linux-kernel - Re: [PATCH v2 4/5] media: i2c: ov5645: Return zero for s

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Date:   Sat, 15 Oct 2022 09:25:37 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Prabhakar <prabhakar.csengg@...il.com>
Cc:     Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hverkuil@...all.nl>,
        Shawn Tu <shawnx.tu@...el.com>,
        Jacopo Mondi <jacopo@...ndi.org>, linux-media@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org,
        Biju Das <biju.das.jz@...renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v2 4/5] media: i2c: ov5645: Return zero for s_stream(0)

Hi Prabhakar,

Thank you for the patch.

On Fri, Oct 14, 2022 at 07:34:58PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> Always return zero while stopping the stream as the caller will ignore the
> return value.
> 
> This patch drops checking the return value of ov5645_write_reg() and
> continues further in the code path while stopping stream. The user anyway
> gets an error message in case ov5645_write_reg() fails.

Continuing all the way to pm_runtime_put() is fine, but I don't think
the function should return 0. It's not up to the driver to decide if a
failure would be useful to signal to the caller or not.

> Suggested-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> ---
> v1->v2
> * New patch
> ---
>  drivers/media/i2c/ov5645.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> index a0b9d0c43b78..b3825294aaf1 100644
> --- a/drivers/media/i2c/ov5645.c
> +++ b/drivers/media/i2c/ov5645.c
> @@ -995,14 +995,11 @@ static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
>  		if (ret < 0)
>  			goto err_rpm_put;
>  	} else {
> -		ret = ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x40);
> -		if (ret < 0)
> -			return ret;
> +		ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x40);
> +
> +		ov5645_write_reg(ov5645, OV5645_SYSTEM_CTRL0,
> +				 OV5645_SYSTEM_CTRL0_STOP);
>  
> -		ret = ov5645_write_reg(ov5645, OV5645_SYSTEM_CTRL0,
> -				       OV5645_SYSTEM_CTRL0_STOP);
> -		if (ret < 0)
> -			return ret;
>  		pm_runtime_put(ov5645->dev);
>  	}
>  

-- 
Regards,

Laurent Pinchart