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:

quoted

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?

quoted

nodes would be validated to have them properly utilized.

Signed-off-by: Serge Semin <redacted>
Reviewed-by: Rob Herring <robh@kernel.org>

---

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

quoted

 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;
+    };