drivers/rtc/rtc-dev.c - maze/linux - Git at Google

 /*
  * RTC subsystem, dev interface
  *
  * Copyright (C) 2005 Tower Technologies
  * Author: Alessandro Zummo <a.zummo@towertech.it>
  *
  * based on arch/arm/common/rtctime.c
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
 */

 #include <linux/module.h>
 #include <linux/rtc.h>

 static struct class *rtc_dev_class;
 static dev_t rtc_devt;

 #define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */

 static int rtc_dev_open(struct inode *inode, struct file *file)
 {
 	int err;
 	struct rtc_device *rtc = container_of(inode->i_cdev,
 					struct rtc_device, char_dev);
 	struct rtc_class_ops *ops = rtc->ops;

 	/* We keep the lock as long as the device is in use
 	 * and return immediately if busy
 	 */
 	if (!(mutex_trylock(&rtc->char_lock)))
 		return -EBUSY;

 	file->private_data = &rtc->class_dev;

 	err = ops->open ? ops->open(rtc->class_dev.dev) : 0;
 	if (err == 0) {
 		spin_lock_irq(&rtc->irq_lock);
 		rtc->irq_data = 0;
 		spin_unlock_irq(&rtc->irq_lock);

 		return 0;
 	}

 	/* something has gone wrong, release the lock */
 	mutex_unlock(&rtc->char_lock);
 	return err;
 }


 static ssize_t
 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
 	struct rtc_device *rtc = to_rtc_device(file->private_data);

 	DECLARE_WAITQUEUE(wait, current);
 	unsigned long data;
 	ssize_t ret;

 	if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
 		return -EINVAL;

 	add_wait_queue(&rtc->irq_queue, &wait);
 	do {
 		__set_current_state(TASK_INTERRUPTIBLE);

 		spin_lock_irq(&rtc->irq_lock);
 		data = rtc->irq_data;
 		rtc->irq_data = 0;
 		spin_unlock_irq(&rtc->irq_lock);

 		if (data != 0) {
 			ret = 0;
 			break;
 		}
 		if (file->f_flags & O_NONBLOCK) {
 			ret = -EAGAIN;
 			break;
 		}
 		if (signal_pending(current)) {
 			ret = -ERESTARTSYS;
 			break;
 		}
 		schedule();
 	} while (1);
 	set_current_state(TASK_RUNNING);
 	remove_wait_queue(&rtc->irq_queue, &wait);

 	if (ret == 0) {
 		/* Check for any data updates */
 		if (rtc->ops->read_callback)
 			data = rtc->ops->read_callback(rtc->class_dev.dev,
 						       data);

 		if (sizeof(int) != sizeof(long) &&
 		    count == sizeof(unsigned int))
 			ret = put_user(data, (unsigned int __user *)buf) ?:
 				sizeof(unsigned int);
 		else
 			ret = put_user(data, (unsigned long __user *)buf) ?:
 				sizeof(unsigned long);
 	}
 	return ret;
 }

 static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
 {
 	struct rtc_device *rtc = to_rtc_device(file->private_data);
 	unsigned long data;

 	poll_wait(file, &rtc->irq_queue, wait);

 	data = rtc->irq_data;

 	return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
 }

 static int rtc_dev_ioctl(struct inode *inode, struct file *file,
 		unsigned int cmd, unsigned long arg)
 {
 	int err = 0;
 	struct class_device *class_dev = file->private_data;
 	struct rtc_device *rtc = to_rtc_device(class_dev);
 	struct rtc_class_ops *ops = rtc->ops;
 	struct rtc_time tm;
 	struct rtc_wkalrm alarm;
 	void __user *uarg = (void __user *) arg;

 	/* avoid conflicting IRQ users */
 	if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
 		spin_lock(&rtc->irq_task_lock);
 		if (rtc->irq_task)
 			err = -EBUSY;
 		spin_unlock(&rtc->irq_task_lock);

 		if (err < 0)
 			return err;
 	}

 	/* try the driver's ioctl interface */
 	if (ops->ioctl) {
 		err = ops->ioctl(class_dev->dev, cmd, arg);
 		if (err != -EINVAL)
 			return err;
 	}

