power: supply: core: add POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED

Some battery fuel gauges know when the battery needs to
be recalibrated before providing usable values. This
should be reported via the health property.

Signed-off-by: Sebastian Reichel <[e-mail]>

Documentation/ABI/testing/sysfs-class-power

···
 		Valid values: "Unknown", "Good", "Overheat", "Dead",
 			      "Over voltage", "Unspecified failure", "Cold",
 			      "Watchdog timer expire", "Safety timer expire",
-			      "Over current"
+			      "Over current", "Calibration required"
 
 What:		/sys/class/power_supply/<supply_name>/precharge_current
 Date:		June 2017

drivers/power/supply/power_supply_sysfs.c

···
 	[POWER_SUPPLY_HEALTH_WATCHDOG_TIMER_EXPIRE] = "Watchdog timer expire",
 	[POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE]   = "Safety timer expire",
 	[POWER_SUPPLY_HEALTH_OVERCURRENT]	    = "Over current",
+	[POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED]  = "Calibration required",
 };
 
 static const char * const POWER_SUPPLY_TECHNOLOGY_TEXT[] = {

include/linux/power_supply.h

···
 	POWER_SUPPLY_HEALTH_WATCHDOG_TIMER_EXPIRE,
 	POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE,
 	POWER_SUPPLY_HEALTH_OVERCURRENT,
+	POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED,
 };
 
 enum {