Re: [PATCH 1/2] dt-bindings: usb: Add documentation for AM62 USB Wrapper module

[Krzysztof Kozlowski <krzk@kernel.org>]

On 23/03/2022 10:17, Aswath Govindraju wrote:
> Hi Krzysztof,

(...)

>>> +
>>> +  ti,syscon-phy-pll-refclk:
>>> +    $ref: /schemas/types.yaml#/definitions/phandle-array
>>> +    items:
>>> +      - items:
>>> +          - description: Phandle to the SYSCON entry
>>> +          - description: USB phy control register offset within SYSCON
>>> +    description: Specifier for configuring frequency of ref clock input.
>>
>> This is a bit strange. The ref clock is the "ref" input clock, right? In
>> such case use clk_set_rate()... Using syscon for managing clocks is not
>> the proper way.
>>
> 
> The syscon property is not being used to set the ref clock frequency but
> is rather being used to indicate the input clock frequency for USB PHY
> operation. I think the description seems be misleading. I will update it
> in the respin, to reflect the above description.

Yes, please, it will help.

> 
>> Plus all the issues pointed out by Roger.
>>
>>> +
>>> +  '#address-cells':
>>> +    const: 2
>>> +
>>> +  '#size-cells':
>>> +    const: 2
>>
>> No children allowed?
>>
>> I understand this is a wrapper, which explains why you do not include
>> usb-hcd.yaml schema. But since it is a wrapper, what is it wrapping?
>>
> 
> Yes, there is a child node, which would be the dwc3-contoller node.
> Would adding the child node too in the example help capture this better?

Yes, please, because then you will also spot errors when running
dt_binding_check.

You need patternProperties for "^usb@[0-9a-f]+$" referencing Synopsys
schema. Something like:
Documentation/devicetree/bindings/usb/samsung,exynos-dwc3.yaml



Best regards,
Krzysztof