Re: [PATCH 2/2] opp: Don't create an OPP table from dev_pm_opp_get_opp_table()

[Dmitry Osipenko <digetx@gmail.com>]

06.11.2020 09:24, Viresh Kumar пишет:
> It has been found that some users (like cpufreq-dt and others on LKML)
> have abused the helper dev_pm_opp_get_opp_table() to create the OPP
> table instead of just finding it, which is the wrong thing to do. This
> routine was meant for OPP core's internal working and exposed the whole
> functionality by mistake.
> 
> Change the scope of dev_pm_opp_get_opp_table() to only finding the
> table. The internal helpers _opp_get_opp_table*() are thus renamed to
> _add_opp_table*(), dev_pm_opp_get_opp_table_indexed() is removed (as we
> don't need the index field for finding the OPP table) and so the only
> user, genpd, is updated.
> 
> Note that the prototype of _add_opp_table() was already left in opp.h by
> mistake when it was removed earlier and so we weren't required to add it
> now.

Hello Viresh,

It looks like this is not an entirely correct change because previously
it was possible to get an empty opp_table in order to use it for the
dev_pm_opp_set_rate(), which would fall back to clk_set_rate if table is
empty.

Now it's not possible to get an empty table and
dev_pm_opp_of_add_table() would error out if OPPs are missing in a
device-tree. Hence it's not possible to implement a fall back without
abusing opp_set_regulators() or opp_set_supported_hw() for getting the
empty table. Or am I missing something?