text: /*
   * Atmel AT91 and AVR32 continuous touch screen driver for Wolfson WM97xx AC97
   * codecs.
   *
   * Copyright (C) 2008 - 2009 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/module.h>
  #include <linux/moduleparam.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/delay.h>
  #include <linux/irq.h>
  #include <linux/interrupt.h>
  #include <linux/wm97xx.h>
  #include <linux/timer.h>
  #include <linux/gpio.h>
  #include <linux/io.h>
  
  #define AC97C_ICA		0x10
  #define AC97C_CBRHR		0x30
  #define AC97C_CBSR		0x38
  #define AC97C_CBMR		0x3c
  #define AC97C_IER		0x54
  #define AC97C_IDR		0x58
  
  #define AC97C_RXRDY		(1 << 4)
  #define AC97C_OVRUN		(1 << 5)
  
  #define AC97C_CMR_SIZE_20	(0 << 16)
  #define AC97C_CMR_SIZE_18	(1 << 16)
  #define AC97C_CMR_SIZE_16	(2 << 16)
  #define AC97C_CMR_SIZE_10	(3 << 16)
  #define AC97C_CMR_CEM_LITTLE	(1 << 18)
  #define AC97C_CMR_CEM_BIG	(0 << 18)
  #define AC97C_CMR_CENA		(1 << 21)
  
  #define AC97C_INT_CBEVT		(1 << 4)
  
  #define AC97C_SR_CAEVT		(1 << 3)
  
  #define AC97C_CH_MASK(slot)						\
  	(0x7 << (3 * (slot - 3)))
  #define AC97C_CH_ASSIGN(slot, channel)					\
  	(AC97C_CHANNEL_##channel << (3 * (slot - 3)))
  #define AC97C_CHANNEL_NONE	0x0
  #define AC97C_CHANNEL_B		0x2
  
  #define ac97c_writel(chip, reg, val)			\
  	__raw_writel((val), (chip)->regs + AC97C_##reg)
  #define ac97c_readl(chip, reg)				\
  	__raw_readl((chip)->regs + AC97C_##reg)
  
  #ifdef CONFIG_CPU_AT32AP700X
  #define ATMEL_WM97XX_AC97C_IOMEM	(0xfff02800)
  #define ATMEL_WM97XX_AC97C_IRQ		(29)
  #define ATMEL_WM97XX_GPIO_DEFAULT	(32+16) /* Pin 16 on port B. */
  #else
  #error Unkown CPU, this driver only supports AT32AP700X CPUs.
  #endif
  
  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[] = {
  	{WM9705_ID2, 0, WM_READS(94), 94},
  	{WM9705_ID2, 1, WM_READS(188), 188},
  	{WM9705_ID2, 2, WM_READS(375), 375},
  	{WM9705_ID2, 3, WM_READS(750), 750},
  	{WM9712_ID2, 0, WM_READS(94), 94},
  	{WM9712_ID2, 1, WM_READS(188), 188},
  	{WM9712_ID2, 2, WM_READS(375), 375},
  	{WM9712_ID2, 3, WM_READS(750), 750},
  	{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 = 188;
  module_param(cont_rate, int, 0);
  MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
  
  /*
   * Pen down detection.
   *
   * This driver can either poll or use an interrupt to indicate a pen down
   * event. If the irq request fails then it will fall back to polling mode.
   */
  static int pen_int = 1;
  module_param(pen_int, int, 0);
  MODULE_PARM_DESC(pen_int, "Pen down detection (1 = interrupt, 0 = polling)");
  
  /*
   * 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");
  
