[coreboot-gerrit] New patch to review for coreboot: reef: tune trackpad i2c frequency to 400kHz

[Aaron Durbin (adurbin@chromium.org)]

Aaron Durbin (adurbin at chromium.org) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17215

-gerrit

commit 544cbd8304009d6d2988b2053fda5be70a78464c
Author: Aaron Durbin <adurbin at chromium.org>
Date:   Thu Nov 3 13:34:13 2016 -0500

    reef: tune trackpad i2c frequency to 400kHz
    
    This brings the frequency down to 400kHz which is spec for
    fast i2c.
    
    BUG=chrome-os-partner:58889
    
    Change-Id: Ibc5f152e55ed618f18ac6425264f086b1f2d1ffa
    Signed-off-by: Aaron Durbin <adurbin at chromium.org>
---
 src/mainboard/google/reef/variants/baseboard/devicetree.cb | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/mainboard/google/reef/variants/baseboard/devicetree.cb b/src/mainboard/google/reef/variants/baseboard/devicetree.cb
index 559b007..5aa1d32 100644
--- a/src/mainboard/google/reef/variants/baseboard/devicetree.cb
+++ b/src/mainboard/google/reef/variants/baseboard/devicetree.cb
@@ -84,6 +84,17 @@ chip soc/intel/apollolake
 		}
 	}"
 
+	# Limit trackpad speed to 400kHz with manually tuned values.
+	register "i2c[4]" = "{
+		.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"