drivers/input/touchscreen/wm9713.c - kernel/msm-4.9 - Gitiles

 /*
  * wm9713.c  --  Codec touch driver for Wolfson WM9713 AC97 Codec.
  *
  * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
  * Author: Liam Girdwood
  *         liam.girdwood@wolfsonmicro.com or linux@wolfsonmicro.com
  * Parts Copyright : Ian Molton <spyro@f2s.com>
  *                   Andrew Zabolotny <zap@homelink.ru>
  *                   Russell King <rmk@arm.linux.org.uk>
  *
  *  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;  either version 2 of the  License, or (at your
  *  option) any later version.
  *
  */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/kernel.h>
 #include <linux/input.h>
 #include <linux/delay.h>
 #include <linux/bitops.h>
 #include <linux/wm97xx.h>

 #define TS_NAME			"wm97xx"
 #define WM9713_VERSION		"1.00"
 #define DEFAULT_PRESSURE	0xb0c0

 /*
  * Module parameters
  */

 /*
  * Set internal pull up for pen detect.
  *
  * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
  * i.e. pull up resistance = 64k Ohms / rpu.
  *
  * Adjust this value if you are having problems with pen detect not
  * detecting any down event.
  */
 static int rpu = 8;
 module_param(rpu, int, 0);
 MODULE_PARM_DESC(rpu, "Set internal pull up resitor for pen detect.");

 /*
  * Set current used for pressure measurement.
  *
  * Set pil = 2 to use 400uA
  *     pil = 1 to use 200uA and
  *     pil = 0 to disable pressure measurement.
  *
  * This is used to increase the range of values returned by the adc
  * when measureing touchpanel pressure.
  */
 static int pil;
 module_param(pil, int, 0);
 MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");

 /*
  * Set threshold for pressure measurement.
  *
  * Pen down pressure below threshold is ignored.
  */
 static int pressure = DEFAULT_PRESSURE & 0xfff;
 module_param(pressure, int, 0);
 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");

 /*
  * Set adc sample delay.
  *
  * For accurate touchpanel measurements, some settling time may be
  * required between the switch matrix applying a voltage across the
  * touchpanel plate and the ADC sampling the signal.
  *
  * This delay can be set by setting delay = n, where n is the array
  * position of the delay in the array delay_table below.
  * Long delays > 1ms are supported for completeness, but are not
  * recommended.
  */
 static int delay = 4;
 module_param(delay, int, 0);
 MODULE_PARM_DESC(delay, "Set adc sample delay.");

 /*
  * Set five_wire = 1 to use a 5 wire touchscreen.
  *
  * NOTE: Five wire mode does not allow for readback of pressure.
  */
 static int five_wire;
 module_param(five_wire, int, 0);
 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");

 /*
  * Set adc mask function.
  *
  * Sources of glitch noise, such as signals driving an LCD display, may feed
  * through to the touch screen plates and affect measurement accuracy. In
  * order to minimise this, a signal may be applied to the MASK pin to delay or
  * synchronise the sampling.
  *
  * 0 = No delay or sync
  * 1 = High on pin stops conversions
  * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
  * 3 = Edge triggered, edge on pin starts conversion after delay param
  */
 static int mask;
 module_param(mask, int, 0);
 MODULE_PARM_DESC(mask, "Set adc mask function.");

 /*
  * Coordinate Polling Enable.
  *
  * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
  * for every poll.
  */
 static int coord;
 module_param(coord, int, 0);
 MODULE_PARM_DESC(coord, "Polling coordinate mode");

 /*
  * ADC sample delay times in uS
  */
 static const int delay_table[] = {
 	21,    /* 1 AC97 Link frames */
 	42,    /* 2 */
 	84,    /* 4 */
 	167,   /* 8 */
 	333,   /* 16 */
 	667,   /* 32 */
 	1000,  /* 48 */
 	1333,  /* 64 */
 	2000,  /* 96 */
 	2667,  /* 128 */
 	3333,  /* 160 */
 	4000,  /* 192 */
 	4667,  /* 224 */
 	5333,  /* 256 */
 	6000,  /* 288 */
 	0      /* No delay, switch matrix always on */
 };

