Re: [PATCH 2/3] thermal: qoriq_thermal: only enable supported sensors

[Daniel Lezcano]

On 31/05/2023 14:05, Peng Fan wrote:
> > Subject: Re: [PATCH 2/3] thermal: qoriq_thermal: only enable supported
> > sensors
> >
> > On 16/05/2023 10:37, Peng Fan (OSS) wrote:
> > > From: Peng Fan <peng.fan@xxxxxxx>
> > >
> > > There are MAX 16 sensors, but not all of them supported. Such as
> > > i.MX8MQ, there are only 3 sensors. Enabling all 16 sensors will touch
> > > reserved bits from i.MX8MQ reference mannual, and TMU will stuck,
> > > temperature will not update anymore.
> > >
> > > Fixes: 45038e03d633 ("thermal: qoriq: Enable all sensors before
> > > registering them")
> > > Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> > > ---
> > >    drivers/thermal/qoriq_thermal.c | 30 +++++++++++++++++++-----------
> > >    1 file changed, 19 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/drivers/thermal/qoriq_thermal.c
> > > b/drivers/thermal/qoriq_thermal.c index b806a0929459..53748c4a5be1
> > > 100644
> > > --- a/drivers/thermal/qoriq_thermal.c
> > > +++ b/drivers/thermal/qoriq_thermal.c
> > > @@ -31,7 +31,6 @@
> > >    #define TMR_DISABLE	0x0
> > >    #define TMR_ME		0x80000000
> > >    #define TMR_ALPF	0x0c000000
> > > -#define TMR_MSITE_ALL	GENMASK(15, 0)
> > >
> > >    #define REGS_TMTMIR	0x008	/* Temperature measurement
> > interval Register */
> > >    #define TMTMIR_DEFAULT	0x0000000f
> > > @@ -105,6 +104,11 @@ static int tmu_get_temp(struct
> > thermal_zone_device *tz, int *temp)
> > >    	 * within sensor range. TEMP is an 9 bit value representing
> > >    	 * temperature in KelVin.
> > >    	 */
> > > +
> > > +	regmap_read(qdata->regmap, REGS_TMR, &val);
> > > +	if (!(val & TMR_ME))
> > > +		return -EAGAIN;
> >
> > How is this change related to what is described in the changelog?
>
> devm_thermal_zone_of_sensor_register will invoke get temp,
> since we reverted the 45038e03d633 did, we need to check TMR_ME
> to avoid return invalid temperature.


From a higher perspective if the sensor won't be enabled, then the 
thermal zone should not be registered, the get_temp won't happen on a 
disabled sensor and this test won't be necessary, no ?

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