Rob, On Tue, May 13, 2025 at 07:25:50PM +0200, Niklas Cassel wrote: > On Mon, May 12, 2025 at 08:59:09AM -0500, Rob Herring wrote: > > I do realize that, for boards supporting more than a single mode (Common > Clock/SRNS/SRIS), this device tree property is basically a configuration > option. For boards only supporting a single mode, it is actually describing > the hardware. > > E.g. Rock 5b can run in both SRNS and SRIS mode (Common Clock is not > supported), and since this has to be configured before starting the link, > I cannot think of a better way to control this than a device tree property. Just to provide some additional context (although it was mentioned in the commit log), basically what I am trying to accomplish is to replace the vendor specific properties "nvidia,enable-ext-refclk" (Common Clock) and "nvidia,enable-srns" (SRNS) (the tegra SoC does not support SRIS, that is why it doesn't have a property for that) with a generic property that can be used by all PCIe endpoint controller drivers. IMO, there is really no reason to have two properties for this, it is cleaner to just have a single property which is basically an enum (as suggested by this patch). To bring some additional insight of how it will be used, one could grep for nvidia,enable-ext-refclk and nvidia,enable-srns in the tree. My plan was to get some feedback on this binding before implementing support for SRIS in the dw-rockchip driver, but I can also modify the tegra driver to also support this new property in V2. Kind regards, Niklas
