On 18-08-21, 18:55, Dmitry Osipenko wrote:

18.08.2021 12:41, Ulf Hansson пишет:

Either way gives the equal result. The new callback allows to remove the
boilerplate dev_pm_opp_set_rate(clk_get_rate() code from the rpm-resume
of consumer devices, that's it.

It may not be equal, as dev_pm_opp_set_rate() may do additional stuff,
now or in a later implementation. Currently it only does
regulator_enable() as a special case, but it can be clk_enable() as
well. Also, this tries to solve the problem in a tricky/hacky way,
while all you wanted was to make the genpd aware of what the
performance state should be.

Your driver can break tomorrow if we started to do more stuff from
this API at another time.

quoted

dev_pm_opp_set_rate() is best called from consumer drivers, as they
need to be in control.

quoted

What we need here is just configure. So something like this then:

The intent wasn't to use dev_pm_opp_set_rate() from
__genpd_dev_pm_attach(), but to set genpd->rpm_pstate in accordance to
the h/w configuration.

Right.

On Tegra we have a chain of PDs and it's not trivial to convert the
device's OPP into pstate because only the parent domain can translate
the required OPP.

The driver should just be required to make a call, and OPP/genpd core
should return it a value. This is already done today while setting the
pstate for a device. The same frameworks must be able to supply a
value to be used for the device.

Viresh, please take a look at what I did in [1]. Maybe it could be done
in another way.

I looked into this and looked like too much trouble. The
implementation needs to be simple. I am not sure I understand all the
problems you faced while doing that, would be better to start with a
simpler implementation of get_performance_state() kind of API for
genpd, after the domain is attached and its OPP table is initialized.

Note, that the OPP table isn't required to be fully initialized for
the device at this point, we can parse the DT as well if needed be.

-- 
viresh