diff options
| author | Vic Yang <victoryang@google.com> | 2015-02-04 11:28:53 -0800 |
|---|---|---|
| committer | ChromeOS Commit Bot <chromeos-commit-bot@chromium.org> | 2015-02-10 10:47:07 +0000 |
| commit | 049463f8ad985f9cb996caa7dbc5438383bd3084 (patch) | |
| tree | 93ff78695657a998919c6d6e28101cd158489368 /chip/stm32/usart.c | |
| parent | a9ae00b10129feca28713a7b88978ff6cfe7c2a6 (diff) | |
| download | chrome-ec-049463f8ad985f9cb996caa7dbc5438383bd3084.tar.gz | |
stm32: Add delay after enabling peripheral clock
We need a dummy read after enabling AHB peripheral clock before we can
access the peripheral. For APB, we also need a dummy read for STM32F3.
BRANCH=All affected
BUG=chrome-os-partner:33007
TEST=make buildall
Change-Id: I47f4a024dca294f555428c3f2053c1d32835ebe0
Signed-off-by: Vic Yang <victoryang@google.com>
Reviewed-on: https://chromium-review.googlesource.com/246181
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Tested-by: Vic Yang <victoryang@chromium.org>
Commit-Queue: Vic Yang <victoryang@chromium.org>
Diffstat (limited to 'chip/stm32/usart.c')
| -rw-r--r-- | chip/stm32/usart.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/chip/stm32/usart.c b/chip/stm32/usart.c index 264fa35a75..29cb0b705f 100644 --- a/chip/stm32/usart.c +++ b/chip/stm32/usart.c @@ -76,6 +76,12 @@ void usart_init(struct usart_config const *config) *(config->hw->clock_register) |= config->hw->clock_enable; /* + * For STM32F3, A delay of 1 APB clock cycles is needed before we + * can access any USART register. Fortunately, we have + * gpio_config_module() below and thus don't need to add the delay. + */ + + /* * Switch all GPIOs assigned to the USART module over to their USART * alternate functions. */ |