Wisley Chen (wisley.chen@quantatw.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17634
-gerrit
commit 8d4f27af90d3aaffc5a677ec50b6eef12393d2ed Author: Wisley Chen wisley.chen@quantatw.com Date: Sun Nov 27 16:56:30 2016 +0800
mainboard/google/snappy: Tune i2c frequency to 400 Khz
tune i2c devices clk for snappy: I2C0: audio I2C2: TPM H1 I2C3: elan touchscreen I2C4: elan touchpad I2C5: wacom digitizer
BUG=chrome-os-partner:59034 BRANCH=master TEST=emerge-snappy coreboot chromeos-bootimage, and measured on EVT. audio: Freq. 393.7kHz Rise Time 58.8ns Fall time 12.11ns TPM H1: Freq. 398.8kHz Rise Time 31.71ns Fall time 13.28ns elan touchscreen: Freq. 390.5kHz Rise Time 235.7ns Fall time 37.64ns elan touchpad: Freq. 393.7kHz Rise Time 288.8ns Fall time 51.67ns wacom digitizer: Freq. 388.8kHz Rise Time 124.1ns Fall time 21.10ns
Change-Id: Ib2be9e1575d4962476423eafa80f9bb10ba40e17 Signed-off-by: Wisley Chen wisley.chen@quantatw.com --- .../google/reef/variants/snappy/devicetree.cb | 37 ++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-)
diff --git a/src/mainboard/google/reef/variants/snappy/devicetree.cb b/src/mainboard/google/reef/variants/snappy/devicetree.cb index 00df9bd..91e2e96 100644 --- a/src/mainboard/google/reef/variants/snappy/devicetree.cb +++ b/src/mainboard/google/reef/variants/snappy/devicetree.cb @@ -71,8 +71,41 @@ chip soc/intel/apollolake register "gpe0_dw2" = "PMC_GPE_N_63_32" register "gpe0_dw3" = "PMC_GPE_SW_31_0"
- # Enable I2C2 bus early for TPM access - register "i2c[2].early_init" = "1" + # Enable I2C0 for audio codec at 400kHz + register "i2c[0]" = "{ + .speed = I2C_SPEED_FAST, + .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 = 40, + .fall_time_ns = 20, + }" + + # touchscreen at 400kHz + register "i2c[3]" = "{ + .speed = I2C_SPEED_FAST, + .rise_time_ns = 70, + .fall_time_ns = 164, + }" + + # trackpad at 400kHz + register "i2c[4]" = "{ + .speed = I2C_SPEED_FAST, + .rise_time_ns = 20, + .fall_time_ns = 164, + }" + + # digitizer at 400kHz + register "i2c[5]" = "{ + .speed = I2C_SPEED_FAST, + .rise_time_ns = 152, + .fall_time_ns = 30, + }"
# Minimum SLP S3 assertion width 28ms. register "slp_s3_assertion_width_usecs" = "28000"