linux-kernel - Re: [PATCH v3 16/17] spi: s3c64xx: drop a superfluous bitwise NOT operation

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Date: Fri, 26 Jan 2024 14:09:34 -0600
From: Sam Protsenko <semen.protsenko@...aro.org>
To: Tudor Ambarus <tudor.ambarus@...aro.org>
Cc: broonie@...nel.org, andi.shyti@...nel.org, krzysztof.kozlowski@...aro.org, 
	alim.akhtar@...sung.com, jassi.brar@...sung.com, linux-spi@...r.kernel.org, 
	linux-samsung-soc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, andre.draszik@...aro.org, 
	peter.griffin@...aro.org, kernel-team@...roid.com, willmcvicker@...gle.com
Subject: Re: [PATCH v3 16/17] spi: s3c64xx: drop a superfluous bitwise NOT operation

On Fri, Jan 26, 2024 at 11:16 AM Tudor Ambarus <tudor.ambarus@...aro.org> wrote:
>
> val &= ~mask;
> val |= mask;
>
> is equivalent to:
> val |= mask;
>
> Drop the superfluous bitwise NOT operation.
>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@...aro.org>
> ---

That's much more clear. Also I'm pretty sure if you compare .o file
before and after the patch, they would be identical -- another way to
argue the patch has no functional change.

Reviewed-by: Sam Protsenko <semen.protsenko@...aro.org>

>  drivers/spi/spi-s3c64xx.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index e9344fe71e56..43b888c8812e 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -1089,7 +1089,6 @@ static void s3c64xx_spi_hwinit(struct s3c64xx_spi_driver_data *sdd)
>
>         val = readl(regs + S3C64XX_SPI_MODE_CFG);
>         val &= ~S3C64XX_SPI_MODE_4BURST;
> -       val &= ~(S3C64XX_SPI_MAX_TRAILCNT << S3C64XX_SPI_TRAILCNT_OFF);
>         val |= (S3C64XX_SPI_MAX_TRAILCNT << S3C64XX_SPI_TRAILCNT_OFF);
>         writel(val, regs + S3C64XX_SPI_MODE_CFG);
>
> --
> 2.43.0.429.g432eaa2c6b-goog
>