Hi Lee,
On 13/05/15 15:39, Lee Jones 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 <abres...@chromium.org>
>> Cc: Rob Herring <robh...@kernel.org>
>> Cc: Pawel Moll <pawel.m...@arm.com>
>> Cc: Mark Rutland <mark.rutl...@arm.com>
>> Cc: Ian Campbell <ijc+devicet...@hellion.org.uk>
>> Cc: Kumar Gala <ga...@codeaurora.org>
>> Cc: Samuel Ortiz <sa...@linux.intel.com>
>> Cc: Lee Jones <lee.jo...@linaro.org>
>> ---
>> 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]>;
> };
>
I am assuming that Andrew had laid it out like this to reflect the hw
structure. The mailbox and xhci controller are part of the xusb
sub-system and hence appear as child nodes. My understanding is that for
device-tree we want the device-tree structure to reflect the actual hw.
Is this not the case?
Cheers
Jon
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