TSADCC_TSR,
 		(pdata->ts_sample_hold_time << 24) & ATMEL_TSADCC_TSSHTIM);

 	atmel_tsadcc_read(ATMEL_TSADCC_SR);
 	atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);

 	/* All went ok, so register to the input system */
 	err = input_register_device(input_dev);
 	if (err)
 		goto err_fail;

 	return 0;

 err_fail:
 	clk_disable(ts_dev->clk);
 	clk_put(ts_dev->clk);
 err_free_irq:
 	free_irq(ts_dev->irq, ts_dev);
 err_unmap_regs:
 	iounmap(tsc_base);
 err_release_mem:
 	release_mem_region(res->start, resource_size(res));
 err_free_dev:
 	input_free_device(input_dev);
 err_free_mem:
 	kfree(ts_dev);
 	return err;
 }

 static int __devexit atmel_tsadcc_remove(struct platform_device *pdev)
 {
 	struct atmel_tsadcc *ts_dev = dev_get_drvdata(&pdev->dev);
 	struct resource *res;

 	free_irq(ts_dev->irq, ts_dev);

 	input_unregister_device(ts_dev->input);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	iounmap(tsc_base);
 	release_mem_region(res->start, resource_size(res));

 	clk_disable(ts_dev->clk);
 	clk_put(ts_dev->clk);

 	kfree(ts_dev);

 	return 0;
 }

 static struct platform_driver atmel_tsadcc_driver = {
 	.probe		= atmel_tsadcc_probe,
 	.remove		= __devexit_p(atmel_tsadcc_remove),
 	.driver		= {
 		.name	= "atmel_tsadcc",
 	},
 };

 static int __init atmel_tsadcc_init(void)
 {
 	return platform_driver_register(&atmel_tsadcc_driver);
 }

 static void __exit atmel_tsadcc_exit(void)
 {
 	platform_driver_unregister(&atmel_tsadcc_driver);
 }

 module_init(atmel_tsadcc_init);
 module_exit(atmel_tsadcc_exit);


 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Atmel TouchScreen Driver");
 MODULE_AUTHOR("Dan Liang <dan.liang@atmel.com>");
	/*
	* Atmel Touch Screen Driver
	*
	* Copyright (c) 2008 ATMEL
	* Copyright (c) 2008 Dan Liang
	* Copyright (c) 2008 TimeSys Corporation
	* Copyright (c) 2008 Justin Waters
	*
	* Based on touchscreen code from Atmel Corporation.
	*
	* 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/err.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/input.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/clk.h>
	#include <linux/platform_device.h>
	#include <linux/io.h>
	#include <mach/board.h>
	#include <mach/cpu.h>

	/* Register definitions based on AT91SAM9RL64 preliminary draft datasheet */

	#define ATMEL_TSADCC_CR 0x00 /* Control register */
	#define ATMEL_TSADCC_SWRST (1 << 0) /* Software Reset*/
	#define ATMEL_TSADCC_START (1 << 1) /* Start conversion */

	#define ATMEL_TSADCC_MR 0x04 /* Mode register */
	#define ATMEL_TSADCC_TSAMOD (3 << 0) /* ADC mode */
	#define ATMEL_TSADCC_TSAMOD_ADC_ONLY_MODE (0x0) /* ADC Mode */
	#define ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE (0x1) /* Touch Screen Only Mode */
	#define ATMEL_TSADCC_LOWRES (1 << 4) /* Resolution selection */
	#define ATMEL_TSADCC_SLEEP (1 << 5) /* Sleep mode */
	#define ATMEL_TSADCC_PENDET (1 << 6) /* Pen Detect selection */
	#define ATMEL_TSADCC_PRES (1 << 7) /* Pressure Measurement Selection */
	#define ATMEL_TSADCC_PRESCAL (0x3f << 8) /* Prescalar Rate Selection */
	#define ATMEL_TSADCC_EPRESCAL (0xff << 8) /* Prescalar Rate Selection (Extended) */
	#define ATMEL_TSADCC_STARTUP (0x7f << 16) /* Start Up time */
	#define ATMEL_TSADCC_SHTIM (0xf << 24) /* Sample & Hold time */
	#define ATMEL_TSADCC_PENDBC (0xf << 28) /* Pen Detect debouncing time */

