Re: [PATCH] ARM: pxa: make pwm driver module_platform_driver

[Marek Vasut <marex@denx.de>]

Dear Mike Dunn,

> Commit 76abbdde2d95a3807d0dc6bf9f84d03d0dbd4f3d
> 
>     pwm: Add sysfs interface
> 
> causes a kernel oops due to a null pointer dereference on pxa platforms. 
> This happens because the class added by the patch is registered in a
> subsys_initcall (initcall4), but the pxa pwm driver is registered in
> arch_initcall (initcall3). If the class is not registered before the
> driver probe function runs, the oops occurs in device_add() when the
> uninitialized pointers in struct class are dereferenced.  I don't see a
> reason that the driver must be an arch_initcall, so this patch makes it a
> regular module_platform_driver (initcall6), preventing the oops.
> 
> Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
> ---
>  drivers/pwm/pwm-pxa.c | 12 +-----------
>  1 file changed, 1 insertion(+), 11 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
> index dc97175..a4d2164 100644
> --- a/drivers/pwm/pwm-pxa.c
> +++ b/drivers/pwm/pwm-pxa.c
> @@ -182,16 +182,6 @@ static struct platform_driver pwm_driver = {
>  	.id_table	= pwm_id_table,
>  };
> 
> -static int __init pwm_init(void)
> -{
> -	return platform_driver_register(&pwm_driver);
> -}
> -arch_initcall(pwm_init);
> -
> -static void __exit pwm_exit(void)
> -{
> -	platform_driver_unregister(&pwm_driver);
> -}
> -module_exit(pwm_exit);
> +module_platform_driver(pwm_driver);
> 
>  MODULE_LICENSE("GPL v2");

Acked-by: Marek Vasut <marex@denx.de>

Best regards,
Marek Vasut