Re: [PATCH v2 0/2] usb: dwc2: Use clk bulk API for supporting multiple clocks

[Rob Herring <robh@kernel.org>]

On Mon, Jan 25, 2021 at 10:38:23AM +0100, Sascha Hauer wrote:
> Currently the dwc2 driver only supports a single clock. I have a board
> here which has a dwc2 controller with a somewhat special clock routing
> to the phy. Both the dwc2 controller and the ULPI phy get their phy
> clock from a SI5351 clock generator. This clock generator has multiple
> clock outputs which each is modelled as a separate clk in Linux.
> Unfortunately the clock to the phy and the clock to the dwc2 core are on
> two different output pins of the SI5351, so we have two clocks which
> must be enabled.  The phy is driven by the usb-nop-xceiver driver which
> supports a single clock. My first approach was to add support for a
> second clock to that driver, but technically the other clock is
> connected to the dwc2 core, so instead I added support for a second
> clock to the dwc2 driver.  This can easily be archieved with the clk
> bulk API as done in this series.

Where is the usb-nop-xceiver single clock coming from? 

Maybe you shouldn't be using usb-nop-xceiver? There is a ULPI binding 
though that alone doesn't really help you.

Rob