	#define ATMEL_TSADCC_TRGR 0x08 /* Trigger register */
	#define ATMEL_TSADCC_TRGMOD (7 << 0) /* Trigger mode */
	#define ATMEL_TSADCC_TRGMOD_NONE (0 << 0)
	#define ATMEL_TSADCC_TRGMOD_EXT_RISING (1 << 0)
	#define ATMEL_TSADCC_TRGMOD_EXT_FALLING (2 << 0)
	#define ATMEL_TSADCC_TRGMOD_EXT_ANY (3 << 0)
	#define ATMEL_TSADCC_TRGMOD_PENDET (4 << 0)
	#define ATMEL_TSADCC_TRGMOD_PERIOD (5 << 0)
	#define ATMEL_TSADCC_TRGMOD_CONTINUOUS (6 << 0)
	#define ATMEL_TSADCC_TRGPER (0xffff << 16) /* Trigger period */

	#define ATMEL_TSADCC_TSR 0x0C /* Touch Screen register */
	#define ATMEL_TSADCC_TSFREQ (0xf << 0) /* TS Frequency in Interleaved mode */
	#define ATMEL_TSADCC_TSSHTIM (0xf << 24) /* Sample & Hold time */

	#define ATMEL_TSADCC_CHER 0x10 /* Channel Enable register */
	#define ATMEL_TSADCC_CHDR 0x14 /* Channel Disable register */
	#define ATMEL_TSADCC_CHSR 0x18 /* Channel Status register */
	#define ATMEL_TSADCC_CH(n) (1 << (n)) /* Channel number */

	#define ATMEL_TSADCC_SR 0x1C /* Status register */
	#define ATMEL_TSADCC_EOC(n) (1 << ((n)+0)) /* End of conversion for channel N */
	#define ATMEL_TSADCC_OVRE(n) (1 << ((n)+8)) /* Overrun error for channel N */
	#define ATMEL_TSADCC_DRDY (1 << 16) /* Data Ready */
	#define ATMEL_TSADCC_GOVRE (1 << 17) /* General Overrun Error */
	#define ATMEL_TSADCC_ENDRX (1 << 18) /* End of RX Buffer */
	#define ATMEL_TSADCC_RXBUFF (1 << 19) /* TX Buffer full */
	#define ATMEL_TSADCC_PENCNT (1 << 20) /* Pen contact */
	#define ATMEL_TSADCC_NOCNT (1 << 21) /* No contact */

	#define ATMEL_TSADCC_LCDR 0x20 /* Last Converted Data register */
	#define ATMEL_TSADCC_DATA (0x3ff << 0) /* Channel data */

	#define ATMEL_TSADCC_IER 0x24 /* Interrupt Enable register */
	#define ATMEL_TSADCC_IDR 0x28 /* Interrupt Disable register */
	#define ATMEL_TSADCC_IMR 0x2C /* Interrupt Mask register */
	#define ATMEL_TSADCC_CDR0 0x30 /* Channel Data 0 */
	#define ATMEL_TSADCC_CDR1 0x34 /* Channel Data 1 */
	#define ATMEL_TSADCC_CDR2 0x38 /* Channel Data 2 */
	#define ATMEL_TSADCC_CDR3 0x3C /* Channel Data 3 */
	#define ATMEL_TSADCC_CDR4 0x40 /* Channel Data 4 */
	#define ATMEL_TSADCC_CDR5 0x44 /* Channel Data 5 */

	#define ATMEL_TSADCC_XPOS 0x50
	#define ATMEL_TSADCC_Z1DAT 0x54
	#define ATMEL_TSADCC_Z2DAT 0x58

	#define PRESCALER_VAL(x) ((x) >> 8)

	#define ADC_DEFAULT_CLOCK 100000

	struct atmel_tsadcc {
	struct input_dev *input;
	char phys[32];
	struct clk *clk;
	int irq;
	unsigned int prev_absx;
	unsigned int prev_absy;
	unsigned char bufferedmeasure;
	};

	static void __iomem *tsc_base;

	#define atmel_tsadcc_read(reg) __raw_readl(tsc_base + (reg))
	#define atmel_tsadcc_write(reg, val) __raw_writel((val), tsc_base + (reg))

	static irqreturn_t atmel_tsadcc_interrupt(int irq, void *dev)
	{
	struct atmel_tsadcc ts_dev = (struct atmel_tsadcc )dev;
	struct input_dev *input_dev = ts_dev->input;

	unsigned int status;
	unsigned int reg;

	status = atmel_tsadcc_read(ATMEL_TSADCC_SR);
	status &= atmel_tsadcc_read(ATMEL_TSADCC_IMR);

	if (status & ATMEL_TSADCC_NOCNT) {
	/* Contact lost */
	reg = atmel_tsadcc_read(ATMEL_TSADCC_MR) \| ATMEL_TSADCC_PENDBC;

	atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
	atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
	atmel_tsadcc_write(ATMEL_TSADCC_IDR,
	ATMEL_TSADCC_EOC(3) \| ATMEL_TSADCC_NOCNT);
	atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);

	input_report_key(input_dev, BTN_TOUCH, 0);
	ts_dev->bufferedmeasure = 0;
	input_sync(input_dev);

