RE: [PATCH 1/2] ARM: imx: drop uneccessary of_platform_default_populate

From: Peng Fan
Date: Sun Mar 17 2019 - 22:31:43 EST




> -----Original Message-----
> From: Aisheng Dong
> Sent: 2019年3月15日 21:39
> To: Peng Fan <peng.fan@xxxxxxx>; shawnguo@xxxxxxxxxx;
> s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx;
> dl-linux-imx <linux-imx@xxxxxxx>; Anson Huang <anson.huang@xxxxxxx>;
> arnd@xxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Cc: van.freenix@xxxxxxxxx
> Subject: RE: [PATCH 1/2] ARM: imx: drop uneccessary
> of_platform_default_populate
>
> [...]
>
> > > Originally devices are registered in arch_initcall. Now it will be a
> > > bit later in arch_initcall_sync and this may cause a bit risk if the
> > > code under the default_populate want to access the device service
> > > provided
> > by early probe.
> > >
> > > Probably it's more safe to leave as it is unless you can double
> > > confirm there're no such code depends on accessing early probed
> > > devices as follows before we can make the change.
> >
> > This has been boot tested on 6Q-SDB/6UL-EVK/6SL-EVK board.
> > For i.MX, I only see pinctrl driver use arch_initcall from the link,
> > https://elixir.bootlin.com/linux/latest/ident/arch_initcall
> >
> > From my boot test, the pinctrl driver probe will be delayed a bit, but
> > I do not see issues.
> >
>
> From what I saw, imx6q_1588_init() and imx6q_axi_init() will use syscon which
> is registered with postcore_initcall. Without having syscon devices populated,
> I wonder those calls may fall.
> Can you double check it?

I do not see failure in imx6q_1588_init by adding a return value check of
regmap_update_bits, But the imx6q_pm_init will find ocram device for
suspend usage, postpone the device population will make imx6q_pm_init
fail, so drop this patch and leave the code as it is.

Thanks,
Peng.

>
> Regards
> Dong Aisheng