inexio.c

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/*
 * iNexio serial touchscreen driver
 *
 * Copyright (c) 2008 Richard Lemon
 * Based on the mtouch driver (c) Vojtech Pavlik and Dan Streetman
 *
 */

/*
 * 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.
 */

/*
 * 2008/06/19 Richard Lemon <[email protected]>
 *   Copied mtouch.c and edited for iNexio 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 "iNexio serial touchscreen driver"

MODULE_AUTHOR("Richard Lemon <[email protected]>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * Definitions & global arrays.
 */

#define INEXIO_FORMAT_TOUCH_BIT 0x01
#define INEXIO_FORMAT_LENGTH 5
#define INEXIO_RESPONSE_BEGIN_BYTE 0x80

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

#define INEXIO_MIN_XC 0
#define INEXIO_MAX_XC 0x3fff
#define INEXIO_MIN_YC 0
#define INEXIO_MAX_YC 0x3fff

#define INEXIO_GET_XC(data) (((data[1])<<7) | data[2])
#define INEXIO_GET_YC(data) (((data[3])<<7) | data[4])
#define INEXIO_GET_TOUCHED(data) (INEXIO_FORMAT_TOUCH_BIT & data[0])

/*
 * Per-touchscreen data.
 */

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

static void inexio_process_data(struct inexio *pinexio)
{
    struct input_dev *dev = pinexio->dev;

    if (INEXIO_FORMAT_LENGTH == ++pinexio->idx) {
        input_report_abs(dev, ABS_X, INEXIO_GET_XC(pinexio->data));
        input_report_abs(dev, ABS_Y, INEXIO_GET_YC(pinexio->data));
        input_report_key(dev, BTN_TOUCH, INEXIO_GET_TOUCHED(pinexio->data));
        input_sync(dev);

        pinexio->idx = 0;
    }
}

static irqreturn_t inexio_interrupt(struct serio *serio,
        unsigned char data, unsigned int flags)
{
    struct inexio* pinexio = serio_get_drvdata(serio);

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

    if (INEXIO_RESPONSE_BEGIN_BYTE&pinexio->data[0])
        inexio_process_data(pinexio);
    else
        printk(KERN_DEBUG "inexio.c: unknown/unsynchronized data from device, byte %x\n",pinexio->data[0]);

    return IRQ_HANDLED;
}

/*
 * inexio_disconnect() is the opposite of inexio_connect()
 */

static void inexio_disconnect(struct serio *serio)
{
    struct inexio* pinexio = serio_get_drvdata(serio);

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

/*
 * inexio_connect() is the routine that is called when someone adds a
 * new serio device that supports iNexio protocol and registers it as
 * an input device. This is usually accomplished using inputattach.
 */

static int inexio_connect(struct serio *serio, struct serio_driver *drv)
{
    struct inexio *pinexio;
    struct input_dev *input_dev;
    int err;

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

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

    input_dev->name = "iNexio Serial TouchScreen";
    input_dev->phys = pinexio->phys;
    input_dev->id.bustype = BUS_RS232;
    input_dev->id.vendor = SERIO_INEXIO;
    input_dev->id.product = 0;
    input_dev->id.version = 0x0001;
    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(pinexio->dev, ABS_X, INEXIO_MIN_XC, INEXIO_MAX_XC, 0, 0);
    input_set_abs_params(pinexio->dev, ABS_Y, INEXIO_MIN_YC, INEXIO_MAX_YC, 0, 0);

    serio_set_drvdata(serio, pinexio);

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

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

    return 0;

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

/*
 * The serio driver structure.
 */

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

MODULE_DEVICE_TABLE(serio, inexio_serio_ids);

static struct serio_driver inexio_drv = {
    .driver     = {
        .name   = "inexio",
    },
    .description    = DRIVER_DESC,
    .id_table   = inexio_serio_ids,
    .interrupt  = inexio_interrupt,
    .connect    = inexio_connect,
    .disconnect = inexio_disconnect,
};

module_serio_driver(inexio_drv);