arch/sh/drivers/push-switch.c

   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
  17 static 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 }
  24 static DEVICE_ATTR_RO(switch);
  25
  26 static 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
  33 static 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
  43 static 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
  87 err_irq:
  88         free_irq(irq, pdev);
  89 err:
  90         kfree(psw);
  91         return ret;
  92 }
  93
  94 static void 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         timer_shutdown_sync(&psw->debounce);
 105         flush_work(&psw->work);
 106         free_irq(irq, pdev);
 107
 108         kfree(psw);
 109 }
 110
 111 static struct platform_driver switch_driver = {
 112         .probe          = switch_drv_probe,
 113         .remove         = switch_drv_remove,
 114         .driver         = {
 115                 .name   = DRV_NAME,
 116         },
 117 };
 118
 119 static int __init switch_init(void)
 120 {
 121         printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
 122         return platform_driver_register(&switch_driver);
 123 }
 124
 125 static void __exit switch_exit(void)
 126 {
 127         platform_driver_unregister(&switch_driver);
 128 }
 129 module_init(switch_init);
 130 module_exit(switch_exit);
 131
 132 MODULE_VERSION(DRV_VERSION);
 133 MODULE_AUTHOR("Paul Mundt");
 134 MODULE_DESCRIPTION("Generic push-switch framework");
 135 MODULE_LICENSE("GPL v2");