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Commit e824290e authored by Alessandro Zummo's avatar Alessandro Zummo Committed by Linus Torvalds
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[PATCH] RTC subsystem: dev interface 



Add the dev interface to the RTC subsystem.

Each RTC will be available under /dev/rtcX .  A symlink from /dev/rtc0 to
/dev/rtc cab be obtained with the following udev rule:

KERNEL=="rtc0", SYMLINK+="rtc"

Signed-off-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 728a2947

drivers/rtc/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -62,6 +62,17 @@ config RTC_INTF_PROC 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-proc.



config RTC_INTF_DEV

	tristate "dev"

	depends on RTC_CLASS

	default RTC_CLASS

	help

	  Say yes here if you want to use your RTC using the dev

	  interface, /dev/rtc .



	  This driver can also be built as a module. If so, the module

	  will be called rtc-dev.



comment "RTC drivers"

	depends on RTC_CLASS

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,3 +9,4 @@ rtc-core-y := class.o interface.o 


obj-$(CONFIG_RTC_INTF_SYSFS)	+= rtc-sysfs.o

obj-$(CONFIG_RTC_INTF_PROC)	+= rtc-proc.o

obj-$(CONFIG_RTC_INTF_DEV)	+= rtc-dev.o

drivers/rtc/rtc-dev.c

0 → 100644
+382 −0
Original line number Diff line number Diff line 
/*

 * 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 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);



		ret = put_user(data, (unsigned long __user *)buf);

		if (ret == 0)

			ret = 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");