 /*
  * Delay after issuing a POLL command.
  *
  * The delay is 3 AC97 link frames + the touchpanel settling delay
  */
 static inline void poll_delay(int d)
 {
 	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
 }

 /*
  * set up the physical settings of the WM9713
  */
 static void wm9713_phy_init(struct wm97xx *wm)
 {
 	u16 dig1 = 0, dig2, dig3;

 	/* default values */
 	dig2 = WM97XX_DELAY(4) | WM97XX_SLT(5);
 	dig3 = WM9712_RPU(1);

 	/* rpu */
 	if (rpu) {
 		dig3 &= 0xffc0;
 		dig3 |= WM9712_RPU(rpu);
 		dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
 			 64000 / rpu);
 	}

 	/* Five wire panel? */
 	if (five_wire) {
 		dig3 |= WM9713_45W;
 		dev_info(wm->dev, "setting 5-wire touchscreen mode.");

 		if (pil) {
 			dev_warn(wm->dev,
 				 "Pressure measurement not supported in 5 "
 				 "wire mode, disabling\n");
 			pil = 0;
 		}
 	}

 	/* touchpanel pressure */
 	if (pil == 2) {
 		dig3 |= WM9712_PIL;
 		dev_info(wm->dev,
 			 "setting pressure measurement current to 400uA.");
 	} else if (pil)
 		dev_info(wm->dev,
 			 "setting pressure measurement current to 200uA.");
 	if (!pil)
 		pressure = 0;

 	/* sample settling delay */
 	if (delay < 0 || delay > 15) {
 		dev_info(wm->dev, "supplied delay out of range.");
 		delay = 4;
 		dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
 			 delay_table[delay]);
 	}
 	dig2 &= 0xff0f;
 	dig2 |= WM97XX_DELAY(delay);

 	/* mask */
 	dig3 |= ((mask & 0x3) << 4);
 	if (coord)
 		dig3 |= WM9713_WAIT;

 	wm->misc = wm97xx_reg_read(wm, 0x5a);

 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
 	wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
 }

 static void wm9713_dig_enable(struct wm97xx *wm, int enable)
 {
 	u16 val;

 	if (enable) {
 		val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
 		wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] |
 				 WM97XX_PRP_DET_DIG);
 		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 	} else {
 		wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
 					~WM97XX_PRP_DET_DIG);
 		val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, val | 0x8000);
 	}
 }

 static void wm9713_dig_restore(struct wm97xx *wm)
 {
 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
 }

 static void wm9713_aux_prepare(struct wm97xx *wm)
 {
 	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
 }

 static inline int is_pden(struct wm97xx *wm)
 {
 	return wm->dig[2] & WM9713_PDEN;
 }

 /*
  * Read a sample from the WM9713 adc in polling mode.
  */
 static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 {
 	u16 dig1;
 	int timeout = 5 * delay;

 	if (!wm->pen_probably_down) {
 		u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 		if (!(data & WM97XX_PEN_DOWN))
 			return RC_PENUP;
 		wm->pen_probably_down = 1;
 	}

 	/* set up digitiser */
 	if (adcsel & 0x8000)
 		adcsel = 1 << ((adcsel & 0x7fff) + 3);

 	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 	dig1 &= ~WM9713_ADCSEL_MASK;

 	if (wm->mach_ops && wm->mach_ops->pre_sample)
 		wm->mach_ops->pre_sample(adcsel);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 | adcsel | WM9713_POLL);

 	/* wait 3 AC97 time slots + delay for conversion */
 	poll_delay(delay);

