On 12/6/22 21:17, Stephen Boyd wrote: > Quoting Sean Anderson (2022-11-01 16:27:21) >> On 11/1/22 16:10, Stephen Boyd wrote: >> >> >> >> Oh, I remember why I did this. I need the reference clock for clk_hw_round_rate, >> >> which is AFAICT the only correct way to implement round_rate. >> >> >> > >> > Is the reference clk the parent of the clk implementing >> > clk_ops::round_rate()? >> >> Yes. We may be able to produce a given output with multiple reference >> rates. However, the clock API provides no mechanism to say "Don't ask >> for the parent clock to be rate X, you just tried it and the parent >> clock can't support it." So instead, we loop over the possible reference >> rates and pick the first one which the parent says it can round to. >> > > Sorry, I'm lost. Why can't you loop over possible reference rates in > determine_rate/round_rate clk op here? This is what I do currently, but you need to have the parent clock to do so. With your suggested method, we never actually get a struct clk(_hw) which we can query for rate support. --Sean