Add POWER_SUPPLY_HEALTH_UNDERVOLTAGE status for power supply
to report under voltage lockout failures.

Signed-off-by: Dzmitry Sankouski <dsankouski@gmail.com>
---
Changes for v5:
- update Documentation/ABI/testing/sysfs-class-power and
  drivers/power/supply/power_supply_sysfs.c
---
 Documentation/ABI/testing/sysfs-class-power | 2 +-
 drivers/power/supply/power_supply_sysfs.c   | 1 +
 include/linux/power_supply.h                | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-class-power b/Documentation/ABI/testing/sysfs-class-power
index 45180b62d426..32c018c5d088 100644
--- a/Documentation/ABI/testing/sysfs-class-power
+++ b/Documentation/ABI/testing/sysfs-class-power
@@ -433,7 +433,7 @@ Description:
 
 		Valid values:
 			      "Unknown", "Good", "Overheat", "Dead",
-			      "Over voltage", "Unspecified failure", "Cold",
+			      "Over voltage", "Under voltage", "Unspecified failure", "Cold",
 			      "Watchdog timer expire", "Safety timer expire",
 			      "Over current", "Calibration required", "Warm",
 			      "Cool", "Hot", "No battery"
diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index 16b3c5880cd8..82b2275de465 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -99,6 +99,7 @@ static const char * const POWER_SUPPLY_HEALTH_TEXT[] = {
 	[POWER_SUPPLY_HEALTH_OVERHEAT]		    = "Overheat",
 	[POWER_SUPPLY_HEALTH_DEAD]		    = "Dead",
 	[POWER_SUPPLY_HEALTH_OVERVOLTAGE]	    = "Over voltage",
+	[POWER_SUPPLY_HEALTH_UNDERVOLTAGE]	    = "Under voltage",
 	[POWER_SUPPLY_HEALTH_UNSPEC_FAILURE]	    = "Unspecified failure",
 	[POWER_SUPPLY_HEALTH_COLD]		    = "Cold",
 	[POWER_SUPPLY_HEALTH_WATCHDOG_TIMER_EXPIRE] = "Watchdog timer expire",
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 910d407ebe63..8682e6466544 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -58,6 +58,7 @@ enum {
 	POWER_SUPPLY_HEALTH_OVERHEAT,
 	POWER_SUPPLY_HEALTH_DEAD,
 	POWER_SUPPLY_HEALTH_OVERVOLTAGE,
+	POWER_SUPPLY_HEALTH_UNDERVOLTAGE,
 	POWER_SUPPLY_HEALTH_UNSPEC_FAILURE,
 	POWER_SUPPLY_HEALTH_COLD,
 	POWER_SUPPLY_HEALTH_WATCHDOG_TIMER_EXPIRE,

-- 
2.39.2