Re: [PATCH v3 2/2] clocksource: Add renesas-ostm timer driver

[Geert Uytterhoeven <geert@linux-m68k.org>]

On Tue, Jan 24, 2017 at 9:19 PM, Chris Brandt <Chris.Brandt@renesas.com> wrote:
> On Tuesday, January 24, 2017, Daniel Lezcano wrote:
>> > > > +early_platform_init("earlytimer", &ostm_timer);
>> > > > +subsys_initcall(ostm_init); module_exit(ostm_exit);
>> > > > +
>> > > > +MODULE_AUTHOR("Chris Brandt");
>> > > > +MODULE_DESCRIPTION("Renesas OSTM Timer Driver");
>> > > > +MODULE_LICENSE("GPL v2");
>> > >
>> > > Maybe you can try with builtin_platform ?
>> >
>> > Good idea. But, now I get a "Section mismatch" during link time so
>> > I'll have to figure out why that is.
>>
>> Mmh, I think it would be more consistent to convert this to:
>>
>> CLOCKSOURCE_OF_DECLARE(ostm, "renesas,ostm", ostm_init);
>>
>> The only problem is to get the struct device associated to the of_node
>> passed as parameter to ostm_init in order to use the devm_* API.
>>
>> I think of_find_device_by_node should return the platform_device, then
>> pdev->dev. If that works the other drivers will benefit from that to
>> pdev->remove all
>> the rollback code everywhere.
>
> It was a good idea....but it will not work.
>
> While CLOCKSOURCE_OF_DECLARE is good at putting the driver at the
> front of the line for loading, it's too early in boot to detect
> a platform_device.

That's correct. All those *_OF_DECLARE() style initializations start
to break as soon as power and/or clock domains are involved.
That's one reason why some subsystems (e.g. clock) are moving away from it.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds