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-rw-r--r--include/linux/clocksource.h37
1 files changed, 34 insertions, 3 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 573819ef..5a40d14 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -143,7 +143,9 @@ extern u64 timecounter_cyc2time(struct timecounter *tc,
* 400-499: Perfect
* The ideal clocksource. A must-use where
* available.
- * @read: returns a cycle value
+ * @read: returns a cycle value, passes clocksource as argument
+ * @enable: optional function to enable the clocksource
+ * @disable: optional function to disable the clocksource
* @mask: bitmask for two's complement
* subtraction of non 64 bit counters
* @mult: cycle to nanosecond multiplier (adjusted by NTP)
@@ -162,7 +164,9 @@ struct clocksource {
char *name;
struct list_head list;
int rating;
- cycle_t (*read)(void);
+ cycle_t (*read)(struct clocksource *cs);
+ int (*enable)(struct clocksource *cs);
+ void (*disable)(struct clocksource *cs);
cycle_t mask;
u32 mult;
u32 mult_orig;
@@ -271,7 +275,34 @@ static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
*/
static inline cycle_t clocksource_read(struct clocksource *cs)
{
- return cs->read();
+ return cs->read(cs);
+}
+
+/**
+ * clocksource_enable: - enable clocksource
+ * @cs: pointer to clocksource
+ *
+ * Enables the specified clocksource. The clocksource callback
+ * function should start up the hardware and setup mult and field
+ * members of struct clocksource to reflect hardware capabilities.
+ */
+static inline int clocksource_enable(struct clocksource *cs)
+{
+ return cs->enable ? cs->enable(cs) : 0;
+}
+
+/**
+ * clocksource_disable: - disable clocksource
+ * @cs: pointer to clocksource
+ *
+ * Disables the specified clocksource. The clocksource callback
+ * function should power down the now unused hardware block to
+ * save power.
+ */
+static inline void clocksource_disable(struct clocksource *cs)
+{
+ if (cs->disable)
+ cs->disable(cs);
}
/**
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