On 10/23/2015 11:11 AM, Tom Warren wrote:
This patch adds the device tree binding doc for the Tegra114
SPI controller and the Tegra210 QSPI controller.

Initially, this should be sent as a Linux kernel patch, since the kernel currently holds the definitive repository for DT bindings.

The binding should be based on the Tegra SPI binding present there, not on the non-standard binding for Tegra114 SPI that's evidently in the U-Boot tree.

That would imply sending the patch to the people/lists listed in the following Linux kernel MAINTAINERS entry for DT bindings, plus at least the Tegra mailing list and maintainers too:

OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
M:      Rob Herring <robh...@kernel.org>
M:      Pawel Moll <pawel.m...@arm.com>
M:      Mark Rutland <mark.rutl...@arm.com>
M:      Ian Campbell <ijc+devicet...@hellion.org.uk>
M:      Kumar Gala <ga...@codeaurora.org>
L:      devicet...@vger.kernel.org

diff --git a/doc/device-tree-bindings/spi/spi-tegra.txt 
b/doc/device-tree-bindings/spi/spi-tegra.txt
new file mode 100644
index 0000000..e215efe
--- /dev/null
+++ b/doc/device-tree-bindings/spi/spi-tegra.txt
@@ -0,0 +1,47 @@
+NVIDIA Tegra114 SPI controller.

Isn't this intended to be a binding for the QSPI controller?

+Required properties:
+- compatible : should be "nvidia,tegra114-spi".

This should be "qspi" not "spi", assuming the HW really is different. This is a separate HW module, right?

+- reg: Should contain SPI registers location and length.
+- interrupts: Should contain SPI interrupts.
+- clocks : Should contain an entry for SPI clock.

Reset- and DMA-related properties are missing here.

You could mark the DMA properties optional, and leave it up to drivers to support PIO mode if the DMA properties are missing.

+Recommended properties:
+- spi-max-frequency: Definition as per
+                     doc/device-tree-bindings/spi/spi-bus.txt

That should use a relative path ("spi-bus.txt"), so that the same text applies irrespective of whether the file is contained within the Linux kernel or U-Boot source trees.

+NVIDIA Tegra210 QSPI controller.

The binding for Tegra114 and Tegra210 should be (and appears to be) identical. There's no need to duplicate the text. Instead, simply say something like the following for the compatible value in the one copy of the text:

- compatible : should be one of the following:
 "nvidia,tegra114-qspi" (for Tegra114)
 "nvidia,tegra210-qspi" (for Tegra210)

However, if a driver that supports Tegra114 could operate correctly on Tegra210 without knowledge that it was running on different HW, the following compatible values area appropriate:

- compatible : should be one of the following:
  "nvidia,tegra114-qspi" (for Tegra114)
  "nvidia,tegra210-qspi", "nvidia,tegra114-qspi" (for Tegra210)
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