text: /*
   * Copyright (c) 2008 Nuvoton technology corporation.
   *
   * Wan ZongShun <mcuos.com@gmail.com>
   *
   * 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.
   *
   */
  
  #include <linux/delay.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/io.h>
  #include <linux/clk.h>
  #include <linux/input.h>
  #include <linux/interrupt.h>
  #include <linux/slab.h>
  
  /* ADC controller bit defines */
  #define ADC_DELAY	0xf00
  #define ADC_DOWN	0x01
  #define ADC_TSC_Y	(0x01 << 8)
  #define ADC_TSC_X	(0x00 << 8)
  #define TSC_FOURWIRE	(~(0x03 << 1))
  #define ADC_CLK_EN	(0x01 << 28)	/* ADC clock enable */
  #define ADC_READ_CON	(0x01 << 12)
  #define ADC_CONV	(0x01 << 13)
  #define ADC_SEMIAUTO	(0x01 << 14)
  #define ADC_WAITTRIG	(0x03 << 14)
  #define ADC_RST1	(0x01 << 16)
  #define ADC_RST0	(0x00 << 16)
  #define ADC_EN		(0x01 << 17)
  #define ADC_INT		(0x01 << 18)
  #define WT_INT		(0x01 << 20)
  #define ADC_INT_EN	(0x01 << 21)
  #define LVD_INT_EN	(0x01 << 22)
  #define WT_INT_EN	(0x01 << 23)
  #define ADC_DIV		(0x04 << 1)	/* div = 6 */
  
  enum ts_state {
  	TS_WAIT_NEW_PACKET,	/* We are waiting next touch report */
  	TS_WAIT_X_COORD,	/* We are waiting for ADC to report X coord */
  	TS_WAIT_Y_COORD,	/* We are waiting for ADC to report Y coord */
  	TS_IDLE,		/* Input device is closed, don't do anything */
  };
  
  struct w90p910_ts {
  	struct input_dev *input;
  	struct timer_list timer;
  	struct clk *clk;
  	int irq_num;
  	void __iomem *ts_reg;
  	spinlock_t lock;
  	enum ts_state state;
  };
  
  static void w90p910_report_event(struct w90p910_ts *w90p910_ts, bool down)
  {
  	struct input_dev *dev = w90p910_ts->input;
  
  	if (down) {
  		input_report_abs(dev, ABS_X,
  				 __raw_readl(w90p910_ts->ts_reg + 0x0c));
  		input_report_abs(dev, ABS_Y,
  				 __raw_readl(w90p910_ts->ts_reg + 0x10));
  	}
  
  	input_report_key(dev, BTN_TOUCH, down);
  	input_sync(dev);
  }
  
  static void w90p910_prepare_x_reading(struct w90p910_ts *w90p910_ts)
  {
  	unsigned long ctlreg;
  
  	__raw_writel(ADC_TSC_X, w90p910_ts->ts_reg + 0x04);
  	ctlreg = __raw_readl(w90p910_ts->ts_reg);
  	ctlreg &= ~(ADC_WAITTRIG | WT_INT | WT_INT_EN);
  	ctlreg |= ADC_SEMIAUTO | ADC_INT_EN | ADC_CONV;
  	__raw_writel(ctlreg, w90p910_ts->ts_reg);
  
  	w90p910_ts->state = TS_WAIT_X_COORD;
  }
  
  static void w90p910_prepare_y_reading(struct w90p910_ts *w90p910_ts)
  {
  	unsigned long ctlreg;
  
  	__raw_writel(ADC_TSC_Y, w90p910_ts->ts_reg + 0x04);
  	ctlreg = __raw_readl(w90p910_ts->ts_reg);
  	ctlreg &= ~(ADC_WAITTRIG | ADC_INT | WT_INT_EN);
  	ctlreg |= ADC_SEMIAUTO | ADC_INT_EN | ADC_CONV;
  	__raw_writel(ctlreg, w90p910_ts->ts_reg);
  
  	w90p910_ts->state = TS_WAIT_Y_COORD;
  }
  
  static void w90p910_prepare_next_packet(struct w90p910_ts *w90p910_ts)
  {
  	unsigned long ctlreg;
  
