Messages in this thread | | | From | Tomeu Vizoso <> | Date | Tue, 27 Oct 2015 15:46:07 +0100 | Subject | Re: [PATCH v6 04/22] of: add function to allow probing a device from a OF node |
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On 26 October 2015 at 09:16, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > On Mon, Sep 21, 2015 at 4:02 PM, Tomeu Vizoso > <tomeu.vizoso@collabora.com> wrote: >> Walks the OF tree up and finds the closest ancestor that has a struct >> device associated with it, probing it if isn't bound to a driver yet. >> >> The above should ensure that the dependency represented by the passed OF >> node is available, because probing a device should cause its descendants >> to be probed as well (when they get registered). >> >> Subsystems can use this when looking up resources for drivers, to reduce >> the chances of deferred probes because of the probing order of devices. >> >> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> > > Don't know to which response I should post this comment, so I'm responding > to the original email. > > Some subsystems already do this. > If you call e.g. syscon_regmap_lookup_by_phandle(), it will call > of_syscon_register() if the syscon device pointed to hasn't been registered yet.
Hi Geert,
I think I prefer if devices are registered as early as possible and then only probed on-demand, as registration is very much device-specific but probing is the same for all devices.
But I think in general we should be doing more things on demand and depending less on the order in which we mass initialize stuff (devices, classes, drivers, etc).
Regards,
Tomeu
> 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 > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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