On Thu, Apr 06, 2017 at 07:01:47PM +0200, Axel Holzinger wrote:
> So the values for cpts_clock_mult and cpts_clock_shift are configured like
> you proposed.
Sorry, I didn't mean that those are the correct values. Those two
properties define the clock constants:
nanoseconds = ticks * cpts_clock_mult / 2^cpts_clock_shift
The values from the beaglebone are
cpts_clock_mult = <0x80000000>;
cpts_clock_shift = <29>;
and so
nanoseconds = ticks * 2^31 / 2^29
nanoseconds = ticks * 4
which is correct if the input clock is 250 MHz. If your SoC uses a
different clock, then the values in the DTS are wrong.
> Is there anything else I can check?
The two values are calculated automatically as of commit:
v4.10-rc1~202^2~61^2~1 88f0f0b net: ethernet: ti: cpts: calc mult and shift
from refclk freq
You can try kernel v4.10 and remove those two properties from the DTS.
It should "just work" then.
HTH,
Richard
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