[PATCH] power: supply: max17040: handle missing status supplier

["jianing.li" <m13940358460@163.com>]

MAX17040 does not report charger state itself, so the driver forwards
POWER_SUPPLY_PROP_STATUS to a supplier power supply. If no supplier is
registered, power_supply_get_property_from_supplier() returns -ENODEV and
leaves the output value untouched.

max17040_get_property() currently ignores that error and returns success,
so userspace can read an uninitialized status value from the battery power
supply. This happens on systems that use the fuel gauge without a charger
supplier relationship in firmware.

Return POWER_SUPPLY_STATUS_UNKNOWN when no supplier provides STATUS, and
propagate other supplier lookup errors.

Fixes: f4b782af61ae ("power: max17040: pass status property from supplier")
Cc: stable@vger.kernel.org # 6.7+
Signed-off-by: jianing.li <m13940358460@163.com>
---
 drivers/power/supply/max17040_battery.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/max17040_battery.c b/drivers/power/supply/max17040_battery.c
index 60c38e822b52..bba6d91c9b9b 100644
--- a/drivers/power/supply/max17040_battery.c
+++ b/drivers/power/supply/max17040_battery.c
@@ -405,7 +405,11 @@ static int max17040_get_property(struct power_supply *psy,
 		val->intval = chip->low_soc_alert;
 		break;
 	case POWER_SUPPLY_PROP_STATUS:
-		power_supply_get_property_from_supplier(psy, psp, val);
+		ret = power_supply_get_property_from_supplier(psy, psp, val);
+		if (ret == -ENODEV)
+			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+		else if (ret)
+			return ret;
 		break;
 	case POWER_SUPPLY_PROP_TEMP:
 		if (!chip->channel_temp)
-- 
2.39.0