[PATCH] RTC subsystem: dev interface
authorAlessandro Zummo <a.zummo@towertech.it>
Mon, 27 Mar 2006 09:16:41 +0000 (01:16 -0800)
committerLinus Torvalds <torvalds@g5.osdl.org>
Mon, 27 Mar 2006 16:44:51 +0000 (08:44 -0800)
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 <a.zummo@towertech.it>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-dev.c [new file with mode: 0644]

index 200fb06..8e4dc32 100644 (file)
@@ -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
 
index 137aef0..38a9212 100644 (file)
@@ -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 (file)
index 0000000..b1e3e61
--- /dev/null
@@ -0,0 +1,382 @@
+/*
+ * 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");