 	/* if the driver does not provide the ioctl interface
 	 * or if that particular ioctl was not implemented
 	 * (-EINVAL), we will try to emulate here.
 	 */

 	switch (cmd) {
 	case RTC_ALM_READ:
 		err = rtc_read_alarm(class_dev, &alarm);
 		if (err < 0)
 			return err;

 		if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
 			return -EFAULT;
 		break;

 	case RTC_ALM_SET:
 		if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
 			return -EFAULT;

 		alarm.enabled = 0;
 		alarm.pending = 0;
 		alarm.time.tm_mday = -1;
 		alarm.time.tm_mon = -1;
 		alarm.time.tm_year = -1;
 		alarm.time.tm_wday = -1;
 		alarm.time.tm_yday = -1;
 		alarm.time.tm_isdst = -1;
 		err = rtc_set_alarm(class_dev, &alarm);
 		break;

 	case RTC_RD_TIME:
 		err = rtc_read_time(class_dev, &tm);
 		if (err < 0)
 			return err;

 		if (copy_to_user(uarg, &tm, sizeof(tm)))
 			return -EFAULT;
 		break;

 	case RTC_SET_TIME:
 		if (!capable(CAP_SYS_TIME))
 			return -EACCES;

 		if (copy_from_user(&tm, uarg, sizeof(tm)))
 			return -EFAULT;

 		err = rtc_set_time(class_dev, &tm);
 		break;
 #if 0
 	case RTC_EPOCH_SET:
 #ifndef rtc_epoch
 		/*
 		 * There were no RTC clocks before 1900.
 		 */
 		if (arg < 1900) {
 			err = -EINVAL;
 			break;
 		}
 		if (!capable(CAP_SYS_TIME)) {
 			err = -EACCES;
 			break;
 		}
 		rtc_epoch = arg;
 		err = 0;
 #endif
 		break;

 	case RTC_EPOCH_READ:
 		err = put_user(rtc_epoch, (unsigned long __user *)uarg);
 		break;
 #endif
 	case RTC_WKALM_SET:
 		if (copy_from_user(&alarm, uarg, sizeof(alarm)))
 			return -EFAULT;

 		err = rtc_set_alarm(class_dev, &alarm);
 		break;

 	case RTC_WKALM_RD:
 		err = rtc_read_alarm(class_dev, &alarm);
 		if (err < 0)
 			return err;

 		if (copy_to_user(uarg, &alarm, sizeof(alarm)))
 			return -EFAULT;
 		break;

 	default:
 		err = -EINVAL;
 		break;
 	}

 	return err;
 }

 static int rtc_dev_release(struct inode *inode, struct file *file)
 {
 	struct rtc_device *rtc = to_rtc_device(file->private_data);

 	if (rtc->ops->release)
 		rtc->ops->release(rtc->class_dev.dev);

 	mutex_unlock(&rtc->char_lock);
 	return 0;
 }

 static int rtc_dev_fasync(int fd, struct file *file, int on)
 {
 	struct rtc_device *rtc = to_rtc_device(file->private_data);
 	return fasync_helper(fd, file, on, &rtc->async_queue);
 }

 static struct file_operations rtc_dev_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.read		= rtc_dev_read,
 	.poll		= rtc_dev_poll,
 	.ioctl		= rtc_dev_ioctl,
 	.open		= rtc_dev_open,
 	.release	= rtc_dev_release,
 	.fasync		= rtc_dev_fasync,
 };

 /* insertion/removal hooks */

 static int rtc_dev_add_device(struct class_device *class_dev,
 				struct class_interface *class_intf)
 {
 	int err = 0;
 	struct rtc_device *rtc = to_rtc_device(class_dev);

 	if (rtc->id >= RTC_DEV_MAX) {
 		dev_err(class_dev->dev, "too many RTCs\n");
 		return -EINVAL;
 	}

 	mutex_init(&rtc->char_lock);
 	spin_lock_init(&rtc->irq_lock);
 	init_waitqueue_head(&rtc->irq_queue);

 	cdev_init(&rtc->char_dev, &rtc_dev_fops);
 	rtc->char_dev.owner = rtc->owner;

 	if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) {
 		cdev_del(&rtc->char_dev);
 		dev_err(class_dev->dev,
 			"failed to add char device %d:%d\n",
 			MAJOR(rtc_devt), rtc->id);
 		return -ENODEV;
 	}

