Re: [PATCH 1/3] dt-bindings: spi: Update clocks property for ARM pl022

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On 2022-02-28 15:11, Mark Brown wrote:
On Mon, Feb 28, 2022 at 02:26:12PM +0000, Robin Murphy wrote:

Who says that minItems is missing? Looking at the PL022 TRM[1] it seems
clear that SSPCLK is pretty fundamental to useful operation. If that DT ever
worked, it must be that the same clock is wired to both inputs, and the fact
that that's how the neighbouring PL011 is described is strongly suggestive.

Well, it could also be that the clock is wired to some other clock which
is always on (which I guess is why the driver allows this in the first
place, there's a lot of sloppy code around stuff like that in the tree).

I wouldn't say the driver "allows" it, so much as it just blindly grabs the first clock assuming it's SSPCLK per the binding, and thus it will happen to work out if the underlying physical clock is the same as, or equivalent to, the APB PCLK. Otherwise, it's already into some degree of not working properly, by virtue of reading the wrong clock rate.

Robin.



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