zylonite-wm97xx.c

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/*
 * zylonite-wm97xx.c  --  Zylonite Continuous Touch screen driver
 *
 * Copyright 2004, 2007, 2008 Wolfson Microelectronics PLC.
 * Author: Mark Brown <[email protected]>
 * Parts Copyright : Ian Molton <[email protected]>
 *                   Andrew Zabolotny <[email protected]>
 *
 *  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/init.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\n",
            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\n",
         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 <[email protected]>");
MODULE_DESCRIPTION("wm97xx continuous touch driver for Zylonite");
MODULE_LICENSE("GPL");