push-switch.c

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/*
 * Generic push-switch framework
 *
 * Copyright (C) 2006  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <asm/push-switch.h>

#define DRV_NAME "push-switch"
#define DRV_VERSION "0.1.1"

static ssize_t switch_show(struct device *dev,
               struct device_attribute *attr,
               char *buf)
{
    struct push_switch_platform_info *psw_info = dev->platform_data;
    return sprintf(buf, "%s\n", psw_info->name);
}
static DEVICE_ATTR(switch, S_IRUGO, switch_show, NULL);

static void switch_timer(unsigned long data)
{
    struct push_switch *psw = (struct push_switch *)data;

    schedule_work(&psw->work);
}

static void switch_work_handler(struct work_struct *work)
{
    struct push_switch *psw = container_of(work, struct push_switch, work);
    struct platform_device *pdev = psw->pdev;

    psw->state = 0;

    kobject_uevent(&pdev->dev.kobj, KOBJ_CHANGE);
}

static int switch_drv_probe(struct platform_device *pdev)
{
    struct push_switch_platform_info *psw_info;
    struct push_switch *psw;
    int ret, irq;

    psw = kzalloc(sizeof(struct push_switch), GFP_KERNEL);
    if (unlikely(!psw))
        return -ENOMEM;

    irq = platform_get_irq(pdev, 0);
    if (unlikely(irq < 0)) {
        ret = -ENODEV;
        goto err;
    }

    psw_info = pdev->dev.platform_data;
    BUG_ON(!psw_info);

    ret = request_irq(irq, psw_info->irq_handler,
              psw_info->irq_flags,
              psw_info->name ? psw_info->name : DRV_NAME, pdev);
    if (unlikely(ret < 0))
        goto err;

    if (psw_info->name) {
        ret = device_create_file(&pdev->dev, &dev_attr_switch);
        if (unlikely(ret)) {
            dev_err(&pdev->dev, "Failed creating device attrs\n");
            ret = -EINVAL;
            goto err_irq;
        }
    }

    INIT_WORK(&psw->work, switch_work_handler);
    init_timer(&psw->debounce);

    psw->debounce.function = switch_timer;
    psw->debounce.data = (unsigned long)psw;

    /* Workqueue API brain-damage */
    psw->pdev = pdev;

    platform_set_drvdata(pdev, psw);

    return 0;

err_irq:
    free_irq(irq, pdev);
err:
    kfree(psw);
    return ret;
}

static int switch_drv_remove(struct platform_device *pdev)
{
    struct push_switch *psw = platform_get_drvdata(pdev);
    struct push_switch_platform_info *psw_info = pdev->dev.platform_data;
    int irq = platform_get_irq(pdev, 0);

    if (psw_info->name)
        device_remove_file(&pdev->dev, &dev_attr_switch);

    platform_set_drvdata(pdev, NULL);
    flush_work(&psw->work);
    del_timer_sync(&psw->debounce);
    free_irq(irq, pdev);

    kfree(psw);

    return 0;
}

static struct platform_driver switch_driver = {
    .probe      = switch_drv_probe,
    .remove     = switch_drv_remove,
    .driver     = {
        .name   = DRV_NAME,
    },
};

static int __init switch_init(void)
{
    printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
    return platform_driver_register(&switch_driver);
}

static void __exit switch_exit(void)
{
    platform_driver_unregister(&switch_driver);
}
module_init(switch_init);
module_exit(switch_exit);

MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR("Paul Mundt");
MODULE_LICENSE("GPL v2");