hdctools: servo: Add battery support for daisy overlay

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BUG=chrome-os-partner:11745
TEST=dut-control ppvar_vbat_ma ppvar_vbat_mv ppvar_vbat_mw

Change-Id: Ie30d1fb3f366416b1ba819d2eca4fc0b56d17910
Reviewed-on: https://gerrit.chromium.org/gerrit/28386
Reviewed-by: Tom Wai-Hong Tam <waihong@chromium.org>
Commit-Ready: Vic Yang <victoryang@chromium.org>
Tested-by: Vic Yang <victoryang@chromium.org>
diff --git a/servo/data/servo_daisy_overlay.xml b/servo/data/servo_daisy_overlay.xml
index f17400e..64ff39c 100644
--- a/servo/data/servo_daisy_overlay.xml
+++ b/servo/data/servo_daisy_overlay.xml
@@ -31,4 +31,24 @@
     <params subtype="kbd_m2_a1" interface="7" drv="ec" map="onoff"
     clobber_ok=""></params>
   </control>
+  <control>
+    <name>ppvar_vbat_ma</name>
+    <doc>milliamps being consumed (discharging/positive) or
+    supplied (charging/negative) to the battery</doc>
+    <params cmd="get" subtype="milliamps" interface="7" drv="ec"
+    clobber_ok=""></params>
+  </control>
+  <control>
+    <name>ppvar_vbat_mv</name>
+    <doc>millivolts of the battery</doc>
+    <params cmd="get" subtype="millivolts" interface="7" drv="ec"
+    clobber_ok=""></params>
+  </control>
+  <control>
+    <name>ppvar_vbat_mw</name>
+    <doc>milliwatts being consumed (discharging) or supplied
+    (charging) to the battery</doc>
+    <params cmd="get" subtype="milliwatts" interface="7" drv="ec"
+    clobber_ok=""></params>
+  </control>
 </root>