linux-kernel - Re: [PATCH] simplefb: Disable and release clocks and regulators in destroy callback

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Date:   Wed, 7 Sep 2016 11:31:47 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Chen-Yu Tsai <wens@...e.org>,
        Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
        Tomi Valkeinen <tomi.valkeinen@...com>
Cc:     linux-fbdev@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] simplefb: Disable and release clocks and regulators in
 destroy callback

Hi,

On 07-09-16 11:09, Chen-Yu Tsai wrote:
> simplefb gets unregister when a proper framebuffer driver comes in and
> kicks it out. However the claimed clocks and regulators stay enabled
> as they are only released in the platform device remove function, which
> in theory would never get called.
>
> Move the clock/regulator cleanup into the framebuffer destroy callback,
> which gets called as part of the framebuffer unregister process.
>
> Note this introduces asymmetry in how the resources are claimed and
> released.
>
> Signed-off-by: Chen-Yu Tsai <wens@...e.org>

Good catch, patch LGTM:

Reviewed-by: Hans de Goede <hdegoede@...hat.com>

Regards,

Hans



> ---
>  drivers/video/fbdev/simplefb.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
> index e9cf19977285..3620d10a0d00 100644
> --- a/drivers/video/fbdev/simplefb.c
> +++ b/drivers/video/fbdev/simplefb.c
> @@ -74,8 +74,14 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
>  	return 0;
>  }
>
> +struct simplefb_par;
> +static void simplefb_clocks_destroy(struct simplefb_par *par);
> +static void simplefb_regulators_destroy(struct simplefb_par *par);
> +
>  static void simplefb_destroy(struct fb_info *info)
>  {
> +	simplefb_regulators_destroy(info->par);
> +	simplefb_clocks_destroy(info->par);
>  	if (info->screen_base)
>  		iounmap(info->screen_base);
>  }
> @@ -487,11 +493,8 @@ error_fb_release:
>  static int simplefb_remove(struct platform_device *pdev)
>  {
>  	struct fb_info *info = platform_get_drvdata(pdev);
> -	struct simplefb_par *par = info->par;
>
>  	unregister_framebuffer(info);
> -	simplefb_regulators_destroy(par);
> -	simplefb_clocks_destroy(par);
>  	framebuffer_release(info);
>
>  	return 0;
>