linux-kernel - Re: [PATCH 28/31] iio: gyro: use parity32 in adxrs450.c

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Message-ID: <56F8ECDE.3010701@kernel.org>
Date:	Mon, 28 Mar 2016 09:35:42 +0100
From:	Jonathan Cameron <jic23@...nel.org>
To:	"zhaoxiu.zeng" <zhaoxiu.zeng@...il.com>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Michael Hennerich <Michael.Hennerich@...log.com>,
	Hartmut Knaack <knaack.h@....de>,
	Peter Meerwald <pmeerw@...erw.net>
Cc:	linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org
Subject: Re: [PATCH 28/31] iio: gyro: use parity32 in adxrs450.c

On 27/03/16 08:42, zhaoxiu.zeng wrote:
> From: Zeng Zhaoxiu <zhaoxiu.zeng@...il.com>
> 
> Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng@...il.com>
Interesting.  Whilst obviously correct I wonder if this obscures the
intent of the code a little. Lars, what do you think?

Jonathan
> ---
>  drivers/iio/gyro/adxrs450.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/gyro/adxrs450.c b/drivers/iio/gyro/adxrs450.c
> index a330d42..f1f19fc20 100644
> --- a/drivers/iio/gyro/adxrs450.c
> +++ b/drivers/iio/gyro/adxrs450.c
> @@ -108,9 +108,7 @@ static int adxrs450_spi_read_reg_16(struct iio_dev *indio_dev,
>  
>  	mutex_lock(&st->buf_lock);
>  	tx = ADXRS450_READ_DATA | (reg_address << 17);
> -
> -	if (!(hweight32(tx) & 1))
> -		tx |= ADXRS450_P;
> +	tx |= !parity32(tx) * ADXRS450_P;
>  
>  	st->tx = cpu_to_be32(tx);
>  	ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers));
> @@ -144,9 +142,7 @@ static int adxrs450_spi_write_reg_16(struct iio_dev *indio_dev,
>  
>  	mutex_lock(&st->buf_lock);
>  	tx = ADXRS450_WRITE_DATA | (reg_address << 17) | (val << 1);
> -
> -	if (!(hweight32(tx) & 1))
> -		tx |= ADXRS450_P;
> +	tx |= !parity32(tx) * ADXRS450_P;
>  
>  	st->tx = cpu_to_be32(tx);
>  	ret = spi_write(st->us, &st->tx, sizeof(st->tx));
>