Date:   Wed, 10 May 2023 15:17:05 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Michal Simek <michal.simek@....com>, linux-kernel@...r.kernel.org,
        monstr@...str.eu, michal.simek@...inx.com, git@...inx.com,
        ilias.apalodimas@...aro.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Piyush Mehta <piyush.mehta@....com>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: Re: [PATCH v2] dt-bindings: usb: Add binding for Microchip usb5744
 hub controller

On 10/05/2023 13:00, Michal Simek wrote:
> 
> 
> On 5/9/23 18:04, Krzysztof Kozlowski wrote:
>> On 09/05/2023 16:19, Michal Simek wrote:
>>>
>>>
>>> On 5/7/23 10:07, Krzysztof Kozlowski wrote:
>>>> On 05/05/2023 15:25, Michal Simek wrote:
>>>>> The Microchip usb5744 is a SS/HS USB 3.0 hub controller with 4 ports.
>>>>> The binding describes USB related aspects of the USB5744 hub, it as
>>>>> well cover the option of connecting the controller as an i2c slave.
>>>>> When i2c interface is connected hub needs to be initialized first.
>>>>> Hub itself has fixed i2c address 0x2D but hardcoding address is not good
>>>>> idea because address can be shifted by i2c address translator in the
>>>>> middle.
>>>>>
>>>>> Signed-off-by: Piyush Mehta <piyush.mehta@....com>
>>>>> Signed-off-by: Michal Simek <michal.simek@....com>
>>>>> ---
>>>>>
>>>>> Changes in v2:
>>>>> - fix i2c-bus property
>>>>> - swap usb2.0/3.0 compatible strings
>>>>> - fix indentation in example (4 spaces)
>>>>> - add new i2c node with microchip,usb5744 compatible property
>>>>>
>>>>> It looks like that usb8041 has also an optional i2c interface which is not
>>>>> covered. But it is mentioned at commit 40e58a8a7ca6 ("dt-bindings: usb:
>>>>> Add binding for TI USB8041 hub controller").
>>>>>
>>>>> i2c-bus name property was suggested by Rob at
>>>>> https://lore.kernel.org/all/CAL_JsqJedhX6typpUKbnzV7CLK6UZVjq3CyG9iY_j5DLPqvVdw@mail.gmail.com/
>>>>> and
>>>>> https://lore.kernel.org/all/CAL_JsqJZBbu+UXqUNdZwg-uv0PAsNg55026PTwhKr5wQtxCjVQ@mail.gmail.com/
>>>>>
>>>>> the question is if adding address like this is acceptable.
>>>>> But it must be specified.
>>>>>
>>>>> Driver will follow based on final dt-binding.
>>>>>
>>>>> $ref: usb-device.yaml# should be also added but have no idea how to wire it
>>>>> up to be applied only on usb node not i2c one.
>>>>>
>>>>> ---
>>>>>    .../bindings/usb/microchip,usb5744.yaml       | 110 ++++++++++++++++++
>>>>>    1 file changed, 110 insertions(+)
>>>>>    create mode 100644 Documentation/devicetree/bindings/usb/microchip,usb5744.yaml
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/usb/microchip,usb5744.yaml b/Documentation/devicetree/bindings/usb/microchip,usb5744.yaml
>>>>> new file mode 100644
>>>>> index 000000000000..7e0a3472ea95
>>>>> --- /dev/null
>>>>> +++ b/Documentation/devicetree/bindings/usb/microchip,usb5744.yaml
>>>>> @@ -0,0 +1,110 @@
>>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>>> +%YAML 1.2
>>>>> +---
>>>>> +$id: http://devicetree.org/schemas/usb/microchip,usb5744.yaml#
>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>>> +
>>>>> +title: Microchip USB5744 4-port Hub Controller
>>>>> +
>>>>> +description:
>>>>> +  Microchip's USB5744 SmartHubTM IC is a 4 port, SuperSpeed (SS)/Hi-Speed (HS),
>>>>> +  low power, low pin count configurable and fully compliant with the USB 3.1
>>>>> +  Gen 1 specification. The USB5744 also supports Full Speed (FS) and Low Speed
>>>>> +  (LS) USB signaling, offering complete coverage of all defined USB operating
>>>>> +  speeds. The new SuperSpeed hubs operate in parallel with the USB 2.0
>>>>> +  controller, so 5 Gbps SuperSpeed data transfers are not affected by slower
>>>>> +  USB 2.0 traffic.
>>>>> +
>>>>> +maintainers:
>>>>> +  - Piyush Mehta <piyush.mehta@....com>
>>>>> +  - Michal Simek <michal.simek@....com>
>>>>> +
>>>>> +select:
>>>>> +  properties:
>>>>> +    compatible:
>>>>> +      contains:
>>>>> +        const: microchip,usb5744
>>>>> +  required:
>>>>> +    - compatible
>>>>
>>>> I don't understand why do you need this select. It basically disables
>>>> schema matching for other ones.
>>>
>>> I didn't find a way how to have usbXXX,XXXX compatible strings and
>>> microchip,usb5744 compatible in the same file. I am definitely lacking knowledge
>>> how to write it properly that's why any advise is welcome.
>>
>> Hm, if you just have both of them like you have now, what happens?
> 
> 
> make 
> DT_SCHEMA_FILES=Documentation/devicetree/bindings/usb/microchip,usb5744.yaml 
> dt_binding_check
>    DTEX    Documentation/devicetree/bindings/usb/microchip,usb5744.example.dts
>    LINT    Documentation/devicetree/bindings
>    CHKDT   Documentation/devicetree/bindings/processed-schema.json
>    SCHEMA  Documentation/devicetree/bindings/processed-schema.json
>    DTC_CHK Documentation/devicetree/bindings/usb/microchip,usb5744.example.dtb
> /home/monstr/data/disk/linux/Documentation/devicetree/bindings/usb/microchip,usb5744.example.dtb: 
> hub@1: 'i2c-bus', 'peer-hub', 'reset-gpios' do not match any of the regexes: 
> 'pinctrl-[0-9]+'
> 	From schema: 
> /home/monstr/data/disk/linux/Documentation/devicetree/bindings/usb/microchip,usb5744.yaml
> /home/monstr/data/disk/linux/Documentation/devicetree/bindings/usb/microchip,usb5744.example.dtb: 
> hub@2: 'i2c-bus', 'peer-hub', 'reset-gpios' do not match any of the regexes: 
> 'pinctrl-[0-9]+'
> 	From schema: 
> /home/monstr/data/disk/linux/Documentation/devicetree/bindings/usb/microchip,usb5744.yaml
> 
> And this is even without usb-device.yaml wired.

Yeah, you cannot define properties in allOf:if:then. Your select just
makes the schema not selected thus it is a NOOP and error is hidden.

I gave you examples how these should be expressed and the examples *do
not* define properties in allOf:if:then, right?

Best regards,
Krzysztof

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