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From:   Aisheng Dong <aisheng.dong@nxp.com>
To:     Peng Fan <peng.fan@nxp.com>,
        "shawnguo@kernel.org" <shawnguo@kernel.org>,
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        Anson Huang <anson.huang@nxp.com>,
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CC:     "van.freenix@gmail.com" <van.freenix@gmail.com>
Subject: RE: [PATCH 1/2] ARM: imx: drop uneccessary
 of_platform_default_populate
Thread-Topic: [PATCH 1/2] ARM: imx: drop uneccessary
 of_platform_default_populate
Thread-Index: AQHU2Xv1SFnRc4p0SkOOn59vTkEkO6YMepnA
Date:   Fri, 15 Mar 2019 10:16:53 +0000
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> From: Peng Fan
>=20
> "arch_initcall_sync(of_platform_default_populate_init);" could be used to
> populate the device tree, there is no need to call of_platform_default_po=
pulate
> in machine code.
>=20
> Tested on i.MX6Q-SDB i.MX6SL-EVK i.MX6UL-EVK board.
>=20
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  arch/arm/mach-imx/mach-imx6q.c  | 2 --
>  arch/arm/mach-imx/mach-imx6sl.c | 2 --
>  arch/arm/mach-imx/mach-imx6sx.c | 2 --
>  arch/arm/mach-imx/mach-imx6ul.c | 1 -
>  4 files changed, 7 deletions(-)
>=20
> diff --git a/arch/arm/mach-imx/mach-imx6q.c
> b/arch/arm/mach-imx/mach-imx6q.c index 7d80a0ae723c..655398c20256
> 100644
> --- a/arch/arm/mach-imx/mach-imx6q.c
> +++ b/arch/arm/mach-imx/mach-imx6q.c
> @@ -278,8 +278,6 @@ static void __init imx6q_init_machine(void)
>=20
>  	imx6q_enet_phy_init();
>=20
> -	of_platform_default_populate(NULL, NULL, parent);
> -

This slightly change the device register sequence as well as possible drive=
r probe
sequence as a consequence.

Originally devices are registered in arch_initcall. Now it will be a bit la=
ter
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=20
there're no such code depends on accessing early probed devices as follows
before we can make the change.

>  	imx_anatop_init();
>  	cpu_is_imx6q() ?  imx6q_pm_init() : imx6dl_pm_init();
>  	imx6q_1588_init();

Regards
Dong Aisheng

> diff --git a/arch/arm/mach-imx/mach-imx6sl.c
> b/arch/arm/mach-imx/mach-imx6sl.c index 99be4225297a..9743bdbb68fa
> 100644
> --- a/arch/arm/mach-imx/mach-imx6sl.c
> +++ b/arch/arm/mach-imx/mach-imx6sl.c
> @@ -56,8 +56,6 @@ static void __init imx6sl_init_machine(void)
>  	if (parent =3D=3D NULL)
>  		pr_warn("failed to initialize soc device\n");
>=20
> -	of_platform_default_populate(NULL, NULL, parent);
> -
>  	if (cpu_is_imx6sl())
>  		imx6sl_fec_init();
>  	imx_anatop_init();
> diff --git a/arch/arm/mach-imx/mach-imx6sx.c
> b/arch/arm/mach-imx/mach-imx6sx.c index 7f52d9b1e8a4..19b9f2dd309e
> 100644
> --- a/arch/arm/mach-imx/mach-imx6sx.c
> +++ b/arch/arm/mach-imx/mach-imx6sx.c
> @@ -72,8 +72,6 @@ static void __init imx6sx_init_machine(void)
>  	if (parent =3D=3D NULL)
>  		pr_warn("failed to initialize soc device\n");
>=20
> -	of_platform_default_populate(NULL, NULL, parent);
> -
>  	imx6sx_enet_init();
>  	imx_anatop_init();
>  	imx6sx_pm_init();
> diff --git a/arch/arm/mach-imx/mach-imx6ul.c
> b/arch/arm/mach-imx/mach-imx6ul.c index 6cb8a22b617d..c57b9df791b1
> 100644
> --- a/arch/arm/mach-imx/mach-imx6ul.c
> +++ b/arch/arm/mach-imx/mach-imx6ul.c
> @@ -65,7 +65,6 @@ static void __init imx6ul_init_machine(void)
>  	if (parent =3D=3D NULL)
>  		pr_warn("failed to initialize soc device\n");
>=20
> -	of_platform_default_populate(NULL, NULL, parent);
>  	imx6ul_enet_init();
>  	imx_anatop_init();
>  	imx6ul_pm_init();
> --
> 2.16.4