diff options
Diffstat (limited to 'include/linux/clocksource.h')
| -rw-r--r-- | include/linux/clocksource.h | 37 |
1 files changed, 34 insertions, 3 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 573819ef4cc0..5a40d14daa9f 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); } /** |