mainstone-wm97xx.c

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/*
 * mainstone-wm97xx.c  --  Mainstone Continuous Touch screen driver for
 *                         Wolfson WM97xx AC97 Codecs.
 *
 * Copyright 2004, 2007 Wolfson Microelectronics PLC.
 * Author: Liam Girdwood <[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 to capture touch
 *     data in a continuous manner on the Intel XScale architecture
 *
 *  Features:
 *       - codecs supported:- WM9705, WM9712, WM9713
 *       - processors supported:- Intel XScale PXA25x, PXA26x, PXA27x
 *
 */

#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/io.h>
#include <linux/gpio.h>

#include <mach/regs-ac97.h>

#include <asm/mach-types.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[] = {
    {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;
static u16 last, tries;
static int irq;

/*
 * 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)");

/*
 * 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;
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");


/* flush AC97 slot 5 FIFO on pxa machines */
#ifdef CONFIG_PXA27x
static void wm97xx_acc_pen_up(struct wm97xx *wm)
{
    schedule_timeout_uninterruptible(1);

    while (MISR & (1 << 2))
        MODR;
}
#else
static void wm97xx_acc_pen_up(struct wm97xx *wm)
{
    unsigned int count;

    schedule_timeout_uninterruptible(1);

    for (count = 0; count < 16; count++)
        MODR;
}
#endif

static int wm97xx_acc_pen_down(struct wm97xx *wm)
{
    u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
    int reads = 0;

    /* 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.
     */
    schedule_timeout_uninterruptible(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 = 0, ret = 0;

    /* 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,
         "mainstone accelerated touchscreen driver, %d samples/sec\n",
         cinfo[sp_idx].speed);

    /* IRQ driven touchscreen is used on Palm hardware */
    if (machine_is_palmt5() || machine_is_palmtx() || machine_is_palmld()) {
        pen_int = 1;
        irq = 27;
        /* There is some obscure mutant of WM9712 interbred with WM9713
         * used on Palm HW */
        wm->variant = WM97xx_WM1613;
    } else if (machine_is_mainstone() && pen_int)
        irq = 4;

    if (irq) {
        ret = gpio_request(irq, "Touchscreen IRQ");
        if (ret)
            goto out;

        ret = gpio_direction_input(irq);
        if (ret) {
            gpio_free(irq);
            goto out;
        }

        wm->pen_irq = gpio_to_irq(irq);
        irq_set_irq_type(wm->pen_irq, IRQ_TYPE_EDGE_BOTH);
    } else /* pen irq not supported */
        pen_int = 0;

    /* codec specific irq config */
    if (pen_int) {
        switch (wm->id) {
        case WM9705_ID2:
            break;
        case WM9712_ID2:
        case WM9713_ID2:
            /* use PEN_DOWN GPIO 13 to assert IRQ on GPIO line 2 */
            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);
            break;
        default:
            dev_err(wm->dev,
                "pen down irq not supported on this device\n");
            pen_int = 0;
            break;
        }
    }

out:
    return ret;
}

static void wm97xx_acc_shutdown(struct wm97xx *wm)
{
    /* codec specific deconfig */
    if (pen_int) {
        if (irq)
            gpio_free(irq);
        wm->pen_irq = 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 mainstone_mach_ops = {
    .acc_enabled = 1,
    .acc_pen_up = wm97xx_acc_pen_up,
    .acc_pen_down = wm97xx_acc_pen_down,
    .acc_startup = wm97xx_acc_startup,
    .acc_shutdown = wm97xx_acc_shutdown,
    .irq_enable = wm97xx_irq_enable,
    .irq_gpio = WM97XX_GPIO_2,
};

static int mainstone_wm97xx_probe(struct platform_device *pdev)
{
    struct wm97xx *wm = platform_get_drvdata(pdev);

    return wm97xx_register_mach_ops(wm, &mainstone_mach_ops);
}

static int mainstone_wm97xx_remove(struct platform_device *pdev)
{
    struct wm97xx *wm = platform_get_drvdata(pdev);

    wm97xx_unregister_mach_ops(wm);
    return 0;
}

static struct platform_driver mainstone_wm97xx_driver = {
    .probe = mainstone_wm97xx_probe,
    .remove = mainstone_wm97xx_remove,
    .driver = {
        .name = "wm97xx-touch",
    },
};
module_platform_driver(mainstone_wm97xx_driver);

/* Module information */
MODULE_AUTHOR("Liam Girdwood <[email protected]>");
MODULE_DESCRIPTION("wm97xx continuous touch driver for mainstone");
MODULE_LICENSE("GPL");