diff options
| author | Wisley Chen <wisley.chen@quantatw.com> | 2016-11-27 16:56:30 +0800 |
|---|---|---|
| committer | Martin Roth <martinroth@google.com> | 2016-11-30 16:53:02 +0100 |
| commit | 1612cef81f20cb955d591f3cebcf864d784856ac (patch) | |
| tree | 7cd5c7153f568f4ed0f67d18dfc85097d4bae189 | |
| parent | 96e9ff168ca52f3bb06606b65fb07ba5e4e7bb50 (diff) | |
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>
Reviewed-on: https://review.coreboot.org/17634
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
| -rw-r--r-- | src/mainboard/google/reef/variants/snappy/devicetree.cb | 37 |
1 files 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 b024682aae..e46483e3b0 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" |