[coreboot-gerrit] New patch to review for coreboot: mainboard/google/snappy: Tune i2c frequency to 400 Khz
Wisley Chen (wisley.chen@quantatw.com)
gerrit at coreboot.org
Tue Nov 29 04:58:27 CET 2016
Wisley Chen (wisley.chen at 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 at 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 at 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"
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