How to properly take a boost::optional

I need to have a function accept a boost::optional<std::chrono::duration>. I would like to be able to pass it, for example, either std::chrono::milliseconds, std::chrono::seconds, or boost::none.

I have a couple of solutions which do not exactly achieve what I want.

Attempt 1:

template <class PeriodT> void foo(boost::optional<std::chrono::duration<int64_t, PeriodT>> duration);

Problems with attempt 1:

I cannot simply pass an std::chrono::duration or even boost::none. To pass boost::none I have to do the following:

boost::optional<std::chrono::seconds> input = boost::none; foo(input);

I cannot call
foo(boost::none);
or
std::chrono::seconds input(10); foo(input);

Attempt 2:

void foo(boost::optional<std::chrono::milliseconds> duration);

Problems with attempt 2:

Automatic conversion won't happen.
foo(std::chrono::seconds(10));
Will not compile.
foo(std::chrono::milliseconds(10));
Will compile, and so will
foo(boost::none);

Is there any way I can have a function cleanly accept a boost::optional
of any rep/period?