diff options
| author | Doug Anderson <dianders@chromium.org> | 2013-08-27 12:55:09 -0700 |
|---|---|---|
| committer | Caroline Tice <cmtice@chromium.org> | 2013-08-29 22:51:11 +0000 |
| commit | 3f4899b6b0e97d6fca4cde0a9bb44c98c258a012 (patch) | |
| tree | 658cfe3d4dfce7e12347fb18fd5910904f5e1da7 /chip/stm32/clock-stm32l.c | |
| parent | fcd388df8eef2f723cb4ff7277fa44d3754bb966 (diff) | |
| download | chrome-ec-3f4899b6b0e97d6fca4cde0a9bb44c98c258a012.tar.gz | |
stm32l: Add a "PRE_FREQ_CHANGE" hook to allow other code to prepare
Before this change drivers had no way of knowing that a frequency
change was coming. This could cause problems for some drivers (like
i2c) that need to make sure that a transaction isn't happening while a
frequency change is happening.
The PRE_FREQ_CHANGE archiecture is very simple here and we don't allow
any way to cancel it.
At the moment, we guarantee:
- We won't call PRE_FREQ_CHANGE with interrupts disabled, so acquiring
locks / sleeping is OK.
- We'll call the actual HOOK_FREQ_CHANGE after the PRE_FREQ_CHANGE.
PRE_FREQ_CHANGE and HOOK_FREQ_CHANGE should not use deferred function
calls.
BRANCH=pit
BUG=chrome-os-partner:22093
TEST=With all patches together:
- on AP: suspend_stress_test
- on EC: battery 10000 50
Change-Id: I2731a3e85d41e749fa571fdb74b5c9b12043cda6
Signed-off-by: Doug Anderson <dianders@chromium.org>
Previous-Reviewed-on: https://chromium-review.googlesource.com/167101
(cherry picked from commit d84c0dbbf7c5a72917a820e292ecfdfa698d0fb9)
Reviewed-on: https://chromium-review.googlesource.com/167148
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Diffstat (limited to 'chip/stm32/clock-stm32l.c')
| -rw-r--r-- | chip/stm32/clock-stm32l.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/chip/stm32/clock-stm32l.c b/chip/stm32/clock-stm32l.c index 4d5b1babeb..e89c2e3ef5 100644 --- a/chip/stm32/clock-stm32l.c +++ b/chip/stm32/clock-stm32l.c @@ -59,6 +59,9 @@ static void clock_set_osc(enum clock_osc osc) if (osc == current_osc) return; + if (current_osc != OSC_INIT) + hook_notify(HOOK_PRE_FREQ_CHANGE); + switch (osc) { case OSC_HSI: /* Ensure that HSI is ON */ |