 	rtc->rtc_dev = class_device_create(rtc_dev_class, NULL,
 						MKDEV(MAJOR(rtc_devt), rtc->id),
 						class_dev->dev, "rtc%d", rtc->id);
 	if (IS_ERR(rtc->rtc_dev)) {
 		dev_err(class_dev->dev, "cannot create rtc_dev device\n");
 		err = PTR_ERR(rtc->rtc_dev);
 		goto err_cdev_del;
 	}

 	dev_info(class_dev->dev, "rtc intf: dev (%d:%d)\n",
 		MAJOR(rtc->rtc_dev->devt),
 		MINOR(rtc->rtc_dev->devt));

 	return 0;

 err_cdev_del:

 	cdev_del(&rtc->char_dev);
 	return err;
 }

 static void rtc_dev_remove_device(struct class_device *class_dev,
 					struct class_interface *class_intf)
 {
 	struct rtc_device *rtc = to_rtc_device(class_dev);

 	if (rtc->rtc_dev) {
 		dev_dbg(class_dev->dev, "removing char %d:%d\n",
 			MAJOR(rtc->rtc_dev->devt),
 			MINOR(rtc->rtc_dev->devt));

 		class_device_unregister(rtc->rtc_dev);
 		cdev_del(&rtc->char_dev);
 	}
 }

 /* interface registration */

 static struct class_interface rtc_dev_interface = {
 	.add = &rtc_dev_add_device,
 	.remove = &rtc_dev_remove_device,
 };

 static int __init rtc_dev_init(void)
 {
 	int err;

 	rtc_dev_class = class_create(THIS_MODULE, "rtc-dev");
 	if (IS_ERR(rtc_dev_class))
 		return PTR_ERR(rtc_dev_class);

 	err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
 	if (err < 0) {
 		printk(KERN_ERR "%s: failed to allocate char dev region\n",
 			__FILE__);
 		goto err_destroy_class;
 	}

 	err = rtc_interface_register(&rtc_dev_interface);
 	if (err < 0) {
 		printk(KERN_ERR "%s: failed to register the interface\n",
 			__FILE__);
 		goto err_unregister_chrdev;
 	}

 	return 0;

 err_unregister_chrdev:
 	unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);

 err_destroy_class:
 	class_destroy(rtc_dev_class);

 	return err;
 }

 static void __exit rtc_dev_exit(void)
 {
 	class_interface_unregister(&rtc_dev_interface);
 	class_destroy(rtc_dev_class);
 	unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
 }

 module_init(rtc_dev_init);
 module_exit(rtc_dev_exit);

 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 MODULE_DESCRIPTION("RTC class dev interface");
 MODULE_LICENSE("GPL");
	/*
	* RTC subsystem, dev interface
	*
	* Copyright (C) 2005 Tower Technologies
	* Author: Alessandro Zummo <a.zummo@towertech.it>
	*
	* based on arch/arm/common/rtctime.c
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/module.h>
	#include <linux/rtc.h>

	static struct class *rtc_dev_class;
	static dev_t rtc_devt;

	#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */

	static int rtc_dev_open(struct inode inode, struct file file)
	{
	int err;
	struct rtc_device *rtc = container_of(inode->i_cdev,
	struct rtc_device, char_dev);
	struct rtc_class_ops *ops = rtc->ops;

	/* We keep the lock as long as the device is in use
	* and return immediately if busy
	*/
	if (!(mutex_trylock(&rtc->char_lock)))
	return -EBUSY;

	file->private_data = &rtc->class_dev;

	err = ops->open ? ops->open(rtc->class_dev.dev) : 0;
	if (err == 0) {
	spin_lock_irq(&rtc->irq_lock);
	rtc->irq_data = 0;
	spin_unlock_irq(&rtc->irq_lock);

	return 0;
	}

	/* something has gone wrong, release the lock */
	mutex_unlock(&rtc->char_lock);
	return err;
	}


	static ssize_t
	rtc_dev_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	{
	struct rtc_device *rtc = to_rtc_device(file->private_data);

