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authorAaron Durbin <adurbin@chromium.org>2016-11-03 08:34:23 -0500
committerAaron Durbin <adurbin@chromium.org>2016-11-04 23:19:10 +0100
commit242cb3b601396a5178680f7731b8d5f9d257c646 (patch)
treecfe84021ad5268d1e768af6b57689783979a1af2 /src/mainboard/google
parent46575fb1d4f00e0d1e69e9ad38acb4c1e4b38711 (diff)
reef: tune tpm i2c frequency to 400kHz
This brings the frequency down to 400kHz which is spec for fast i2c. BUG=chrome-os-partner:58889 Change-Id: I8689a062b5457aa431eaa7fb688a7170dad83fcf Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/17214 Reviewed-by: Duncan Laurie <dlaurie@chromium.org> Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Diffstat (limited to 'src/mainboard/google')
-rw-r--r--src/mainboard/google/reef/variants/baseboard/devicetree.cb14
1 files changed, 12 insertions, 2 deletions
diff --git a/src/mainboard/google/reef/variants/baseboard/devicetree.cb b/src/mainboard/google/reef/variants/baseboard/devicetree.cb
index 30d61f63d4..559b0071be 100644
--- a/src/mainboard/google/reef/variants/baseboard/devicetree.cb
+++ b/src/mainboard/google/reef/variants/baseboard/devicetree.cb
@@ -71,8 +71,18 @@ chip soc/intel/apollolake
register "gpe0_dw2" = "PMC_GPE_N_63_32"
register "gpe0_dw3" = "PMC_GPE_SW_31_0"
- # Enable I2C2 bus early for TPM access
- register "i2c[2].early_init" = "1"
+ # Enable I2C2 bus early for TPM access and configure as 400kHz
+ # with manually tuned values.
+ register "i2c[2]" = "{
+ .early_init = 1,
+ .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"