  /*
   * GPIO line number.
   *
   * Set to GPIO number where the signal from the WM97xx device is hooked up.
   */
  static int atmel_gpio_line = ATMEL_WM97XX_GPIO_DEFAULT;
  module_param(atmel_gpio_line, int, 0);
  MODULE_PARM_DESC(atmel_gpio_line, "GPIO line number connected to WM97xx");
  
  struct atmel_wm97xx {
  	struct wm97xx		*wm;
  	struct timer_list	pen_timer;
  	void __iomem		*regs;
  	unsigned long		ac97c_irq;
  	unsigned long		gpio_pen;
  	unsigned long		gpio_irq;
  	unsigned short		x;
  	unsigned short		y;
  };
  
  static irqreturn_t atmel_wm97xx_channel_b_interrupt(int irq, void *dev_id)
  {
  	struct atmel_wm97xx *atmel_wm97xx = dev_id;
  	struct wm97xx *wm = atmel_wm97xx->wm;
  	int status = ac97c_readl(atmel_wm97xx, CBSR);
  	irqreturn_t retval = IRQ_NONE;
  
  	if (status & AC97C_OVRUN) {
  		dev_dbg(&wm->touch_dev->dev, "AC97C overrun\n");
  		ac97c_readl(atmel_wm97xx, CBRHR);
  		retval = IRQ_HANDLED;
  	} else if (status & AC97C_RXRDY) {
  		u16 data;
  		u16 value;
  		u16 source;
  		u16 pen_down;
  
  		data = ac97c_readl(atmel_wm97xx, CBRHR);
  		value = data & 0x0fff;
  		source = data & WM97XX_ADCSRC_MASK;
  		pen_down = (data & WM97XX_PEN_DOWN) >> 8;
  
  		if (source == WM97XX_ADCSEL_X)
  			atmel_wm97xx->x = value;
  		if (source == WM97XX_ADCSEL_Y)
  			atmel_wm97xx->y = value;
  
  		if (!pressure && source == WM97XX_ADCSEL_Y) {
  			input_report_abs(wm->input_dev, ABS_X, atmel_wm97xx->x);
  			input_report_abs(wm->input_dev, ABS_Y, atmel_wm97xx->y);
  			input_report_key(wm->input_dev, BTN_TOUCH, pen_down);
  			input_sync(wm->input_dev);
  		} else if (pressure && source == WM97XX_ADCSEL_PRES) {
  			input_report_abs(wm->input_dev, ABS_X, atmel_wm97xx->x);
  			input_report_abs(wm->input_dev, ABS_Y, atmel_wm97xx->y);
  			input_report_abs(wm->input_dev, ABS_PRESSURE, value);
  			input_report_key(wm->input_dev, BTN_TOUCH, value);
  			input_sync(wm->input_dev);
  		}
  
  		retval = IRQ_HANDLED;
  	}
  
  	return retval;
  }
  
  static void atmel_wm97xx_acc_pen_up(struct wm97xx *wm)
  {
  	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(wm->touch_dev);
  	struct input_dev *input_dev = wm->input_dev;
  	int pen_down = gpio_get_value(atmel_wm97xx->gpio_pen);
  
  	if (pen_down != 0) {
  		mod_timer(&atmel_wm97xx->pen_timer,
  			  jiffies + msecs_to_jiffies(1));
  	} else {
  		if (pressure)
  			input_report_abs(input_dev, ABS_PRESSURE, 0);
  		input_report_key(input_dev, BTN_TOUCH, 0);
  		input_sync(input_dev);
  	}
  }
  
  static void atmel_wm97xx_pen_timer(unsigned long data)
  {
  	atmel_wm97xx_acc_pen_up((struct wm97xx *)data);
  }
  
  static int atmel_wm97xx_acc_startup(struct wm97xx *wm)
  {
  	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(wm->touch_dev);
  	int idx = 0;
  
  	if (wm->ac97 == NULL)
  		return -ENODEV;
  
