/*
   * zylonite-wm97xx.c  --  Zylonite Continuous Touch screen driver
   *
   * Copyright 2004, 2007, 2008 Wolfson Microelectronics PLC.
   * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   * Parts Copyright : Ian Molton <spyro@f2s.com>
   *                   Andrew Zabolotny <zap@homelink.ru>
   *
   *  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.
   *
   * Notes:
   *     This is a wm97xx extended touch driver supporting interrupt driven
   *     and continuous operation on Marvell Zylonite development systems
   *     (which have a WM9713 on board).
   */
  
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/kernel.h>
  #include <linux/delay.h>
  #include <linux/gpio.h>
  #include <linux/irq.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/wm97xx.h>
  
  #include <mach/hardware.h>
  #include <mach/mfp.h>
  #include <mach/regs-ac97.h>
  
  struct continuous {
  	u16 id;    /* codec id */
  	u8 code;   /* continuous code */
  	u8 reads;  /* number of coord reads per read cycle */
  	u32 speed; /* number of coords per second */
  };
  
  #define WM_READS(sp) ((sp / HZ) + 1)
  
  static const struct continuous cinfo[] = {
  	{ WM9713_ID2, 0, WM_READS(94),  94  },
  	{ WM9713_ID2, 1, WM_READS(120), 120 },
  	{ WM9713_ID2, 2, WM_READS(154), 154 },
  	{ WM9713_ID2, 3, WM_READS(188), 188 },
  };
  
  /* continuous speed index */
  static int sp_idx;
  
  /*
   * Pen sampling frequency (Hz) in continuous mode.
   */
  static int cont_rate = 200;
  module_param(cont_rate, int, 0);
  MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
  
  /*
   * Pressure readback.
   *
   * Set to 1 to read back pen down pressure
   */
  static int pressure;
  module_param(pressure, int, 0);
  MODULE_PARM_DESC(pressure, "Pressure readback (1 = pressure, 0 = no pressure)");
  
  /*
   * AC97 touch data slot.
   *
   * Touch screen readback data ac97 slot
   */
  static int ac97_touch_slot = 5;
  module_param(ac97_touch_slot, int, 0);
  MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
  
  
  /* flush AC97 slot 5 FIFO machines */
  static void wm97xx_acc_pen_up(struct wm97xx *wm)
  {
  	int i;
  
  	msleep(1);
  
  	for (i = 0; i < 16; i++)
  		MODR;
  }
  
  static int wm97xx_acc_pen_down(struct wm97xx *wm)
  {
  	u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
  	int reads = 0;
  	static u16 last, tries;
  
  	/* When the AC97 queue has been drained we need to allow time
  	 * to buffer up samples otherwise we end up spinning polling
  	 * for samples.  The controller can't have a suitably low
  	 * threshold set to use the notifications it gives.
  	 */
  	msleep(1);
  
  	if (tries > 5) {
  		tries = 0;
  		return RC_PENUP;
  	}
  
  	x = MODR;
  	if (x == last) {
  		tries++;
  		return RC_AGAIN;
  	}
  	last = x;
  	do {
  		if (reads)
  			x = MODR;
  		y = MODR;
  		if (pressure)
  			p = MODR;
  
  		dev_dbg(wm->dev, "Raw coordinates: x=%x, y=%x, p=%x
  ",
  			x, y, p);
  
  		/* are samples valid */
  		if ((x & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_X ||
  		    (y & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_Y ||
  		    (p & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_PRES)
  			goto up;
  
  		/* coordinate is good */
  		tries = 0;
  		input_report_abs(wm->input_dev, ABS_X, x & 0xfff);
  		input_report_abs(wm->input_dev, ABS_Y, y & 0xfff);
  		input_report_abs(wm->input_dev, ABS_PRESSURE, p & 0xfff);
  		input_report_key(wm->input_dev, BTN_TOUCH, (p != 0));
  		input_sync(wm->input_dev);
  		reads++;
  	} while (reads < cinfo[sp_idx].reads);
  up:
  	return RC_PENDOWN | RC_AGAIN;
  }
  
  static int wm97xx_acc_startup(struct wm97xx *wm)
  {
  	int idx;
  
  	/* check we have a codec */
  	if (wm->ac97 == NULL)
  		return -ENODEV;
  
  	/* Go you big red fire engine */
  	for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
  		if (wm->id != cinfo[idx].id)
  			continue;
  		sp_idx = idx;
  		if (cont_rate <= cinfo[idx].speed)
  			break;
  	}
  	wm->acc_rate = cinfo[sp_idx].code;
  	wm->acc_slot = ac97_touch_slot;
  	dev_info(wm->dev,
  		 "zylonite accelerated touchscreen driver, %d samples/sec
  ",
  		 cinfo[sp_idx].speed);
  
  	return 0;
  }
  
  static void wm97xx_irq_enable(struct wm97xx *wm, int enable)
  {
  	if (enable)
  		enable_irq(wm->pen_irq);
  	else
  		disable_irq_nosync(wm->pen_irq);
  }
  
  static struct wm97xx_mach_ops zylonite_mach_ops = {
  	.acc_enabled	= 1,
  	.acc_pen_up	= wm97xx_acc_pen_up,
  	.acc_pen_down	= wm97xx_acc_pen_down,
  	.acc_startup	= wm97xx_acc_startup,
  	.irq_enable	= wm97xx_irq_enable,
  	.irq_gpio	= WM97XX_GPIO_2,
  };
  
  static int zylonite_wm97xx_probe(struct platform_device *pdev)
  {
  	struct wm97xx *wm = platform_get_drvdata(pdev);
  	int gpio_touch_irq;
  
  	if (cpu_is_pxa320())
  		gpio_touch_irq = mfp_to_gpio(MFP_PIN_GPIO15);
  	else
  		gpio_touch_irq = mfp_to_gpio(MFP_PIN_GPIO26);
  
  	wm->pen_irq = gpio_to_irq(gpio_touch_irq);
  	irq_set_irq_type(wm->pen_irq, IRQ_TYPE_EDGE_BOTH);
  
  	wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
  			   WM97XX_GPIO_POL_HIGH,
  			   WM97XX_GPIO_STICKY,
  			   WM97XX_GPIO_WAKE);
  	wm97xx_config_gpio(wm, WM97XX_GPIO_2, WM97XX_GPIO_OUT,
  			   WM97XX_GPIO_POL_HIGH,
  			   WM97XX_GPIO_NOTSTICKY,
  			   WM97XX_GPIO_NOWAKE);
  
  	return wm97xx_register_mach_ops(wm, &zylonite_mach_ops);
  }
  
  static int zylonite_wm97xx_remove(struct platform_device *pdev)
  {
  	struct wm97xx *wm = platform_get_drvdata(pdev);
  
  	wm97xx_unregister_mach_ops(wm);
  
  	return 0;
  }
  
  static struct platform_driver zylonite_wm97xx_driver = {
  	.probe	= zylonite_wm97xx_probe,
  	.remove	= zylonite_wm97xx_remove,
  	.driver	= {
  		.name	= "wm97xx-touch",
  	},
  };
  module_platform_driver(zylonite_wm97xx_driver);
  
  /* Module information */
  MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
  MODULE_DESCRIPTION("wm97xx continuous touch driver for Zylonite");
  MODULE_LICENSE("GPL");