chromeec: Add wakeup delay after SPI /CS assertion

Hardware / Coreboot - David Hendricks [chromium.org] - 2 April 2015 10:28 UTC

Some ECs may require a few microseconds to ramp up their clock after being awaken by /CS assertion. This adds a Kconfig variable that can be overridden at the mainboard-level which will force a delay between asserting /CS and beginning a transfer.

BUG=chrome-os-partner:32223 BRANCH=none TEST=verified ~100us delay using logic analyzer

Change-Id: I6d9b8beaa808252f008efb10e7448afdf96d2004

767d245 chromeec: Add wakeup delay after SPI /CS assertion
src/ec/google/chromeec/Kconfig | 7 +++++++
src/ec/google/chromeec/ec_spi.c | 5 +++++
2 files changed, 12 insertions(+)

Upstream: review.coreboot.org

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