power: supply: bq27xxx: expose battery data when CI=1

When the Capacity Inaccurate flag is set, the chip still provides data
about the battery, albeit inaccurate. Instead of discarding capacity
values for CI=1, expose the stale data and use the
POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED property to indicate that the
values should be used with care.
Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Sicelo A. Mhlongo <absicsz@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/bq27xxx_battery.c

@@ -1572,14 +1572,6 @@ static int bq27xxx_battery_read_charge(struct bq27xxx_device_info *di, u8 reg)
  */
 static inline int bq27xxx_battery_read_nac(struct bq27xxx_device_info *di)
 {
-	int flags;
-
-	if (di->opts & BQ27XXX_O_ZERO) {
-		flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, true);
-		if (flags >= 0 && (flags & BQ27000_FLAG_CI))
-			return -ENODATA;
-	}
-
 	return bq27xxx_battery_read_charge(di, BQ27XXX_REG_NAC);
 }
 
@@ -1742,6 +1734,18 @@ static bool bq27xxx_battery_dead(struct bq27xxx_device_info *di, u16 flags)
 		return flags & (BQ27XXX_FLAG_SOC1 | BQ27XXX_FLAG_SOCF);
 }
 
+/*
+ * Returns true if reported battery capacity is inaccurate
+ */
+static bool bq27xxx_battery_capacity_inaccurate(struct bq27xxx_device_info *di,
+						 u16 flags)
+{
+	if (di->opts & BQ27XXX_O_HAS_CI)
+		return (flags & BQ27000_FLAG_CI);
+	else
+		return false;
+}
+
 static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
 {
 	/* Unlikely but important to return first */
@@ -1751,6 +1755,8 @@ static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
 		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;
 }
@@ -1758,7 +1764,6 @@ static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
 void bq27xxx_battery_update(struct bq27xxx_device_info *di)
 {
 	struct bq27xxx_reg_cache cache = {0, };
-	bool has_ci_flag = di->opts & BQ27XXX_O_HAS_CI;
 	bool has_singe_flag = di->opts & BQ27XXX_O_ZERO;
 
 	cache.flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, has_singe_flag);
@@ -1766,30 +1771,19 @@ void bq27xxx_battery_update(struct bq27xxx_device_info *di)
 		cache.flags = -1; /* read error */
 	if (cache.flags >= 0) {
 		cache.temperature = bq27xxx_battery_read_temperature(di);
-		if (has_ci_flag && (cache.flags & BQ27000_FLAG_CI)) {
-			dev_info_once(di->dev, "battery is not calibrated! ignoring capacity values\n");
-			cache.capacity = -ENODATA;
-			cache.energy = -ENODATA;
-			cache.time_to_empty = -ENODATA;
-			cache.time_to_empty_avg = -ENODATA;
-			cache.time_to_full = -ENODATA;
-			cache.charge_full = -ENODATA;
-			cache.health = -ENODATA;
-		} else {
-			if (di->regs[BQ27XXX_REG_TTE] != INVALID_REG_ADDR)
-				cache.time_to_empty = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTE);
-			if (di->regs[BQ27XXX_REG_TTECP] != INVALID_REG_ADDR)
-				cache.time_to_empty_avg = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTECP);
-			if (di->regs[BQ27XXX_REG_TTF] != INVALID_REG_ADDR)
-				cache.time_to_full = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTF);
-
-			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);
-			di->cache.flags = cache.flags;
-			cache.health = bq27xxx_battery_read_health(di);
-		}
+		if (di->regs[BQ27XXX_REG_TTE] != INVALID_REG_ADDR)
+			cache.time_to_empty = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTE);
+		if (di->regs[BQ27XXX_REG_TTECP] != INVALID_REG_ADDR)
+			cache.time_to_empty_avg = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTECP);
+		if (di->regs[BQ27XXX_REG_TTF] != INVALID_REG_ADDR)
+			cache.time_to_full = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTF);
+
+		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);
+		di->cache.flags = cache.flags;
+		cache.health = bq27xxx_battery_read_health(di);
 		if (di->regs[BQ27XXX_REG_CYCT] != INVALID_REG_ADDR)
 			cache.cycle_count = bq27xxx_battery_read_cyct(di);