	} else if (status & ATMEL_TSADCC_PENCNT) {
	/* Pen detected */
	reg = atmel_tsadcc_read(ATMEL_TSADCC_MR);
	reg &= ~ATMEL_TSADCC_PENDBC;

	atmel_tsadcc_write(ATMEL_TSADCC_IDR, ATMEL_TSADCC_PENCNT);
	atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
	atmel_tsadcc_write(ATMEL_TSADCC_IER,
	ATMEL_TSADCC_EOC(3) \| ATMEL_TSADCC_NOCNT);
	atmel_tsadcc_write(ATMEL_TSADCC_TRGR,
	ATMEL_TSADCC_TRGMOD_PERIOD \| (0x0FFF << 16));

	} else if (status & ATMEL_TSADCC_EOC(3)) {
	/* Conversion finished */

	if (ts_dev->bufferedmeasure) {
	/* Last measurement is always discarded, since it can
	* be erroneous.
	* Always report previous measurement */
	input_report_abs(input_dev, ABS_X, ts_dev->prev_absx);
	input_report_abs(input_dev, ABS_Y, ts_dev->prev_absy);
	input_report_key(input_dev, BTN_TOUCH, 1);
	input_sync(input_dev);
	} else
	ts_dev->bufferedmeasure = 1;

	/* Now make new measurement */
	ts_dev->prev_absx = atmel_tsadcc_read(ATMEL_TSADCC_CDR3) << 10;
	ts_dev->prev_absx /= atmel_tsadcc_read(ATMEL_TSADCC_CDR2);

	ts_dev->prev_absy = atmel_tsadcc_read(ATMEL_TSADCC_CDR1) << 10;
	ts_dev->prev_absy /= atmel_tsadcc_read(ATMEL_TSADCC_CDR0);
	}

	return IRQ_HANDLED;
	}

	/*
	* The functions for inserting/removing us as a module.
	*/

	static int __devinit atmel_tsadcc_probe(struct platform_device *pdev)
	{
	struct atmel_tsadcc *ts_dev;
	struct input_dev *input_dev;
	struct resource *res;
	struct at91_tsadcc_data *pdata = pdev->dev.platform_data;
	int err = 0;
	unsigned int prsc;
	unsigned int reg;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
	dev_err(&pdev->dev, "no mmio resource defined.\n");
	return -ENXIO;
	}

	/* Allocate memory for device */
	ts_dev = kzalloc(sizeof(struct atmel_tsadcc), GFP_KERNEL);
	if (!ts_dev) {
	dev_err(&pdev->dev, "failed to allocate memory.\n");
	return -ENOMEM;
	}
	platform_set_drvdata(pdev, ts_dev);

	input_dev = input_allocate_device();
	if (!input_dev) {
	dev_err(&pdev->dev, "failed to allocate input device.\n");
	err = -EBUSY;
	goto err_free_mem;
	}

	ts_dev->irq = platform_get_irq(pdev, 0);
	if (ts_dev->irq < 0) {
	dev_err(&pdev->dev, "no irq ID is designated.\n");
	err = -ENODEV;
	goto err_free_dev;
	}

	if (!request_mem_region(res->start, resource_size(res),
	"atmel tsadcc regs")) {
	dev_err(&pdev->dev, "resources is unavailable.\n");
	err = -EBUSY;
	goto err_free_dev;
	}

	tsc_base = ioremap(res->start, resource_size(res));
	if (!tsc_base) {
	dev_err(&pdev->dev, "failed to map registers.\n");
	err = -ENOMEM;
	goto err_release_mem;
	}

	err = request_irq(ts_dev->irq, atmel_tsadcc_interrupt, 0,
	pdev->dev.driver->name, ts_dev);
	if (err) {
	dev_err(&pdev->dev, "failed to allocate irq.\n");
	goto err_unmap_regs;
	}

	ts_dev->clk = clk_get(&pdev->dev, "tsc_clk");
	if (IS_ERR(ts_dev->clk)) {
	dev_err(&pdev->dev, "failed to get ts_clk\n");
	err = PTR_ERR(ts_dev->clk);
	goto err_free_irq;
	}

	ts_dev->input = input_dev;
	ts_dev->bufferedmeasure = 0;

	snprintf(ts_dev->phys, sizeof(ts_dev->phys),
	"%s/input0", dev_name(&pdev->dev));

	input_dev->name = "atmel touch screen controller";
	input_dev->phys = ts_dev->phys;
	input_dev->dev.parent = &pdev->dev;

