Quelle  push-switch.c   Sprache: C

// 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(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);
 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");