gpio_mouse.c

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/*
 * Driver for simulating a mouse on GPIO lines.
 *
 * Copyright (C) 2007 Atmel Corporation
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/input-polldev.h>
#include <linux/gpio.h>
#include <linux/gpio_mouse.h>


/*
 * Timer function which is run every scan_ms ms when the device is opened.
 * The dev input variable is set to the the input_dev pointer.
 */
static void gpio_mouse_scan(struct input_polled_dev *dev)
{
    struct gpio_mouse_platform_data *gpio = dev->private;
    struct input_dev *input = dev->input;
    int x, y;

    if (gpio->bleft >= 0)
        input_report_key(input, BTN_LEFT,
                gpio_get_value(gpio->bleft) ^ gpio->polarity);
    if (gpio->bmiddle >= 0)
        input_report_key(input, BTN_MIDDLE,
                gpio_get_value(gpio->bmiddle) ^ gpio->polarity);
    if (gpio->bright >= 0)
        input_report_key(input, BTN_RIGHT,
                gpio_get_value(gpio->bright) ^ gpio->polarity);

    x = (gpio_get_value(gpio->right) ^ gpio->polarity)
        - (gpio_get_value(gpio->left) ^ gpio->polarity);
    y = (gpio_get_value(gpio->down) ^ gpio->polarity)
        - (gpio_get_value(gpio->up) ^ gpio->polarity);

    input_report_rel(input, REL_X, x);
    input_report_rel(input, REL_Y, y);
    input_sync(input);
}

static int __devinit gpio_mouse_probe(struct platform_device *pdev)
{
    struct gpio_mouse_platform_data *pdata = pdev->dev.platform_data;
    struct input_polled_dev *input_poll;
    struct input_dev *input;
    int pin, i;
    int error;

    if (!pdata) {
        dev_err(&pdev->dev, "no platform data\n");
        error = -ENXIO;
        goto out;
    }

    if (pdata->scan_ms < 0) {
        dev_err(&pdev->dev, "invalid scan time\n");
        error = -EINVAL;
        goto out;
    }

    for (i = 0; i < GPIO_MOUSE_PIN_MAX; i++) {
        pin = pdata->pins[i];

        if (pin < 0) {

            if (i <= GPIO_MOUSE_PIN_RIGHT) {
                /* Mouse direction is required. */
                dev_err(&pdev->dev,
                    "missing GPIO for directions\n");
                error = -EINVAL;
                goto out_free_gpios;
            }

            if (i == GPIO_MOUSE_PIN_BLEFT)
                dev_dbg(&pdev->dev, "no left button defined\n");

        } else {
            error = gpio_request(pin, "gpio_mouse");
            if (error) {
                dev_err(&pdev->dev, "fail %d pin (%d idx)\n",
                    pin, i);
                goto out_free_gpios;
            }

            gpio_direction_input(pin);
        }
    }

    input_poll = input_allocate_polled_device();
    if (!input_poll) {
        dev_err(&pdev->dev, "not enough memory for input device\n");
        error = -ENOMEM;
        goto out_free_gpios;
    }

    platform_set_drvdata(pdev, input_poll);

    /* set input-polldev handlers */
    input_poll->private = pdata;
    input_poll->poll = gpio_mouse_scan;
    input_poll->poll_interval = pdata->scan_ms;

    input = input_poll->input;
    input->name = pdev->name;
    input->id.bustype = BUS_HOST;
    input->dev.parent = &pdev->dev;

    input_set_capability(input, EV_REL, REL_X);
    input_set_capability(input, EV_REL, REL_Y);
    if (pdata->bleft >= 0)
        input_set_capability(input, EV_KEY, BTN_LEFT);
    if (pdata->bmiddle >= 0)
        input_set_capability(input, EV_KEY, BTN_MIDDLE);
    if (pdata->bright >= 0)
        input_set_capability(input, EV_KEY, BTN_RIGHT);

    error = input_register_polled_device(input_poll);
    if (error) {
        dev_err(&pdev->dev, "could not register input device\n");
        goto out_free_polldev;
    }

    dev_dbg(&pdev->dev, "%d ms scan time, buttons: %s%s%s\n",
            pdata->scan_ms,
            pdata->bleft < 0 ? "" : "left ",
            pdata->bmiddle < 0 ? "" : "middle ",
            pdata->bright < 0 ? "" : "right");

    return 0;

 out_free_polldev:
    input_free_polled_device(input_poll);
    platform_set_drvdata(pdev, NULL);

 out_free_gpios:
    while (--i >= 0) {
        pin = pdata->pins[i];
        if (pin)
            gpio_free(pin);
    }
 out:
    return error;
}

static int __devexit gpio_mouse_remove(struct platform_device *pdev)
{
    struct input_polled_dev *input = platform_get_drvdata(pdev);
    struct gpio_mouse_platform_data *pdata = input->private;
    int pin, i;

    input_unregister_polled_device(input);
    input_free_polled_device(input);

    for (i = 0; i < GPIO_MOUSE_PIN_MAX; i++) {
        pin = pdata->pins[i];
        if (pin >= 0)
            gpio_free(pin);
    }

    platform_set_drvdata(pdev, NULL);

    return 0;
}

static struct platform_driver gpio_mouse_device_driver = {
    .probe      = gpio_mouse_probe,
    .remove     = __devexit_p(gpio_mouse_remove),
    .driver     = {
        .name   = "gpio_mouse",
        .owner  = THIS_MODULE,
    }
};
module_platform_driver(gpio_mouse_device_driver);

MODULE_AUTHOR("Hans-Christian Egtvedt <[email protected]>");
MODULE_DESCRIPTION("GPIO mouse driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */