Re: [PATCH 2/6] dt-bindings: pinctrl: mt7620: add proper function muxing binding

[Arınç ÜNAL]

On 14.12.2022 14:55, Krzysztof Kozlowski wrote:
> On 13/12/2022 14:04, Arınç ÜNAL wrote:
> > Not every function can be muxed to a group. Add proper binding which
> > documents which function can be muxed to a group or set of groups.
> >
> > Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> > ---
> >   .../pinctrl/ralink,mt7620-pinctrl.yaml        | 632 +++++++++++++++++-
> >   1 file changed, 596 insertions(+), 36 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
> > index 6f17f3991640..06880c80ba80 100644
> > --- a/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
> > +++ b/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
> > @@ -29,47 +29,608 @@ patternProperties:
> >           $ref: pinmux-node.yaml#
> >   
> >           properties:
> > -          groups:
> > -            description: The pin group to select.
> > -            enum: [
> > -              # common
> > -              i2c, spi, wdt,
> > -
> > -              # For MT7620 SoC
> > -              ephy, mdio, nd_sd, pa, pcie, rgmii1, rgmii2, spi refclk,
> > -              uartf, uartlite, wled,
> > -
> > -              # For MT7628 and MT7688 SoCs
> > -              gpio, i2s, p0led_an, p0led_kn, p1led_an, p1led_kn, p2led_an,
> > -              p2led_kn, p3led_an, p3led_kn, p4led_an, p4led_kn, perst, pwm0,
> > -              pwm1, refclk, sdmode, spi cs1, spis, uart0, uart1, uart2,
> > -              wled_an, wled_kn,
> > -            ]
> > -
> >             function:
> > -            description: The mux function to select.
> > -            enum: [
> > -              # common
> > -              gpio, i2c, refclk, spi,
> > -
> > -              # For MT7620 SoC
> > -              ephy, gpio i2s, gpio uartf, i2s uartf, mdio, nand, pa,
> > -              pcie refclk, pcie rst, pcm gpio, pcm i2s, pcm uartf,
> > -              rgmii1, rgmii2, sd, spi refclk, uartf, uartlite, wdt refclk,
> > -              wdt rst, wled,
> > -
> > -              # For MT7628 and MT7688 SoCs
> > -              antenna, debug, i2s, jtag, p0led_an, p0led_kn,
> > -              p1led_an, p1led_kn, p2led_an, p2led_kn, p3led_an, p3led_kn,
> > -              p4led_an, p4led_kn, pcie, pcm, perst, pwm, pwm0, pwm1, pwm_uart2,
> > -              rsvd, sdxc, sdxc d5 d4, sdxc d6, sdxc d7, spi cs1,
> > -              spis, sw_r, uart0, uart1, uart2, utif, wdt, wled_an, wled_kn, -,
> > -            ]
> > +            description:
> > +              A string containing the name of the function to mux to the group.
> > +            anyOf:
> > +              - description: For MT7620 SoC
> > +                enum: [ephy, gpio, gpio i2s, gpio uartf, i2c, i2s uartf, mdio, nand, pa,
> > +                       pcie refclk, pcie rst, pcm gpio, pcm i2s, pcm uartf, refclk,
> > +                       rgmii1, rgmii2, sd, spi, spi refclk, uartf, uartlite, wdt refclk,
> > +                       wdt rst, wled]
> > +
> > +              - description: For MT7628 and MT7688 SoCs
> > +                enum: [antenna, debug, gpio, i2c, i2s, jtag, p0led_an, p0led_kn,
> > +                       p1led_an, p1led_kn, p2led_an, p2led_kn, p3led_an, p3led_kn,
> > +                       p4led_an, p4led_kn, pcie, pcm, perst, pwm, pwm0, pwm1, pwm_uart2,
> > +                       refclk, rsvd, sdxc, sdxc d5 d4, sdxc d6, sdxc d7, spi, spi cs1,
> > +                       spis, sw_r, uart0, uart1, uart2, utif, wdt, wled_an, wled_kn, -]
> > +
> > +          groups:
> > +            description:
> > +              An array of strings. Each string contains the name of a group.
> >   
> >           required:
> >             - groups
> >             - function
> >   
> > +        allOf:
> > +          - if:
> > +              properties:
> > +                function:
> > +                  const: antenna
> > +            then:
> > +              properties:
> > +                groups:
> > +                  enum: [i2s]
>
> I have doubts such setup is maintainable and readable. I would suggest
> to leave just few - maybe for gpio, jtag, refclk, utif.

These bindings are not going to change once all properly defined and I'm 
here as a maintainer so I don't see an issue with maintaining the binding.

It's the whole pin configuration of an SoC squashed under a single 
document. I guess this is the fate of the pinctrl bindings. The bindings 
for mt7622 is not so different:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pinctrl/mediatek%2Cmt7622-pinctrl.yaml#n63

It's still much better than reading the code:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pinctrl/ralink/pinctrl-mt7620.c

Arınç