	__set_bit(EV_ABS, input_dev->evbit);
	input_set_abs_params(input_dev, ABS_X, 0, 0x3FF, 0, 0);
	input_set_abs_params(input_dev, ABS_Y, 0, 0x3FF, 0, 0);

	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);

	/* clk_enable() always returns 0, no need to check it */
	clk_enable(ts_dev->clk);

	prsc = clk_get_rate(ts_dev->clk);
	dev_info(&pdev->dev, "Master clock is set at: %d Hz\n", prsc);

	if (!pdata)
	goto err_fail;

	if (!pdata->adc_clock)
	pdata->adc_clock = ADC_DEFAULT_CLOCK;

	prsc = (prsc / (2 * pdata->adc_clock)) - 1;

	/* saturate if this value is too high */
	if (cpu_is_at91sam9rl()) {
	if (prsc > PRESCALER_VAL(ATMEL_TSADCC_PRESCAL))
	prsc = PRESCALER_VAL(ATMEL_TSADCC_PRESCAL);
	} else {
	if (prsc > PRESCALER_VAL(ATMEL_TSADCC_EPRESCAL))
	prsc = PRESCALER_VAL(ATMEL_TSADCC_EPRESCAL);
	}

	dev_info(&pdev->dev, "Prescaler is set at: %d\n", prsc);

	reg = ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE \|
	((0x00 << 5) & ATMEL_TSADCC_SLEEP) \| /* Normal Mode */
	((0x01 << 6) & ATMEL_TSADCC_PENDET) \| /* Enable Pen Detect */
	(prsc << 8) \|
	((0x26 << 16) & ATMEL_TSADCC_STARTUP) \|
	((pdata->pendet_debounce << 28) & ATMEL_TSADCC_PENDBC);

	atmel_tsadcc_write(ATMEL_TSADCC_CR, ATMEL_TSADCC_SWRST);
	atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
	atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
	atmel_tsadcc_write(ATMEL_TSADCC_TSR,
	(pdata->ts_sample_hold_time << 24) & ATMEL_TSADCC_TSSHTIM);

	atmel_tsadcc_read(ATMEL_TSADCC_SR);
	atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);

	/* All went ok, so register to the input system */
	err = input_register_device(input_dev);
	if (err)
	goto err_fail;

	return 0;

	err_fail:
	clk_disable(ts_dev->clk);
	clk_put(ts_dev->clk);
	err_free_irq:
	free_irq(ts_dev->irq, ts_dev);
	err_unmap_regs:
	iounmap(tsc_base);
	err_release_mem:
	release_mem_region(res->start, resource_size(res));
	err_free_dev:
	input_free_device(input_dev);
	err_free_mem:
	kfree(ts_dev);
	return err;
	}

	static int __devexit atmel_tsadcc_remove(struct platform_device *pdev)
	{
	struct atmel_tsadcc *ts_dev = dev_get_drvdata(&pdev->dev);
	struct resource *res;

	free_irq(ts_dev->irq, ts_dev);

	input_unregister_device(ts_dev->input);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	iounmap(tsc_base);
	release_mem_region(res->start, resource_size(res));

	clk_disable(ts_dev->clk);
	clk_put(ts_dev->clk);

	kfree(ts_dev);

	return 0;
	}

	static struct platform_driver atmel_tsadcc_driver = {
	.probe = atmel_tsadcc_probe,
	.remove = __devexit_p(atmel_tsadcc_remove),
	.driver = {
	.name = "atmel_tsadcc",
	},
	};

	static int __init atmel_tsadcc_init(void)
	{
	return platform_driver_register(&atmel_tsadcc_driver);
	}

	static void __exit atmel_tsadcc_exit(void)
	{
	platform_driver_unregister(&atmel_tsadcc_driver);
	}

	module_init(atmel_tsadcc_init);
	module_exit(atmel_tsadcc_exit);


	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Atmel TouchScreen Driver");
	MODULE_AUTHOR("Dan Liang <dan.liang@atmel.com>");