Re: [PATCH v2 1/2] spi: dt-bindings: amlogic, meson-gx-spicc: Add pinctrl names for SPI signal states

[Neil Armstrong]

On 06/10/2022 16:11, Krzysztof Kozlowski wrote:
> On 06/10/2022 12:57, Amjad Ouled-Ameur wrote:
> > Hi Krzysztof,
> >
> > Thank you for the review.
> >
> > On 10/5/22 10:14, Krzysztof Kozlowski wrote:
> > > On 04/10/2022 13:10, Amjad Ouled-Ameur wrote:
> > > > SPI pins of the SPICC Controller in Meson-GX needs to be controlled by
> > > > pin biais when idle. Therefore define three pinctrl names:
> > > > - default: SPI pins are controlled by spi function.
> > > > - idle-high: SCLK pin is pulled-up, but MOSI/MISO are still controlled
> > > > by spi function.
> > > > - idle-low: SCLK pin is pulled-down, but MOSI/MISO are still controlled
> > > > by spi function.
> > > >
> > > > Reported-by: Da Xue <da@libre.computer>
> > > > Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> > > > Signed-off-by: Amjad Ouled-Ameur <aouledameur@xxxxxxxxxxxx>
> > > > ---
> > > >    .../devicetree/bindings/spi/amlogic,meson-gx-spicc.yaml   | 15 +++++++++++++++
> > > >    1 file changed, 15 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/spi/amlogic,meson-gx-spicc.yaml b/Documentation/devicetree/bindings/spi/amlogic,meson-gx-spicc.yaml
> > > > index 0c10f7678178..53013e27f507 100644
> > > > --- a/Documentation/devicetree/bindings/spi/amlogic,meson-gx-spicc.yaml
> > > > +++ b/Documentation/devicetree/bindings/spi/amlogic,meson-gx-spicc.yaml
> > > > @@ -43,6 +43,14 @@ properties:
> > > >        minItems: 1
> > > >        maxItems: 2
> > > >    
> > > > +  pinctrl-0:
> > > > +    minItems: 1
> > > maxItems?
> > Will fill it in next version.
> > > > +
> > > > +  pinctrl-1:
> > > > +    maxItems: 1
> > > > +
> > > > +  pinctrl-names: true
> > > Why do you need all these in the bindings?
> >
> > SPI clock bias needs to change at runtime depending on SPI mode, here is an example of
> >
> > how this is supposed to be used ("spi_idle_low_pins" and "spi_idle_low_pins" are defined
> >
> > in the second patch of this series):
>
> I know what it the point in general of pinctrl configuration... But the
> question is why do you need to specify them in the bindings? Core
> handles that. IOW, do you require them and missing/incomplete pinctrl
> should be reported?

Looking at other bindings, when specific pinctrl state names were requires, they were
documented.

There's some bindings with pinctrl-names for specific states like rockchip/rockchip,dw-hdmi.yaml,
mediatek/mediatek,dpi.yaml, mmc/mtk-sd.yaml or mmc/fsl-imx-esdhc.yaml

Neil


> Best regards,
> Krzysztof