From b7ec252d378deee1d07175c8fdc8d2302f7fbcef Mon Sep 17 00:00:00 2001 From: Philip Chen Date: Wed, 24 Jul 2019 14:35:44 -0700 Subject: [PATCH] mb/google/hatch: Fine-tune Kohaku I2C CLK frequency Add rise time / fall time to I2C config in device tree to ensure I2C CLK runs accurately at I2C_SPEED_FAST (400 kHz). BUG=b:138258384 BRANCH=none TEST=probe I2C0/I2C2/I2C3 SCL on Kohaku board, verify all of them run at 395-399 kHz. Change-Id: Id98079e717f0db3fdcb88f85e45693925d11d7fd Signed-off-by: Philip Chen Reviewed-on: https://review.coreboot.org/c/coreboot/+/34559 Reviewed-by: Tim Wawrzynczak Reviewed-by: Furquan Shaikh Reviewed-by: Paul Fagerburg Tested-by: build bot (Jenkins) --- src/mainboard/google/hatch/variants/kohaku/overridetree.cb | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/mainboard/google/hatch/variants/kohaku/overridetree.cb b/src/mainboard/google/hatch/variants/kohaku/overridetree.cb index fa64d60483..b3ae1bc240 100644 --- a/src/mainboard/google/hatch/variants/kohaku/overridetree.cb +++ b/src/mainboard/google/hatch/variants/kohaku/overridetree.cb @@ -32,15 +32,21 @@ chip soc/intel/cannonlake register "common_soc_config" = "{ .i2c[0] = { .speed = I2C_SPEED_FAST, + .rise_time_ns = 135, + .fall_time_ns = 45, }, .i2c[1] = { .speed = I2C_SPEED_FAST, }, .i2c[2] = { .speed = I2C_SPEED_FAST, + .rise_time_ns = 95, + .fall_time_ns = 55, }, .i2c[4] = { .speed = I2C_SPEED_FAST, + .rise_time_ns = 100, + .fall_time_ns = 20, }, .gspi[0] = { .speed_mhz = 1, -- 2.11.4.GIT