Re: [PATCH v2 1/1] drm/bridge: imx93-mipi-dsi: Use dev_err_probe

From: Alexander Stein <alexander.stein@ew.tq-group.com>
To: Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>, Liu Ying <victor.liu@nxp.com>
Cc: dri-devel@lists.freedesktop.org, imx@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/1] drm/bridge: imx93-mipi-dsi: Use dev_err_probe
Date: Wed, 29 May 2024 10:15:18 +0200	[thread overview]
Message-ID: <6130653.lOV4Wx5bFT@steina-w> (raw)
In-Reply-To: <091f1d5c-0bff-4dcb-b823-b82989eac628@nxp.com>

Hi,

Am Mittwoch, 29. Mai 2024, 09:50:24 CEST schrieb Liu Ying:
> On 05/29/2024, Alexander Stein wrote:
> > Although very unlike to occur (media_blk_ctrl needs 'syscon' compatible
> > removed), it lines up with the other error paths in probe function.
> 
> Why media_blk_ctrl needs 'syscon' compatible removed?

No, it does not. As media_blk_ctrl is also used as power-domain the device
will not even be probed if media_blk_ctrl is not available.
I just mentioned it under which conditions this error path could happen.

Best regards,
Alexander

> device_node_get_regmap may return error pointer other than
> ERR_PTR(-EPROBE_DEFER), like ERR_PTR(-ENOMEM).
> 
> struct regmap *syscon_node_to_regmap(struct device_node *np)                     
> {                                                                                
>         if (!of_device_is_compatible(np, "syscon"))                              
>                 return ERR_PTR(-EINVAL);                                         
>                                                                                  
>         return device_node_get_regmap(np, true);                                 
> }                                                                                
> EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
> 
> Regard,
> Liu Ying
> 
> > 
> > Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> > ---
> > Changes in v2:
> > * Removed unused variable
> > * Added missing \n at end of string
> > 
> >  drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c | 9 +++------
> >  1 file changed, 3 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c b/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > index 2347f8dd632f9..13025f47f3902 100644
> > --- a/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > +++ b/drivers/gpu/drm/bridge/imx/imx93-mipi-dsi.c
> > @@ -834,18 +834,15 @@ static int imx93_dsi_probe(struct platform_device *pdev)
> >  	struct device *dev = &pdev->dev;
> >  	struct device_node *np = dev->of_node;
> >  	struct imx93_dsi *dsi;
> > -	int ret;
> >  
> >  	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> >  	if (!dsi)
> >  		return -ENOMEM;
> >  
> >  	dsi->regmap = syscon_regmap_lookup_by_phandle(np, "fsl,media-blk-ctrl");
> > -	if (IS_ERR(dsi->regmap)) {
> > -		ret = PTR_ERR(dsi->regmap);
> > -		dev_err(dev, "failed to get block ctrl regmap: %d\n", ret);
> > -		return ret;
> > -	}
> > +	if (IS_ERR(dsi->regmap))
> > +		return dev_err_probe(dev, PTR_ERR(dsi->regmap),
> > +				     "failed to get block ctrl regmap\n");
> >  
> >  	dsi->clk_pixel = devm_clk_get(dev, "pix");
> >  	if (IS_ERR(dsi->clk_pixel))
> 
> 

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