 	/* wait for POLL to go low */
 	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
 		timeout) {
 		udelay(AC97_LINK_FRAME);
 		timeout--;
 	}

 	if (timeout <= 0) {
 		/* If PDEN is set, we can get a timeout when pen goes up */
 		if (is_pden(wm))
 			wm->pen_probably_down = 0;
 		else
 			dev_dbg(wm->dev, "adc sample timeout");
 		return RC_PENUP;
 	}

 	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 	if (wm->mach_ops && wm->mach_ops->post_sample)
 		wm->mach_ops->post_sample(adcsel);

 	/* check we have correct sample */
 	if ((*sample & WM97XX_ADCSRC_MASK) != ffs(adcsel >> 1) << 12) {
 		dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
 			*sample & WM97XX_ADCSRC_MASK);
 		return RC_PENUP;
 	}

 	if (!(*sample & WM97XX_PEN_DOWN)) {
 		wm->pen_probably_down = 0;
 		return RC_PENUP;
 	}

 	return RC_VALID;
 }

 /*
  * Read a coordinate from the WM9713 adc in polling mode.
  */
 static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
 {
 	u16 dig1;
 	int timeout = 5 * delay;

 	if (!wm->pen_probably_down) {
 		u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 		if (!(val & WM97XX_PEN_DOWN))
 			return RC_PENUP;
 		wm->pen_probably_down = 1;
 	}

 	/* set up digitiser */
 	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 	dig1 &= ~WM9713_ADCSEL_MASK;
 	if (pil)
 		dig1 |= WM9713_ADCSEL_PRES;

 	if (wm->mach_ops && wm->mach_ops->pre_sample)
 		wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG1,
 			 dig1 | WM9713_POLL | WM9713_COO);

 	/* wait 3 AC97 time slots + delay for conversion */
 	poll_delay(delay);
 	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 	/* wait for POLL to go low */
 	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
 	       && timeout) {
 		udelay(AC97_LINK_FRAME);
 		timeout--;
 	}

 	if (timeout <= 0) {
 		/* If PDEN is set, we can get a timeout when pen goes up */
 		if (is_pden(wm))
 			wm->pen_probably_down = 0;
 		else
 			dev_dbg(wm->dev, "adc sample timeout");
 		return RC_PENUP;
 	}

 	/* read back data */
 	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 	if (pil)
 		data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 	else
 		data->p = DEFAULT_PRESSURE;

 	if (wm->mach_ops && wm->mach_ops->post_sample)
 		wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);

 	/* check we have correct sample */
 	if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
 		goto err;
 	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
 		goto err;

 	if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
 		wm->pen_probably_down = 0;
 		return RC_PENUP;
 	}
 	return RC_VALID;
 err:
 	return 0;
 }

 /*
  * Sample the WM9713 touchscreen in polling mode
  */
 static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 {
 	int rc;

 	if (coord) {
 		rc = wm9713_poll_coord(wm, data);
 		if (rc != RC_VALID)
 			return rc;
 	} else {
 		rc = wm9713_poll_sample(wm, WM9713_ADCSEL_X, &data->x);
 		if (rc != RC_VALID)
 			return rc;
 		rc = wm9713_poll_sample(wm, WM9713_ADCSEL_Y, &data->y);
 		if (rc != RC_VALID)
 			return rc;
 		if (pil) {
 			rc = wm9713_poll_sample(wm, WM9713_ADCSEL_PRES,
 						&data->p);
 			if (rc != RC_VALID)
 				return rc;
 		} else
 			data->p = DEFAULT_PRESSURE;
 	}
 	return RC_VALID;
 }

