// SPDX-License-Identifier: GPL-2.0
/*
 * Generic push-switch framework
 *
 * Copyright (C) 2006  Paul Mundt
 */
#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_RO(switch);

static void switch_timer(struct timer_list *t)
{
        struct push_switch *psw = timer_container_of(psw, t, debounce);

        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_obj(struct push_switch);
        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);
        timer_setup(&psw->debounce, switch_timer, 0);

        /* 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 void 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);
        timer_shutdown_sync(&psw->debounce);
        flush_work(&psw->work);
        free_irq(irq, pdev);

        kfree(psw);
}

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_DESCRIPTION("Generic push-switch framework");
MODULE_LICENSE("GPL v2");