Re: [PATCH v2 0/2] usb: dwc3: support clocks and resets for DWC3 core

[Manu Gautam <mgautam@codeaurora.org>]

HI,


On 4/19/2018 4:03 AM, Masahiro Yamada wrote:
> In the current design of DWC3 driver,
> the DT typically becomes a nested structure like follows:
>
>   dwc3-glue {
>           compatible = "foo,dwc3";
>           ...
>
>           dwc3 {
>                   compatible = "snps,dwc3";
>                   ...
>           };
>   }
>
> The current DWC3 core (drivers/usb/dwc3/core.c) can not handle
> clocks / resets at all.
>
> The only solution we have now, is to put DWC3 core node under
> the glue layer node, then add clocks and resets there.
> Actually, dwc3-of-simple.c exists to handle clocks and resets.
>
> As always for digital circuits, DWC3 core IP itself needs clock input.
> This is specific to this IP.  So, supporting clocks and resets in
> dwc3/core.c makes sense.

Why can't dwc3-of-simple be used with this IP?
Adding core/reset handling in both core and glue drivers might
only add to confusion and I cant think of a reason why having a parent
node representing dwc3-of-simple glue would be any concern.
Or are you planning to remove dwc3-of-simple.c driver?

>
> In this version, the number of clocks (and names) is specific
> to this IP, with clock names taken from Synopsys datasheet.

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