On Fri, Mar 12, 2021 at 01:30:02PM +0100, Michael Walle wrote:

The card calls set_sysclk(), which eventually ends up in the codec.
The codec therefore, could figure out if it needs to configure the
clock or if it can use its internal FLL.
Is that what you mean?

Yes.

But the set_sysclk() of the codec isn't even called, because the
card itself already tries to call clk_set_rate() on the Codec's MCLK,
which returns with an error [0].

OK, so I think we need to push this down a level so that the clock
setting is implemented by the core/CODEC rather than by simple-card,
with the helpers being something the CODEC can opt out of.