Re: [PATCH v8 4/9] mfd: Add binding document for NVIDIA Tegra XUSB

[Lee Jones]

On Thu, 14 May 2015, Jon Hunter wrote:

> 
> On 14/05/15 08:29, Lee Jones wrote:
> > On Wed, 13 May 2015, Andrew Bresticker wrote:
> > 
> >> On Wed, May 13, 2015 at 9:50 AM, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> >>> On Wed, 13 May 2015, Andrew Bresticker wrote:
> >>>
> >>>> Lee,
> >>>>
> >>>> On Wed, May 13, 2015 at 7:39 AM, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> >>>>> On Mon, 04 May 2015, Andrew Bresticker wrote:
> >>>>>
> >>>>>> Add a binding document for the XUSB host complex on NVIDIA Tegra124
> >>>>>> and later SoCs.  The XUSB host complex includes a mailbox for
> >>>>>> communication with the XUSB micro-controller and an xHCI host-controller.
> >>>>>>
> >>>>>> Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
> >>>>>> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> >>>>>> Cc: Pawel Moll <pawel.moll@xxxxxxx>
> >>>>>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> >>>>>> Cc: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx>
> >>>>>> Cc: Kumar Gala <galak@xxxxxxxxxxxxxx>
> >>>>>> Cc: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
> >>>>>> Cc: Lee Jones <lee.jones@xxxxxxxxxx>
> >>>>>> ---
> >>>>>> Changes from v7:
> >>>>>>  - Move non-shared resources into child nodes.
> >>>>>> New for v7.
> >>>>>> ---
> >>>>>>  .../bindings/mfd/nvidia,tegra124-xusb.txt          | 37 ++++++++++++++++++++++
> >>>>>>  1 file changed, 37 insertions(+)
> >>>>>>  create mode 100644 Documentation/devicetree/bindings/mfd/nvidia,tegra124-xusb.txt
> >>>>>>
> >>>>>> diff --git a/Documentation/devicetree/bindings/mfd/nvidia,tegra124-xusb.txt b/Documentation/devicetree/bindings/mfd/nvidia,tegra124-xusb.txt
> >>>>>> new file mode 100644
> >>>>>> index 0000000..bc50110
> >>>>>> --- /dev/null
> >>>>>> +++ b/Documentation/devicetree/bindings/mfd/nvidia,tegra124-xusb.txt
> >>>>>> @@ -0,0 +1,37 @@
> >>>>>> +NVIDIA Tegra XUSB host copmlex
> >>>>>> +==============================
> >>>>>> +
> >>>>>> +The XUSB host complex on Tegra124 and later SoCs contains an xHCI host
> >>>>>> +controller and a mailbox for communication with the XUSB micro-controller.
> >>>>>> +
> >>>>>> +Required properties:
> >>>>>> +--------------------
> >>>>>> + - compatible: For Tegra124, must contain "nvidia,tegra124-xusb".
> >>>>>> +   Otherwise, must contain '"nvidia,<chip>-xusb", "nvidia,tegra124-xusb"'
> >>>>>> +   where <chip> is tegra132.
> >>>>>> + - reg: Must contain the base and length of the XUSB FPCI registers.
> >>>>>> + - ranges: Bus address mapping for the XUSB block.  Can be empty since the
> >>>>>> +   mapping is 1:1.
> >>>>>> + - #address-cells: Must be 2.
> >>>>>> + - #size-cells: Must be 2.
> >>>>>> +
> >>>>>> +Example:
> >>>>>> +--------
> >>>>>> +     usb@0,70098000 {
> >>>>>> +             compatible = "nvidia,tegra124-xusb";
> >>>>>> +             reg = <0x0 0x70098000 0x0 0x1000>;
> >>>>>> +             ranges;
> >>>>>> +
> >>>>>> +             #address-cells = <2>;
> >>>>>> +             #size-cells = <2>;
> >>>>>> +
> >>>>>> +             usb-host@0,70090000 {
> >>>>>> +                     compatible = "nvidia,tegra124-xhci";
> >>>>>> +                     ...
> >>>>>> +             };
> >>>>>> +
> >>>>>> +             mailbox {
> >>>>>> +                     compatible = "nvidia,tegra124-xusb-mbox";
> >>>>>> +                     ...
> >>>>>> +             };
> >>>>>
> >>>>> This doesn't appear to be a proper MFD.  I would have the USB and
> >>>>> Mailbox devices probe seperately and use a phandle to point the USB
> >>>>> device to its Mailbox.
> >>>>>
> >>>>> usb@xyz {
> >>>>>         mboxes = <&xusb-mailbox, [chan]>;
> >>>>> };
> >>>>
> >>>> Then what will set up the shared regmap?  The point of using an MFD
> >>>> here was to share a register set with both the mailbox and xHCI
> >>>> drivers and avoid having to map the same register set twice in two
> >>>> separate drivers.
> >>>
> >>> Can you share the mapping please?
> >>
> >> What do you mean?  That's what the MFD is doing now by setting up an
> >> MMIO regmap to be shared between the two devices.
> > 
> > I mean, can you share the documentation with me. :)
> 
> You can download the documentation from here [1]. See chapter 19 USB
> complex. However, I will warn you that unfortunately, you need to sign
> up for an account :-(

I'll give that a miss for the time being.  See my other mail for now.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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