  	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->touch_dev->dev, "atmel accelerated touchscreen driver, "
  			"%d samples/sec\n", cinfo[sp_idx].speed);
  
  	if (pen_int) {
  		unsigned long reg;
  
  		wm->pen_irq = atmel_wm97xx->gpio_irq;
  
  		switch (wm->id) {
  		case WM9712_ID2: /* Fall through. */
  		case WM9713_ID2:
  			/*
  			 * Use GPIO 13 (PEN_DOWN) to assert GPIO line 3
  			 * (PENDOWN).
  			 */
  			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_3, WM97XX_GPIO_OUT,
  					WM97XX_GPIO_POL_HIGH,
  					WM97XX_GPIO_NOTSTICKY,
  					WM97XX_GPIO_NOWAKE);
  		case WM9705_ID2: /* Fall through. */
  			/*
  			 * Enable touch data slot in AC97 controller channel B.
  			 */
  			reg = ac97c_readl(atmel_wm97xx, ICA);
  			reg &= ~AC97C_CH_MASK(wm->acc_slot);
  			reg |= AC97C_CH_ASSIGN(wm->acc_slot, B);
  			ac97c_writel(atmel_wm97xx, ICA, reg);
  
  			/*
  			 * Enable channel and interrupt for RXRDY and OVERRUN.
  			 */
  			ac97c_writel(atmel_wm97xx, CBMR, AC97C_CMR_CENA
  					| AC97C_CMR_CEM_BIG
  					| AC97C_CMR_SIZE_16
  					| AC97C_OVRUN
  					| AC97C_RXRDY);
  			/* Dummy read to empty RXRHR. */
  			ac97c_readl(atmel_wm97xx, CBRHR);
  			/*
  			 * Enable interrupt for channel B in the AC97
  			 * controller.
  			 */
  			ac97c_writel(atmel_wm97xx, IER, AC97C_INT_CBEVT);
  			break;
  		default:
  			dev_err(&wm->touch_dev->dev, "pen down irq not "
  					"supported on this device\n");
  			pen_int = 0;
  			break;
  		}
  	}
  
  	return 0;
  }
  
  static void atmel_wm97xx_acc_shutdown(struct wm97xx *wm)
  {
  	if (pen_int) {
  		struct atmel_wm97xx *atmel_wm97xx =
  			platform_get_drvdata(wm->touch_dev);
  		unsigned long ica;
  
  		switch (wm->id & 0xffff) {
  		case WM9705_ID2: /* Fall through. */
  		case WM9712_ID2: /* Fall through. */
  		case WM9713_ID2:
  			/* Disable slot and turn off channel B interrupts. */
  			ica = ac97c_readl(atmel_wm97xx, ICA);
  			ica &= ~AC97C_CH_MASK(wm->acc_slot);
  			ac97c_writel(atmel_wm97xx, ICA, ica);
  			ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
  			ac97c_writel(atmel_wm97xx, CBMR, 0);
  			wm->pen_irq = 0;
  			break;
  		default:
  			dev_err(&wm->touch_dev->dev, "unknown codec\n");
  			break;
  		}
  	}
  }
  
  static void atmel_wm97xx_irq_enable(struct wm97xx *wm, int enable)
  {
  	/* Intentionally left empty. */
  }
  
  static struct wm97xx_mach_ops atmel_mach_ops = {
  	.acc_enabled	= 1,
  	.acc_pen_up	= atmel_wm97xx_acc_pen_up,
  	.acc_startup	= atmel_wm97xx_acc_startup,
  	.acc_shutdown	= atmel_wm97xx_acc_shutdown,
  	.irq_enable	= atmel_wm97xx_irq_enable,
  	.irq_gpio	= WM97XX_GPIO_3,
  };
  
  static int __init atmel_wm97xx_probe(struct platform_device *pdev)
  {
  	struct wm97xx *wm = platform_get_drvdata(pdev);
  	struct atmel_wm97xx *atmel_wm97xx;
  	int ret;
  
