Re: [PATCH v4 2/8] dt-bindings: mmc: mmc-spi-slot: Change voltage-ranges to uint32-matrix

[Frank Li <Frank.li@nxp.com>]

On Tue, Jun 11, 2024 at 02:23:11PM -0600, Rob Herring wrote:
> On Tue, Jun 11, 2024 at 12:01:47PM -0400, Frank Li wrote:
> > According to common mmc core, voltages-ranges should be matrix.
> > 
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > 
> > ---
> > Not sure why it impact other mmc yaml's voltage-ranges.
> 
> It's a quirk of the tools. When decoding properties, the tools only know 
> all possible types. Types are global, not per binding. Sometimes it can 
> be figured out, but cases like this cannot be.
> 
> > ---
> >  Documentation/devicetree/bindings/mmc/mmc-spi-slot.yaml | 17 ++++++++++-------
> >  1 file changed, 10 insertions(+), 7 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/mmc/mmc-spi-slot.yaml b/Documentation/devicetree/bindings/mmc/mmc-spi-slot.yaml
> > index 36acc40c7d181..05815b837219d 100644
> > --- a/Documentation/devicetree/bindings/mmc/mmc-spi-slot.yaml
> > +++ b/Documentation/devicetree/bindings/mmc/mmc-spi-slot.yaml
> > @@ -27,17 +27,20 @@ properties:
> >      maxItems: 1
> >  
> >    voltage-ranges:
> > -    $ref: /schemas/types.yaml#/definitions/uint32-array
> > +    $ref: /schemas/types.yaml#/definitions/uint32-matrix
> >      description: |
> >        Two cells are required, first cell specifies minimum slot voltage (mV),
> >        second cell specifies maximum slot voltage (mV).
> >      items:
> > -      - description: |
> > -          value for minimum slot voltage in mV
> > -        default: 3200
> > -      - description: |
> > -          value for maximum slot voltage in mV
> > -        default: 3400
> > +      items:
> > +        - description: |
> > +            value for minimum slot voltage in mV
> > +          default: 3200
> > +        - description: |
> > +            value for maximum slot voltage in mV
> > +          default: 3400
> > +    minItems: 1
> > +    maxItems: 8
> 
> From what I remember, SPI mode doesn't support voltage changes. 
> Switching to 1.8V came much later in the spec. So it should be 
> 'maxItems: 1'. Or better yet, make the outer 'items' a list (of 1 
> entry).

I don't understand "make the outer 'items' a list (of 1 entry)." Can guide
me how to write it?

Frank 

> 
> Rob