Re: [PATCH v8 5/5] thermal: mediatek: try again if first temp read is bogus

[Amjad Ouled-Ameur]

Hi Daniel,

On 1/25/23 11:58, Daniel Lezcano wrote:
> On 25/01/2023 10:50, Amjad Ouled-Ameur wrote:
> > In mtk_thermal_bank_temperature, return -EAGAIN instead of 0
> > on the first read of sensor that often are bogus values.
> >
> > Signed-off-by: Michael Kao <michael.kao@xxxxxxxxxxxx>
> > Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> > Signed-off-by: Amjad Ouled-Ameur <aouledameur@xxxxxxxxxxxx>
> > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> > ---
> >   drivers/thermal/mtk_thermal.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/thermal/mtk_thermal.c b/drivers/thermal/mtk_thermal.c
> > index b8e06f6c7c42..e7be450cd40a 100644
> > --- a/drivers/thermal/mtk_thermal.c
> > +++ b/drivers/thermal/mtk_thermal.c
> > @@ -736,7 +736,7 @@ static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
> >            * not immediately shut down.
> >            */
> >           if (temp > 200000)
> > -            temp = 0;
> > +            temp = -EAGAIN;
>
> Did you try to add a delay between the bank init and the thermal zone device register (eg. 1ms) ?
>
> May be the HW did not have time to initialize and capture a temperature before thermal_zone_device_register() is called (this one calls get_temp) ?

A delay of 29 ms actually fixed the issue, thanks for the suggestion. I can send a V9 with this improvement.

Is there anything else to fix perhaps ?


Regards,

Amjad

> >           if (temp > max)
> >               max = temp;