  	atmel_wm97xx = kzalloc(sizeof(struct atmel_wm97xx), GFP_KERNEL);
  	if (!atmel_wm97xx) {
  		dev_dbg(&pdev->dev, "out of memory\n");
  		return -ENOMEM;
  	}
  
  	atmel_wm97xx->wm	= wm;
  	atmel_wm97xx->regs	= (void *)ATMEL_WM97XX_AC97C_IOMEM;
  	atmel_wm97xx->ac97c_irq	= ATMEL_WM97XX_AC97C_IRQ;
  	atmel_wm97xx->gpio_pen	= atmel_gpio_line;
  	atmel_wm97xx->gpio_irq	= gpio_to_irq(atmel_wm97xx->gpio_pen);
  
  	setup_timer(&atmel_wm97xx->pen_timer, atmel_wm97xx_pen_timer,
  			(unsigned long)wm);
  
  	ret = request_irq(atmel_wm97xx->ac97c_irq,
  			  atmel_wm97xx_channel_b_interrupt,
  			  IRQF_SHARED, "atmel-wm97xx-ch-b", atmel_wm97xx);
  	if (ret) {
  		dev_dbg(&pdev->dev, "could not request ac97c irq\n");
  		goto err;
  	}
  
  	platform_set_drvdata(pdev, atmel_wm97xx);
  
  	ret = wm97xx_register_mach_ops(wm, &atmel_mach_ops);
  	if (ret)
  		goto err_irq;
  
  	return ret;
  
  err_irq:
  	free_irq(atmel_wm97xx->ac97c_irq, atmel_wm97xx);
  err:
  	platform_set_drvdata(pdev, NULL);
  	kfree(atmel_wm97xx);
  	return ret;
  }
  
  static int __exit atmel_wm97xx_remove(struct platform_device *pdev)
  {
  	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
  	struct wm97xx *wm = atmel_wm97xx->wm;
  
  	ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
  	free_irq(atmel_wm97xx->ac97c_irq, atmel_wm97xx);
  	del_timer_sync(&atmel_wm97xx->pen_timer);
  	wm97xx_unregister_mach_ops(wm);
  	platform_set_drvdata(pdev, NULL);
  	kfree(atmel_wm97xx);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM
  static int atmel_wm97xx_suspend(struct platform_device *pdev, pm_message_t msg)
  {
  	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
  
  	ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
  	disable_irq(atmel_wm97xx->gpio_irq);
  	del_timer_sync(&atmel_wm97xx->pen_timer);
  
  	return 0;
  }
  
  static int atmel_wm97xx_resume(struct platform_device *pdev)
  {
  	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
  	struct wm97xx *wm = atmel_wm97xx->wm;
  
  	if (wm->input_dev->users) {
  		enable_irq(atmel_wm97xx->gpio_irq);
  		ac97c_writel(atmel_wm97xx, IER, AC97C_INT_CBEVT);
  	}
  
  	return 0;
  }
  #else
  #define atmel_wm97xx_suspend	NULL
  #define atmel_wm97xx_resume	NULL
  #endif
  
  static struct platform_driver atmel_wm97xx_driver = {
  	.remove		= __exit_p(atmel_wm97xx_remove),
  	.driver		= {
  		.name = "wm97xx-touch",
  	},
  	.suspend	= atmel_wm97xx_suspend,
  	.resume		= atmel_wm97xx_resume,
  };
  
  static int __init atmel_wm97xx_init(void)
  {
  	return platform_driver_probe(&atmel_wm97xx_driver, atmel_wm97xx_probe);
  }
  module_init(atmel_wm97xx_init);
  
  static void __exit atmel_wm97xx_exit(void)
  {
  	platform_driver_unregister(&atmel_wm97xx_driver);
  }
  module_exit(atmel_wm97xx_exit);
  
  MODULE_AUTHOR("Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>");
  MODULE_DESCRIPTION("wm97xx continuous touch driver for Atmel AT91 and AVR32");
  MODULE_LICENSE("GPL");
  