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

As charge state 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/20240325203129.150030-3-afd@ti.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Author: glneo

drivers/power/supply/bq27xxx_battery.c

@@ -1545,7 +1545,8 @@ static int bq27xxx_battery_read_soc(struct bq27xxx_device_info *di)
  * Return a battery charge value in µAh
  * Or < 0 if something fails.
  */
-static int bq27xxx_battery_read_charge(struct bq27xxx_device_info *di, u8 reg)
+static int bq27xxx_battery_read_charge(struct bq27xxx_device_info *di, u8 reg,
+				       union power_supply_propval *val)
 {
 	int charge;
 
@@ -1561,34 +1562,39 @@ static int bq27xxx_battery_read_charge(struct bq27xxx_device_info *di, u8 reg)
 	else
 		charge *= 1000;
 
-	return charge;
+	val->intval = charge;
+
+	return 0;
 }
 
 /*
  * Return the battery Nominal available capacity in µAh
  * Or < 0 if something fails.
  */
-static inline int bq27xxx_battery_read_nac(struct bq27xxx_device_info *di)
+static inline int bq27xxx_battery_read_nac(struct bq27xxx_device_info *di,
+					   union power_supply_propval *val)
 {
-	return bq27xxx_battery_read_charge(di, BQ27XXX_REG_NAC);
+	return bq27xxx_battery_read_charge(di, BQ27XXX_REG_NAC, val);
 }
 
 /*
  * Return the battery Remaining Capacity in µAh
  * Or < 0 if something fails.
  */
-static inline int bq27xxx_battery_read_rc(struct bq27xxx_device_info *di)
+static inline int bq27xxx_battery_read_rc(struct bq27xxx_device_info *di,
+					  union power_supply_propval *val)
 {
-	return bq27xxx_battery_read_charge(di, BQ27XXX_REG_RC);
+	return bq27xxx_battery_read_charge(di, BQ27XXX_REG_RC, val);
 }
 
 /*
  * Return the battery Full Charge Capacity in µAh
  * Or < 0 if something fails.
  */
-static inline int bq27xxx_battery_read_fcc(struct bq27xxx_device_info *di)
+static inline int bq27xxx_battery_read_fcc(struct bq27xxx_device_info *di,
+					   union power_supply_propval *val)
 {
-	return bq27xxx_battery_read_charge(di, BQ27XXX_REG_FCC);
+	return bq27xxx_battery_read_charge(di, BQ27XXX_REG_FCC, val);
 }
 
 /*
@@ -1860,7 +1866,6 @@ static void bq27xxx_battery_update_unlocked(struct bq27xxx_device_info *di)
 	if ((cache.flags & 0xff) == 0xff)
 		cache.flags = -1; /* read error */
 	if (cache.flags >= 0) {
-		cache.charge_full = bq27xxx_battery_read_fcc(di);
 		cache.capacity = bq27xxx_battery_read_soc(di);
 		if (di->regs[BQ27XXX_REG_AE] != INVALID_REG_ADDR)
 			cache.energy = bq27xxx_battery_read_energy(di);
@@ -2058,12 +2063,12 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_NOW:
 		if (di->regs[BQ27XXX_REG_NAC] != INVALID_REG_ADDR)
-			ret = bq27xxx_simple_value(bq27xxx_battery_read_nac(di), val);
+			ret = bq27xxx_battery_read_nac(di, val);
 		else
-			ret = bq27xxx_simple_value(bq27xxx_battery_read_rc(di), val);
+			ret = bq27xxx_battery_read_rc(di, val);
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_FULL:
-		ret = bq27xxx_simple_value(di->cache.charge_full, val);
+		ret = bq27xxx_battery_read_fcc(di, val);
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 		ret = bq27xxx_battery_read_dcap(di, val);

include/linux/power/bq27xxx_battery.h

@@ -47,7 +47,6 @@ struct bq27xxx_access_methods {
 };
 
 struct bq27xxx_reg_cache {
-	int charge_full;
 	int cycle_count;
 	int capacity;
 	int energy;