Re: [PATCH] fixup! dt-bindings: media: i2c: Add bindings for Maxima Integrated MAX9286

[Jacopo Mondi <jacopo@jmondi.org>]

Hi Kieran,

On Thu, May 14, 2020 at 10:43:10AM +0100, Kieran Bingham wrote:
> Hi Jacopo,
>
> On 13/05/2020 13:54, Jacopo Mondi wrote:
> > Subject: [PATCH] fixup! dt-bindings: media: i2c: Add bindings for Maxima Integrated MAX9286
> >
> > Temporary fixup to ease review. To be squashed into v10 if accepted.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >
> > While fixing Rob's reported bug on v9 I realized thanks to a
> > dt_binding_check warning that the i2c-mux child nodes where under-specified.
> >
> > This fixup epxands the i2c-mux child nodes description and updates the
> > example to match our currently-out-of-tree DTS files for GMSL platforms.
> >
> > dt_binding_check still reports a warning:
> >
> > Documentation/devicetree/bindings/media/i2c/maxim,max9286.example.dt.yaml: camera@51: reg: [[81, 97]] is too short
> > Documentation/devicetree/bindings/media/i2c/maxim,max9286.example.dt.yaml: camera@52: reg: [[82, 98]] is too short
> > Documentation/devicetree/bindings/media/i2c/maxim,max9286.example.dt.yaml: camera@53: reg: [[83, 99]] is too short
> > Documentation/devicetree/bindings/media/i2c/maxim,max9286.example.dt.yaml: camera@54: reg: [[84, 100]] is too short
>
> Is too short? That seems odd. We accept 1, 2, or 3 values in the reg
> (for the serializer, camera, mcu addresses) but those values are
> specific to the camera device, and are managed by that driver and
> shouldn't be validated here.

I think it's expected them to be validated against this schema, not
sure what's the warning about though.

>
>
> >
> > Which I was not able to silence.
> > ---
> >  .../bindings/media/i2c/maxim,max9286.yaml     | 86 +++++++++++++++++--
> >  1 file changed, 77 insertions(+), 9 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> > index f9d3e5712c59..d9bd19caed2f 100644
> > --- a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> > +++ b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> > @@ -130,9 +130,7 @@ properties:
> >      description: |
> >        Each GMSL link is modelled as a child bus of an i2c bus
> >        multiplexer/switch, in accordance with bindings described in
> > -      Documentation/devicetree/bindings/i2c/i2c-mux.txt. The serializer
> > -      device on the remote end of the GMSL link shall be modelled as a child
> > -      node of the corresponding I2C bus.
> > +      Documentation/devicetree/bindings/i2c/i2c-mux.txt.
> >
> >      properties:
> >        '#address-cells':
> > @@ -141,7 +139,74 @@ properties:
> >        '#size-cells':
> >          const: 0
> >
> > -  additionalProperties: false
> > +    patternProperties:
> > +      "^i2c@[0-3]$":
> > +        type: object
> > +        description: |
> > +          Child node of the i2c bus multiplexer which represents a GMSL link.
> > +          Each serializer device on the GMSL link remote end is represented with
> > +          an i2c-mux child node. The MAX9286 chip supports up to 4 GMSL
> > +          channels.
> > +
> > +        properties:
> > +          '#address-cells':
> > +            const: 1
> > +
> > +          '#size-cells':
> > +            const: 0
> > +
> > +          reg:
> > +            description: The index of the GMSL channel.
> > +            maxItems: 1
> > +
> > +        patternProperties:
> > +          "^camera@[0-9]+":
>
> This value after @ represents a non 0x prefixed hex value, where your
> regex will only match numerical values.
>
> 	"^camera@[a-f0-9]+":
>
>
>
> is likely therefore required.
>

Uh, correct

> I see other uses of this patternProperties also terminate the regex with
> a $ (end of line) but that confuses me, as the node is often presented
> with the opening brace after the name and identifier:
>
>  (i.e.)
>    camera@52 {
>
> But perhaps the validator extracts the node name and reg and matches on
> that directly in which case it would be
>
> 	"^camera@[a-f0-9]+$":

I've initially used '$' as well then removed it for the same reason.
MAybe the patter is only matched against the node name, leaving out the
rest of the line.

>
>
>
> > +            type: object
> > +            description: |
> > +              The remote camera device, composed by a GMSL serializer and a
> > +              connected video source.
> > +
> > +            properties:
> > +              compatible:
> > +                description: The remote device compatible string.
> > +
> > +              reg:
> > +                description: |
> > +                  The I2C addresses to be assigned to the remote devices through
> > +                  address reprogramming. The number of entries depends on the
> > +                  requirements of the currently connected remote device.
> > +
> > +              port:
> > +                type: object
> > +
> > +                properties:
> > +                  endpoint:
> > +                    type: object
> > +
> > +                    properties:
> > +                      remote-endpoint:
> > +                        description: phandle to the MAX9286 sink endpoint.
> > +
> > +                    required:
> > +                      - remote-endpoint
> > +
> > +                    additionalProperties: false
> > +
> > +                required:
> > +                  - endpoint
> > +
> > +                additionalProperties: false
> > +
> > +            required:
> > +              - compatible
> > +              - reg
> > +              - port
> > +
> > +            additionalProperties: false
> > +
> > +        additionalProperties: false
> > +
> > +    additionalProperties: false
> >
>
>
> Wow, is it required to specify additionalProperties: false quite so many
> times?

I -think- so, it's one per section, and unless it's by default it
makes sense to have it there ?

>
>
> >  required:
> >    - compatible
> > @@ -220,11 +285,11 @@ examples:
> >            i2c@0 {
> >              #address-cells = <1>;
> >              #size-cells = <0>;
> > -
> >              reg = <0>;
> >
> >              camera@51 {
> > -              reg = <0x51>;
> > +              compatible = "imi,rdacm20";
> > +              reg = <0x51 0x61>;
> >
> >                port {
> >                  rdacm20_out0: endpoint {
> > @@ -241,7 +306,8 @@ examples:
> >              reg = <1>;
> >
> >              camera@52 {
> > -              reg = <0x52>;
> > +              compatible = "imi,rdacm20";
> > +              reg = <0x52 0x62>;
> >
> >                port {
> >                  rdacm20_out1: endpoint {
> > @@ -257,7 +323,8 @@ examples:
> >              reg = <2>;
> >
> >              camera@53 {
> > -              reg = <0x53>;
> > +              compatible = "imi,rdacm20";
> > +              reg = <0x53 0x63>;
> >
> >                port {
> >                  rdacm20_out2: endpoint {
> > @@ -273,7 +340,8 @@ examples:
> >              reg = <3>;
> >
> >              camera@54 {
> > -              reg = <0x54>;
> > +              compatible = "imi,rdacm20";
> > +              reg = <0x54 0x64>;
> >
> >                port {
> >                  rdacm20_out3: endpoint {
> > --
> > 2.26.2
> >
>