[PATCH 5.10.y] power: supply: generic-adc-battery: fix status with no supplier

[Sasha Levin <sashal@kernel.org>]

From: Tim Douglas <me@timdoug.com>

[ Upstream commit 8ae5a3f40045ff486826ed6b6a83e39a0f380073 ]

power_supply_am_i_supplied() returns -ENODEV when no registered power
supply supplies the battery. generic-adc-battery's gab_work() tests this
return value as a boolean, so -ENODEV takes the supplied branch and
reports CHARGING, or NOT_CHARGING if the charge-finished GPIO is asserted,
instead of DISCHARGING.

This was noticed while bringing up an out-of-tree Linux port to the
WikiReader: the driver reported CHARGING on a device powered by two AAA
batteries with no charging hardware.

Only a positive return value indicates an online supplier, so treat zero
and negative returns as discharging.

Fixes: 46cecd130d55 ("power: supply: Fix power_supply_am_i_supplied to return -ENODEV when apropriate")
Cc: stable@vger.kernel.org
Signed-off-by: Tim Douglas <me@timdoug.com>
Link: https://patch.msgid.link/20261013022153.6707-1-me@timdoug.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
[ sashal: Adapted the direct supplier check to a > 0 comparison in the existing is_plugged assignment. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/power/supply/generic-adc-battery.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/supply/generic-adc-battery.c b/drivers/power/supply/generic-adc-battery.c
index 09bb4ff291cb0..8bf37e06e3f62 100644
--- a/drivers/power/supply/generic-adc-battery.c
+++ b/drivers/power/supply/generic-adc-battery.c
@@ -212,7 +212,7 @@ static void gab_work(struct work_struct *work)
 	adc_bat = container_of(delayed_work, struct gab, bat_work);
 	status = adc_bat->status;
 
-	is_plugged = power_supply_am_i_supplied(adc_bat->psy);
+	is_plugged = power_supply_am_i_supplied(adc_bat->psy) > 0;
 	adc_bat->cable_plugged = is_plugged;
 
 	if (!is_plugged)
-- 
2.53.0