On Fri, Nov 04, 2022 at 09:09:02AM -0400, Krzysztof Kozlowski wrote: > It is not valid to put spi-max-frequency = 1 GHz in > spi-peripheral-props.yaml. ... > IOW, CPHA/CPOL are not valid for most devices, so they cannot be in > spi-peripheral-props.yaml. Your understanding of SPI clock polarity/phase is probably not the same as mine. "Not valid for most devices" is a gross misrepresentation. There are 4 electrical modes of communication between a SPI controller and a peripheral, formed by the 0/1 combination of the CPOL and CPHA bits. Some peripherals support only a subset of these modes of operation, that is completely true and I agree with it. But they're still SPI devices, and all 4 modes of communication apply to them all. That's why I made the comparison with the 1 GHz frequency. The spi-peripheral-props.yaml schema only says what properties are valid for a peripheral, and both CPOL and CPHA are valid for all SPI peripherals, even if some combos don't work (when neither spi-cpol nor spi-cpha is present, they are 0 and 0, so the connection works in SPI mode 0).
