Re: [PATCH v7 04/16] dt-bindings: imx6q-pcie: Add linux,pci-domain as required for iMX8MQ

Frank Li
2024-01-07T04:47:50Z

On Sun, Jan 07, 2024 at 08:45:06AM +0530, Manivannan Sadhasivam wrote:
> On Wed, Dec 27, 2023 at 01:27:15PM -0500, Frank Li wrote:
> > iMX8MQ have two pci controllers. Adds "linux,pci-domain" as required
> > proptery for iMX8MQ to indicate pci controller index.
> >
>
> property
>
> > This adjustment paves the way for eliminating the hardcoded check on the
> > base register for acquiring the controller_id.
> >
> > ...
> > if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
> > imx6_pcie->controller_id = 1;
> > ...
> >
> > The controller_id is crucial and utilized for certain register bit
> > positions. It must align precisely with the controller index in the SoC.
> > An auto-incremented ID don't fit this case. The DTS or fuse configurations
> > may deactivate specific PCI controllers.
> >
>
> You cannot change the binding for the sake of driver. But you can make this
> change in other way. See below...
>
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> >
> > Notes:
> > Change from v5 to v6
> > - rework commit message to explain why need required and why auto increase
> > id not work
> >
> > Change from v4 to v5
> > - new patch at v5
> >
> > .../bindings/pci/fsl,imx6q-pcie-common.yaml | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie-common.yaml b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie-common.yaml
> > index d91b639ae7ae7..8f39b4e6e8491 100644
> > --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie-common.yaml
> > +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie-common.yaml
> > @@ -265,6 +265,17 @@ allOf:
> > - const: apps
> > - const: turnoff
> >
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + enum:
> > + - fsl,imx8mq-pcie
> > + - fsl,imx8mq-pcie-ep
>
> "linux,pci-domain" is a generic property. So you cannot make it required only
> for certain SoCs.

Sorry, why not? there are many generic property.

> But you can make it so for all SoCs. This way, the drivers
> can also rely on it.
>
> Now, you should get rid of the commit message about driver internals:

Not all dts already added "linux,pci-domain" yet. If required for all SOCs,
it will cause dtb check warnings.

Frank
>
> > This adjustment paves the way for eliminating the hardcoded check on the
> > base register for acquiring the controller_id.
> >
> > ...
> > if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
> > imx6_pcie->controller_id = 1;
> > ...
> >
> > The controller_id is crucial and utilized for certain register bit
> > positions. It must align precisely with the controller index in the SoC.
> > An auto-incremented ID don't fit this case. The DTS or fuse configurations
> > may deactivate specific PCI controllers.
> >
>
> - Mani
>
> > + then:
> > + required:
> > + - linux,pci-domain
> > +
> > additionalProperties: true
> >
> > ...
> > --
> > 2.34.1
> >
>
> --
> மணிவண்ணன் சதாசிவம்