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

From: Laurent Pinchart <laurent.pinchart@ideasonboard•com>
To: Vasily Khoruzhick <anarsoul@gmail•com>
Cc: Mark Rutland <mark.rutland@arm•com>,
	Neil Armstrong <narmstrong@baylibre•com>,
	David Airlie <airlied@linux•ie>,
	Linus Walleij <linus.walleij@linaro•org>,
	dri-devel@lists•freedesktop.org,
	Andrzej Hajda <a.hajda@samsung•com>,
	Thierry Reding <thierry.reding@gmail•com>,
	Sam Ravnborg <sam@ravnborg•org>,
	Stephen Rothwell <sfr@canb•auug.org.au>,
	Samuel Holland <samuel@sholland•org>,
	Heiko Stuebner <heiko.stuebner@theobroma-systems•com>,
	Chen-Yu Tsai <wens@csie•org>, Icenowy Zheng <icenowy@aosc•io>,
	Stephan Gerhold <stephan@gerhold•net>,
	Jonas Karlman <jonas@kwiboo•se>, Torsten Duwe <duwe@suse•de>,
	Rob Herring <robh+dt@kernel•org>,
	Maxime Ripard <maxime@cerno•tech>,
	linux-arm-kernel@lists•infradead.org,
	Jernej Skrabec <jernej.skrabec@siol•net>,
	linux-kernel@vger•kernel.org, Mark Brown <broonie@kernel•org>,
	Daniel Vetter <daniel@ffwll•ch>
Subject: Re: [PATCH 2/6] drm/bridge: anx6345: Clean up error handling in probe()
Date: Thu, 20 Feb 2020 15:52:59 +0200	[thread overview]
Message-ID: <20200220135259.GC4998@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20200220083508.792071-3-anarsoul@gmail.com>

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@gmail•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@ideasonboard•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

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