power: supply: add undervoltage health status property

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

Signed-off-by: Dzmitry Sankouski <[email protected]>
Link: https://lore.kernel.org/r/20250108-starqltechn_integration_upstream-v14-1-f6e84ec20d96@gmail.com
Signed-off-by: Sebastian Reichel <[email protected]>

Author: Dzmitry Sankouski

Documentation/ABI/testing/sysfs-class-power

@@ -453,7 +453,7 @@ 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"

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",

include/linux/power_supply.h

@@ -60,6 +60,7 @@ 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,