  	ctlreg = __raw_readl(w90p910_ts->ts_reg);
  	ctlreg &= ~(ADC_INT | ADC_INT_EN | ADC_SEMIAUTO | ADC_CONV);
  	ctlreg |= ADC_WAITTRIG | WT_INT_EN;
  	__raw_writel(ctlreg, w90p910_ts->ts_reg);
  
  	w90p910_ts->state = TS_WAIT_NEW_PACKET;
  }
  
  static irqreturn_t w90p910_ts_interrupt(int irq, void *dev_id)
  {
  	struct w90p910_ts *w90p910_ts = dev_id;
  	unsigned long flags;
  
  	spin_lock_irqsave(&w90p910_ts->lock, flags);
  
  	switch (w90p910_ts->state) {
  	case TS_WAIT_NEW_PACKET:
  		/*
  		 * The controller only generates interrupts when pen
  		 * is down.
  		 */
  		del_timer(&w90p910_ts->timer);
  		w90p910_prepare_x_reading(w90p910_ts);
  		break;
  
  	case TS_WAIT_X_COORD:
  		w90p910_prepare_y_reading(w90p910_ts);
  		break;
  
  	case TS_WAIT_Y_COORD:
  		w90p910_report_event(w90p910_ts, true);
  		w90p910_prepare_next_packet(w90p910_ts);
  		mod_timer(&w90p910_ts->timer, jiffies + msecs_to_jiffies(100));
  		break;
  
  	case TS_IDLE:
  		break;
  	}
  
  	spin_unlock_irqrestore(&w90p910_ts->lock, flags);
  
  	return IRQ_HANDLED;
  }
  
  static void w90p910_check_pen_up(unsigned long data)
  {
  	struct w90p910_ts *w90p910_ts = (struct w90p910_ts *) data;
  	unsigned long flags;
  
  	spin_lock_irqsave(&w90p910_ts->lock, flags);
  
  	if (w90p910_ts->state == TS_WAIT_NEW_PACKET &&
  	    !(__raw_readl(w90p910_ts->ts_reg + 0x04) & ADC_DOWN)) {
  
  		w90p910_report_event(w90p910_ts, false);
  	}
  
  	spin_unlock_irqrestore(&w90p910_ts->lock, flags);
  }
  
  static int w90p910_open(struct input_dev *dev)
  {
  	struct w90p910_ts *w90p910_ts = input_get_drvdata(dev);
  	unsigned long val;
  
  	/* enable the ADC clock */
  	clk_enable(w90p910_ts->clk);
  
  	__raw_writel(ADC_RST1, w90p910_ts->ts_reg);
  	msleep(1);
  	__raw_writel(ADC_RST0, w90p910_ts->ts_reg);
  	msleep(1);
  
  	/* set delay and screen type */
  	val = __raw_readl(w90p910_ts->ts_reg + 0x04);
  	__raw_writel(val & TSC_FOURWIRE, w90p910_ts->ts_reg + 0x04);
  	__raw_writel(ADC_DELAY, w90p910_ts->ts_reg + 0x08);
  
  	w90p910_ts->state = TS_WAIT_NEW_PACKET;
  	wmb();
  
  	/* set trigger mode */
  	val = __raw_readl(w90p910_ts->ts_reg);
  	val |= ADC_WAITTRIG | ADC_DIV | ADC_EN | WT_INT_EN;
  	__raw_writel(val, w90p910_ts->ts_reg);
  
  	return 0;
  }
  
  static void w90p910_close(struct input_dev *dev)
  {
  	struct w90p910_ts *w90p910_ts = input_get_drvdata(dev);
  	unsigned long val;
  
  	/* disable trigger mode */
  
  	spin_lock_irq(&w90p910_ts->lock);
  
  	w90p910_ts->state = TS_IDLE;
  
  	val = __raw_readl(w90p910_ts->ts_reg);
  	val &= ~(ADC_WAITTRIG | ADC_DIV | ADC_EN | WT_INT_EN | ADC_INT_EN);
  	__raw_writel(val, w90p910_ts->ts_reg);
  
  	spin_unlock_irq(&w90p910_ts->lock);
  
  	/* Now that interrupts are shut off we can safely delete timer */
  	del_timer_sync(&w90p910_ts->timer);
  