 /*
  * Enable WM9713 continuous mode, i.e. touch data is streamed across
  * an AC97 slot
  */
 static int wm9713_acc_enable(struct wm97xx *wm, int enable)
 {
 	u16 dig1, dig2, dig3;
 	int ret = 0;

 	dig1 = wm->dig[0];
 	dig2 = wm->dig[1];
 	dig3 = wm->dig[2];

 	if (enable) {
 		/* continous mode */
 		if (wm->mach_ops->acc_startup &&
 			(ret = wm->mach_ops->acc_startup(wm)) < 0)
 			return ret;

 		dig1 &= ~WM9713_ADCSEL_MASK;
 		dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
 			WM9713_ADCSEL_Y;
 		if (pil)
 			dig1 |= WM9713_ADCSEL_PRES;
 		dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK  |
 			WM97XX_CM_RATE_MASK);
 		dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
 		WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
 		dig3 |= WM9713_PDEN;
 	} else {
 		dig1 &= ~(WM9713_CTC | WM9713_COO);
 		dig2 &= ~WM97XX_SLEN;
 		dig3 &= ~WM9713_PDEN;
 		if (wm->mach_ops->acc_shutdown)
 			wm->mach_ops->acc_shutdown(wm);
 	}

 	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);

 	return ret;
 }

 struct wm97xx_codec_drv wm9713_codec = {
 	.id = WM9713_ID2,
 	.name = "wm9713",
 	.poll_sample = wm9713_poll_sample,
 	.poll_touch = wm9713_poll_touch,
 	.acc_enable = wm9713_acc_enable,
 	.phy_init = wm9713_phy_init,
 	.dig_enable = wm9713_dig_enable,
 	.dig_restore = wm9713_dig_restore,
 	.aux_prepare = wm9713_aux_prepare,
 };
 EXPORT_SYMBOL_GPL(wm9713_codec);

 /* Module information */
 MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>");
 MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
 MODULE_LICENSE("GPL");
	/*
	* wm9713.c -- Codec touch driver for Wolfson WM9713 AC97 Codec.
	*
	* Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
	* Author: Liam Girdwood
	* liam.girdwood@wolfsonmicro.com or linux@wolfsonmicro.com
	* Parts Copyright : Ian Molton <spyro@f2s.com>
	* Andrew Zabolotny <zap@homelink.ru>
	* Russell King <rmk@arm.linux.org.uk>
	*
	* 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; either version 2 of the License, or (at your
	* option) any later version.
	*
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/kernel.h>
	#include <linux/input.h>
	#include <linux/delay.h>
	#include <linux/bitops.h>
	#include <linux/wm97xx.h>

	#define TS_NAME "wm97xx"
	#define WM9713_VERSION "1.00"
	#define DEFAULT_PRESSURE 0xb0c0

	/*
	* Module parameters
	*/

	/*
	* Set internal pull up for pen detect.
	*
	* Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
	* i.e. pull up resistance = 64k Ohms / rpu.
	*
	* Adjust this value if you are having problems with pen detect not
	* detecting any down event.
	*/
	static int rpu = 8;
	module_param(rpu, int, 0);
	MODULE_PARM_DESC(rpu, "Set internal pull up resitor for pen detect.");

	/*
	* Set current used for pressure measurement.
	*
	* Set pil = 2 to use 400uA
	* pil = 1 to use 200uA and
	* pil = 0 to disable pressure measurement.
	*
	* This is used to increase the range of values returned by the adc
	* when measureing touchpanel pressure.
	*/
	static int pil;
	module_param(pil, int, 0);
	MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");

	/*
	* Set threshold for pressure measurement.
	*
	* Pen down pressure below threshold is ignored.
	*/
	static int pressure = DEFAULT_PRESSURE & 0xfff;
	module_param(pressure, int, 0);
	MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");

	/*
	* Set adc sample delay.
	*
	* For accurate touchpanel measurements, some settling time may be
	* required between the switch matrix applying a voltage across the
	* touchpanel plate and the ADC sampling the signal.
	*
	* This delay can be set by setting delay = n, where n is the array
	* position of the delay in the array delay_table below.
	* Long delays > 1ms are supported for completeness, but are not
	* recommended.
	*/
	static int delay = 4;
	module_param(delay, int, 0);
	MODULE_PARM_DESC(delay, "Set adc sample delay.");

