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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>
This commit is contained in:
Furquan Shaikh 2016-11-09 10:35:23 -08:00 committed by Furquan Shaikh
parent 73edd2b7c0
commit ee019d016d
1 changed files with 11 additions and 0 deletions
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11
src/mainboard/google/reef/variants/baseboard/devicetree.cb
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@ -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"