Re: [PATCH 2/3] dt-bindings: spi: Add DT schema for Tegra SPIDEV controller

From: Jon Hunter
Date: Mon Mar 31 2025 - 08:35:26 EST



On 27/03/2025 15:33, Mark Brown wrote:
On Wed, Mar 26, 2025 at 12:16:53PM +0000, Jon Hunter wrote:
On 25/03/2025 17:05, Mark Brown wrote:

The way I imagine it, exporting would involve writing a chip-select to a
specific SPI controller's "export" sysfs attribute to have a SPI device
created for that particular chip-select and bind it to spidev.

My general feeling with those is that if you're building for them you're
probably either already modifiying your kernel or easily able to cope
with doing so.

That's definitely what we do today, modify the kernel directly to achieve
what we need. I am trying to avoid carrying too many out of tree patches for
stuff like this and have something in the kernel that works by default. This
is even more important for 3rd party Linux distros that will not accept
non-upstream code.

Overlays should work well for that case too!


If you mean device-tree overlays, I don't see how that will work today. Unless we are to use one of the existing compatible strings, but that feels wrong because we are not using any of those devices and like I mentioned, just using 'spidev' alone in device-tree does not work with the latest kernels.

Jon

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