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SubjectRe: [PATCH] clk: renesas: r9a06g032: Avoid needless probe deferring
Hi Phil,

On Wed, Jul 18, 2018 at 4:34 PM Phil Edworthy <phil.edworthy@renesas.com> wrote:
> To avoid all SoC peripheral drivers deferring their probes, both clock and
> pinctrl drivers should already be probed. Since the pinctrl driver requires
> a clock to access the registers, the clock driver should be probed before
> the pinctrl driver.
>
> Therefore, move the clock driver from subsys_initcall to core_initcall.
>
> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>

Thanks for your patch!

The (not yet upstreamed) pinctrl driver uses postcore_initcall(), right?

> --- a/drivers/clk/renesas/r9a06g032-clocks.c
> +++ b/drivers/clk/renesas/r9a06g032-clocks.c
> @@ -877,17 +877,18 @@ static const struct of_device_id r9a06g032_match[] = {
> { }
> };
>
> -static struct platform_driver r9a06g032_clock_driver = {
> +static struct platform_driver r9a06g032_clock_driver __refdata = {
> .driver = {
> .name = "renesas,r9a06g032-sysctrl",
> .of_match_table = r9a06g032_match,
> },
> + .probe = r9a06g032_clocks_probe,
> };
>
> static int __init r9a06g032_clocks_init(void)
> {
> - return platform_driver_probe(&r9a06g032_clock_driver,
> - r9a06g032_clocks_probe);
> + platform_driver_register(&r9a06g032_clock_driver);
> + return 0;
> }

Why are all of the above changes needed?
Shouldn't the platform_driver_probe() keep on working?
If it does not, it means the clock driver has some other dependency, and
cannot be bound immediately. This is potentially a dangerous situation,
as r9a06g032_clocks_probe() is __init, but can still be called at any time
later. Hence using platform_driver_probe() is the safe thing to do,
possibly with a different reshuffling of the clock and pinctrl initcall
priorities.

> -subsys_initcall(r9a06g032_clocks_init);
> +core_initcall(r9a06g032_clocks_init);

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

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