touchright.c

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/*
 * Touchright serial touchscreen driver
 *
 * Copyright (c) 2006 Rick Koch <[email protected]>
 *
 * Based on MicroTouch driver (drivers/input/touchscreen/mtouch.c)
 * Copyright (c) 2004 Vojtech Pavlik
 * and Dan Streetman <[email protected]>
 */

/*
 * 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/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 "Touchright serial touchscreen driver"

MODULE_AUTHOR("Rick Koch <[email protected]>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * Definitions & global arrays.
 */

#define TR_FORMAT_TOUCH_BIT 0x01
#define TR_FORMAT_STATUS_BYTE   0x40
#define TR_FORMAT_STATUS_MASK   ~TR_FORMAT_TOUCH_BIT

#define TR_LENGTH 5

#define TR_MIN_XC 0
#define TR_MAX_XC 0x1ff
#define TR_MIN_YC 0
#define TR_MAX_YC 0x1ff

/*
 * Per-touchscreen data.
 */

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

static irqreturn_t tr_interrupt(struct serio *serio,
        unsigned char data, unsigned int flags)
{
    struct tr *tr = serio_get_drvdata(serio);
    struct input_dev *dev = tr->dev;

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

    if ((tr->data[0] & TR_FORMAT_STATUS_MASK) == TR_FORMAT_STATUS_BYTE) {
        if (++tr->idx == TR_LENGTH) {
            input_report_abs(dev, ABS_X,
                (tr->data[1] << 5) | (tr->data[2] >> 1));
            input_report_abs(dev, ABS_Y,
                (tr->data[3] << 5) | (tr->data[4] >> 1));
            input_report_key(dev, BTN_TOUCH,
                tr->data[0] & TR_FORMAT_TOUCH_BIT);
            input_sync(dev);
            tr->idx = 0;
        }
    }

    return IRQ_HANDLED;
}

/*
 * tr_disconnect() is the opposite of tr_connect()
 */

static void tr_disconnect(struct serio *serio)
{
    struct tr *tr = serio_get_drvdata(serio);

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

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

static int tr_connect(struct serio *serio, struct serio_driver *drv)
{
    struct tr *tr;
    struct input_dev *input_dev;
    int err;

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

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

    input_dev->name = "Touchright Serial TouchScreen";
    input_dev->phys = tr->phys;
    input_dev->id.bustype = BUS_RS232;
    input_dev->id.vendor = SERIO_TOUCHRIGHT;
    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(tr->dev, ABS_X, TR_MIN_XC, TR_MAX_XC, 0, 0);
    input_set_abs_params(tr->dev, ABS_Y, TR_MIN_YC, TR_MAX_YC, 0, 0);

    serio_set_drvdata(serio, tr);

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

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

    return 0;

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

/*
 * The serio driver structure.
 */

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

MODULE_DEVICE_TABLE(serio, tr_serio_ids);

static struct serio_driver tr_drv = {
    .driver     = {
        .name   = "touchright",
    },
    .description    = DRIVER_DESC,
    .id_table   = tr_serio_ids,
    .interrupt  = tr_interrupt,
    .connect    = tr_connect,
    .disconnect = tr_disconnect,
};

module_serio_driver(tr_drv);