Lee,

On Wed, May 13, 2015 at 7:39 AM, Lee Jones [off-list ref] wrote:

On Mon, 04 May 2015, Andrew Bresticker wrote:

quoted

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 <redacted>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <redacted>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <redacted>
Cc: Kumar Gala <redacted>
Cc: Samuel Ortiz <redacted>
Cc: Lee Jones <redacted>
---
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 at 0,70098000 {
+             compatible = "nvidia,tegra124-xusb";
+             reg = <0x0 0x70098000 0x0 0x1000>;
+             ranges;
+
+             #address-cells = <2>;
+             #size-cells = <2>;
+
+             usb-host at 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 at 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.

Thanks,
Andrew