google/scarlet: Adjust K&D power sequence from software

Hardware updates have suggested we need to configure the K&D panel's
power sequence in software, not in hardware. Without this change, K&D
panels will no longer power on correctly and will instead display a
black screen.

Per K&D's suggestion, we tweak these two commands. From the little HW
docs I have, this looks like it's:

(Address 0xB7, Value 0x02) -> set BC_CTRL=bit(1) (Back light control) to
(Address 0xF1, Value 0x22) -> change GPO2_SEL=bits(0:3) from
                              MIPI_TE(0001b) to BC_CTRL (0010b)

TEST=KD display with and without HW fix on Scarlet

Change-Id: Ia076a378b10417dd9891746f9bc1086360a0f6e6
Signed-off-by: Brian Norris <>
Reviewed-by: Patrick Georgi <>
Reviewed-by: Matthias Kaehlcke <>
Reviewed-by: Julius Werner <>
Tested-by: build bot (Jenkins) <>
1 file changed