linux-kernel - Re: [PATCH 1/2] media: ov6650: Move v4l2_clk_get() to ov6650_video

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Date:   Fri, 29 Mar 2019 20:39:24 +0200
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Janusz Krzysztofik <jmkrzyszt@...il.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hans.verkuil@...co.com>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] media: ov6650: Move v4l2_clk_get() to
 ov6650_video_probe() helper

Hi Janus,

Thanks for the patchset.

On Mon, Mar 25, 2019 at 01:35:00AM +0100, Janusz Krzysztofik wrote:
> In preparation for adding asynchronous subdevice support to the driver,
> don't acquire v4l2_clk from the driver .probe() callback as that may
> fail if the clock is provided by a bridge driver which may be not yet
> initialized.  Move the v4l2_clk_get() to ov6650_video_probe() helper
> which is going to be converted to v4l2_subdev_internal_ops.registered()
> callback, executed only when the bridge driver is ready.
> 
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@...il.com>
> ---
>  drivers/media/i2c/ov6650.c | 25 ++++++++++++++-----------
>  1 file changed, 14 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov6650.c b/drivers/media/i2c/ov6650.c
> index c33fd584cb44..f10b8053ed73 100644
> --- a/drivers/media/i2c/ov6650.c
> +++ b/drivers/media/i2c/ov6650.c
> @@ -810,9 +810,16 @@ static int ov6650_video_probe(struct i2c_client *client)
>  	u8		pidh, pidl, midh, midl;
>  	int		ret;
>  
> +	priv->clk = v4l2_clk_get(&client->dev, NULL);
> +	if (IS_ERR(priv->clk)) {
> +		ret = PTR_ERR(priv->clk);
> +		dev_err(&client->dev, "v4l2_clk request err: %d\n", ret);
> +		return ret;
> +	}
> +
>  	ret = ov6650_s_power(&priv->subdev, 1);
>  	if (ret < 0)
> -		return ret;
> +		goto eclkput;
>  
>  	/*
>  	 * check and show product ID and manufacturer ID
> @@ -847,6 +854,11 @@ static int ov6650_video_probe(struct i2c_client *client)
>  
>  done:
>  	ov6650_s_power(&priv->subdev, 0);
> +	if (ret) {
> +eclkput:
> +		v4l2_clk_put(priv->clk);

Could you rework the error handling, please? Labels should be outside
conditionals. See e.g. the smiapp driver
(drivers/media/i2c/smiapp/smiapp-core.c). I've pushed my master branch
here:

<URL:https://git.linuxtv.org/sailus/media_tree.git/log/>

The patch also does not apply on top of the media tree master + your
earlier patch cleanly.

> +	}
> +
>  	return ret;
>  }
>  
> @@ -989,18 +1001,9 @@ static int ov6650_probe(struct i2c_client *client,
>  	priv->code	  = MEDIA_BUS_FMT_YUYV8_2X8;
>  	priv->colorspace  = V4L2_COLORSPACE_JPEG;
>  
> -	priv->clk = v4l2_clk_get(&client->dev, NULL);
> -	if (IS_ERR(priv->clk)) {
> -		ret = PTR_ERR(priv->clk);
> -		goto eclkget;
> -	}
> -
>  	ret = ov6650_video_probe(client);
> -	if (ret) {
> -		v4l2_clk_put(priv->clk);
> -eclkget:
> +	if (ret)
>  		v4l2_ctrl_handler_free(&priv->hdl);
> -	}
>  
>  	return ret;
>  }

-- 
Kind regards,

Sakari Ailus
sakari.ailus@...ux.intel.com