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authorDavid Hendricks <dhendrix@chromium.org>2014-09-27 20:04:49 -0700
committerPatrick Georgi <pgeorgi@google.com>2015-04-02 17:28:14 +0200
commit767d245ebf2d6d797bf759d23778553ed6f2a0b2 (patch)
tree247940814ab4844978218296b1e81409d9798d74 /src/ec/google/chromeec/Kconfig
parent842978631580333becf635cc78f1901615d34929 (diff)
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chromeec: Add wakeup delay after SPI /CS assertion
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 Signed-off-by: Stefan Reinauer <reinauer@chromium.org> Original-Commit-Id: ec6b10e4e3f0362dea0dc8046cfd4e4615a42585 Original-Change-Id: Ibba356e4af18f80a7da73c96dadfda0f25251381 Original-Signed-off-by: David Hendricks <dhendrix@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/220242 Original-Reviewed-by: Julius Werner <jwerner@chromium.org> Original-Reviewed-by: Alexandru Stan <amstan@chromium.org> Reviewed-on: http://review.coreboot.org/9217 Reviewed-by: David Hendricks <dhendrix@chromium.org> Tested-by: build bot (Jenkins)
Diffstat (limited to 'src/ec/google/chromeec/Kconfig')
-rw-r--r--src/ec/google/chromeec/Kconfig7
1 files changed, 7 insertions, 0 deletions
diff --git a/src/ec/google/chromeec/Kconfig b/src/ec/google/chromeec/Kconfig
index bec12fb10..32a42133f 100644
--- a/src/ec/google/chromeec/Kconfig
+++ b/src/ec/google/chromeec/Kconfig
@@ -43,6 +43,13 @@ config EC_GOOGLE_CHROMEEC_SPI_BUS
depends on EC_GOOGLE_CHROMEEC_SPI
hex "SPI bus for Google's Chrome EC"
+config EC_GOOGLE_CHROMEEC_SPI_WAKEUP_DELAY_US
+ depends on EC_GOOGLE_CHROMEEC_SPI
+ int
+ default 0
+ help
+ Force delay after asserting /CS to allow EC to wakeup.
+
config EC_GOOGLE_CHROMEEC_SPI_CHIP
depends on EC_GOOGLE_CHROMEEC_SPI
hex