/*
   * wm9705.c  --  Codec driver for Wolfson WM9705 AC97 Codec.
   *
   * Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC.
   * Author: Liam Girdwood <lrg@slimlogic.co.uk>
   * 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 WM9705_VERSION		"1.00"
  #define DEFAULT_PRESSURE	0xb0c0
  
  /*
   * Module parameters
   */
  
  /*
   * 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.");
  
  /*
   * Pen detect comparator threshold.
   *
   * 0 to Vmid in 15 steps, 0 = use zero power comparator with Vmid threshold
   * i.e. 1 =  Vmid/15 threshold
   *      15 =  Vmid/1 threshold
   *
   * Adjust this value if you are having problems with pen detect not
   * detecting any down events.
   */
  static int pdd = 8;
  module_param(pdd, int, 0);
  MODULE_PARM_DESC(pdd, "Set pen detect comparator threshold");
  
  /*
   * 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.");
  
  /*
   * 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 WM9705
   */
  static void wm9705_phy_init(struct wm97xx *wm)
  {
  	u16 dig1 = 0, dig2 = WM97XX_RPR;
  
  	/*
  	* mute VIDEO and AUX as they share X and Y touchscreen
  	* inputs on the WM9705
  	*/
  	wm97xx_reg_write(wm, AC97_AUX, 0x8000);
  	wm97xx_reg_write(wm, AC97_VIDEO, 0x8000);
  
  	/* touchpanel pressure current*/
  	if (pil == 2) {
  		dig2 |= WM9705_PIL;
  		dev_dbg(wm->dev,
  			"setting pressure measurement current to 400uA.");
  	} else if (pil)
  		dev_dbg(wm->dev,
  			"setting pressure measurement current to 200uA.");
  	if (!pil)
  		pressure = 0;
  
  	/* polling mode sample settling delay */
  	if (delay != 4) {
  		if (delay < 0 || delay > 15) {
  			dev_dbg(wm->dev, "supplied delay out of range.");
  			delay = 4;
  		}
  	}
  	dig1 &= 0xff0f;
  	dig1 |= WM97XX_DELAY(delay);
  	dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
  		delay_table[delay]);
  
  	/* WM9705 pdd */
  	dig2 |= (pdd & 0x000f);
  	dev_dbg(wm->dev, "setting pdd to Vmid/%d", 1 - (pdd & 0x000f));
  
  	/* mask */
  	dig2 |= ((mask & 0x3) << 4);
  
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
  }
  
  static void wm9705_dig_enable(struct wm97xx *wm, int enable)
  {
  	if (enable) {
  		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
  				 wm->dig[2] | WM97XX_PRP_DET_DIG);
  		wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
  	} else
  		wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
  				 wm->dig[2] & ~WM97XX_PRP_DET_DIG);
  }
  
  static void wm9705_aux_prepare(struct wm97xx *wm)
  {
  	memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
  }
  
  static void wm9705_dig_restore(struct wm97xx *wm)
  {
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
  }
  
  static inline int is_pden(struct wm97xx *wm)
  {
  	return wm->dig[2] & WM9705_PDEN;
  }
  
  /*
   * Read a sample from the WM9705 adc in polling mode.
   */
  static int wm9705_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
  {
  	int timeout = 5 * delay;
  	bool wants_pen = adcsel & WM97XX_PEN_DOWN;
  
  	if (wants_pen && !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 (wm->mach_ops && wm->mach_ops->pre_sample)
  		wm->mach_ops->pre_sample(adcsel);
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
  				| WM97XX_POLL | WM97XX_DELAY(delay));
  
  	/* wait 3 AC97 time slots + delay for conversion */
  	poll_delay(delay);
  
  	/* wait for POLL to go low */
  	while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_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 ^ adcsel) & WM97XX_ADCSEL_MASK) {
  		dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
  			adcsel & WM97XX_ADCSEL_MASK,
  			*sample & WM97XX_ADCSEL_MASK);
  		return RC_PENUP;
  	}
  
  	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
  		wm->pen_probably_down = 0;
  		return RC_PENUP;
  	}
  
  	return RC_VALID;
  }
  
  /*
   * Sample the WM9705 touchscreen in polling mode
   */
  static int wm9705_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
  {
  	int rc;
  
  	rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
  	if (rc != RC_VALID)
  		return rc;
  	rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
  	if (rc != RC_VALID)
  		return rc;
  	if (pil) {
  		rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN, &data->p);
  		if (rc != RC_VALID)
  			return rc;
  	} else
  		data->p = DEFAULT_PRESSURE;
  
  	return RC_VALID;
  }
  
  /*
   * Enable WM9705 continuous mode, i.e. touch data is streamed across
   * an AC97 slot
   */
  static int wm9705_acc_enable(struct wm97xx *wm, int enable)
  {
  	u16 dig1, dig2;
  	int ret = 0;
  
  	dig1 = wm->dig[1];
  	dig2 = wm->dig[2];
  
  	if (enable) {
  		/* continuous mode */
  		if (wm->mach_ops->acc_startup &&
  		    (ret = wm->mach_ops->acc_startup(wm)) < 0)
  			return ret;
  		dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
  			  WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
  		dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
  			WM97XX_DELAY(delay) |
  			WM97XX_SLT(wm->acc_slot) |
  			WM97XX_RATE(wm->acc_rate);
  		if (pil)
  			dig1 |= WM97XX_ADCSEL_PRES;
  		dig2 |= WM9705_PDEN;
  	} else {
  		dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
  		dig2 &= ~WM9705_PDEN;
  		if (wm->mach_ops->acc_shutdown)
  			wm->mach_ops->acc_shutdown(wm);
  	}
  
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
  	wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
  
  	return ret;
  }
  
  struct wm97xx_codec_drv wm9705_codec = {
  	.id = WM9705_ID2,
  	.name = "wm9705",
  	.poll_sample = wm9705_poll_sample,
  	.poll_touch = wm9705_poll_touch,
  	.acc_enable = wm9705_acc_enable,
  	.phy_init = wm9705_phy_init,
  	.dig_enable = wm9705_dig_enable,
  	.dig_restore = wm9705_dig_restore,
  	.aux_prepare = wm9705_aux_prepare,
  };
  EXPORT_SYMBOL_GPL(wm9705_codec);
  
  /* Module information */
  MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
  MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
  MODULE_LICENSE("GPL");