From: Alessandro Zummo Date: Mon, 27 Mar 2006 09:16:41 +0000 (-0800) Subject: [PATCH] RTC subsystem: dev interface X-Git-Tag: v2.6.17-rc1~365 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e824290e5dcfaf2120da587b16d10dfdff8d5d3e;p=linux-2.6 [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: Alessandro Zummo Acked-by: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 200fb06b78..8e4dc32058 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -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 diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 137aef0e29..38a9212a7f 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -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 diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c new file mode 100644 index 0000000000..b1e3e6179e --- /dev/null +++ b/drivers/rtc/rtc-dev.c @@ -0,0 +1,382 @@ +/* + * RTC subsystem, dev interface + * + * Copyright (C) 2005 Tower Technologies + * Author: Alessandro Zummo + * + * 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 +#include + +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 "); +MODULE_DESCRIPTION("RTC class dev interface"); +MODULE_LICENSE("GPL");