[PATCH v2 1/2] hwmon: (gpd-fan) Reset both fans to automatic on duo boards

[Alexei Solcanu via B4 Relay]

From: Alexei Solcanu <alexei.solcanu@xxxxx>

On boards using gpd_duo_drvdata (GPD Duo, GPD Win 5), writing
pwm1_enable=2 only returns the first fan to EC control. The second fan
keeps its last manual duty cycle, e.g. full speed after pwm1=255, so a
fan control tool that exits leaves it running at that speed.

gpd_duo_write_pwm() writes both fan registers (pwm_write and
pwm_write + 1), but switching to automatic only clears pwm_write.
Also clear pwm_write + 1, so both fans return to EC control.

Tested on a GPD Win 5 (G1618-05). Not tested on the GPD Duo.

Fixes: 0ab88e239439 ("hwmon: add GPD devices sensor driver")
Assisted-by: LLM
Signed-off-by: Alexei Solcanu <alexei.solcanu@xxxxx>
---
 drivers/hwmon/gpd-fan.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/hwmon/gpd-fan.c b/drivers/hwmon/gpd-fan.c
index ed212615b2f..b3b75f99f58 100644
--- a/drivers/hwmon/gpd-fan.c
+++ b/drivers/hwmon/gpd-fan.c
@@ -444,6 +444,7 @@ static void gpd_duo_set_pwm_enable(struct gpd_fan_data *data, enum FAN_PWM_ENABL
 		break;
 	case AUTOMATIC:
 		gpd_ecram_write(data->drvdata, data->drvdata->pwm_write, 0);
+		gpd_ecram_write(data->drvdata, data->drvdata->pwm_write + 1, 0);
 		break;
 	}
 }

-- 
2.55.0