Quoting Maxime Ripard (2023-03-29 12:50:49) > On Wed, Mar 22, 2023 at 04:31:04PM -0700, Stephen Boyd wrote: > > > The clk_set_parent() path is valid for those cases. Probably nobody > > cares about determine_rate because they don't set rates on these clks. > > Some drivers even explicitly left out determine_rate()/round_rate() > > because they didn't want to have some other clk round up to the mux > > and change the parent. > > > > Eventually we want drivers to migrate to determine_rate op so we can get > > rid of the round_rate op and save a pointer (we're so greedy). It's been > > 10 years though, and that hasn't been done. Sigh! I can see value in > > this series from the angle of migrating, but adding a determine_rate op > > when there isn't a round_rate op makes it hard to reason about. What if > > something copies the clk_ops or sets a different flag? Now we've just > > added parent changing support to clk_set_rate(). What if the clk has > > CLK_SET_RATE_PARENT flag set? Now we're going to ask the parent clk to > > change rate. Fun bugs. > > > > TL;DR: If the set_parent op exists but determine_rate/round_rate doesn't > > then the clk is a mux that doesn't want to support clk_set_rate(). Make > > a new mux function that's the contents of the CLK_SET_RATE_NO_REPARENT > > branch in clk_mux_determine_rate_flags() and call that directly from the > > clk_ops so it is clear what's happening, > > clk_hw_mux_same_parent_determine_rate() or something with a better name. > > Otherwise migrate the explicit determine_rate op to this new function > > and don't set the flag. > > > > It may be possible to entirely remove the CLK_SET_RATE_NO_REPARENT flag > > with this design, if the determine_rate clk_op can call the inner > > wrapper function instead of __clk_mux_determine_rate*() (those > > underscores are awful, we should just prefix them with clk_hw_mux_*() > > and live happier). That should be another patch series. > > Sorry but it's not really clear to me what you expect in the v2 of this > series (if you even expect one). It looks that you don't like the > assignment-if-missing idea Mark suggested, but should I just > rebase/resend or did you expect something else? > Yes, we want explicit code. Just rebase & resend. Don't add a determine_rate if there isn't a round_rate. Don't add more users of CLK_SET_RATE_NO_REPARENT. Instead, make an explicit determine_rate function for that. If you want to work on the removal of CLK_SET_RATE_NO_REPARENT go for it. Otherwise I'll take care of it after this series.
