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authorFurquan Shaikh <furquan@chromium.org>2016-11-09 10:35:23 -0800
committerFurquan Shaikh <furquan@google.com>2016-11-10 20:40:19 +0100
commitee019d016d1f1d61cbba3a4b8bdc897f209981bb (patch)
treebe19fc9e0a31847d96be7a59c21315b7e2da60e5 /src/mainboard/google/reef/variants
parent73edd2b7c07fb8ad5455086f126c079734a904b7 (diff)
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 <furquan@chromium.org> Reviewed-on: https://review.coreboot.org/17342 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'src/mainboard/google/reef/variants')
-rw-r--r--src/mainboard/google/reef/variants/baseboard/devicetree.cb11
1 files changed, 11 insertions, 0 deletions
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"