chromeec: Add support for reading second battery info

We share the same shared memory fields for both batteries. When
the host wants to switch battery to read out, it will:
 - Set BTID (EC_ACPI_MEM_BATTERY_INDEX) to the required index
 - Wait for BITX (EC_MEMMAP_BATT_INDEX) to have the required value
 - Then fetch the data

BRANCH=none
BUG=b:65697620
TEST=Boot lux, both /sys/class/power_supply/BAT0 and BAT1 are
     present, data is valid.

Change-Id: Ib06176e6ab4c45a899259f0917e6292121865ed6
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-on: https://review.coreboot.org/23598
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

0 files changed, 0 insertions, 0 deletions