From ee019d016d1f1d61cbba3a4b8bdc897f209981bb Mon Sep 17 00:00:00 2001 From: Furquan Shaikh Date: Wed, 9 Nov 2016 10:35:23 -0800 Subject: mainboard/google/reef: Tune digitizer I2C frequency to 400kHz This brings the I2C frequency down to 400kHz which is spec for fast I2C. BUG=chrome-os-partner:56246 BRANCH=None TEST=Verified frequency in kernel. Change-Id: Ib83c57eec8644903cb9c4b2ab50c94038eb690c1 Signed-off-by: Furquan Shaikh Reviewed-on: https://review.coreboot.org/17342 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin --- src/mainboard/google/reef/variants/baseboard/devicetree.cb | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'src/mainboard') diff --git a/src/mainboard/google/reef/variants/baseboard/devicetree.cb b/src/mainboard/google/reef/variants/baseboard/devicetree.cb index 5aa1d32ec2..6c8cd8f20d 100644 --- a/src/mainboard/google/reef/variants/baseboard/devicetree.cb +++ b/src/mainboard/google/reef/variants/baseboard/devicetree.cb @@ -95,6 +95,17 @@ chip soc/intel/apollolake } }" + # Limit digitizer speed to 400kHz with manually tuned values. + register "i2c[5]" = "{ + .speed = I2C_SPEED_FAST, + .speed_config[0] = { + .speed = I2C_SPEED_FAST, + .scl_lcnt = 0xd0, + .scl_hcnt = 0x68, + .sda_hold = 0x27, + } + }" + # Minimum SLP S3 assertion width 28ms. register "slp_s3_assertion_width_usecs" = "28000" -- cgit v1.2.3