Most systems don't have a lightbar. Those that do need a way to detect that
one exists. That's easily done by just sending a EC_CMD_LIGHTBAR_CMD command
to the EC and checking the result. If the response is
EC_RES_INVALID_COMMAND, there isn't a lightbar.
But what .cmd value should we use in struct ec_params_lightbar? Future
lightbar implementations (if any), could remove existing functions or add
new ones, so there isn't a safe choice.
This change adds a LIGHTBAR_CMD_VERSION operation to determine if any new
implementation exists. Future systems should return some useful information
in response to this command. Existing systems will return
EC_RES_INVALID_PARAM, which is enough to distinguish them.
BUG=chromium:239205
BRANCH=none
TEST=manual
make BOARD=link
make BOARD=link runtests
There are no user-visible changes in functionality to anything.
Change-Id: Ibe37f74a4dcbf68dd6bfd1963530aec907e67534
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/167549
Reviewed-by: Randall Spangler <rspangler@chromium.org>
32045efb23