linux-kernel - Re: [PATCH v2 2/4] media: i2c: alvium: removal of fr field

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Message-ID: <20231220091309.GG29638@pendragon.ideasonboard.com>
Date: Wed, 20 Dec 2023 11:13:09 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Tommaso Merciai <tomm.merciai@...il.com>
Cc: linuxfancy@...glegroups.com, martin.hecht@...et.eu,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/4] media: i2c: alvium: removal of fr field

Hi Tommaso,

Thank you for the patch.

Use the imperative in the subject line:

media: i2c: alvium: Remove the fr field of the alvium_dev structure

On Wed, Dec 20, 2023 at 09:56:07AM +0100, Tommaso Merciai wrote:
> The fr (frame rate) field of the alvium_dev structure is
> only used to pass result from alvium_set_frame_interval() to
> alvium_set_frame_rate() that writes this info into the hw reg.
> Replace them with function parameter.

Replace it with a function parameter.

> 
> Signed-off-by: Tommaso Merciai <tomm.merciai@...il.com>
> ---
>  drivers/media/i2c/alvium-csi2.c | 24 ++++++++++++------------
>  drivers/media/i2c/alvium-csi2.h |  1 -
>  2 files changed, 12 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/media/i2c/alvium-csi2.c b/drivers/media/i2c/alvium-csi2.c
> index 0dcd69bf9f92..a9ff6cc97cff 100644
> --- a/drivers/media/i2c/alvium-csi2.c
> +++ b/drivers/media/i2c/alvium-csi2.c
> @@ -1185,19 +1185,19 @@ static int alvium_get_frame_interval(struct alvium_dev *alvium,
>  	return ret;
>  }
>  
> -static int alvium_set_frame_rate(struct alvium_dev *alvium)
> +static int alvium_set_frame_rate(struct alvium_dev *alvium, u64 fr)
>  {
>  	struct device *dev = &alvium->i2c_client->dev;
>  	int ret;
>  
>  	ret = alvium_write_hshake(alvium, REG_BCRM_ACQUISITION_FRAME_RATE_RW,
> -				  alvium->fr);
> +				  fr);
>  	if (ret) {
>  		dev_err(dev, "Fail to set frame rate lanes reg\n");
>  		return ret;
>  	}
>  
> -	dev_dbg(dev, "set frame rate: %llu us\n", alvium->fr);
> +	dev_dbg(dev, "set frame rate: %llu us\n", fr);
>  
>  	return 0;
>  }
> @@ -1661,10 +1661,11 @@ static int alvium_g_frame_interval(struct v4l2_subdev *sd,
>  }
>  
>  static int alvium_set_frame_interval(struct alvium_dev *alvium,
> -				     struct v4l2_subdev_frame_interval *fi)
> +				     struct v4l2_subdev_frame_interval *fi,
> +				     u64 *req_fr)
>  {
>  	struct device *dev = &alvium->i2c_client->dev;
> -	u64 req_fr, dft_fr, min_fr, max_fr;
> +	u64 dft_fr, min_fr, max_fr;
>  	int ret;
>  
>  	if (fi->interval.denominator == 0)
> @@ -1681,13 +1682,12 @@ static int alvium_set_frame_interval(struct alvium_dev *alvium,
>  	dev_dbg(dev, "fi->interval.denominator = %d\n",
>  		fi->interval.denominator);
>  
> -	req_fr = (u64)((fi->interval.denominator * USEC_PER_SEC) /
> +	*req_fr = (u64)((fi->interval.denominator * USEC_PER_SEC) /
>  		       fi->interval.numerator);
>  
> -	if (req_fr >= max_fr && req_fr <= min_fr)
> -		req_fr = dft_fr;
> +	if (*req_fr >= max_fr && *req_fr <= min_fr)
> +		*req_fr = dft_fr;

Shouldn't we clamp the value to [min, max] instead of using the default
if it's out of range ? Something like

	*req_fr = clamp(*req_fr, min_fr, max_fr)

This makes me realize that the current code is wrong, req_fr can't be >=
max and <= min at the same time. You probably meant || instead of &&.

This should be fixed in a separate patch.

>  
> -	alvium->fr = req_fr;
>  	alvium->frame_interval.numerator = fi->interval.numerator;
>  	alvium->frame_interval.denominator = fi->interval.denominator;
>  
> @@ -1699,6 +1699,7 @@ static int alvium_s_frame_interval(struct v4l2_subdev *sd,
>  				   struct v4l2_subdev_frame_interval *fi)
>  {
>  	struct alvium_dev *alvium = sd_to_alvium(sd);
> +	u64 req_fr = ALVIUM_DEFAULT_FR_HZ;

Do you need to initialize the variable ? It doesn't seem to be required.

With these small issues fixed,

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

>  	int ret;
>  
>  	/*
> @@ -1711,9 +1712,9 @@ static int alvium_s_frame_interval(struct v4l2_subdev *sd,
>  	if (alvium->streaming)
>  		return -EBUSY;
>  
> -	ret = alvium_set_frame_interval(alvium, fi);
> +	ret = alvium_set_frame_interval(alvium, fi, &req_fr);
>  	if (!ret)
> -		ret = alvium_set_frame_rate(alvium);
> +		ret = alvium_set_frame_rate(alvium, req_fr);
>  
>  	return ret;
>  }
> @@ -2273,7 +2274,6 @@ static int alvium_subdev_init(struct alvium_dev *alvium)
>  	/* Setup initial frame interval*/
>  	alvium->frame_interval.numerator = 1;
>  	alvium->frame_interval.denominator = ALVIUM_DEFAULT_FR_HZ;
> -	alvium->fr = ALVIUM_DEFAULT_FR_HZ;
>  
>  	/* Setup the initial mode */
>  	alvium->mode.fmt = alvium_csi2_default_fmt;
> diff --git a/drivers/media/i2c/alvium-csi2.h b/drivers/media/i2c/alvium-csi2.h
> index 17f0bbbd1839..80066ac25047 100644
> --- a/drivers/media/i2c/alvium-csi2.h
> +++ b/drivers/media/i2c/alvium-csi2.h
> @@ -443,7 +443,6 @@ struct alvium_dev {
>  
>  	struct alvium_mode mode;
>  	struct v4l2_fract frame_interval;
> -	u64 fr;
>  
>  	u8 h_sup_csi_lanes;
>  	u64 link_freq;

-- 
Regards,

Laurent Pinchart