	DECLARE_WAITQUEUE(wait, current);
	unsigned long data;
	ssize_t ret;

	if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
	return -EINVAL;

	add_wait_queue(&rtc->irq_queue, &wait);
	do {
	__set_current_state(TASK_INTERRUPTIBLE);

	spin_lock_irq(&rtc->irq_lock);
	data = rtc->irq_data;
	rtc->irq_data = 0;
	spin_unlock_irq(&rtc->irq_lock);

	if (data != 0) {
	ret = 0;
	break;
	}
	if (file->f_flags & O_NONBLOCK) {
	ret = -EAGAIN;
	break;
	}
	if (signal_pending(current)) {
	ret = -ERESTARTSYS;
	break;
	}
	schedule();
	} while (1);
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&rtc->irq_queue, &wait);

	if (ret == 0) {
	/* Check for any data updates */
	if (rtc->ops->read_callback)
	data = rtc->ops->read_callback(rtc->class_dev.dev,
	data);

	if (sizeof(int) != sizeof(long) &&
	count == sizeof(unsigned int))
	ret = put_user(data, (unsigned int __user *)buf) ?:
	sizeof(unsigned int);
	else
	ret = put_user(data, (unsigned long __user *)buf) ?:
	sizeof(unsigned long);
	}
	return ret;
	}

	static unsigned int rtc_dev_poll(struct file file, poll_table wait)
	{
	struct rtc_device *rtc = to_rtc_device(file->private_data);
	unsigned long data;

	poll_wait(file, &rtc->irq_queue, wait);

	data = rtc->irq_data;

	return (data != 0) ? (POLLIN \| POLLRDNORM) : 0;
	}

	static int rtc_dev_ioctl(struct inode inode, struct file file,
	unsigned int cmd, unsigned long arg)
	{
	int err = 0;
	struct class_device *class_dev = file->private_data;
	struct rtc_device *rtc = to_rtc_device(class_dev);
	struct rtc_class_ops *ops = rtc->ops;
	struct rtc_time tm;
	struct rtc_wkalrm alarm;
	void __user uarg = (void __user ) arg;

	/* avoid conflicting IRQ users */
	if (cmd == RTC_PIE_ON \|\| cmd == RTC_PIE_OFF \|\| cmd == RTC_IRQP_SET) {
	spin_lock(&rtc->irq_task_lock);
	if (rtc->irq_task)
	err = -EBUSY;
	spin_unlock(&rtc->irq_task_lock);

	if (err < 0)
	return err;
	}

	/* try the driver's ioctl interface */
	if (ops->ioctl) {
	err = ops->ioctl(class_dev->dev, cmd, arg);
	if (err != -EINVAL)
	return err;
	}

	/* if the driver does not provide the ioctl interface
	* or if that particular ioctl was not implemented
	* (-EINVAL), we will try to emulate here.
	*/

	switch (cmd) {
	case RTC_ALM_READ:
	err = rtc_read_alarm(class_dev, &alarm);
	if (err < 0)
	return err;

	if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
	return -EFAULT;
	break;

	case RTC_ALM_SET:
	if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
	return -EFAULT;

	alarm.enabled = 0;
	alarm.pending = 0;
	alarm.time.tm_mday = -1;
	alarm.time.tm_mon = -1;
	alarm.time.tm_year = -1;
	alarm.time.tm_wday = -1;
	alarm.time.tm_yday = -1;
	alarm.time.tm_isdst = -1;
	err = rtc_set_alarm(class_dev, &alarm);
	break;

	case RTC_RD_TIME:
	err = rtc_read_time(class_dev, &tm);
	if (err < 0)
	return err;

	if (copy_to_user(uarg, &tm, sizeof(tm)))
	return -EFAULT;
	break;

	case RTC_SET_TIME:
	if (!capable(CAP_SYS_TIME))
	return -EACCES;

	if (copy_from_user(&tm, uarg, sizeof(tm)))
	return -EFAULT;

	err = rtc_set_time(class_dev, &tm);
	break;
	#if 0
	case RTC_EPOCH_SET:
	#ifndef rtc_epoch
	/*
	* There were no RTC clocks before 1900.
	*/
	if (arg < 1900) {
	err = -EINVAL;
	break;
	}
	if (!capable(CAP_SYS_TIME)) {
	err = -EACCES;
	break;
	}
	rtc_epoch = arg;
	err = 0;
	#endif
	break;

	case RTC_EPOCH_READ:
	err = put_user(rtc_epoch, (unsigned long __user *)uarg);
	break;
	#endif
	case RTC_WKALM_SET:
	if (copy_from_user(&alarm, uarg, sizeof(alarm)))
	return -EFAULT;

	err = rtc_set_alarm(class_dev, &alarm);
	break;

	case RTC_WKALM_RD:
	err = rtc_read_alarm(class_dev, &alarm);
	if (err < 0)
	return err;

	if (copy_to_user(uarg, &alarm, sizeof(alarm)))
	return -EFAULT;
	break;

