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cobalt_btns.c

/*
 *  Cobalt button interface driver.
 *
 *  Copyright (C) 2007  Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include <linux/init.h>
#include <linux/input-polldev.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#define BUTTONS_POLL_INTERVAL 30    /* msec */
#define BUTTONS_COUNT_THRESHOLD     3
#define BUTTONS_STATUS_MASK   0xfe000000

struct buttons_dev {
      struct input_polled_dev *poll_dev;
      void __iomem *reg;
};

struct buttons_map {
      uint32_t mask;
      int keycode;
      int count;
};

static struct buttons_map buttons_map[] = {
      { 0x02000000, KEY_RESTART, },
      { 0x04000000, KEY_LEFT, },
      { 0x08000000, KEY_UP, },
      { 0x10000000, KEY_DOWN, },
      { 0x20000000, KEY_RIGHT, },
      { 0x40000000, KEY_ENTER, },
      { 0x80000000, KEY_SELECT, },
};

static void handle_buttons(struct input_polled_dev *dev)
{
      struct buttons_map *button = buttons_map;
      struct buttons_dev *bdev = dev->private;
      struct input_dev *input = dev->input;
      uint32_t status;
      int i;

      status = readl(bdev->reg);
      status = ~status & BUTTONS_STATUS_MASK;

      for (i = 0; i < ARRAY_SIZE(buttons_map); i++) {
            if (status & button->mask) {
                  button->count++;
            } else {
                  if (button->count >= BUTTONS_COUNT_THRESHOLD) {
                        input_report_key(input, button->keycode, 0);
                        input_sync(input);
                  }
                  button->count = 0;
            }

            if (button->count == BUTTONS_COUNT_THRESHOLD) {
                  input_report_key(input, button->keycode, 1);
                  input_sync(input);
            }

            button++;
      }
}

static int __devinit cobalt_buttons_probe(struct platform_device *pdev)
{
      struct buttons_dev *bdev;
      struct input_polled_dev *poll_dev;
      struct input_dev *input;
      struct resource *res;
      int error, i;

      bdev = kzalloc(sizeof(struct buttons_dev), GFP_KERNEL);
      poll_dev = input_allocate_polled_device();
      if (!bdev || !poll_dev) {
            error = -ENOMEM;
            goto err_free_mem;
      }

      poll_dev->private = bdev;
      poll_dev->poll = handle_buttons;
      poll_dev->poll_interval = BUTTONS_POLL_INTERVAL;

      input = poll_dev->input;
      input->name = "Cobalt buttons";
      input->phys = "cobalt/input0";
      input->id.bustype = BUS_HOST;
      input->cdev.dev = &pdev->dev;

      input->evbit[0] = BIT_MASK(EV_KEY);
      for (i = 0; i < ARRAY_SIZE(buttons_map); i++) {
            set_bit(buttons_map[i].keycode, input->keybit);
            buttons_map[i].count = 0;
      }

      res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
      if (!res) {
            error = -EBUSY;
            goto err_free_mem;
      }

      bdev->poll_dev = poll_dev;
      bdev->reg = ioremap(res->start, res->end - res->start + 1);
      dev_set_drvdata(&pdev->dev, bdev);

      error = input_register_polled_device(poll_dev);
      if (error)
            goto err_iounmap;

      return 0;

 err_iounmap:
      iounmap(bdev->reg);
 err_free_mem:
      input_free_polled_device(poll_dev);
      kfree(bdev);
      dev_set_drvdata(&pdev->dev, NULL);
      return error;
}

static int __devexit cobalt_buttons_remove(struct platform_device *pdev)
{
      struct device *dev = &pdev->dev;
      struct buttons_dev *bdev = dev_get_drvdata(dev);

      input_unregister_polled_device(bdev->poll_dev);
      input_free_polled_device(bdev->poll_dev);
      iounmap(bdev->reg);
      kfree(bdev);
      dev_set_drvdata(dev, NULL);

      return 0;
}

static struct platform_driver cobalt_buttons_driver = {
      .probe      = cobalt_buttons_probe,
      .remove     = __devexit_p(cobalt_buttons_remove),
      .driver     = {
            .name = "Cobalt buttons",
            .owner      = THIS_MODULE,
      },
};

static int __init cobalt_buttons_init(void)
{
      return platform_driver_register(&cobalt_buttons_driver);
}

static void __exit cobalt_buttons_exit(void)
{
      platform_driver_unregister(&cobalt_buttons_driver);
}

module_init(cobalt_buttons_init);
module_exit(cobalt_buttons_exit);

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