Re: [PATCH 7/7] staging:iio:ade7854: Add proper error handling condition

[Rodrigo Siqueira]

On 03/15, Dan Carpenter wrote:
> On Wed, Mar 14, 2018 at 03:12:18PM -0300, Rodrigo Siqueira wrote:
> > There is some improper error handling for IRQ and device register.  This
> > patch adds a proper verification. The IRQ correction was extracted from
> > John Syne patches.
> > 
> > Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@xxxxxxxxx>
> > Signed-off-by: John Syne <john3909@xxxxxxxxx>
> > ---
> >  drivers/staging/iio/meter/ade7854.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/staging/iio/meter/ade7854.c b/drivers/staging/iio/meter/ade7854.c
> > index 09fd8c067738..49cbe365e43d 100644
> > --- a/drivers/staging/iio/meter/ade7854.c
> > +++ b/drivers/staging/iio/meter/ade7854.c
> > @@ -436,7 +436,7 @@ static int ade7854_initial_setup(struct iio_dev *indio_dev)
> >  
> >  	/* Disable IRQ */
> >  	ret = ade7854_set_irq(dev, false);
> > -	if (ret) {
> > +	if (ret < 0) {
> >  		dev_err(dev, "disable irq failed");
> >  		goto err_ret;
> >  	}
> 
> Why is the original wrong?  It seems fine.

Hi,

If you look at "drivers/staging/iio/meter/ade7854-(i2c|spi).c", you will
find a line like this: " st->write_reg = ade7854_(i2c|spi)_write_reg;".
Than, if you go through the "ade7854_i2c_write_reg" (focus only on i2c
for while) you will see "i2c_master_send(st->i2c, st->tx, count)",
which can returns a positive number that does not necessary means an
error. If you find the same for the spi case, you will end up in the
function "spi_sync_transfer" that only return 0 for success or negative
for failure. So, handling the negative case better fit the i2c and spi case.

Thanks

> regards,
> dan carpenter
> 
>