linux-kernel - Re: [PATCH v2 7/7] media: uvcvideo: Replace get_mapping with filter

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Message-ID: <20240616221733.GA28126@pendragon.ideasonboard.com>
Date: Mon, 17 Jun 2024 01:17:33 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Ricardo Ribalda <ribalda@...omium.org>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 7/7] media: uvcvideo: Replace get_mapping with
 filter_mapping

Hi Ricardo,

Thank you for the patch.

On Mon, Jun 10, 2024 at 11:09:58PM +0000, Ricardo Ribalda wrote:
> If the callback returns a mapping instead of adding it, the codeflow is
> more clean and we do not need a forward declaration of
> __uvc_ctrl_add_mapping_to_list().
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>

This should have been squashed in the previous patches as appropriate.
It's hard to review the new version this way.

The diff with v1 looks good, so I don't expect to have further comments.

> ---
>  drivers/media/usb/uvc/uvc_ctrl.c | 40 ++++++++++++++++++----------------------
>  drivers/media/usb/uvc/uvcvideo.h |  6 +++---
>  2 files changed, 21 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 1c1710e3c486..4a13f2685d9e 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -495,11 +495,8 @@ static const struct uvc_control_mapping uvc_ctrl_power_line_mapping_uvc15 = {
>  				  V4L2_CID_POWER_LINE_FREQUENCY_DISABLED),
>  };
>  
> -static int __uvc_ctrl_add_mapping_to_list(struct uvc_video_chain *chain,
> -	struct uvc_control *ctrl, const struct uvc_control_mapping *mapping);
> -
> -static int uvc_ctrl_add_plf_mapping(struct uvc_video_chain *chain,
> -	struct uvc_control *ctrl, const struct uvc_control_mapping *mapping)
> +static const struct uvc_control_mapping *uvc_ctrl_filter_plf_mapping
> +		(struct uvc_video_chain *chain, struct uvc_control *ctrl)
>  {
>  	const struct uvc_control_mapping *out_mapping =
>  					&uvc_ctrl_power_line_mapping_uvc11;
> @@ -509,7 +506,7 @@ static int uvc_ctrl_add_plf_mapping(struct uvc_video_chain *chain,
>  
>  	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
>  	if (!buf)
> -		return -ENOMEM;
> +		return NULL;
>  
>  	/* Save the default PLF value, so we can restore it. */
>  	ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, ctrl->entity->id,
> @@ -517,7 +514,7 @@ static int uvc_ctrl_add_plf_mapping(struct uvc_video_chain *chain,
>  			     buf, sizeof(*buf));
>  	/* If we cannot read the control skip it. */
>  	if (ret)
> -		return ret;
> +		return NULL;
>  	init_val = *buf;
>  
>  	/* If PLF value cannot be set to off, it is limited. */
> @@ -526,8 +523,7 @@ static int uvc_ctrl_add_plf_mapping(struct uvc_video_chain *chain,
>  			     chain->dev->intfnum, ctrl->info.selector,
>  			     buf, sizeof(*buf));
>  	if (ret)
> -		return __uvc_ctrl_add_mapping_to_list(chain, ctrl,
> -					&uvc_ctrl_power_line_mapping_limited);
> +		return &uvc_ctrl_power_line_mapping_limited;
>  
>  	/* UVC 1.1 does not define auto, we can exit. */
>  	if (chain->dev->uvc_version < 0x150)
> @@ -548,7 +544,7 @@ static int uvc_ctrl_add_plf_mapping(struct uvc_video_chain *chain,
>  		       chain->dev->intfnum, ctrl->info.selector,
>  		       buf, sizeof(*buf));
>  
> -	return __uvc_ctrl_add_mapping_to_list(chain, ctrl, out_mapping);
> +	return out_mapping;
>  }
>  
>  static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> @@ -843,7 +839,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
>  	{
>  		.entity		= UVC_GUID_UVC_PROCESSING,
>  		.selector	= UVC_PU_POWER_LINE_FREQUENCY_CONTROL,
> -		.add_mapping	= uvc_ctrl_add_plf_mapping,
> +		.filter_mapping	= uvc_ctrl_filter_plf_mapping,
>  	},
>  };
>  
> @@ -2411,8 +2407,9 @@ static int uvc_ctrl_add_info(struct uvc_device *dev, struct uvc_control *ctrl,
>  /*
>   * Add a control mapping to a given control.
>   */
> -static int __uvc_ctrl_add_mapping_to_list(struct uvc_video_chain *chain,
> -	struct uvc_control *ctrl, const struct uvc_control_mapping *mapping)
> +static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> +				  struct uvc_control *ctrl,
> +				  const struct uvc_control_mapping *mapping)
>  {
>  	struct uvc_control_mapping *map;
>  	unsigned int size;
> @@ -2485,14 +2482,6 @@ static int __uvc_ctrl_add_mapping_to_list(struct uvc_video_chain *chain,
>  	return -ENOMEM;
>  }
>  
> -static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> -	struct uvc_control *ctrl, const struct uvc_control_mapping *mapping)
> -{
> -	if (mapping && mapping->add_mapping)
> -		return mapping->add_mapping(chain, ctrl, mapping);
> -	return __uvc_ctrl_add_mapping_to_list(chain, ctrl, mapping);
> -}
> -
>  int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
>  	const struct uvc_control_mapping *mapping)
>  {
> @@ -2681,7 +2670,14 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
>  
>  	/* Process common mappings. */
>  	for (i = 0; i < ARRAY_SIZE(uvc_ctrl_mappings); ++i) {
> -		const struct uvc_control_mapping *mapping = &uvc_ctrl_mappings[i];
> +		const struct uvc_control_mapping *mapping = NULL;
> +
> +		/* Try to get a custom mapping from the device. */
> +		if (uvc_ctrl_mappings[i].filter_mapping)
> +			mapping = uvc_ctrl_mappings[i].filter_mapping(chain,
> +								      ctrl);
> +		if (!mapping)
> +			mapping = &uvc_ctrl_mappings[i];
>  
>  		if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
>  		    ctrl->info.selector == mapping->selector)
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index ff9545dcf716..a9547795fe22 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -125,9 +125,9 @@ struct uvc_control_mapping {
>  	s32 master_manual;
>  	u32 slave_ids[2];
>  
> -	int (*add_mapping)(struct uvc_video_chain *chain,
> -			   struct uvc_control *ctrl,
> -			   const struct uvc_control_mapping *mapping);
> +	const struct uvc_control_mapping *(*filter_mapping)
> +				(struct uvc_video_chain *chain,
> +				struct uvc_control *ctrl);
>  	s32 (*get)(struct uvc_control_mapping *mapping, u8 query,
>  		   const u8 *data);
>  	void (*set)(struct uvc_control_mapping *mapping, s32 value,
> 

-- 
Regards,

Laurent Pinchart