linux-kernel - Re: [PATCH 02/10] iio: imu: adis16400: check ret val for non-zero vs less-than-zero

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Message-ID: <6f4b3e17865f2f628acb86c84633b813ad85ee69.camel@analog.com>
Date:   Mon, 4 Nov 2019 07:40:44 +0000
From:   "Ardelean, Alexandru" <alexandru.Ardelean@...log.com>
To:     "jic23@...nel.org" <jic23@...nel.org>
CC:     "Hennerich, Michael" <Michael.Hennerich@...log.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
        "Bogdan, Dragos" <Dragos.Bogdan@...log.com>,
        "lars@...afoo.de" <lars@...afoo.de>
Subject: Re: [PATCH 02/10] iio: imu: adis16400: check ret val for non-zero vs
 less-than-zero

On Sun, 2019-11-03 at 10:21 +0000, Jonathan Cameron wrote:
> On Fri, 1 Nov 2019 11:34:57 +0200
> Alexandru Ardelean <alexandru.ardelean@...log.com> wrote:
> 
> > The ADIS library functions return zero on success, and negative values
> > for
> > error. Positive values aren't returned, but we only care about the
> > success
> > value (which is zero).
> > 
> > This change is mostly needed so that the compiler won't make any
> > inferences
> > about some about values being potentially un-initialized. This only
> > triggers after making some functions inline, because the compiler can
> > better follow return paths.
> > 
> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
> Applied,
> 
> An observation whilst I was looking at the driver though...
> 
> It has some cases of goto label; where the label doesn't then do anything
> in *_initial_setup.  Direct returns would be a bit neater.
> 
> Really minor point but if you happen to be touching that driver again
> soon nice to tidy up ;)

As you can probably guess, a lot of cleanups will be coming to the ADIS
family & library.
So, I'll try to include this into the next cleanup set.

I'll try to re-spin the ADIS lock cleanup.
We still need to do the devm_ variants + related cleanup.

Thanks
Alex

> 
> Thanks,
> 
> Jonathan
> 
> 
> > ---
> >  drivers/iio/imu/adis16400.c | 22 +++++++++++-----------
> >  1 file changed, 11 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/iio/imu/adis16400.c b/drivers/iio/imu/adis16400.c
> > index 0575ff706bd4..44e46dc96e00 100644
> > --- a/drivers/iio/imu/adis16400.c
> > +++ b/drivers/iio/imu/adis16400.c
> > @@ -217,16 +217,16 @@ static ssize_t
> > adis16400_show_serial_number(struct file *file,
> >  	int ret;
> >  
> >  	ret = adis_read_reg_16(&st->adis, ADIS16334_LOT_ID1, &lot1);
> > -	if (ret < 0)
> > +	if (ret)
> >  		return ret;
> >  
> >  	ret = adis_read_reg_16(&st->adis, ADIS16334_LOT_ID2, &lot2);
> > -	if (ret < 0)
> > +	if (ret)
> >  		return ret;
> >  
> >  	ret = adis_read_reg_16(&st->adis, ADIS16334_SERIAL_NUMBER,
> >  			&serial_number);
> > -	if (ret < 0)
> > +	if (ret)
> >  		return ret;
> >  
> >  	len = snprintf(buf, sizeof(buf), "%.4x-%.4x-%.4x\n", lot1, lot2,
> > @@ -249,7 +249,7 @@ static int adis16400_show_product_id(void *arg, u64
> > *val)
> >  	int ret;
> >  
> >  	ret = adis_read_reg_16(&st->adis, ADIS16400_PRODUCT_ID, &prod_id);
> > -	if (ret < 0)
> > +	if (ret)
> >  		return ret;
> >  
> >  	*val = prod_id;
> > @@ -266,7 +266,7 @@ static int adis16400_show_flash_count(void *arg,
> > u64 *val)
> >  	int ret;
> >  
> >  	ret = adis_read_reg_16(&st->adis, ADIS16400_FLASH_CNT,
> > &flash_count);
> > -	if (ret < 0)
> > +	if (ret)
> >  		return ret;
> >  
> >  	*val = flash_count;
> > @@ -327,7 +327,7 @@ static int adis16334_get_freq(struct
> > adis16400_state *st)
> >  	uint16_t t;
> >  
> >  	ret = adis_read_reg_16(&st->adis, ADIS16400_SMPL_PRD, &t);
> > -	if (ret < 0)
> > +	if (ret)
> >  		return ret;
> >  
> >  	t >>= ADIS16334_RATE_DIV_SHIFT;
> > @@ -359,7 +359,7 @@ static int adis16400_get_freq(struct
> > adis16400_state *st)
> >  	uint16_t t;
> >  
> >  	ret = adis_read_reg_16(&st->adis, ADIS16400_SMPL_PRD, &t);
> > -	if (ret < 0)
> > +	if (ret)
> >  		return ret;
> >  
> >  	sps = (t & ADIS16400_SMPL_PRD_TIME_BASE) ? 52851 : 1638404;
> > @@ -416,7 +416,7 @@ static int adis16400_set_filter(struct iio_dev
> > *indio_dev, int sps, int val)
> >  	}
> >  
> >  	ret = adis_read_reg_16(&st->adis, ADIS16400_SENS_AVG, &val16);
> > -	if (ret < 0)
> > +	if (ret)
> >  		return ret;
> >  
> >  	ret = adis_write_reg_16(&st->adis, ADIS16400_SENS_AVG,
> > @@ -615,7 +615,7 @@ static int adis16400_read_raw(struct iio_dev
> > *indio_dev,
> >  		ret = adis_read_reg_16(&st->adis,
> >  						ADIS16400_SENS_AVG,
> >  						&val16);
> > -		if (ret < 0) {
> > +		if (ret) {
> >  			mutex_unlock(&indio_dev->mlock);
> >  			return ret;
> >  		}
> > @@ -626,12 +626,12 @@ static int adis16400_read_raw(struct iio_dev
> > *indio_dev,
> >  			*val2 = (ret % 1000) * 1000;
> >  		}
> >  		mutex_unlock(&indio_dev->mlock);
> > -		if (ret < 0)
> > +		if (ret)
> >  			return ret;
> >  		return IIO_VAL_INT_PLUS_MICRO;
> >  	case IIO_CHAN_INFO_SAMP_FREQ:
> >  		ret = st->variant->get_freq(st);
> > -		if (ret < 0)
> > +		if (ret)
> >  			return ret;
> >  		*val = ret / 1000;
> >  		*val2 = (ret % 1000) * 1000;