On Thu, Oct 17, 2019 at 1:43 PM Mickael GUENE <mickael.guene@xxxxxx> wrote:
>
> Hello Chuhong,
>
> Is this check necessary ?
> since looking into code it seems to me devm_gpiod_get_optional() can only
> return NULL in case of error due to following check in devm_gpiod_get_index_optional()
> if (IS_ERR(desc)) {
> if (PTR_ERR(desc) == -ENOENT)
> return NULL;
> }
> And in that case reset_gpio is not used
>
The problem may not be a null return value, but a returned error,
which is a minus value,
like -EPROBE_DEFER or -EINVAL returned by gpiod_find in gpiod_get_index.
In these cases, devm_gpiod_get_index_optional will not return null but
return the error.
Therefore, this check is necessary.
> Regards
> Mickael
>
> On 10/16/19 12:56, Chuhong Yuan wrote:
> > mipid02_probe misses a check for devm_gpiod_get_optional and may miss
> > the failure.
> > Add a check to fix the problem.
> >
> > Signed-off-by: Chuhong Yuan <hslester96@xxxxxxxxx>
> > ---
> > drivers/media/i2c/st-mipid02.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/media/i2c/st-mipid02.c b/drivers/media/i2c/st-mipid02.c
> > index 81285b8d5cfb..d38e888b0a43 100644
> > --- a/drivers/media/i2c/st-mipid02.c
> > +++ b/drivers/media/i2c/st-mipid02.c
> > @@ -971,6 +971,9 @@ static int mipid02_probe(struct i2c_client *client)
> > bridge->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> > GPIOD_OUT_HIGH);
> >
> > + if (IS_ERR(bridge->reset_gpio))
> > + return PTR_ERR(bridge->reset_gpio);
> > +
> > ret = mipid02_get_regulators(bridge);
> > if (ret) {
> > dev_err(dev, "failed to get regulators %d", ret);
> >
