Tim Chen (Tim-Chen@quantatw.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/18284
-gerrit
commit 8fca0ab3999413daeadb990aca4cb5fcad41b366 Author: Tim Chen Tim-Chen@quantatw.com Date: Fri Feb 3 16:57:39 2017 +0800
mainboard/google/reef: Tune i2c frequency to under 400 Khz
tune i2c devices clk for reef: I2C0: audio I2C2: TPM H1 I2C4: elan touchpad
BUG=chrome-os-partner:62593 BRANCH=master TEST=emerge-reef coreboot chromeos-bootimage, and measured on EVT. audio: Freq. 393.1kHz TPM H1: Freq. 369.5kHz elan touchpad: Freq. 397.0kHz
Change-Id: If27b7a1333d5f1e14c850a0dfb3c6eb90f0072fc --- src/mainboard/google/reef/variants/baseboard/devicetree.cb | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/src/mainboard/google/reef/variants/baseboard/devicetree.cb b/src/mainboard/google/reef/variants/baseboard/devicetree.cb index 2ccf277..e40bfee 100644 --- a/src/mainboard/google/reef/variants/baseboard/devicetree.cb +++ b/src/mainboard/google/reef/variants/baseboard/devicetree.cb @@ -76,16 +76,16 @@ chip soc/intel/apollolake # Enable I2C0 for audio codec at 400kHz register "i2c[0]" = "{ .speed = I2C_SPEED_FAST, - .rise_time_ns = 104, - .fall_time_ns = 52, + .rise_time_ns = 44, + .fall_time_ns = 22, }"
# Enable I2C2 bus early for TPM at 400kHz register "i2c[2]" = "{ .early_init = 1, .speed = I2C_SPEED_FAST, - .rise_time_ns = 57, - .fall_time_ns = 28, + .rise_time_ns = 30, + .fall_time_ns = 15, }"
# touchscreen at 400kHz @@ -98,8 +98,8 @@ chip soc/intel/apollolake # trackpad at 400kHz register "i2c[4]" = "{ .speed = I2C_SPEED_FAST, - .rise_time_ns = 114, - .fall_time_ns = 164, + .rise_time_ns = 57, + .fall_time_ns = 82, }"
# digitizer at 400kHz