Re: [PATCH v3 09/19] dt-bindings: nvmem: microchip-otpc: Add required clocks

[Alexander Dahl]

Hello Claudiu,

Am Sat, Jan 31, 2026 at 05:47:05PM +0200 schrieb Claudiu Beznea:
> 
> 
> On 1/20/26 17:44, Alexander Dahl wrote:
> > The OTPC requires both the peripheral clock through PMC and the main RC
> > oscillator.  Seemed to work without explicitly enabling those clocks on
> > sama7g5 before, but did not on sam9x60.
> > 
> > Older datasheets were not clear and explicit about this, but recent are,
> > e.g. SAMA7G5 series datasheet (DS60001765B),
> > section 30.4.1 Power Management:
> > 
> > > The OTPC is clocked through the Power Management Controller (PMC).
> > > The user must power on the main RC oscillator and enable the
> > > peripheral clock of the OTPC prior to reading or writing the OTP
> > > memory.
> 
> As this was not mentioned in the previous datasheet versions, the current
> driver don't handle those clocks, and it probably worked as the clocks were
> enabled by bootloaders, I think the clocks should be marked as required and
> this patch to be propagated as a fix along with fixes on driver and device
> trees.

What do you mean by "clocks should be marked as required"?  Where?
How?  Is something more necessary, than already done here?

> I'll let DT binding maintainers for the final decision on this.
> 
> > 
> > Link: https://lore.kernel.org/linux-clk/ec34efc2-2051-4b8a-b5d8-6e2fd5e08c28@xxxxxxxxxxxxx/T/#u
> 
> Why this link here?

That was the original discussion and at the time the sama7g5 datasheet
mentioned a thing missing in the sam9x60 datasheet.  So that
discussion was the only reference for why this change is needed for
sam9x60.  Will drop the line in v4 then.

Greets
Alex

> 
> > Signed-off-by: Alexander Dahl <ada@xxxxxxxxxxx>
> > ---
> > 
> > Notes:
> >      v3:
> >      - Removed clock-names (led to confusion, and not used by the driver anyways)
> >      - Removed redundant example
> >      v2:
> >      - new patch, not present in v1
> > 
> >   .../devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml | 8 ++++++++
> >   1 file changed, 8 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml b/Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
> > index 9a7aaf64eef32..847dfb67c6b72 100644
> > --- a/Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
> > +++ b/Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
> > @@ -29,6 +29,11 @@ properties:
> >     reg:
> >       maxItems: 1
> > +  clocks:
> > +    items:
> > +      - description: main rc oscillator
> > +      - description: otpc peripheral clock
> > +
> >   required:
> >     - compatible
> >     - reg
> > @@ -37,6 +42,8 @@ unevaluatedProperties: false
> >   examples:
> >     - |
> > +    #include <dt-bindings/clock/at91.h>
> > +    #include <dt-bindings/clock/microchip,sama7g5-pmc.h>
> >       #include <dt-bindings/nvmem/microchip,sama7g5-otpc.h>
> >       otpc: efuse@e8c00000 {
> > @@ -44,6 +51,7 @@ examples:
> >           reg = <0xe8c00000 0xec>;
> >           #address-cells = <1>;
> >           #size-cells = <1>;
> > +        clocks = <&pmc PMC_TYPE_CORE SAMA7G5_PMC_MAIN_RC>, <&pmc PMC_TYPE_PERIPHERAL 67>;
> >           temperature_calib: calib@1 {
> >               reg = <OTP_PKT(1) 76>;
>