the following patch was just integrated into master: commit 573429b09dafa94dac4e1c2b0d9ed33d64676963 Author: Ben Zhang benzh@chromium.org Date: Mon Nov 17 17:21:09 2014 -0800
samus: Set codec PDM clock output to 3MHz
Currently the rt5677 codec outputs 6MHz PDM clock which is out-of-spec for the speaker amp SSM2537. The amp's GAIN_FS pin is pulled down to PGND with a 47k resistor, so the expected PDM clock is 64*FS (~3MHz) according to its datasheet.
The corresponding kernel patch that adds the PDM clock config option is https://chromium-review.googlesource.com/#/c/230303/
BUG=chrome-os-partner:33303 BRANCH=samus TEST=flash coreboot with this patch and see PDM CLK went from 6MHz to 3MHz on samus with a scope.
Change-Id: Icf2c61930175bede1ee8ebc2b0fb17c2938b806c Signed-off-by: Stefan Reinauer reinauer@chromium.org Original-Commit-Id: b9ba4597515b2fbcc72fa22e296357c454175648 Original-Change-Id: I09acdf47bab4f641981491a84197de234918435e Original-Signed-off-by: Ben Zhang benzh@chromium.org Original-Reviewed-on: https://chromium-review.googlesource.com/230344 Original-Reviewed-by: Dylan Reid dgreid@chromium.org Original-Reviewed-by: Duncan Laurie dlaurie@chromium.org Reviewed-on: http://review.coreboot.org/9277 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi pgeorgi@google.com
See http://review.coreboot.org/9277 for details.
-gerrit