On Thu, Nov 19, 2020 at 02:09:42PM +0000, Aisheng Dong wrote: > > From: Greg Kroah-Hartman <[email protected]> > > Sent: Thursday, November 19, 2020 9:10 PM > > > > On Thu, Nov 19, 2020 at 04:13:34AM +0000, Aisheng Dong wrote: > > > > Long story short, either > > > > > > > > * Don't care about the power domain in your clock driver. > > > > > > > > Or, > > > > > > > > * List the power domain in the clock controller's DT node and then > > > > use the normal APIs to get the power domain. And defer like any > > > > other driver if you can't get the power domain. > > > > > > > > > > Yes, I understand those are for normal cases. But our case is a bit > > > different and we don't want > > > imx_clk_scu() API return PROBE_DEFER which is unnecessary for a hundred of > > clocks. > > > Even we want to defer probe, we prefer to defer in imx_clk_scu_init() > > > rather > > than in imx_clk_scu(). > > > > What is wrong with PROBE_DEFER, that is what it is there for. > > Yes, we can use PROBE_DEFER, just not want to defer in imx_clk_scu_init() > when creating > sub clock devices. Instead, we want to defer at the beginning of clock driver > probe which > can save tens of defer probes due to the same reasons that PD driver is not > ready.
There's nothing wrong with deferring that many times until your proper driver is loaded, what does it cost you to do so? > > > Maybe the things can be simplified as a simple requirement: > > > How users can make Driver A (CLK) to be probed after Driver B (PD) > > > without explicit firmware function dependency description (e.g. phandle in > > DT)? > > > > > > As kernel core does not want to support it, then the left way may be > > > change scu-pd driver Inicall level or provide a private callback to query > > > the > > readiness. > > > > No, do not mess with that, as it totally breaks when things are built as a > > module. > > > > Can't this be addressed by proper module dependency? E.g clock module depends > on power domain module. Then clock driver can only be loaded after power > domain. Sure, if you can do that, make your modules load properly by symbol dependency and all should be fine. Have you done that? thanks, greg k-h