  	/* stop the ADC clock */
  	clk_disable(w90p910_ts->clk);
  }
  
  static int __devinit w90x900ts_probe(struct platform_device *pdev)
  {
  	struct w90p910_ts *w90p910_ts;
  	struct input_dev *input_dev;
  	struct resource *res;
  	int err;
  
  	w90p910_ts = kzalloc(sizeof(struct w90p910_ts), GFP_KERNEL);
  	input_dev = input_allocate_device();
  	if (!w90p910_ts || !input_dev) {
  		err = -ENOMEM;
  		goto fail1;
  	}
  
  	w90p910_ts->input = input_dev;
  	w90p910_ts->state = TS_IDLE;
  	spin_lock_init(&w90p910_ts->lock);
  	setup_timer(&w90p910_ts->timer, w90p910_check_pen_up,
  		    (unsigned long)w90p910_ts);
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!res) {
  		err = -ENXIO;
  		goto fail1;
  	}
  
  	if (!request_mem_region(res->start, resource_size(res),
  				pdev->name)) {
  		err = -EBUSY;
  		goto fail1;
  	}
  
  	w90p910_ts->ts_reg = ioremap(res->start, resource_size(res));
  	if (!w90p910_ts->ts_reg) {
  		err = -ENOMEM;
  		goto fail2;
  	}
  
  	w90p910_ts->clk = clk_get(&pdev->dev, NULL);
  	if (IS_ERR(w90p910_ts->clk)) {
  		err = PTR_ERR(w90p910_ts->clk);
  		goto fail3;
  	}
  
  	input_dev->name = "W90P910 TouchScreen";
  	input_dev->phys = "w90p910ts/event0";
  	input_dev->id.bustype = BUS_HOST;
  	input_dev->id.vendor  = 0x0005;
  	input_dev->id.product = 0x0001;
  	input_dev->id.version = 0x0100;
  	input_dev->dev.parent = &pdev->dev;
  	input_dev->open = w90p910_open;
  	input_dev->close = w90p910_close;
  
  	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
  	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
  
  	input_set_abs_params(input_dev, ABS_X, 0, 0x400, 0, 0);
  	input_set_abs_params(input_dev, ABS_Y, 0, 0x400, 0, 0);
  
  	input_set_drvdata(input_dev, w90p910_ts);
  
  	w90p910_ts->irq_num = platform_get_irq(pdev, 0);
  	if (request_irq(w90p910_ts->irq_num, w90p910_ts_interrupt,
  			IRQF_DISABLED, "w90p910ts", w90p910_ts)) {
  		err = -EBUSY;
  		goto fail4;
  	}
  
  	err = input_register_device(w90p910_ts->input);
  	if (err)
  		goto fail5;
  
  	platform_set_drvdata(pdev, w90p910_ts);
  
  	return 0;
  
  fail5:	free_irq(w90p910_ts->irq_num, w90p910_ts);
  fail4:	clk_put(w90p910_ts->clk);
  fail3:	iounmap(w90p910_ts->ts_reg);
  fail2:	release_mem_region(res->start, resource_size(res));
  fail1:	input_free_device(input_dev);
  	kfree(w90p910_ts);
  	return err;
  }
  
  static int __devexit w90x900ts_remove(struct platform_device *pdev)
  {
  	struct w90p910_ts *w90p910_ts = platform_get_drvdata(pdev);
  	struct resource *res;
  
  	free_irq(w90p910_ts->irq_num, w90p910_ts);
  	del_timer_sync(&w90p910_ts->timer);
  	iounmap(w90p910_ts->ts_reg);
  
  	clk_put(w90p910_ts->clk);
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	release_mem_region(res->start, resource_size(res));
  
  	input_unregister_device(w90p910_ts->input);
  	kfree(w90p910_ts);
  
  	platform_set_drvdata(pdev, NULL);
  
  	return 0;
  }
  
  static struct platform_driver w90x900ts_driver = {
  	.probe		= w90x900ts_probe,
  	.remove		= __devexit_p(w90x900ts_remove),
  	.driver		= {
  		.name	= "nuc900-ts",
  		.owner	= THIS_MODULE,
  	},
  };
  
  static int __init w90x900ts_init(void)
  {
  	return platform_driver_register(&w90x900ts_driver);
  }
  
  static void __exit w90x900ts_exit(void)
  {
  	platform_driver_unregister(&w90x900ts_driver);
  }
  
  module_init(w90x900ts_init);
  module_exit(w90x900ts_exit);
  
  MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
  MODULE_DESCRIPTION("w90p910 touch screen driver!");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:nuc900-ts");
  