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gpio_mouse.c

/*
 * 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/version.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/input-polldev.h>
#include <linux/gpio_mouse.h>

#include <asm/gpio.h>

/*
 * Timer function which is run every scan_ms ms when the device is opened.
 * The dev input varaible 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 __init 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;
}

struct platform_driver gpio_mouse_device_driver = {
      .remove           = __devexit_p(gpio_mouse_remove),
      .driver           = {
            .name = "gpio_mouse",
      }
};

static int __init gpio_mouse_init(void)
{
      return platform_driver_probe(&gpio_mouse_device_driver,
                  gpio_mouse_probe);
}
module_init(gpio_mouse_init);

static void __exit gpio_mouse_exit(void)
{
      platform_driver_unregister(&gpio_mouse_device_driver);
}
module_exit(gpio_mouse_exit);

MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
MODULE_DESCRIPTION("GPIO mouse driver");
MODULE_LICENSE("GPL");

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