power: supply: bq27xxx: Move energy 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 energy reading to match.

As energy 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/20240325203129.150030-4-afd@ti.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Author: glneo

drivers/power/supply/bq27xxx_battery.c

@@ -1639,7 +1639,8 @@ static int bq27xxx_battery_read_dcap(struct bq27xxx_device_info *di,
  * Return the battery Available energy in µWh
  * Or < 0 if something fails.
  */
-static int bq27xxx_battery_read_energy(struct bq27xxx_device_info *di)
+static int bq27xxx_battery_read_energy(struct bq27xxx_device_info *di,
+				       union power_supply_propval *val)
 {
 	int ae;
 
@@ -1654,7 +1655,9 @@ static int bq27xxx_battery_read_energy(struct bq27xxx_device_info *di)
 	else
 		ae *= 1000;
 
-	return ae;
+	val->intval = ae;
+
+	return 0;
 }
 
 /*
@@ -1867,8 +1870,6 @@ static void bq27xxx_battery_update_unlocked(struct bq27xxx_device_info *di)
 		cache.flags = -1; /* read error */
 	if (cache.flags >= 0) {
 		cache.capacity = bq27xxx_battery_read_soc(di);
-		if (di->regs[BQ27XXX_REG_AE] != INVALID_REG_ADDR)
-			cache.energy = bq27xxx_battery_read_energy(di);
 		di->cache.flags = cache.flags;
 		cache.health = bq27xxx_battery_read_health(di);
 		if (di->regs[BQ27XXX_REG_CYCT] != INVALID_REG_ADDR)
@@ -2084,7 +2085,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
 		ret = bq27xxx_simple_value(di->cache.cycle_count, val);
 		break;
 	case POWER_SUPPLY_PROP_ENERGY_NOW:
-		ret = bq27xxx_simple_value(di->cache.energy, val);
+		ret = bq27xxx_battery_read_energy(di, val);
 		break;
 	case POWER_SUPPLY_PROP_POWER_AVG:
 		ret = bq27xxx_battery_pwr_avg(di, val);

include/linux/power/bq27xxx_battery.h

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