On Mon, Jan 30, 2017 at 10:55:51AM -0800, Stephen Boyd wrote:
> On 01/29, Dmitry Torokhov wrote:
> > When converting a driver to managed resources it is desirable to be able to
> > manage all resources in the same fashion. This change allows managing
> > clocks in the same way we manage many other resources.
>
> Can you please add 'managing clock prepared and enabled state in
> the same way'?
>
> The current wording makes it sound like we don't have
> devm_clk_get() when we do.
>
> >
> > This adds the following managed APIs:
> >
> > - devm_clk_prepare()/devm_clk_unprepare();
> > - devm_clk_prepare_enable()/devm_clk_disable_unprepare().
>
> Wouldn't this be preceded by a devm_clk_get() call? Wouldn't it
> be even shorter to have the APIs
>
> devm_clk_get_and_prepare()/devm_clk_unprepare_and_put()
> devm_clk_get_and_prepare_enable()/devm_clk_disable_unprepare_and_put()
>
> instead?
>
In many cases I see
devm_clk_get(clk1);
devm_clk_get(clk2);
clk_prepare_enable(clk1);
clk_prepare_enable(clk2);
Sometimes the calls are intertwined with setting the clock rates.
devm_clk_get(clk);
clk_set_rate(clk, rate);
clk_prepare_enable(clk);
Maybe the additional calls make sense; I can imagine they would.
However, I personally would be a bit wary of changing the initialization
order of multi-clock initializations, and I am not sure how a single call
could address setting the rate ([devm_]clk_get_setrate_prepare_enable()
seems like a bit too much).
[ On a side note, why is there no clk_get_prepare_enable() and
clk_get_prepare() ? Maybe it would be better to introduce those
together with the matching devm_ functions in a separate patch
if they are useful. ]
> Is there any other subsystem that has similar functionality?
> Regulators? GPIOs? Resets? I'm just curious if those subsystems
> also need similar changes.
>
Ultimately yes, and most already do. If I recall correctly, I tried to
introduce devm_ functions for regulators some time ago, but that was
rejected with the comment that it would invite misuse. At the time
I accepted that; today my reaction would be to counter that pretty much
everything can be misused, and that the potential for misuse should not
penaltize all the valid use cases.
Thanks,
Guenter
