the following patch was just integrated into master: commit a859aa3df5c56f7d0d2d0969c4de601b93e4c101 Author: Ken Chang kenc@nvidia.com Date: Thu May 22 10:54:16 2014 +0800
nyan*: Set GEN2 I2C pads to open-drain mode
The VDDIO to GEN2 I2C SCL/SDA pins is 1.8V and the external pull-up voltage is 3.3V (the external 3.3V > I/O 1.8V) thus the pinmux E_OD bit of these two pins needs to be set to ensure GEN2 I2C pads work fine on 3.3V.
BRANCH=nyan BUG=none TEST=observed voltage drop from 3.3V to 2.36V on gen2 i2c on blaze w/o this change. the waveform looks good on both scl/sda pins w/ this change.
Original-Change-Id: I1b97f0c9c7580d1e532c3bdf7ac8690241ee7ee3 Original-Signed-off-by: Ken Chang kenc@nvidia.com Original-Reviewed-on: https://chromium-review.googlesource.com/200996 Original-Reviewed-by: Julius Werner jwerner@chromium.org (cherry picked from commit 2db39166ec525e56a19746f38a867305a2687365) Signed-off-by: Marc Jones marc.jones@se-eng.com
Change-Id: I0c84eade89311baf0a6f180cb5cc9e2145f6b7ea Reviewed-on: http://review.coreboot.org/7952 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel paulepanter@users.sourceforge.net Reviewed-by: Kyösti Mälkki kyosti.malkki@gmail.com
See http://review.coreboot.org/7952 for details.
-gerrit