Quoting Maxime Ripard (2022-03-23 01:51:40) > Hi, > > > The whole point of this patch is to give an opportunity to every driver > to change the rate whenever the boundaries have changed, so we very much > want to have the option to change it if clk_set_rate() has never been > called. > > However, I think the issue is why req_rate would be 0 in the first > place? > > req_rate is initialized to what recalc_rate returns: > https://elixir.bootlin.com/linux/latest/source/drivers/clk/clk.c#L3607 > > So the case where req_rate is 0 shouldn't occur unless you had an > explicit clk_set_rate to 0, or if your clock was orphaned at some point. > > Judging from the code, it seems like the latter is the most plausible. > Indeed, __clk_core_init() will set req_rate to 0 if the clock is > orphaned (just like rate and accuracy), and > clk_core_reparent_orphans_nolock will be in charge of updating them when > the clock is no longer an orphan. > > However, clk_core_reparent_orphans_nolock() will update rate by calling > __clk_recalc_rate and accuracy by calling __clk_recalc_accuracies, but > it never sets req_rate. > > I'm not sure if this is the right patch, Stephen will tell, but could > you test: It looks correct to me. Would be helpful to have some comment of course that we're setting a default req_rate because we want a clk_set_rate_range() before clk_set_rate() to work properly when this clk is initially an orphan. We should be able to code up a test case for that too by registering an orphan and then registering the parent and then calling clk_set_rate_range().
