Merge branch 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc

[pandora-kernel.git] / include / linux / rtc.h

diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 6d5e4a4..b01fe00 100644 (file)
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -115,6 +115,23 @@ extern void rtc_time_to_tm(unsigned long time, struct rtc_time *tm);
 
 extern struct class *rtc_class;
 
+/*
+ * For these RTC methods the device parameter is the physical device
+ * on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
+ * was passed to rtc_device_register().  Its driver_data normally holds
+ * device state, including the rtc_device pointer for the RTC.
+ *
+ * Most of these methods are called with rtc_device.ops_lock held,
+ * through the rtc_*(struct rtc_device *, ...) calls.
+ *
+ * The (current) exceptions are mostly filesystem hooks:
+ *   - the proc() hook for procfs
+ *   - non-ioctl() chardev hooks:  open(), release(), read_callback()
+ *   - periodic irq calls:  irq_set_state(), irq_set_freq()
+ *
+ * REVISIT those periodic irq calls *do* have ops_lock when they're
+ * issued through ioctl() ...
+ */
 struct rtc_class_ops {
        int (*open)(struct device *);
        void (*release)(struct device *);
@@ -133,6 +150,9 @@ struct rtc_class_ops {
 #define RTC_DEVICE_NAME_SIZE 20
 struct rtc_task;
 
+/* flags */
+#define RTC_DEV_BUSY 0
+
 struct rtc_device
 {
        struct device dev;
@@ -145,7 +165,7 @@ struct rtc_device
        struct mutex ops_lock;
 
        struct cdev char_dev;
-       struct mutex char_lock;
+       unsigned long flags;
 
        unsigned long irq_data;
        spinlock_t irq_lock;