power: supply: bq27xxx: Move health reading out of update loop

Most of the functions that read values return a status and put the value
itself in an a function parameter. Update health reading to match.

As health is not checked for changes as part of the update loop, remove
the read of this from the periodic update loop. This saves I2C/1W
bandwidth. It also means we do not have to cache it, fresh values are
read when requested.
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240325203129.150030-6-afd@ti.comSigned-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/bq27xxx_battery.c

@@ -1777,19 +1777,26 @@ static bool bq27xxx_battery_capacity_inaccurate(struct bq27xxx_device_info *di,
 		return false;
 }
 
-static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
+static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di,
+				       union power_supply_propval *val)
 {
+	int health;
+
 	/* Unlikely but important to return first */
 	if (unlikely(bq27xxx_battery_overtemp(di, di->cache.flags)))
-		return POWER_SUPPLY_HEALTH_OVERHEAT;
-	if (unlikely(bq27xxx_battery_undertemp(di, di->cache.flags)))
-		return POWER_SUPPLY_HEALTH_COLD;
-	if (unlikely(bq27xxx_battery_dead(di, di->cache.flags)))
-		return POWER_SUPPLY_HEALTH_DEAD;
-	if (unlikely(bq27xxx_battery_capacity_inaccurate(di, di->cache.flags)))
-		return POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED;
-
-	return POWER_SUPPLY_HEALTH_GOOD;
+		health = POWER_SUPPLY_HEALTH_OVERHEAT;
+	else if (unlikely(bq27xxx_battery_undertemp(di, di->cache.flags)))
+		health = POWER_SUPPLY_HEALTH_COLD;
+	else if (unlikely(bq27xxx_battery_dead(di, di->cache.flags)))
+		health = POWER_SUPPLY_HEALTH_DEAD;
+	else if (unlikely(bq27xxx_battery_capacity_inaccurate(di, di->cache.flags)))
+		health = POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED;
+	else
+		health = POWER_SUPPLY_HEALTH_GOOD;
+
+	val->intval = health;
+
+	return 0;
 }
 
 static bool bq27xxx_battery_is_full(struct bq27xxx_device_info *di, int flags)
@@ -1874,7 +1881,6 @@ static void bq27xxx_battery_update_unlocked(struct bq27xxx_device_info *di)
 	if (cache.flags >= 0) {
 		cache.capacity = bq27xxx_battery_read_soc(di);
 		di->cache.flags = cache.flags;
-		cache.health = bq27xxx_battery_read_health(di);
 
 		/*
 		 * On gauges with signed current reporting the current must be
@@ -2092,7 +2098,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
 		ret = bq27xxx_battery_pwr_avg(di, val);
 		break;
 	case POWER_SUPPLY_PROP_HEALTH:
-		ret = bq27xxx_simple_value(di->cache.health, val);
+		ret = bq27xxx_battery_read_health(di, val);
 		break;
 	case POWER_SUPPLY_PROP_MANUFACTURER:
 		val->strval = BQ27XXX_MANUFACTURER;

include/linux/power/bq27xxx_battery.h

@@ -49,7 +49,6 @@ struct bq27xxx_access_methods {
 struct bq27xxx_reg_cache {
 	int capacity;
 	int flags;
-	int health;
 };
 
 struct bq27xxx_device_info {