Re: [PATCH v3 01/16] dt-bindings: usb: usb-hcd: Convert generic USB properties to DT schema

[Serge Semin]

Folks, any comment on my previous message below?

On Wed, Oct 21, 2020 at 06:46:21PM +0300, Serge Semin wrote:
> On Wed, Oct 21, 2020 at 11:00:36AM +0800, Chunfeng Yun wrote:
> > On Tue, 2020-10-20 at 14:20 +0300, Serge Semin wrote:
> > > The generic USB HCD properties have been described in the legacy bindings
> > > text file: Documentation/devicetree/bindings/usb/generic.txt . Let's
> > > convert it' content into the USB HCD DT schema properties so all USB DT
> >           ^ its?
> > > nodes would be validated to have them properly utilized.
> > > 
> > > Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
> > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
> > > 
> > > ---
> > > 
> > > Changelog v2:
> > > - Discard '|' in all the new properties, since we don't need to preserve
> > >   the text formatting.
> > > - Convert abbreviated form of the "maximum-speed" enum restriction into
> > >   the multi-lined version of the list.
> > > - Drop quotes from around the string constants.
> > > ---
> > >  .../devicetree/bindings/usb/generic.txt       | 57 ------------
> > >  .../devicetree/bindings/usb/usb-hcd.yaml      | 88 +++++++++++++++++++
> 
> > Do we need change the file name or modify it's title?
> > the title is "Generic USB Host Controller Device Tree Bindings", but
> > some generic properties, such as, dr_mode, usb-role-switch, otg related
> > ones, are usually used by DRD controller, this may cause some confusion.
> 
> Hm, good question. A problem of the naming and the properties inclusion do
> exist here. I haven't thought that through when moved all the generic
> properties into the usb-hcd.yaml bindings file. But I don't think it's a good
> idea to rename the file. Most likely the best solution would be to split the
> functionality up as follows:
> 
> 1) usb.yaml - common USB controller with generic properties for all USB modes (host, peripheral, otg):
>    + $nodename
>    + phys
>    + phy-names
>    + usb-phy
>    + maximum-speed
>    + phy_type
> 2) usb-hcd.yaml - DT schema for USB host controllers (EHCI/OHCI/UHCI):
>    + allOf: [usb.yaml#]
>    + companion
> 3) usb-xhci.yaml - DT schema for USB host controllers (xHCI):
>    + allOf: [usb-hcd.yaml#]
>    + usb2-lpm-disable
>    + usb3-lpm-capable
>    + quirk-broken-port-ped
>    + imod-interval-ns
> 4) usb-drd.yaml - DT schema for USB OTG controllers:
>    + otg-rev
>    + hnp-disable
>    + srp-disable
>    + adp-disable
>    + usb-role-switch
>    + role-switch-default-mode
>    + tpl-support
>    + dr_mode: [host, peripheral, otg]
> 
> So in case if an USB controller is DRD with EHCI host, then it will need
> to pass evaluation of allOf: [usb-hcd.yaml#, usb-drd.yaml#]. If an USB
> controller is DRD with xHCI host, then the next schema can be applied:
> [usb-xhci.yaml#, usb-drd.yaml#]. A conditional schema is also applicable
> here, like this:
> allOf:
>   - $ref: usb-drd.yaml#
>   - if:
>       properties:
>         dr_mode:
>           const: host
>     then:
>       $ref: usb-hcd.yaml# (or usb-xhci.yaml#)
>     else:
>       #ref: usb.yaml#
> 
> What do you think? @Rob, @Greg, we need your opinion here.
> 
> -Sergey
> 
> > 
> > >  2 files changed, 88 insertions(+), 57 deletions(-)
> > >  delete mode 100644 Documentation/devicetree/bindings/usb/generic.txt
> > > 
> > > diff --git a/Documentation/devicetree/bindings/usb/generic.txt b/Documentation/devicetree/bindings/usb/generic.txt
> > > deleted file mode 100644
> > > index ba472e7aefc9..000000000000
> > > --- a/Documentation/devicetree/bindings/usb/generic.txt
> > > +++ /dev/null
> > > @@ -1,57 +0,0 @@
> > > -Generic USB Properties
> > > -
> > > -Optional properties:
> > > - - maximum-speed: tells USB controllers we want to work up to a certain
> > > -			speed. Valid arguments are "super-speed-plus",
> > > -			"super-speed", "high-speed", "full-speed" and
> > > -			"low-speed". In case this isn't passed via DT, USB
> > > -			controllers should default to their maximum HW
> > > -			capability.
> > > - - dr_mode: tells Dual-Role USB controllers that we want to work on a
> > > -			particular mode. Valid arguments are "host",
> > > -			"peripheral" and "otg". In case this attribute isn't
> > > -			passed via DT, USB DRD controllers should default to
> > > -			OTG.
> > > - - phy_type: tells USB controllers that we want to configure the core to support
> > > -			a UTMI+ PHY with an 8- or 16-bit interface if UTMI+ is
> > > -			selected. Valid arguments are "utmi" and "utmi_wide".
> > > -			In case this isn't passed via DT, USB controllers should
> > > -			default to HW capability.
> > > - - otg-rev: tells usb driver the release number of the OTG and EH supplement
> > > -			with which the device and its descriptors are compliant,
> > > -			in binary-coded decimal (i.e. 2.0 is 0200H). This
> > > -			property is used if any real OTG features(HNP/SRP/ADP)
> > > -			is enabled, if ADP is required, otg-rev should be
> > > -			0x0200 or above.
> > > - - companion: phandle of a companion
> > > - - hnp-disable: tells OTG controllers we want to disable OTG HNP, normally HNP
> > > -			is the basic function of real OTG except you want it
