On Wed, Nov 1, 2023 at 1:59 PM Conor Dooley <conor@xxxxxxxxxx> wrote:
>
> On Wed, Nov 01, 2023 at 07:38:39AM +0600, Binbin Zhou wrote:
> > On Tue, Oct 31, 2023 at 10:58 PM Conor Dooley <conor@xxxxxxxxxx> wrote:
> > >
> > > On Tue, Oct 31, 2023 at 07:05:49PM +0800, Binbin Zhou wrote:
> > > > Add the missing 'thermal-sensor-cells' property which is required for
> > > > every thermal sensor as it's used when using phandles.
> > > > And add the thermal-sensor.yaml reference.
> > > >
> > > > Fixes: 72684d99a854 ("thermal: dt-bindings: add loongson-2 thermal")
> > > > Signed-off-by: Binbin Zhou <zhoubinbin@xxxxxxxxxxx>
> > > > ---
> > > > .../bindings/thermal/loongson,ls2k-thermal.yaml | 10 +++++++++-
> > > > 1 file changed, 9 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/thermal/loongson,ls2k-thermal.yaml b/Documentation/devicetree/bindings/thermal/loongson,ls2k-thermal.yaml
> > > > index 7538469997f9..b634f57cd011 100644
> > > > --- a/Documentation/devicetree/bindings/thermal/loongson,ls2k-thermal.yaml
> > > > +++ b/Documentation/devicetree/bindings/thermal/loongson,ls2k-thermal.yaml
> > > > @@ -10,6 +10,9 @@ maintainers:
> > > > - zhanghongchen <zhanghongchen@xxxxxxxxxxx>
> > > > - Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
> > > >
> > > > +allOf:
> > > > + - $ref: /schemas/thermal/thermal-sensor.yaml#
> > > > +
> > > > properties:
> > > > compatible:
> > > > oneOf:
> > > > @@ -26,12 +29,16 @@ properties:
> > > > interrupts:
> > > > maxItems: 1
> > > >
> > > > + '#thermal-sensor-cells':
> > > > + const: 1
> > > > +
> > > > required:
> > > > - compatible
> > > > - reg
> > > > - interrupts
> > > > + - '#thermal-sensor-cells'
> > >
> > > Why does it need to be a required property now though?
> > > Adding new required properties is technically an ABI break.
> >
> > Hi Conor:
> >
> > I don't think it makes sense to have a separate thermal sensor
> > definition, it needs thermal-zones to describe specific behaviors,
> > e.g. cpu-thermal, so we need '#thermal-sensor-cells' to specify the
> > reference.
> > And the Loongson-2K1000 has 4 sets of control registers, we need to
> > specify the id when referencing it.
>
> Unfortunately, none of this is an answer to my question.
Hi Conor:
Sorry for my late reply.
Over the past few days, I've been communicating offline with Yinbo
(the driver author) about the use of the '#thermal-sensor-cells'
attribute. He retested the attribute and determined that it is
'required'.
We can see that the '#thermal-sensor-cells' attribute in the
dt-binding was dropped between the V12 patchset[1] and the V13
patchset[2]. Yinbo may have misunderstood Daniel's comment and removed
the '#thermal-sensor-cells' attribute from the dt-binding. But the
attribute was carelessly still left in the dts file, resulting in the
issue not being found during functional validation.
Indeed, re-adding the '#thermal-sensor-cells' attribute as "required"
is technically an ABI breakage, but the driver does not work properly
under the current dt-binding rules.
Also, the driver is only valid under LoongArch and will have no effect
on other architectures.
[1]：https://lore.kernel.org/all/20221114024709.7975-2-zhuyinbo@xxxxxxxxxxx/
[2]：https://lore.kernel.org/all/20230221095355.9799-2-zhuyinbo@xxxxxxxxxxx/
Thanks.
Binbin
