> -----Original Message----- > From: Bjorn Helgaas <helgaas@xxxxxxxxxx> > Sent: 2022年7月21日 5:03 > To: Hongxing Zhu <hongxing.zhu@xxxxxxx> > Cc: robh@xxxxxxxxxx; l.stach@xxxxxxxxxxxxxx; galak@xxxxxxxxxxxxxxxxxxx; > shawnguo@xxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > dl-linux-imx <linux-imx@xxxxxxx>; kernel@xxxxxxxxxxxxxx > Subject: Re: [PATCH v2 1/3] dt-bindings: PCI: imx6: convert the imx pcie > controller to dtschema > > On Wed, Jul 20, 2022 at 01:16:45AM +0000, Hongxing Zhu wrote: > > > -----Original Message----- > > > From: Bjorn Helgaas <helgaas@xxxxxxxxxx> > > > Sent: 2022年7月20日 2:00 > > > To: Hongxing Zhu <hongxing.zhu@xxxxxxx> > > > Cc: robh@xxxxxxxxxx; l.stach@xxxxxxxxxxxxxx; > > > galak@xxxxxxxxxxxxxxxxxxx; shawnguo@xxxxxxxxxx; > > > devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > > linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; > > > kernel@xxxxxxxxxxxxxx > > > Subject: Re: [PATCH v2 1/3] dt-bindings: PCI: imx6: convert the imx > > > pcie controller to dtschema > > > > > > On Fri, Aug 27, 2021 at 02:42:58PM +0800, Richard Zhu wrote: > > > > Convert the fsl,imx6q-pcie.txt into a schema. > > > > - ranges property should be grouped by region, with no functional > > > > changes. > > > > - only one propert is allowed in the compatible string, remove > > > > "snps,dw-pcie". > > > > > > > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx> > > > > --- > > > > .../bindings/pci/fsl,imx6q-pcie.txt | 100 --------- > > > > .../bindings/pci/fsl,imx6q-pcie.yaml | 202 > > > ++++++++++++++++++ > > > > MAINTAINERS | 2 +- > > > > 3 files changed, 203 insertions(+), 101 deletions(-) delete mode > > > > 100644 Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt > > > > create mode 100644 > > > > Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml > > > > > > > > diff --git > > > > a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt > > > > b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt > > > > > > > -Optional properties: > > > > -- fsl,tx-deemph-gen1: Gen1 De-emphasis value. Default: 0 > > > > -- fsl,tx-deemph-gen2-3p5db: Gen2 (3.5db) De-emphasis value. Default: > > > > 0 > > > > > > > diff --git > > > > a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml > > > > b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml > > > > > > > + fsl,tx-deemph-gen1: > > > > + description: Gen1 De-emphasis value (optional required). > > > > + $ref: /schemas/types.yaml#/definitions/uint32 > > > > + default: 0 > > > > + > > > > + fsl,tx-deemph-gen2-3p5db: > > > > + description: Gen2 (3.5db) De-emphasis value (optional required). > > > > + $ref: /schemas/types.yaml#/definitions/uint32 > > > > + default: 0 > > > > > > What does "optional required" mean in all these properties? > > > "Optional" is the opposite of "required." > > > > Regarding my understands, the "optional required" means that these > > properties are not mandatory required. The default values are used if > > there are no such kind of properties. If HW board designers want to > > shape their PCIe signals (E.X eye diagram), they should define these > properties. > > That sounds like "optional" to me. > > "Optional required" is meaningless. A property can be either optional OR > required, but not both at the same time. > > If the driver can function without these properties, they are optional. If > designers can use these properties to optimize signal characteristics, the > properties are still optional. > > The properties you describe as "optional required" are: > > fsl,tx-deemph-gen1 > fsl,tx-deemph-gen2-3p5db > fsl,tx-deemph-gen2-6db > fsl,tx-swing-full > fsl,tx-swing-low > fsl,max-link-speed > reset-gpio > reset-gpio-active-high > vpcie-supply > vph-supply > > From reading the code, the driver uses default values for all the "fsl," > properties if they don't exist. And the driver always checks whether the > others exist before using them. > > So I think you should describe all these as "optional". > Yes it is. I would clean them, and set them all "optional" later. Thanks for your reminder. Best Regards Richard Zhu > Bjorn