	/*
	* Set five_wire = 1 to use a 5 wire touchscreen.
	*
	* NOTE: Five wire mode does not allow for readback of pressure.
	*/
	static int five_wire;
	module_param(five_wire, int, 0);
	MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");

	/*
	* Set adc mask function.
	*
	* Sources of glitch noise, such as signals driving an LCD display, may feed
	* through to the touch screen plates and affect measurement accuracy. In
	* order to minimise this, a signal may be applied to the MASK pin to delay or
	* synchronise the sampling.
	*
	* 0 = No delay or sync
	* 1 = High on pin stops conversions
	* 2 = Edge triggered, edge on pin delays conversion by delay param (above)
	* 3 = Edge triggered, edge on pin starts conversion after delay param
	*/
	static int mask;
	module_param(mask, int, 0);
	MODULE_PARM_DESC(mask, "Set adc mask function.");

	/*
	* Coordinate Polling Enable.
	*
	* Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
	* for every poll.
	*/
	static int coord;
	module_param(coord, int, 0);
	MODULE_PARM_DESC(coord, "Polling coordinate mode");

	/*
	* ADC sample delay times in uS
	*/
	static const int delay_table[] = {
	21, /* 1 AC97 Link frames */
	42, /* 2 */
	84, /* 4 */
	167, /* 8 */
	333, /* 16 */
	667, /* 32 */
	1000, /* 48 */
	1333, /* 64 */
	2000, /* 96 */
	2667, /* 128 */
	3333, /* 160 */
	4000, /* 192 */
	4667, /* 224 */
	5333, /* 256 */
	6000, /* 288 */
	0 /* No delay, switch matrix always on */
	};

	/*
	* Delay after issuing a POLL command.
	*
	* The delay is 3 AC97 link frames + the touchpanel settling delay
	*/
	static inline void poll_delay(int d)
	{
	udelay(3 * AC97_LINK_FRAME + delay_table[d]);
	}

	/*
	* set up the physical settings of the WM9713
	*/
	static void wm9713_phy_init(struct wm97xx *wm)
	{
	u16 dig1 = 0, dig2, dig3;

	/* default values */
	dig2 = WM97XX_DELAY(4) \| WM97XX_SLT(5);
	dig3 = WM9712_RPU(1);

	/* rpu */
	if (rpu) {
	dig3 &= 0xffc0;
	dig3 \|= WM9712_RPU(rpu);
	dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
	64000 / rpu);
	}

	/* Five wire panel? */
	if (five_wire) {
	dig3 \|= WM9713_45W;
	dev_info(wm->dev, "setting 5-wire touchscreen mode.");

	if (pil) {
	dev_warn(wm->dev,
	"Pressure measurement not supported in 5 "
	"wire mode, disabling\n");
	pil = 0;
	}
	}

	/* touchpanel pressure */
	if (pil == 2) {
	dig3 \|= WM9712_PIL;
	dev_info(wm->dev,
	"setting pressure measurement current to 400uA.");
	} else if (pil)
	dev_info(wm->dev,
	"setting pressure measurement current to 200uA.");
	if (!pil)
	pressure = 0;

	/* sample settling delay */
	if (delay < 0 \|\| delay > 15) {
	dev_info(wm->dev, "supplied delay out of range.");
	delay = 4;
	dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
	delay_table[delay]);
	}
	dig2 &= 0xff0f;
	dig2 \|= WM97XX_DELAY(delay);

	/* mask */
	dig3 \|= ((mask & 0x3) << 4);
	if (coord)
	dig3 \|= WM9713_WAIT;

	wm->misc = wm97xx_reg_read(wm, 0x5a);