	default:
	err = -EINVAL;
	break;
	}

	return err;
	}

	static int rtc_dev_release(struct inode inode, struct file file)
	{
	struct rtc_device *rtc = to_rtc_device(file->private_data);

	if (rtc->ops->release)
	rtc->ops->release(rtc->class_dev.dev);

	mutex_unlock(&rtc->char_lock);
	return 0;
	}

	static int rtc_dev_fasync(int fd, struct file *file, int on)
	{
	struct rtc_device *rtc = to_rtc_device(file->private_data);
	return fasync_helper(fd, file, on, &rtc->async_queue);
	}

	static struct file_operations rtc_dev_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.read = rtc_dev_read,
	.poll = rtc_dev_poll,
	.ioctl = rtc_dev_ioctl,
	.open = rtc_dev_open,
	.release = rtc_dev_release,
	.fasync = rtc_dev_fasync,
	};

	/* insertion/removal hooks */

	static int rtc_dev_add_device(struct class_device *class_dev,
	struct class_interface *class_intf)
	{
	int err = 0;
	struct rtc_device *rtc = to_rtc_device(class_dev);

	if (rtc->id >= RTC_DEV_MAX) {
	dev_err(class_dev->dev, "too many RTCs\n");
	return -EINVAL;
	}

	mutex_init(&rtc->char_lock);
	spin_lock_init(&rtc->irq_lock);
	init_waitqueue_head(&rtc->irq_queue);

	cdev_init(&rtc->char_dev, &rtc_dev_fops);
	rtc->char_dev.owner = rtc->owner;

	if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) {
	cdev_del(&rtc->char_dev);
	dev_err(class_dev->dev,
	"failed to add char device %d:%d\n",
	MAJOR(rtc_devt), rtc->id);
	return -ENODEV;
	}

	rtc->rtc_dev = class_device_create(rtc_dev_class, NULL,
	MKDEV(MAJOR(rtc_devt), rtc->id),
	class_dev->dev, "rtc%d", rtc->id);
	if (IS_ERR(rtc->rtc_dev)) {
	dev_err(class_dev->dev, "cannot create rtc_dev device\n");
	err = PTR_ERR(rtc->rtc_dev);
	goto err_cdev_del;
	}

	dev_info(class_dev->dev, "rtc intf: dev (%d:%d)\n",
	MAJOR(rtc->rtc_dev->devt),
	MINOR(rtc->rtc_dev->devt));

	return 0;

	err_cdev_del:

	cdev_del(&rtc->char_dev);
	return err;
	}

	static void rtc_dev_remove_device(struct class_device *class_dev,
	struct class_interface *class_intf)
	{
	struct rtc_device *rtc = to_rtc_device(class_dev);

	if (rtc->rtc_dev) {
	dev_dbg(class_dev->dev, "removing char %d:%d\n",
	MAJOR(rtc->rtc_dev->devt),
	MINOR(rtc->rtc_dev->devt));

	class_device_unregister(rtc->rtc_dev);
	cdev_del(&rtc->char_dev);
	}
	}

	/* interface registration */

	static struct class_interface rtc_dev_interface = {
	.add = &rtc_dev_add_device,
	.remove = &rtc_dev_remove_device,
	};

	static int __init rtc_dev_init(void)
	{
	int err;

	rtc_dev_class = class_create(THIS_MODULE, "rtc-dev");
	if (IS_ERR(rtc_dev_class))
	return PTR_ERR(rtc_dev_class);

	err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
	if (err < 0) {
	printk(KERN_ERR "%s: failed to allocate char dev region\n",
	__FILE__);
	goto err_destroy_class;
	}

	err = rtc_interface_register(&rtc_dev_interface);
	if (err < 0) {
	printk(KERN_ERR "%s: failed to register the interface\n",
	__FILE__);
	goto err_unregister_chrdev;
	}

	return 0;

	err_unregister_chrdev:
	unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);

	err_destroy_class:
	class_destroy(rtc_dev_class);

	return err;
	}

	static void __exit rtc_dev_exit(void)
	{
	class_interface_unregister(&rtc_dev_interface);
	class_destroy(rtc_dev_class);
	unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
	}

	module_init(rtc_dev_init);
	module_exit(rtc_dev_exit);

	MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
	MODULE_DESCRIPTION("RTC class dev interface");
	MODULE_LICENSE("GPL");