[PATCH 3/3] dt-bindings: Document the STM32 USB OTG DWC2 core binding

[Rob Herring]

On Fri, Jun 24, 2016 at 03:51:18PM -0300, Bruno Herrera wrote:
> On Fri, Jun 24, 2016 at 12:41 PM, Rob Herring <robh at kernel.org> wrote:
> > On Tue, Jun 21, 2016 at 11:25:49PM -0300, Bruno Herrera wrote:
> >> Signed-off-by: Bruno Herrera <bruherrera at gmail.com>
> >> ---
> >>  Documentation/devicetree/bindings/usb/dwc2.txt | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt
> >> index 20a68bf..79e5370 100644
> >> --- a/Documentation/devicetree/bindings/usb/dwc2.txt
> >> +++ b/Documentation/devicetree/bindings/usb/dwc2.txt
> >> @@ -11,6 +11,7 @@ Required properties:
> >>    - "lantiq,arx100-usb": The DWC2 USB controller instance in Lantiq ARX SoCs;
> >>    - "lantiq,xrx200-usb": The DWC2 USB controller instance in Lantiq XRX SoCs;
> >>    - snps,dwc2: A generic DWC2 USB controller with default parameters.
> >> +  - st,stm32-fsotg: The DWC2 USB controller instance in STM32F4 SoCs in FS mode;
> >
> > This should go above snps,dwc2.
> >
> Ok, tks!
> 
> > What determines FS mode vs. HS?
> >
> Its more HW design decision.
> STM32F429/439/469 has two OTG controllers, one that is FS (internal
> phy) and other that is HS (but can also work in FS mode with
> internal/external phy)
> This bind work with both cores FS and HS working with the internal PHY.
> 
> I tested the following configurations:
> 1 - STM32F429I-DISCOv1 board (OTG HS working in FS mode internal PHY)
> 2 - STM32F469I-DISCO board (OTG FS)
> 
> I did not tested OTG HS core working in FS mode with external PHY (I2C).

You shouldn't be setting the compatible string based on which mode you 
want. So for the HS block, you need a different compatible string than 
the FS block and set the speed in another way (not sure if we have a 
standard way). Or perhaps the phy should determine the speed.

Rob