	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
	wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
	}

	static void wm9713_dig_enable(struct wm97xx *wm, int enable)
	{
	u16 val;

	if (enable) {
	val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
	wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] \|
	WM97XX_PRP_DET_DIG);
	wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
	} else {
	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
	~WM97XX_PRP_DET_DIG);
	val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
	wm97xx_reg_write(wm, AC97_EXTENDED_MID, val \| 0x8000);
	}
	}

	static void wm9713_dig_restore(struct wm97xx *wm)
	{
	wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
	wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
	}

	static void wm9713_aux_prepare(struct wm97xx *wm)
	{
	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
	wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
	wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
	wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
	}

	static inline int is_pden(struct wm97xx *wm)
	{
	return wm->dig[2] & WM9713_PDEN;
	}

	/*
	* Read a sample from the WM9713 adc in polling mode.
	*/
	static int wm9713_poll_sample(struct wm97xx wm, int adcsel, int sample)
	{
	u16 dig1;
	int timeout = 5 * delay;

	if (!wm->pen_probably_down) {
	u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
	if (!(data & WM97XX_PEN_DOWN))
	return RC_PENUP;
	wm->pen_probably_down = 1;
	}

	/* set up digitiser */
	if (adcsel & 0x8000)
	adcsel = 1 << ((adcsel & 0x7fff) + 3);

	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
	dig1 &= ~WM9713_ADCSEL_MASK;

	if (wm->mach_ops && wm->mach_ops->pre_sample)
	wm->mach_ops->pre_sample(adcsel);
	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 \| adcsel \| WM9713_POLL);

	/* wait 3 AC97 time slots + delay for conversion */
	poll_delay(delay);

	/* wait for POLL to go low */
	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
	timeout) {
	udelay(AC97_LINK_FRAME);
	timeout--;
	}

	if (timeout <= 0) {
	/* If PDEN is set, we can get a timeout when pen goes up */
	if (is_pden(wm))
	wm->pen_probably_down = 0;
	else
	dev_dbg(wm->dev, "adc sample timeout");
	return RC_PENUP;
	}

	*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
	if (wm->mach_ops && wm->mach_ops->post_sample)
	wm->mach_ops->post_sample(adcsel);

	/* check we have correct sample */
	if ((*sample & WM97XX_ADCSRC_MASK) != ffs(adcsel >> 1) << 12) {
	dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
	*sample & WM97XX_ADCSRC_MASK);
	return RC_PENUP;
	}

	if (!(*sample & WM97XX_PEN_DOWN)) {
	wm->pen_probably_down = 0;
	return RC_PENUP;
	}

	return RC_VALID;
	}

	/*
	* Read a coordinate from the WM9713 adc in polling mode.
	*/
	static int wm9713_poll_coord(struct wm97xx wm, struct wm97xx_data data)
	{
	u16 dig1;
	int timeout = 5 * delay;

	if (!wm->pen_probably_down) {
	u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
	if (!(val & WM97XX_PEN_DOWN))
	return RC_PENUP;
	wm->pen_probably_down = 1;
	}

	/* set up digitiser */
	dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
	dig1 &= ~WM9713_ADCSEL_MASK;
	if (pil)
	dig1 \|= WM9713_ADCSEL_PRES;

	if (wm->mach_ops && wm->mach_ops->pre_sample)
	wm->mach_ops->pre_sample(WM97XX_ADCSEL_X \| WM97XX_ADCSEL_Y);
	wm97xx_reg_write(wm, AC97_WM9713_DIG1,
	dig1 \| WM9713_POLL \| WM9713_COO);

	/* wait 3 AC97 time slots + delay for conversion */
	poll_delay(delay);
	data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
	/* wait for POLL to go low */
	while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
	&& timeout) {
	udelay(AC97_LINK_FRAME);
	timeout--;
	}

	if (timeout <= 0) {
	/* If PDEN is set, we can get a timeout when pen goes up */
	if (is_pden(wm))
	wm->pen_probably_down = 0;
	else
	dev_dbg(wm->dev, "adc sample timeout");
	return RC_PENUP;
	}