> > > -			to be a srp-capable only B device.
> > > - - srp-disable: tells OTG controllers we want to disable OTG SRP, SRP is
> > > -			optional for OTG device.
> > > - - adp-disable: tells OTG controllers we want to disable OTG ADP, ADP is
> > > -			optional for OTG device.
> > > - - usb-role-switch: boolean, indicates that the device is capable of assigning
> > > -			the USB data role (USB host or USB device) for a given
> > > -			USB connector, such as Type-C, Type-B(micro).
> > > -			see connector/usb-connector.yaml.
> > > - - role-switch-default-mode: indicating if usb-role-switch is enabled, the
> > > -			device default operation mode of controller while usb
> > > -			role is USB_ROLE_NONE. Valid arguments are "host" and
> > > -			"peripheral". Defaults to "peripheral" if not
> > > -			specified.
> > > -
> > > -
> > > -This is an attribute to a USB controller such as:
> > > -
> > > -dwc3@4a030000 {
> > > -	compatible = "synopsys,dwc3";
> > > -	reg = <0x4a030000 0xcfff>;
> > > -	interrupts = <0 92 4>
> > > -	usb-phy = <&usb2_phy>, <&usb3,phy>;
> > > -	maximum-speed = "super-speed";
> > > -	dr_mode = "otg";
> > > -	phy_type = "utmi_wide";
> > > -	otg-rev = <0x0200>;
> > > -	adp-disable;
> > > -};
> > > diff --git a/Documentation/devicetree/bindings/usb/usb-hcd.yaml b/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > index 7263b7f2b510..ee7ea205c71d 100644
> > > --- a/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > +++ b/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > @@ -22,9 +22,97 @@ properties:
> > >      description:
> > >        Name specifier for the USB PHY
> > >  
> > > +  maximum-speed:
> > > +   description:
> > > +     Tells USB controllers we want to work up to a certain speed. In case this
> > > +     isn't passed via DT, USB controllers should default to their maximum HW
> > > +     capability.
> > > +   $ref: /schemas/types.yaml#/definitions/string
> > > +   enum:
> > > +     - low-speed
> > > +     - full-speed
> > > +     - high-speed
> > > +     - super-speed
> > > +     - super-speed-plus
> > > +
> > > +  dr_mode:
> > > +    description:
> > > +      Tells Dual-Role USB controllers that we want to work on a particular
> > > +      mode. In case this attribute isn't passed via DT, USB DRD controllers
> > > +      should default to OTG.
> > > +    $ref: /schemas/types.yaml#/definitions/string
> > > +    enum: [host, peripheral, otg]
> > > +
> > > +  phy_type:
> > > +    description:
> > > +      Tells USB controllers that we want to configure the core to support a
> > > +      UTMI+ PHY with an 8- or 16-bit interface if UTMI+ is selected. In case
> > > +      this isn't passed via DT, USB controllers should default to HW
> > > +      capability.
> > > +    $ref: /schemas/types.yaml#/definitions/string
> > > +    enum: [utmi, utmi_wide]
> > > +
> > > +  otg-rev:
> > > +    description:
> > > +      Tells usb driver the release number of the OTG and EH supplement with
> > > +      which the device and its descriptors are compliant, in binary-coded
> > > +      decimal (i.e. 2.0 is 0200H). This property is used if any real OTG
> > > +      features (HNP/SRP/ADP) is enabled. If ADP is required, otg-rev should be
> > > +      0x0200 or above.
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +
> > > +  companion:
> > > +    description: Phandle of a companion device
> > > +    $ref: /schemas/types.yaml#/definitions/phandle
> > > +
> > > +  hnp-disable:
> > > +    description:
> > > +      Tells OTG controllers we want to disable OTG HNP. Normally HNP is the
> > > +      basic function of real OTG except you want it to be a srp-capable only B
> > > +      device.
> > > +    type: boolean
> > > +
> > > +  srp-disable:
> > > +    description:
> > > +      Tells OTG controllers we want to disable OTG SRP. SRP is optional for OTG
> > > +      device.
> > > +    type: boolean
> > > +
> > > +  adp-disable:
> > > +    description:
> > > +      Tells OTG controllers we want to disable OTG ADP. ADP is optional for OTG
> > > +      device.
> > > +    type: boolean
> > > +
> > > +  usb-role-switch:
> > > +    description:
> > > +      Indicates that the device is capable of assigning the USB data role
> > > +      (USB host or USB device) for a given USB connector, such as Type-C,
> > > +      Type-B(micro). See connector/usb-connector.yaml.
> > > +
> > > +  role-switch-default-mode:
> > > +    description:
> > > +      Indicates if usb-role-switch is enabled, the device default operation
> > > +      mode of controller while usb role is USB_ROLE_NONE.
> > > +    $ref: /schemas/types.yaml#/definitions/string
> > > +    enum: [host, peripheral]
> > > +    default: peripheral
> > > +
> > >  examples:
> > >    - |
> > >      usb {
> > >          phys = <&usb2_phy1>, <&usb3_phy1>;
> > >          phy-names = "usb";
> > >      };
> > > +  - |
> > > +    usb@4a030000 {
> > > +        compatible = "snps,dwc3";
> > > +        reg = <0x4a030000 0xcfff>;
> > > +        interrupts = <0 92 4>;
> > > +        usb-phy = <&usb2_phy>, <&usb3_phy>;
> > > +        maximum-speed = "super-speed";
> > > +        dr_mode = "otg";
> > > +        phy_type = "utmi_wide";
> > > +        otg-rev = <0x0200>;
> > > +        adp-disable;
> > > +    };
> >