Re: [PATCH 1/6] dt-bindings: mfd: add bindings for QIXIS CPLD

Ioana Ciornei
2025-05-06T18:11:01Z

On Fri, May 02, 2025 at 09:01:59AM +0200, Krzysztof Kozlowski wrote:
> On Wed, Apr 30, 2025 at 06:36:29PM GMT, Ioana Ciornei wrote:
> > This adds device tree bindings for the board management controller -
> > QIXIS CPLD - found on some Layerscape based boards such as LX2160A-RDB,
> > LX2160AQDS, LS1028AQDS etc.
> >
> > Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
> > ---
> > .../bindings/mfd/fsl,qixis-i2c.yaml | 65 +++++++++++++++++++
> > 1 file changed, 65 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/mfd/fsl,qixis-i2c.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/mfd/fsl,qixis-i2c.yaml b/Documentation/devicetree/bindings/mfd/fsl,qixis-i2c.yaml
> > new file mode 100644
> > index 000000000000..562878050916
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mfd/fsl,qixis-i2c.yaml
>
> Filename matching compatible.

How to choose one if there are multiple compatible strings?

>
> > @@ -0,0 +1,65 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mfd/fsl,qixis-i2c.yaml
> > +$schema: http://devicetree.org/meta-schemas/core.yaml
> > +
> > +title: NXP's QIXIS CPLD board management controller
> > +
> > +maintainers:
> > + - Ioana Ciornei <ioana.ciornei@nxp.com>
> > +
> > +description: |
> > + The board management controller found on some Layerscape boards contains
> > + different IP blocks like GPIO controllers, interrupt controllers, reg-muxes
> > + etc.
> > +
> > +properties:
> > + compatible:
> > + enum:
> > + - fsl,lx2160a-qds-qixis-i2c
> > + - fsl,lx2162a-qds-qixis-i2c
> > + - fsl,ls1028a-qds-qixis-i2c
>
> Keep alphabetical order.
>
> What is actual device name? I2C? Is this an I2C controller or device?
>
> > +
> > + reg:
> > + description:
> > + I2C device address.
>
> This says device, so i2c in compatible is wrong.
>
> Anyway drop description, redundant.

Ok, will drop.

>
>
> > + maxItems: 1
> > +
> > + "#address-cells":
> > + const: 1
>
> Why?
>
> > +
> > + "#size-cells":
> > + const: 0
>
> Why? Drop cells.
>

See below.

> > +
> > + mux-controller:
> > + $ref: /schemas/mux/reg-mux.yaml#
> > +
> > +required:
> > + - "#address-cells"
> > + - "#size-cells"
> > + - compatible
> > + - reg
>
> Keep same order as in properties

Ok.

>
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + i2c {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + qixis@66 {
>
> Node names should be generic. See also an explanation and list of
> examples (not exhaustive) in DT specification:
> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation

In this case, an accepted node name is 'cpld'?

>
> > + compatible = "fsl,lx2160a-qds-qixis-i2c";
> > + reg = <0x66>;
> > + #address-cells = <1>;
> > + #size-cells = <0>;
>
> So were do you use address/size cells?
>

For example, fsl-ls1028a-qds.dts looks like this:

fpga@66 {
compatible = "fsl,ls1028a-qds-qixis-i2c";
reg = <0x66>;
#address-cells = <1>;
#size-cells = <0>;

mux: mux-controller@54 {
compatible = "reg-mux";
reg = <0x54>;
#mux-control-cells = <1>;
mux-reg-masks = <0x54 0xf0>; /* 0: reg 0x54, bits 7:4 */
};
};

Also, some boards have in their qixis CPLD gpio controllers and I am
planning to add them as the next step.

Ioana