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

[Tim Douglas <me@timdoug.com>]

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>
---
 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 185f55d2f..9bfd8c9b7 100644
--- a/drivers/power/supply/generic-adc-battery.c
+++ b/drivers/power/supply/generic-adc-battery.c
@@ -130,7 +130,7 @@ static void gab_work(struct work_struct *work)
 	adc_bat = container_of(delayed_work, struct gab, bat_work);
 	status = adc_bat->status;
 
-	if (!power_supply_am_i_supplied(adc_bat->psy))
+	if (power_supply_am_i_supplied(adc_bat->psy) <= 0)
 		adc_bat->status =  POWER_SUPPLY_STATUS_DISCHARGING;
 	else if (gab_charge_finished(adc_bat))
 		adc_bat->status = POWER_SUPPLY_STATUS_NOT_CHARGING;

base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
-- 
2.54.0 (Apple Git-157)