	/* read back data */
	data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
	if (pil)
	data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
	else
	data->p = DEFAULT_PRESSURE;

	if (wm->mach_ops && wm->mach_ops->post_sample)
	wm->mach_ops->post_sample(WM97XX_ADCSEL_X \| WM97XX_ADCSEL_Y);

	/* check we have correct sample */
	if (!(data->x & WM97XX_ADCSEL_X) \|\| !(data->y & WM97XX_ADCSEL_Y))
	goto err;
	if (pil && !(data->p & WM97XX_ADCSEL_PRES))
	goto err;

	if (!(data->x & WM97XX_PEN_DOWN) \|\| !(data->y & WM97XX_PEN_DOWN)) {
	wm->pen_probably_down = 0;
	return RC_PENUP;
	}
	return RC_VALID;
	err:
	return 0;
	}

	/*
	* Sample the WM9713 touchscreen in polling mode
	*/
	static int wm9713_poll_touch(struct wm97xx wm, struct wm97xx_data data)
	{
	int rc;

	if (coord) {
	rc = wm9713_poll_coord(wm, data);
	if (rc != RC_VALID)
	return rc;
	} else {
	rc = wm9713_poll_sample(wm, WM9713_ADCSEL_X, &data->x);
	if (rc != RC_VALID)
	return rc;
	rc = wm9713_poll_sample(wm, WM9713_ADCSEL_Y, &data->y);
	if (rc != RC_VALID)
	return rc;
	if (pil) {
	rc = wm9713_poll_sample(wm, WM9713_ADCSEL_PRES,
	&data->p);
	if (rc != RC_VALID)
	return rc;
	} else
	data->p = DEFAULT_PRESSURE;
	}
	return RC_VALID;
	}

	/*
	* Enable WM9713 continuous mode, i.e. touch data is streamed across
	* an AC97 slot
	*/
	static int wm9713_acc_enable(struct wm97xx *wm, int enable)
	{
	u16 dig1, dig2, dig3;
	int ret = 0;

	dig1 = wm->dig[0];
	dig2 = wm->dig[1];
	dig3 = wm->dig[2];

	if (enable) {
	/* continous mode */
	if (wm->mach_ops->acc_startup &&
	(ret = wm->mach_ops->acc_startup(wm)) < 0)
	return ret;

	dig1 &= ~WM9713_ADCSEL_MASK;
	dig1 \|= WM9713_CTC \| WM9713_COO \| WM9713_ADCSEL_X \|
	WM9713_ADCSEL_Y;
	if (pil)
	dig1 \|= WM9713_ADCSEL_PRES;
	dig2 &= ~(WM97XX_DELAY_MASK \| WM97XX_SLT_MASK \|
	WM97XX_CM_RATE_MASK);
	dig2 \|= WM97XX_SLEN \| WM97XX_DELAY(delay) \|
	WM97XX_SLT(wm->acc_slot) \| WM97XX_RATE(wm->acc_rate);
	dig3 \|= WM9713_PDEN;
	} else {
	dig1 &= ~(WM9713_CTC \| WM9713_COO);
	dig2 &= ~WM97XX_SLEN;
	dig3 &= ~WM9713_PDEN;
	if (wm->mach_ops->acc_shutdown)
	wm->mach_ops->acc_shutdown(wm);
	}

	wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
	wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
	wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);

	return ret;
	}

	struct wm97xx_codec_drv wm9713_codec = {
	.id = WM9713_ID2,
	.name = "wm9713",
	.poll_sample = wm9713_poll_sample,
	.poll_touch = wm9713_poll_touch,
	.acc_enable = wm9713_acc_enable,
	.phy_init = wm9713_phy_init,
	.dig_enable = wm9713_dig_enable,
	.dig_restore = wm9713_dig_restore,
	.aux_prepare = wm9713_aux_prepare,
	};
	EXPORT_SYMBOL_GPL(wm9713_codec);

	/* Module information */
	MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>");
	MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
	MODULE_LICENSE("GPL");