servo_v4: Added support for HW board ID and limit on VBUS voltage
The first two versions of servo_v4 (red and blue) have the TPD2E001
ESD between VBUS and CC1/CC2. This part has a breakdown min voltage of
11V. Therefore for these versions of servo_v4, need to limit VBUS to
less than the default 20V value.
This CL adds support to read two board ID gpios attached to the gpio
expansion part. The max VBUS voltage is limited to 9V for red/blue and
allowed to be 20V for black.
BUG=b:38351574
BRANCH=servo_v4
TEST=Manual
Modified a servo_v4 to add the 2 new pullup resistors. Tested with
this unit and with a unit that does not have the pullups. Verified
that without the pullups the version ID reads a 0 and the max VBUS
voltage that will be requested by the CHG port is 9V. Wih the modified
servo_v4, verified that the version reads 3 and the CHG port will
request up to 20V.
Change-Id: Ic41fcbe3a5c000282552c7322b5ab18ebb203cd2
Signed-off-by: Scott Collyer <scollyer@google.com>
Reviewed-on: https://chromium-review.googlesource.com/507027
Commit-Ready: Scott Collyer <scollyer@chromium.org>
Tested-by: Scott Collyer <scollyer@chromium.org>
Reviewed-by: Nick Sanders <nsanders@chromium.org>
2 files changed
