Re: [PATCH 08/17] clk: vexpress-osc: Support building as a module

From: Sudeep Holla <sudeep.holla@arm.com>
To: Rob Herring <robh@kernel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-pm@vger.kernel.org, Stephen Boyd <sboyd@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Kevin Brodsky <Kevin.Brodsky@arm.com>,
	Liviu Dudau <liviu.dudau@arm.com>,
	Sebastian Reichel <sre@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Will Deacon <will@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Lee Jones <lee.jones@linaro.org>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 08/17] clk: vexpress-osc: Support building as a module
Date: Wed, 22 Apr 2020 22:08:02 +0100	[thread overview]
Message-ID: <20200422210802.GH25585@bogus> (raw)
In-Reply-To: <20200419170810.5738-9-robh@kernel.org>

On Sun, Apr 19, 2020 at 12:08:01PM -0500, Rob Herring wrote:
> Enable building the vexpress-osc clock driver as a module.
>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Liviu Dudau <liviu.dudau@arm.com>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Michael Turquette <mturquette@baylibre.com>
> Cc: Stephen Boyd <sboyd@kernel.org>
> Cc: linux-clk@vger.kernel.org
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
>  drivers/clk/versatile/Kconfig            |  4 ++--
>  drivers/clk/versatile/clk-vexpress-osc.c | 10 ++++------
>  2 files changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/clk/versatile/Kconfig b/drivers/clk/versatile/Kconfig
> index 5bdd5c98990b..9de2396dcf9b 100644
> --- a/drivers/clk/versatile/Kconfig
> +++ b/drivers/clk/versatile/Kconfig
> @@ -15,8 +15,8 @@ config CLK_SP810
>  	  of the ARM SP810 System Controller cell.
>
>  config CLK_VEXPRESS_OSC
> -	bool "Clock driver for Versatile Express OSC clock generators"
> -	depends on VEXPRESS_CONFIG || COMPILE_TEST
> +	tristate "Clock driver for Versatile Express OSC clock generators"
> +	depends on VEXPRESS_CONFIG
>  	default y if ARCH_VEXPRESS
>  	---help---
>  	  Simple regmap-based driver driving clock generators on Versatile
> diff --git a/drivers/clk/versatile/clk-vexpress-osc.c b/drivers/clk/versatile/clk-vexpress-osc.c
> index 5bb1d5a714d0..b2b32fa2d7c3 100644
> --- a/drivers/clk/versatile/clk-vexpress-osc.c
> +++ b/drivers/clk/versatile/clk-vexpress-osc.c
> @@ -7,6 +7,7 @@
>  #include <linux/clkdev.h>
>  #include <linux/clk-provider.h>
>  #include <linux/err.h>
> +#include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
> @@ -108,6 +109,7 @@ static const struct of_device_id vexpress_osc_of_match[] = {
>  	{ .compatible = "arm,vexpress-osc", },
>  	{}
>  };
> +MODULE_DEVICE_TABLE(of, vexpress_osc_of_match);
>
>  static struct platform_driver vexpress_osc_driver = {
>  	.driver	= {
> @@ -116,9 +118,5 @@ static struct platform_driver vexpress_osc_driver = {
>  	},
>  	.probe = vexpress_osc_probe,
>  };
> -
> -static int __init vexpress_osc_init(void)
> -{
> -	return platform_driver_register(&vexpress_osc_driver);
> -}
> -core_initcall(vexpress_osc_init);
> +module_platform_driver(vexpress_osc_driver);

I am not 100% sure of this. This might break the boot on CA9 and TC2
at-least. There are loads of MB peripherals that need this. This will
break the boot. We need to check if all the dependent modules are also
at module_initcall level and if they deal with deferred probe correctly.
Lot of them are legacy and may happen to be working by carefully initcall
level adjustments.

I will take a look at it again. I must be able to run and check on TC2
though I seem to have removed the network cable on my TC2 or office n/w
is acting crazy. I will check tomorrow again or run w/o network.

--
Regards,
Sudeep

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