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    Subject[PATCH 06/11] RTC subsystem, dev interface
    This patch adds 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: Alessandro Zummo <a.zummo@towertech.it>
    --

    drivers/rtc/Kconfig | 11 +
    drivers/rtc/Makefile | 1
    drivers/rtc/rtc-dev.c | 370 ++++++++++++++++++++++++++++++++++++++++++++++++++
    3 files changed, 382 insertions(+)

    --- /dev/null 1970-01-01 00:00:00.000000000 +0000
    +++ linux-rtc/drivers/rtc/rtc-dev.c 2006-02-14 11:37:15.000000000 +0100
    @@ -0,0 +1,370 @@
    +/*
    + * 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 as published by
    + * the Free Software Foundation; version 2 of the License.
    +*/
    +
    +#include <linux/module.h>
    +#include <linux/rtc.h>
    +
    +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:
    + if ((err = rtc_read_alarm(class_dev, &alarm)) < 0)
    + return err;
    +
    + if ((err = copy_to_user(uarg, &alarm.time, sizeof(tm))))
    + return -EFAULT;
    + break;
    +
    + case RTC_ALM_SET:
    + if ((err = 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:
    + if ((err = rtc_read_time(class_dev, &tm)) < 0)
    + return err;
    +
    + if ((err = copy_to_user(uarg, &tm, sizeof(tm))))
    + return -EFAULT;
    + break;
    +
    + case RTC_SET_TIME:
    + if (!capable(CAP_SYS_TIME))
    + return -EACCES;
    +
    + if ((err = 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 ((err = copy_from_user(&alarm, uarg, sizeof(alarm))))
    + return -EFAULT;
    +
    + err = rtc_set_alarm(class_dev, &alarm);
    + break;
    +
    + case RTC_WKALM_RD:
    + if ((err = rtc_read_alarm(class_dev, &alarm)) < 0)
    + return err;
    +
    + if ((err = 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,
    +};
    +
    +static ssize_t rtc_dev_show_dev(struct class_device *class_dev, char *buf)
    +{
    + return print_dev_t(buf, class_dev->devt);
    +}
    +static CLASS_DEVICE_ATTR(dev, S_IRUGO, rtc_dev_show_dev, NULL);
    +
    +/* insertion/removal hooks */
    +
    +static int rtc_dev_add_device(struct class_device *class_dev,
    + struct class_interface *class_intf)
    +{
    + 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;
    + class_dev->devt = MKDEV(MAJOR(rtc_devt), rtc->id);
    +
    + if (cdev_add(&rtc->char_dev, class_dev->devt, 1)) {
    + cdev_del(&rtc->char_dev);
    +
    + dev_err(class_dev->dev,
    + "failed to add char device %d:%d\n",
    + MAJOR(class_dev->devt),
    + MINOR(class_dev->devt));
    +
    + class_dev->devt = MKDEV(0, 0);
    + return -ENODEV;
    + }
    +
    + class_device_create_file(class_dev, &class_device_attr_dev);
    +
    + dev_info(class_dev->dev, "rtc intf: dev (%d:%d)\n",
    + MAJOR(class_dev->devt),
    + MINOR(class_dev->devt));
    +
    + kobject_uevent(&class_dev->kobj, KOBJ_ADD);
    +
    + return 0;
    +}
    +
    +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);
    +
    + class_device_remove_file(class_dev, &class_device_attr_dev);
    +
    + if (MAJOR(class_dev->devt)) {
    + dev_dbg(class_dev->dev, "removing char %d:%d\n",
    + MAJOR(class_dev->devt),
    + MINOR(class_dev->devt));
    + cdev_del(&rtc->char_dev);
    +
    + kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
    +
    + class_dev->devt = MKDEV(0, 0);
    + }
    +}
    +
    +/* interface registration */
    +
    +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;
    +
    + if ((err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc")) < 0) {
    + printk(KERN_ERR "%s: failed to allocate char dev region\n",
    + __FILE__);
    + return err;
    + }
    +
    + if ((err = rtc_interface_register(&rtc_dev_interface)) < 0) {
    + printk(KERN_ERR "%s: failed to register the interface\n",
    + __FILE__);
    + unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
    + return err;
    + }
    +
    + return 0;
    +}
    +
    +static void __exit rtc_dev_exit(void)
    +{
    + class_interface_unregister(&rtc_dev_interface);
    +
    + 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");
    --- linux-rtc.orig/drivers/rtc/Kconfig 2006-02-14 11:34:49.000000000 +0100
    +++ linux-rtc/drivers/rtc/Kconfig 2006-02-14 11:34:50.000000000 +0100
    @@ -58,6 +58,17 @@ 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

    --- linux-rtc.orig/drivers/rtc/Makefile 2006-02-14 11:34:49.000000000 +0100
    +++ linux-rtc/drivers/rtc/Makefile 2006-02-14 11:34:50.000000000 +0100
    @@ -8,3 +8,4 @@ obj-$(CONFIG_RTC_CLASS) += rtc-core.o
    rtc-core-y := class.o interface.o
    obj-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
    obj-$(CONFIG_RTC_INTF_PROC) += rtc-proc.o
    +obj-$(CONFIG_RTC_INTF_DEV) += rtc-dev.o
    --
    -
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