linux-kernel - Re: [PATCH v2 3/3] staging: iio: ad9832: Add minor improvements to ad9832_write

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Message-ID: <e712ec88-d925-4a73-8df4-ca3387a903fd@stanley.mountain>
Date: Tue, 22 Apr 2025 13:08:25 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Gabriel Shahrouzi <gshahrouzi@...il.com>
Cc: gregkh@...uxfoundation.org, jic23@...nel.org, lars@...afoo.de,
	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-staging@...ts.linux.dev, Michael.Hennerich@...log.com,
	skhan@...uxfoundation.org, linux-kernel-mentees@...ts.linux.dev
Subject: Re: [PATCH v2 3/3] staging: iio: ad9832: Add minor improvements to
 ad9832_write_powerdown

On Sun, Apr 20, 2025 at 01:47:25PM -0400, Gabriel Shahrouzi wrote:
> Minimize size of type that needs to be used by replacing unsigned long
> with bool. Avoid redundancy by checking if cached power state is the
> same as the one requested.
> 
> Signed-off-by: Gabriel Shahrouzi <gshahrouzi@...il.com>
> ---
>  drivers/staging/iio/frequency/ad9832.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/staging/iio/frequency/ad9832.c b/drivers/staging/iio/frequency/ad9832.c
> index a8fc20379efed..2ab6026d56b5c 100644
> --- a/drivers/staging/iio/frequency/ad9832.c
> +++ b/drivers/staging/iio/frequency/ad9832.c
> @@ -173,13 +173,19 @@ static ssize_t ad9832_write_powerdown(struct device *dev, struct device_attribut
>  	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>  	struct ad9832_state *st = iio_priv(indio_dev);
>  	int ret;
> -	unsigned long val;
> +	bool val;
> +	bool cur;
>  
> -	ret = kstrtoul(buf, 10, &val);
> +	ret = kstrtobool(buf, &val);
>  	if (ret)
> -		goto error_ret;
> +		return ret;

Fold this whole thing into patch 2.  Don't write something and then fix
it in the next patch.

>  
>  	mutex_lock(&st->lock);
> +
> +	cur = !!(st->ctrl_src & AD9832_SLEEP);
> +	if (val == cur)
> +		goto unlock;
> +
>  	if (val)
>  		st->ctrl_src |= AD9832_SLEEP;
>  	else
> @@ -189,10 +195,10 @@ static ssize_t ad9832_write_powerdown(struct device *dev, struct device_attribut
>  	st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) |
>  				st->ctrl_src);
>  	ret = spi_sync(st->spi, &st->msg);
> -	mutex_unlock(&st->lock);
>  
> -error_ret:
> -	return ret ? ret : len;
> +unlock:
> +	mutex_unlock(&st->lock);
> +	return len;

This should still be:

	return ret ? ret : len;

regards,
dan carpenter