From 2fb5ca81d9b15d956949907c83e61c97d958992e Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Fri, 31 Mar 2017 14:51:40 -0500 Subject: [PATCH] mainboard/google/reef: increase trackpad data hold time Even though the i2c spec has no minimum data hold time in fast mode the trackpad vendor indicates 300ns is their minimum. However, the topology of the board uses FET isolation to cross voltage domains. Therefore, the default 300ns which should work isn't reflected on the device side of the voltage isolation circuit. Therefore, increase the data hold time to show an observed data hold time of more than 300ns on the device side. BUG=b:36469182 Change-Id: I1b70f2f53c5a29cc7cfd5035a71ca5811b3bcba0 Signed-off-by: Aaron Durbin Reviewed-on: https://review.coreboot.org/19065 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel Reviewed-by: Furquan Shaikh --- src/mainboard/google/reef/variants/baseboard/devicetree.cb | 1 + 1 file changed, 1 insertion(+) diff --git a/src/mainboard/google/reef/variants/baseboard/devicetree.cb b/src/mainboard/google/reef/variants/baseboard/devicetree.cb index 443918e037..d5f546c99b 100644 --- a/src/mainboard/google/reef/variants/baseboard/devicetree.cb +++ b/src/mainboard/google/reef/variants/baseboard/devicetree.cb @@ -103,6 +103,7 @@ chip soc/intel/apollolake .speed = I2C_SPEED_FAST, .rise_time_ns = 114, .fall_time_ns = 164, + .data_hold_time_ns = 350, }" # digitizer at 400kHz