RE: [PATCH v3 4/5] dt-bindings: phy: realtek: Add the doc about the Realtek SoC USB 2.0 PHY

["Stanley Chang[昌育德]" <stanley_chang@realtek.com>]

Hi Krzysztof,

> 
> On 07/06/2023 08:24, Stanley Chang wrote:
> > Add the documentation explain the property about Realtek USB PHY driver.
> >
> > Realtek DHC (digital home center) RTD SoCs support DWC3 XHCI USB
> > controller. Added the driver to drive the USB 2.0 PHY transceivers.
> >
> > Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
> > ---
> > v2 to v3 change:
> >     1. Broken down into two patches, one for each of USB 2 & 3.
> >     2. Add more description about Realtek RTD SoCs architecture.
> >     3. Removed parameter v1 support for simplification.
> >     4. Revised the compatible name for fallback compatible.
> >     5. Remove some properties that can be set in the driver.
> > v1 to v2 change:
> >     Add phy-cells for generic phy driver
> > ---
> >  .../bindings/phy/realtek,usb2phy.yaml         | 213
> ++++++++++++++++++
> >  1 file changed, 213 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/phy/realtek,usb2phy.yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/phy/realtek,usb2phy.yaml
> > b/Documentation/devicetree/bindings/phy/realtek,usb2phy.yaml
> > new file mode 100644
> > index 000000000000..69911e20a561
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/phy/realtek,usb2phy.yaml
> > @@ -0,0 +1,213 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) # Copyright 2023
> > +Realtek Semiconductor Corporation %YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/phy/realtek,usb2phy.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Realtek DHC SoCs USB 2.0 PHY
> > +
> > +maintainers:
> > +  - Stanley Chang <stanley_chang@realtek.com>
> > +
> > +description:
> > +  Realtek USB 2.0 PHY support the digital home center (DHC) RTD series
> SoCs.
> > +  The USB 2.0 PHY driver is designed to support the XHCI controller.
> > +The SoCs
> > +  support multiple XHCI controllers. One PHY device node maps to one
> > +XHCI
> > +  controller.
> > +
> > +  RTD1295/RTD1619 SoCs USB
> > +  The USB architecture includes three XHCI controllers.
> > +  Each XHCI maps to one USB 2.0 PHY and map one USB 3.0 PHY on some
> > + controllers.
> > +  XHCI controller#0 -- usb2phy -- phy#0
> > +                    |- usb3phy -- phy#0  XHCI controller#1 -- usb2phy
> > + -- phy#0  XHCI controller#2 -- usb2phy -- phy#0
> > +                    |- usb3phy -- phy#0
> > +
> > +  RTD1395 SoCs USB
> > +  The USB architecture includes two XHCI controllers.
> > +  The controller#0 has one USB 2.0 PHY. The controller#1 includes two
> > + USB 2.0  PHY.
> > +  XHCI controller#0 -- usb2phy -- phy#0  XHCI controller#1 -- usb2phy
> > + -- phy#0
> > +                               |- phy#1
> > +
> > +  RTD1319/RTD1619b SoCs USB
> > +  The USB architecture includes three XHCI controllers.
> > +  Each XHCI maps to one USB 2.0 PHY and map one USB 3.0 PHY on
> controllers#2.
> > +  XHCI controller#0 -- usb2phy -- phy#0  XHCI controller#1 -- usb2phy
> > + -- phy#0  XHCI controller#2 -- usb2phy -- phy#0
> > +                    |- usb3phy -- phy#0
> > +
> > +  RTD1319d SoCs USB
> > +  The USB architecture includes three XHCI controllers.
> > +  Each xhci maps to one USB 2.0 PHY and map one USB 3.0 PHY on
> controllers#0.
> > +  XHCI controller#0 -- usb2phy -- phy#0
> > +                    |- usb3phy -- phy#0  XHCI controller#1 -- usb2phy
> > + -- phy#0  XHCI controller#2 -- usb2phy -- phy#0
> > +
> > +  RTD1312c/RTD1315e SoCs USB
> > +  The USB architecture includes three XHCI controllers.
> > +  Each XHCI maps to one USB 2.0 PHY.
> > +  XHCI controller#0 -- usb2phy -- phy#0  XHCI controller#1 -- usb2phy
> > + -- phy#0  XHCI controller#2 -- usb2phy -- phy#0
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - enum:
> > +          - realtek,rtd1295-usb2phy
> > +          - realtek,rtd1395-usb2phy
> > +          - realtek,rtd1619-usb2phy
> > +          - realtek,rtd1319-usb2phy
> > +          - realtek,rtd1619b-usb2phy
> > +          - realtek,rtd1312c-usb2phy
> > +          - realtek,rtd1319d-usb2phy
> > +          - realtek,rtd1315e-usb2phy
> 
> Keep entries ordered alphabetically.

