netdev - Re: [PATCH v4 03/13] media: pci: cx18-av-vbi: Replace open-coded parity calculation with parity

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Message-ID: <25b7888d-f704-493b-a2d7-c5e8fff9cfb4@broadcom.com>
Date: Wed, 9 Apr 2025 20:43:09 +0200
From: Arend van Spriel <arend.vanspriel@...adcom.com>
To: Kuan-Wei Chiu <visitorckw@...il.com>, tglx@...utronix.de,
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 andrew.cooper3@...rix.com, Yu-Chun Lin <eleanor15x@...il.com>
Subject: Re: [PATCH v4 03/13] media: pci: cx18-av-vbi: Replace open-coded
 parity calculation with parity_odd()

On 4/9/2025 5:43 PM, Kuan-Wei Chiu wrote:
> Refactor parity calculations to use the standard parity_odd() helper.
> This change eliminates redundant implementations.
> 
> Co-developed-by: Yu-Chun Lin <eleanor15x@...il.com>
> Signed-off-by: Yu-Chun Lin <eleanor15x@...il.com>
> Signed-off-by: Kuan-Wei Chiu <visitorckw@...il.com>
> ---
>   drivers/media/pci/cx18/cx18-av-vbi.c | 12 ++----------
>   1 file changed, 2 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/pci/cx18/cx18-av-vbi.c b/drivers/media/pci/cx18/cx18-av-vbi.c
> index 65281d40c681..15b515b95956 100644
> --- a/drivers/media/pci/cx18/cx18-av-vbi.c
> +++ b/drivers/media/pci/cx18/cx18-av-vbi.c

[...]

> @@ -278,7 +270,7 @@ int cx18_av_decode_vbi_line(struct v4l2_subdev *sd,
>   		break;
>   	case 6:
>   		sdid = V4L2_SLICED_CAPTION_525;
> -		err = !odd_parity(p[0]) || !odd_parity(p[1]);
> +		err = !parity_odd(p[0]) || !parity_odd(p[1]);

No need to call parity_odd() twice here. Instead you could do:

		err = !parity_odd(p[0] ^ p[1]);

This is orthogonal to the change to parity_odd() though. More specific 
to the new parity_odd() you can now do following as parity_odd() 
argument is u64:

		err = !parity_odd(*(u16 *)p);

Regards,
Arend