On 08/12/2022 02:15, Xiangsheng Hou (侯祥胜) wrote:

quoted

quoted

There have two rx related timing properties in spi-peripheral-
props.
The rx-sample-delay-ns have been used in Mediatek snfi driver to
adjust
controller sample delay.
However another spi-rx-delay-us is in microseconds. Take 52MHz for
example, the clock cycle will be 19.23ns which lower than 1us. This
may
not easy to by one clock cycle.

I agree, but nothing prevents you from adding your own property for
that.

I propose "mediatek,rx-latch-latency-ns" or "mediatek,rx-latency-ns", 
so that
we can specify the delay in nanoseconds: in that case, when we
specify 19ns,
the driver will safely round that resulting in 52MHz == 19.23ns =>
19ns valid.

Will be fixed in next series.

I am fine with this approach, but after explanations I was also fine
with clock cycles as unit. It's still quite specific unit and I think
several timings on buses are clock-cycle dependent, not time dependent.

Best regards,
Krzysztof


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