linux/arch/sh/drivers/push-switch.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Generic push-switch framework
   4 *
   5 * Copyright (C) 2006  Paul Mundt
   6 */
   7#include <linux/init.h>
   8#include <linux/slab.h>
   9#include <linux/module.h>
  10#include <linux/interrupt.h>
  11#include <linux/platform_device.h>
  12#include <asm/push-switch.h>
  13
  14#define DRV_NAME "push-switch"
  15#define DRV_VERSION "0.1.1"
  16
  17static ssize_t switch_show(struct device *dev,
  18                           struct device_attribute *attr,
  19                           char *buf)
  20{
  21        struct push_switch_platform_info *psw_info = dev->platform_data;
  22        return sprintf(buf, "%s\n", psw_info->name);
  23}
  24static DEVICE_ATTR_RO(switch);
  25
  26static void switch_timer(struct timer_list *t)
  27{
  28        struct push_switch *psw = from_timer(psw, t, debounce);
  29
  30        schedule_work(&psw->work);
  31}
  32
  33static void switch_work_handler(struct work_struct *work)
  34{
  35        struct push_switch *psw = container_of(work, struct push_switch, work);
  36        struct platform_device *pdev = psw->pdev;
  37
  38        psw->state = 0;
  39
  40        kobject_uevent(&pdev->dev.kobj, KOBJ_CHANGE);
  41}
  42
  43static int switch_drv_probe(struct platform_device *pdev)
  44{
  45        struct push_switch_platform_info *psw_info;
  46        struct push_switch *psw;
  47        int ret, irq;
  48
  49        psw = kzalloc(sizeof(struct push_switch), GFP_KERNEL);
  50        if (unlikely(!psw))
  51                return -ENOMEM;
  52
  53        irq = platform_get_irq(pdev, 0);
  54        if (unlikely(irq < 0)) {
  55                ret = -ENODEV;
  56                goto err;
  57        }
  58
  59        psw_info = pdev->dev.platform_data;
  60        BUG_ON(!psw_info);
  61
  62        ret = request_irq(irq, psw_info->irq_handler,
  63                          psw_info->irq_flags,
  64                          psw_info->name ? psw_info->name : DRV_NAME, pdev);
  65        if (unlikely(ret < 0))
  66                goto err;
  67
  68        if (psw_info->name) {
  69                ret = device_create_file(&pdev->dev, &dev_attr_switch);
  70                if (unlikely(ret)) {
  71                        dev_err(&pdev->dev, "Failed creating device attrs\n");
  72                        ret = -EINVAL;
  73                        goto err_irq;
  74                }
  75        }
  76
  77        INIT_WORK(&psw->work, switch_work_handler);
  78        timer_setup(&psw->debounce, switch_timer, 0);
  79
  80        /* Workqueue API brain-damage */
  81        psw->pdev = pdev;
  82
  83        platform_set_drvdata(pdev, psw);
  84
  85        return 0;
  86
  87err_irq:
  88        free_irq(irq, pdev);
  89err:
  90        kfree(psw);
  91        return ret;
  92}
  93
  94static int switch_drv_remove(struct platform_device *pdev)
  95{
  96        struct push_switch *psw = platform_get_drvdata(pdev);
  97        struct push_switch_platform_info *psw_info = pdev->dev.platform_data;
  98        int irq = platform_get_irq(pdev, 0);
  99
 100        if (psw_info->name)
 101                device_remove_file(&pdev->dev, &dev_attr_switch);
 102
 103        platform_set_drvdata(pdev, NULL);
 104        flush_work(&psw->work);
 105        del_timer_sync(&psw->debounce);
 106        free_irq(irq, pdev);
 107
 108        kfree(psw);
 109
 110        return 0;
 111}
 112
 113static struct platform_driver switch_driver = {
 114        .probe          = switch_drv_probe,
 115        .remove         = switch_drv_remove,
 116        .driver         = {
 117                .name   = DRV_NAME,
 118        },
 119};
 120
 121static int __init switch_init(void)
 122{
 123        printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
 124        return platform_driver_register(&switch_driver);
 125}
 126
 127static void __exit switch_exit(void)
 128{
 129        platform_driver_unregister(&switch_driver);
 130}
 131module_init(switch_init);
 132module_exit(switch_exit);
 133
 134MODULE_VERSION(DRV_VERSION);
 135MODULE_AUTHOR("Paul Mundt");
 136MODULE_LICENSE("GPL v2");
 137