Re: [PATCH v4 4/7] media: v4l2-subdev: add stubs for v4l2_subdev_get_try_*

From: Jacopo Mondi <jacopo@jmondi.org>
To: Marco Felsch <m.felsch@pengutronix.de>,
	Hans Verkuil <hverkuil@xs4all.nl>,
	Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: mchehab@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com,
	devicetree@vger.kernel.org, p.zabel@pengutronix.de,
	javierm@redhat.com, afshin.nasser@gmail.com,
	laurent.pinchart@ideasonboard.com, linux-media@vger.kernel.org,
	kernel@pengutronix.de
Subject: Re: [PATCH v4 4/7] media: v4l2-subdev: add stubs for v4l2_subdev_get_try_*
Date: Thu, 21 Mar 2019 11:01:47 +0100	[thread overview]
Message-ID: <20190321100147.eqfnbw6jjatqvfvw@uno.localdomain> (raw)
In-Reply-To: <20190129160757.2314-5-m.felsch@pengutronix.de>

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Hi Marco,

FYI we've been there already:
https://patchwork.kernel.org/patch/10703029/

and that ended with Hans' patch:
https://patchwork.linuxtv.org/patch/53370/
which didn't get far unfortunately.

On Tue, Jan 29, 2019 at 05:07:54PM +0100, Marco Felsch wrote:
> In case of missing CONFIG_VIDEO_V4L2_SUBDEV_API those helpers aren't
> available. So each driver have to add ifdefs around those helpers or
> add the CONFIG_VIDEO_V4L2_SUBDEV_API as dependcy.
>
> Make these helpers available in case of CONFIG_VIDEO_V4L2_SUBDEV_API
> isn't set to avoid ifdefs. This approach is less error prone too.
>
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
>  include/media/v4l2-subdev.h | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index 47af609dc8f1..90c9a301d72a 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -916,8 +916,6 @@ struct v4l2_subdev_fh {
>  #define to_v4l2_subdev_fh(fh)	\
>  	container_of(fh, struct v4l2_subdev_fh, vfh)
>
> -#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
> -
>  /**
>   * v4l2_subdev_get_try_format - ancillary routine to call
>   *	&struct v4l2_subdev_pad_config->try_fmt
> @@ -931,9 +929,13 @@ static inline struct v4l2_mbus_framefmt
>  			    struct v4l2_subdev_pad_config *cfg,
>  			    unsigned int pad)
>  {
> +#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
>  	return &cfg[pad].try_fmt;
> +#else
> +	return NULL;

Since Hans' attempt didn't succeed, maybe we want to reconsider this
approach? I liked Lubomir's version better, but in any case, small
details...

Shouldn't you return ERR_PTR(-ENOTTY) here instead of NULL ?

+ Sakari, Hans:
Alternatively, what if we add CONFIG_VIDEO_V4L2_SUBDEV_API as a
dependency of all sensor drivers that still use the

#ifdef CONFIG_VIDEO_V4L2_SUBDEV_API
v4l2_subdev_get_try_format(sd, cfg, format->pad);
#else
-ENOTTY
#endif

pattern so we could remove that block #ifdef blocks and do not touch the
v4l2-subdev.h header? Should I send a patch?

Thanks
  j

> +#endif
>  }
>
>  /**
> @@ -949,9 +951,13 @@ static inline struct v4l2_rect
>  			  struct v4l2_subdev_pad_config *cfg,
>  			  unsigned int pad)
>  {
> +#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
>  	return &cfg[pad].try_crop;
> +#else
> +	return NULL;
> +#endif
>  }
>
>  /**
> @@ -967,11 +973,14 @@ static inline struct v4l2_rect
>  			     struct v4l2_subdev_pad_config *cfg,
>  			     unsigned int pad)
>  {
> +#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
>  	return &cfg[pad].try_compose;
> -}
> +#else
> +	return NULL;
>  #endif
> +}
>
>  extern const struct v4l2_file_operations v4l2_subdev_fops;
>
> --
> 2.20.1
>

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