mtouch.c

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/*
 * MicroTouch (3M) serial touchscreen driver
 *
 * Copyright (c) 2004 Vojtech Pavlik
 */

/*
 * 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.
 */

/*
 * 2005/02/19 Dan Streetman <[email protected]>
 *   Copied elo.c and edited for MicroTouch protocol
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/init.h>

#define DRIVER_DESC "MicroTouch serial touchscreen driver"

MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * Definitions & global arrays.
 */

#define MTOUCH_FORMAT_TABLET_STATUS_BIT 0x80
#define MTOUCH_FORMAT_TABLET_TOUCH_BIT 0x40
#define MTOUCH_FORMAT_TABLET_LENGTH 5
#define MTOUCH_RESPONSE_BEGIN_BYTE 0x01
#define MTOUCH_RESPONSE_END_BYTE 0x0d

/* todo: check specs for max length of all responses */
#define MTOUCH_MAX_LENGTH 16

#define MTOUCH_MIN_XC 0
#define MTOUCH_MAX_XC 0x3fff
#define MTOUCH_MIN_YC 0
#define MTOUCH_MAX_YC 0x3fff

#define MTOUCH_GET_XC(data) (((data[2])<<7) | data[1])
#define MTOUCH_GET_YC(data) (((data[4])<<7) | data[3])
#define MTOUCH_GET_TOUCHED(data) (MTOUCH_FORMAT_TABLET_TOUCH_BIT & data[0])

/*
 * Per-touchscreen data.
 */

struct mtouch {
    struct input_dev *dev;
    struct serio *serio;
    int idx;
    unsigned char data[MTOUCH_MAX_LENGTH];
    char phys[32];
};

static void mtouch_process_format_tablet(struct mtouch *mtouch)
{
    struct input_dev *dev = mtouch->dev;

    if (MTOUCH_FORMAT_TABLET_LENGTH == ++mtouch->idx) {
        input_report_abs(dev, ABS_X, MTOUCH_GET_XC(mtouch->data));
        input_report_abs(dev, ABS_Y, MTOUCH_MAX_YC - MTOUCH_GET_YC(mtouch->data));
        input_report_key(dev, BTN_TOUCH, MTOUCH_GET_TOUCHED(mtouch->data));
        input_sync(dev);

        mtouch->idx = 0;
    }
}

static void mtouch_process_response(struct mtouch *mtouch)
{
    if (MTOUCH_RESPONSE_END_BYTE == mtouch->data[mtouch->idx++]) {
        /* FIXME - process response */
        mtouch->idx = 0;
    } else if (MTOUCH_MAX_LENGTH == mtouch->idx) {
        printk(KERN_ERR "mtouch.c: too many response bytes\n");
        mtouch->idx = 0;
    }
}

static irqreturn_t mtouch_interrupt(struct serio *serio,
        unsigned char data, unsigned int flags)
{
    struct mtouch* mtouch = serio_get_drvdata(serio);

    mtouch->data[mtouch->idx] = data;

    if (MTOUCH_FORMAT_TABLET_STATUS_BIT & mtouch->data[0])
        mtouch_process_format_tablet(mtouch);
    else if (MTOUCH_RESPONSE_BEGIN_BYTE == mtouch->data[0])
        mtouch_process_response(mtouch);
    else
        printk(KERN_DEBUG "mtouch.c: unknown/unsynchronized data from device, byte %x\n",mtouch->data[0]);

    return IRQ_HANDLED;
}

/*
 * mtouch_disconnect() is the opposite of mtouch_connect()
 */

static void mtouch_disconnect(struct serio *serio)
{
    struct mtouch* mtouch = serio_get_drvdata(serio);

    input_get_device(mtouch->dev);
    input_unregister_device(mtouch->dev);
    serio_close(serio);
    serio_set_drvdata(serio, NULL);
    input_put_device(mtouch->dev);
    kfree(mtouch);
}

/*
 * mtouch_connect() is the routine that is called when someone adds a
 * new serio device that supports MicroTouch (Format Tablet) protocol and registers it as
 * an input device.
 */

static int mtouch_connect(struct serio *serio, struct serio_driver *drv)
{
    struct mtouch *mtouch;
    struct input_dev *input_dev;
    int err;

    mtouch = kzalloc(sizeof(struct mtouch), GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!mtouch || !input_dev) {
        err = -ENOMEM;
        goto fail1;
    }

    mtouch->serio = serio;
    mtouch->dev = input_dev;
    snprintf(mtouch->phys, sizeof(mtouch->phys), "%s/input0", serio->phys);

    input_dev->name = "MicroTouch Serial TouchScreen";
    input_dev->phys = mtouch->phys;
    input_dev->id.bustype = BUS_RS232;
    input_dev->id.vendor = SERIO_MICROTOUCH;
    input_dev->id.product = 0;
    input_dev->id.version = 0x0100;
    input_dev->dev.parent = &serio->dev;
    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(mtouch->dev, ABS_X, MTOUCH_MIN_XC, MTOUCH_MAX_XC, 0, 0);
    input_set_abs_params(mtouch->dev, ABS_Y, MTOUCH_MIN_YC, MTOUCH_MAX_YC, 0, 0);

    serio_set_drvdata(serio, mtouch);

    err = serio_open(serio, drv);
    if (err)
        goto fail2;

    err = input_register_device(mtouch->dev);
    if (err)
        goto fail3;

    return 0;

 fail3: serio_close(serio);
 fail2: serio_set_drvdata(serio, NULL);
 fail1: input_free_device(input_dev);
    kfree(mtouch);
    return err;
}

/*
 * The serio driver structure.
 */

static struct serio_device_id mtouch_serio_ids[] = {
    {
        .type   = SERIO_RS232,
        .proto  = SERIO_MICROTOUCH,
        .id = SERIO_ANY,
        .extra  = SERIO_ANY,
    },
    { 0 }
};

MODULE_DEVICE_TABLE(serio, mtouch_serio_ids);

static struct serio_driver mtouch_drv = {
    .driver     = {
        .name   = "mtouch",
    },
    .description    = DRIVER_DESC,
    .id_table   = mtouch_serio_ids,
    .interrupt  = mtouch_interrupt,
    .connect    = mtouch_connect,
    .disconnect = mtouch_disconnect,
};

module_serio_driver(mtouch_drv);