X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Frtc%2Frtc-dev.c;h=90dfa0df747acb9314b4ed115c2eec0dee1eae0d;hb=3ff2cd230de31e3b7bf2efd254e0393e5fc1d15d;hp=814583bd2fe709c1da0710808ed6f4cffbe8b50f;hpb=4acadb965c4aa587aac29a0a91203c4745d6fb4e;p=linux-2.6

diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 814583bd2f..90dfa0df74 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -26,10 +26,7 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
 					struct rtc_device, char_dev);
 	const 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)))
+	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
 		return -EBUSY;
 
 	file->private_data = rtc;
@@ -43,8 +40,8 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
 		return 0;
 	}
 
-	/* something has gone wrong, release the lock */
-	mutex_unlock(&rtc->char_lock);
+	/* something has gone wrong */
+	clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
 	return err;
 }
 
@@ -249,6 +246,15 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file,
 	/* if the driver does not provide the ioctl interface
 	 * or if that particular ioctl was not implemented
 	 * (-ENOIOCTLCMD), we will try to emulate here.
+	 *
+	 * Drivers *SHOULD NOT* provide ioctl implementations
+	 * for these requests.  Instead, provide methods to
+	 * support the following code, so that the RTC's main
+	 * features are accessible without using ioctls.
+	 *
+	 * RTC and alarm times will be in UTC, by preference,
+	 * but dual-booting with MS-Windows implies RTCs must
+	 * use the local wall clock time.
 	 */
 
 	switch (cmd) {
@@ -405,7 +411,7 @@ static int rtc_dev_release(struct inode *inode, struct file *file)
 	if (rtc->ops->release)
 		rtc->ops->release(rtc->dev.parent);
 
-	mutex_unlock(&rtc->char_lock);
+	clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
 	return 0;
 }
 
@@ -440,7 +446,6 @@ void rtc_dev_prepare(struct rtc_device *rtc)
 
 	rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
 
-	mutex_init(&rtc->char_lock);
 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 	INIT_WORK(&rtc->uie_task, rtc_uie_task);
 	setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);