diff options
author | Simon Glass <sjg@chromium.org> | 2018-08-22 09:43:17 -0600 |
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committer | chrome-bot <chrome-bot@chromium.org> | 2018-09-04 21:03:58 -0700 |
commit | 4c1841b9f30a733c3bcb5fc5ed9b9bf3d7d61c19 (patch) | |
tree | d2f24ea8c958cce2603c00dde9d5b8b6bc1a4f22 /include | |
parent | e192f71aed932b88f3c42df4653a430a2e8ba10e (diff) | |
download | chrome-ec-4c1841b9f30a733c3bcb5fc5ed9b9bf3d7d61c19.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
Diffstat (limited to 'include')
-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); /** |