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| author | Derek Basehore <dbasehore@chromium.org> | 2013-11-18 11:30:48 +0100 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2014-01-06 09:13:23 +0000 |
| commit | 49f91ac3310da217ba877b1872d2aba907022a22 (patch) | |
| tree | d0fda36a016325a775f144892b971abace9c51e4 /drivers/mfd/cros_ec_spi.c | |
| parent | 9981a3146cd9f07075dcac1611ca7c06f597d66b (diff) | |
| download | linux-stable-49f91ac3310da217ba877b1872d2aba907022a22.tar.gz linux-stable-49f91ac3310da217ba877b1872d2aba907022a22.tar.bz2 linux-stable-49f91ac3310da217ba877b1872d2aba907022a22.zip | |
mfd: cros ec: spi: Increase EC transaction delay
50 us is not a long enough delay between EC transactions. At least 70 us
are needed for the 16 MHz STM32L part. Increase the delay to 200 us for
an extra safety margin.
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Signed-off-by: Derek Basehore <dbasehore@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd/cros_ec_spi.c')
| -rw-r--r-- | drivers/mfd/cros_ec_spi.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c index 367ccb58ecb1..ab49fe51a5d1 100644 --- a/drivers/mfd/cros_ec_spi.c +++ b/drivers/mfd/cros_ec_spi.c @@ -50,10 +50,11 @@ /* * Time between raising the SPI chip select (for the end of a * transaction) and dropping it again (for the next transaction). - * If we go too fast, the EC will miss the transaction. It seems - * that 50us is enough with the 16MHz STM32 EC. + * If we go too fast, the EC will miss the transaction. We know that we + * need at least 70 us with the 16 MHz STM32 EC, so go with 200 us to be + * safe. */ -#define EC_SPI_RECOVERY_TIME_NS (50 * 1000) +#define EC_SPI_RECOVERY_TIME_NS (200 * 1000) /** * struct cros_ec_spi - information about a SPI-connected EC |