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authorVic Yang <victoryang@google.com>2015-02-04 11:28:53 -0800
committerChromeOS Commit Bot <chromeos-commit-bot@chromium.org>2015-02-10 10:47:07 +0000
commit049463f8ad985f9cb996caa7dbc5438383bd3084 (patch)
tree93ff78695657a998919c6d6e28101cd158489368 /chip/stm32/spi.c
parenta9ae00b10129feca28713a7b88978ff6cfe7c2a6 (diff)
downloadchrome-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/spi.c')
-rw-r--r--chip/stm32/spi.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/chip/stm32/spi.c b/chip/stm32/spi.c
index d8c88ba34f..21984618be 100644
--- a/chip/stm32/spi.c
+++ b/chip/stm32/spi.c
@@ -9,6 +9,7 @@
*/
#include "chipset.h"
+#include "clock.h"
#include "console.h"
#include "dma.h"
#include "gpio.h"
@@ -630,6 +631,9 @@ static void spi_init(void)
/* Enable clocks to SPI1 module */
STM32_RCC_APB2ENR |= STM32_RCC_PB2_SPI1;
+ /* Delay 1 APB clock cycle after the clock is enabled */
+ clock_wait_bus_cycles(BUS_APB, 1);
+
/*
* Enable rx/tx DMA and get ready to receive our first transaction and
* "disable" FIFO by setting event to happen after only 1 byte