diff options
| author | Simon Glass <sjg@chromium.org> | 2018-08-22 09:43:17 -0600 |
|---|---|---|
| committer | ChromeOS Commit Bot <chromeos-commit-bot@chromium.org> | 2018-09-18 15:38:06 +0000 |
| commit | dab97b3d536aaa42b8a4ca7afed213ccc103d5b1 (patch) | |
| tree | 106984f6aa34c56e91f054e1b49dfe1a55c6b9ef | |
| parent | 06124dc653ab73c0943f4c1d44fd9b69785979a8 (diff) | |
| download | chrome-ec-dab97b3d536aaa42b8a4ca7afed213ccc103d5b1.tar.gz | |
hwtimer: Tidy up and clarify some hw_clock comments
From what I can tell the counter has to tick over at the rate of 1MHz.
Update the comments to make that clear.
BUG=chromium:876737
BRANCH=none
TEST= make buildall -j50
Change-Id: Ib04731c10a68c544973b810cf70ce9ffba556b89
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1185230
Reviewed-on: https://chromium-review.googlesource.com/1230978
Reviewed-by: Martin Roth <martinroth@chromium.org>
Commit-Queue: Martin Roth <martinroth@chromium.org>
Tested-by: Martin Roth <martinroth@chromium.org>
| -rw-r--r-- | include/hwtimer.h | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/include/hwtimer.h b/include/hwtimer.h index e47ac967da..f1e3ca2dc7 100644 --- a/include/hwtimer.h +++ b/include/hwtimer.h @@ -10,7 +10,11 @@ /** * Programs when the next timer should fire an interrupt. - * deadline: timestamp of the event. + * + * The deadline is ahead of the current counter (which may of course wrap) by + * the number of microseconds until the interrupt should fire. + * + * @param deadline timestamp of the event in microseconds */ void __hw_clock_event_set(uint32_t deadline); @@ -20,10 +24,23 @@ uint32_t __hw_clock_event_get(void); /* Cancel the next event programed by __hw_clock_event_set */ void __hw_clock_event_clear(void); -/* Returns the value of the free-running counter used as clock. */ +/** + * Get the value of the free-running counter used as clock + * + * The counter resolution must be 1us, since udelay() relies on this. + * + * @return current counter value + */ uint32_t __hw_clock_source_read(void); -/* Override the current value of the hardware counter */ +/** + * Override the current value of the hardware counter + * + * The new value takes effect immediately and the counter continues counting + * from there, assuming it is enabled + * + * @ts Value to write + */ void __hw_clock_source_set(uint32_t ts); /** |