linux-kernel - Re: [PATCH 2/6] drm/bridge: anx6345: Clean up error handling in probe()

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Message-ID: <20200220135259.GC4998@pendragon.ideasonboard.com>
Date:   Thu, 20 Feb 2020 15:52:59 +0200
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Vasily Khoruzhick <anarsoul@...il.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Sam Ravnborg <sam@...nborg.org>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Maxime Ripard <maxime@...no.tech>,
        Chen-Yu Tsai <wens@...e.org>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Icenowy Zheng <icenowy@...c.io>, Torsten Duwe <duwe@...e.de>,
        Heiko Stuebner <heiko.stuebner@...obroma-systems.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Stephan Gerhold <stephan@...hold.net>,
        Mark Brown <broonie@...nel.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Samuel Holland <samuel@...lland.org>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/6] drm/bridge: anx6345: Clean up error handling in
 probe()

Hi Vasily,

Thank you for the patch.

On Thu, Feb 20, 2020 at 12:35:04AM -0800, Vasily Khoruzhick wrote:
> devm_regulator_get() returns either a dummy regulator or -EPROBE_DEFER,
> we don't need to print scary message in either case.
> 
> Signed-off-by: Vasily Khoruzhick <anarsoul@...il.com>
> ---
>  drivers/gpu/drm/bridge/analogix/analogix-anx6345.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
> index 0d8d083b0207..0204bbe4f0a0 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
> @@ -713,17 +713,13 @@ static int anx6345_i2c_probe(struct i2c_client *client,
>  
>  	/* 1.2V digital core power regulator  */
>  	anx6345->dvdd12 = devm_regulator_get(dev, "dvdd12");
> -	if (IS_ERR(anx6345->dvdd12)) {
> -		DRM_ERROR("dvdd12-supply not found\n");
> +	if (IS_ERR(anx6345->dvdd12))
>  		return PTR_ERR(anx6345->dvdd12);
> -	}

There could be other errors such as -EBUSY or -EPERM. The following
would ensure a message gets printed in those cases, while avoiding
spamming the kernel log in the EPROBE_DEFER case.

	if (IS_ERR(anx6345->dvdd12)) {
		if (PTR_ERR(anx6345->dvdd12) != -EPROBE_DEFER)
			DRM_ERROR("Failed to get dvdd12 supply (%d)\n",
				  PTR_ERR(anx6345->dvdd12));
		return PTR_ERR(anx6345->dvdd12);
	}

But maybe it's overkill ? With or without that change (for the second
regulator below too),

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

>  	/* 2.5V digital core power regulator  */
>  	anx6345->dvdd25 = devm_regulator_get(dev, "dvdd25");
> -	if (IS_ERR(anx6345->dvdd25)) {
> -		DRM_ERROR("dvdd25-supply not found\n");
> +	if (IS_ERR(anx6345->dvdd25))
>  		return PTR_ERR(anx6345->dvdd25);
> -	}
>  
>  	/* GPIO for chip reset */
>  	anx6345->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);

-- 
Regards,

Laurent Pinchart