linux-kernel - Re: [PATCH v2 2/2] spi: realtek-rtl: Improve readability when clearing the size mask

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Message-ID: <fe43a69a23308580eac251fdfdde66d848b64381.camel@svanheule.net>
Date:   Thu, 28 Jul 2022 20:40:33 +0200
From:   Sander Vanheule <sander@...nheule.net>
To:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        linux-spi@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, bert@...t.com, mail@...ger-koblitz.de
Subject: Re: [PATCH v2 2/2] spi: realtek-rtl: Improve readability when
 clearing the size mask

On Thu, 2022-07-28 at 17:21 +0200, Martin Blumenstingl wrote:
> Define the bitmask RTL_SPI_SFCSR_LEN_MASK so it only sets the bits of
> this specific part of the register instead of setting all bits except
> the relevant ones. This makes it consistent with single bit macros in
> the spi-realtek-rtl driver as well as with the approach that many other
> drivers use.
> 
> Suggested-by: Sander Vanheule <sander@...nheule.net>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>

FWIW
Tested-by: Sander Vanheule <sander@...nheule.net>

on my Netgear GS110TPP v1.

> ---
>  drivers/spi/spi-realtek-rtl.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/spi/spi-realtek-rtl.c b/drivers/spi/spi-realtek-rtl.c
> index 866b0477dbd7..0371d44cbfbd 100644
> --- a/drivers/spi/spi-realtek-rtl.c
> +++ b/drivers/spi/spi-realtek-rtl.c
> @@ -20,7 +20,7 @@ struct rtspi {
>  #define RTL_SPI_SFCSR_CSB1             BIT(30)
>  #define RTL_SPI_SFCSR_RDY              BIT(27)
>  #define RTL_SPI_SFCSR_CS               BIT(24)
> -#define RTL_SPI_SFCSR_LEN_MASK         ~(0x03 << 28)
> +#define RTL_SPI_SFCSR_LEN_MASK         (0x03 << 28)
>  #define RTL_SPI_SFCSR_LEN1             (0x00 << 28)
>  #define RTL_SPI_SFCSR_LEN4             (0x03 << 28)
>  
> @@ -49,7 +49,7 @@ static void set_size(struct rtspi *rtspi, int size)
>         u32 value;
>  
>         value = readl(REG(RTL_SPI_SFCSR));
> -       value &= RTL_SPI_SFCSR_LEN_MASK;
> +       value &= ~RTL_SPI_SFCSR_LEN_MASK;
>         if (size == 4)
>                 value |= RTL_SPI_SFCSR_LEN4;
>         else if (size == 1)