Okay.

> > +      - const: realtek,usb2phy
> > +
> > +  reg:
> > +    items:
> > +      - description: PHY data registers
> > +      - description: PHY control registers
> > +
> > +  "#address-cells":
> > +    const: 1
> > +
> > +  "#size-cells":
> > +    const: 0
> > +
> > +  "#phy-cells":
> > +    const: 0
> > +
> > +  realtek,usb-ctrl:
> > +    description: The phandle of syscon used to control USB PHY power
> domain.
> > +    $ref: /schemas/types.yaml#/definitions/phandle
> 
> No, we have power-domains for this.

Maybe I use the word "control power domain" is not well, I just want to control the ldo of usb phy.
Revised:
The phandle of syscon used to control the ldo of USB PHY.

> > +
> > +patternProperties:
> > +  "^phy@[0-3]+$":
> > +    type: object
> > +    description:
> > +      Each sub-node is a PHY device for one XHCI controller.
> 
> I don't think it is true. You claim above that you have 0 as phy-cells, means you
> have one phy. Here you say you can have up to 4 phys.

I mean the driver can support up to 4 phys.
For RTD1295 has only one phy.
For RTD1395 has two phys.

> > +      For most Relatek SoCs, one XHCI controller only support one the USB
> 2.0
> > +      phy. For RTD1395 SoC, the one XHCI controller has two USB 2.0
> PHYs.
> > +    properties:
> > +      realtek,page0-param:
> > +        description: PHY parameter at page 0. The data are the pair of
> the
> > +          offset and value.
> 
> This needs to be specific. What the heck is "PHY parameter"?
> 
> > +        $ref: /schemas/types.yaml#/definitions/uint32-array
> 
> Array? Then maxItems.
I have found other document.
It should be a uint32-matrix.
I will add the maxItems.

> > +
> > +      realtek,page1-param:
> > +        description: PHY parameter at page 1. The data are the pair of
> the
> > +          offset and value.
> > +        $ref: /schemas/types.yaml#/definitions/uint32-array
> > +
> > +      realtek,page2-param:
> > +        description: PHY parameter at page 2. The data are the pair of
> the
> > +          offset and value. If the PHY support the page 2 parameter.
> > +        $ref: /schemas/types.yaml#/definitions/uint32-array
> > +
> > +      realtek,support-page2-param:
> > +        description: Set this flag if PHY support page 2 parameter.
> 
> Why this cannot be deducted from compatible?
It can identify by compatible.

> 
> > +        type: boolean
> > +
> > +      realtek,do-toggle:
> > +        description: Set this flag to enable PHY parameter toggle when
> port
> > +          status change.
> 
> Do not instruct OS what to do. Explain why this is a hardware characteristic.

In my original intention, we hope that this property can be used to control the phy driver do parameter toggle.
Is it a hardware characteristic? I don't think it's exactly a hardware feature.
Maybe it can be specified by the compatible.

> > +        type: boolean
> > +
> > +      realtek,do-toggle-driving:
> > +        description: Set this flag to enable PHY parameter toggle for
> adjust
> > +          the driving when port status change.
> 
> Do not instruct OS what to do. Explain why this is a hardware characteristic.
> 
> 
> > +        type: boolean
> > +
> > +      realtek,check-efuse:
> > +        description: Enable to update PHY parameter from reading otp
> table.
> 
> Do not instruct OS what to do. Explain why this is a hardware characteristic.

Same above.

> > +        type: boolean
> > +
> > +      realtek,use-default-parameter:
> > +        description: Don't set parameter and use default value in
> hardware.
> 
> NAK, you are just making things up.
This is a software flow control.
I will remove it.

> 
> > +        type: boolean
> > +
> > +      realtek,is-double-sensitivity-mode:
> > +        description: Set this flag to enable double sensitivity mode.
> 
> All your descriptions copy the name of property. You basically say nothing more.
> I already mentioned this before. Don't ignore the feedback, but address it.

I will improve this.

> > +        type: boolean
> > +
> > +      realtek,ldo-force-enable:
> > +        description: Set this flag to force enable ldo mode.
> 
> Drop everywhere "Set this flag to", because it is redundant. Now compare what
> is left with property name.
> 
> Property name: realtek,ldo-force-enable
> Your description: "force enable ldo mode"
> 
> How is this helpful to anybody?

This is a software flow control.
I will remove it.

Thanks,
Stanley
.