linux-kernel - Re: [PATCH] staging: iio: accel: remove impossible condition

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Date:	Tue, 31 May 2016 15:13:51 -0500
From:	"Andrew F. Davis" <afd@...com>
To:	Luis de Bethencourt <luisbg@....samsung.com>,
	<linux-kernel@...r.kernel.org>
CC:	<gregkh@...uxfoundation.org>, <knaack.h@....de>, <lars@...afoo.de>,
	<jic23@...nel.org>, <ciorneiioana@...il.com>,
	<janani.rvchndrn@...il.com>, <linux-iio@...r.kernel.org>,
	<devel@...verdev.osuosl.org>
Subject: Re: [PATCH] staging: iio: accel: remove impossible condition

On 05/31/2016 02:47 PM, Luis de Bethencourt wrote:
> val is set to the value of ret right after ret is checked. If ret is not
> zero it goes to error_ret. So only value ret can have is zero, which makes
> the switch (val & 0x03) only match the case 0x00. Removing the switch and
> since val is only used for this, removing val as well.
> 
> Signed-off-by: Luis de Bethencourt <luisbg@....samsung.com>
> ---
>  drivers/staging/iio/accel/sca3000_core.c | 16 ++--------------
>  1 file changed, 2 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/staging/iio/accel/sca3000_core.c b/drivers/staging/iio/accel/sca3000_core.c
> index a8f533a..94656f6 100644
> --- a/drivers/staging/iio/accel/sca3000_core.c
> +++ b/drivers/staging/iio/accel/sca3000_core.c
> @@ -586,7 +586,7 @@ static ssize_t sca3000_read_frequency(struct device *dev,
>  {
>  	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>  	struct sca3000_state *st = iio_priv(indio_dev);
> -	int ret, len = 0, base_freq = 0, val;
> +	int ret, len = 0, base_freq = 0;
>  
>  	mutex_lock(&st->lock);
>  	ret = __sca3000_get_base_freq(st, st->info, &base_freq);
> @@ -596,20 +596,8 @@ static ssize_t sca3000_read_frequency(struct device *dev,
>  	mutex_unlock(&st->lock);
>  	if (ret)

I'm not sure, but I'm guessing this switch serves some purpose and this
was meant to be (ret < 0).

>  		goto error_ret;
> -	val = ret;
>  	if (base_freq > 0)
> -		switch (val & 0x03) {
> -		case 0x00:
> -		case 0x03:
> -			len = sprintf(buf, "%d\n", base_freq);
> -			break;
> -		case 0x01:
> -			len = sprintf(buf, "%d\n", base_freq / 2);
> -			break;
> -		case 0x02:
> -			len = sprintf(buf, "%d\n", base_freq / 4);
> -			break;
> -	}
> +		len = sprintf(buf, "%d\n", base_freq);
>  
>  	return len;
>  error_ret_mut:
>