Re: [PATCH v2] staging: iio: adc: ad7816: Use devm_gpiod_get_optional() for busy GPIO

[Dan Carpenter <error27@gmail.com>]

On Wed, Jun 03, 2026 at 01:37:32PM +0300, Andy Shevchenko wrote:
> On Wed, Jun 03, 2026 at 01:20:08PM +0300, Dan Carpenter wrote:
> > On Wed, Jun 03, 2026 at 12:26:11PM +0300, Andy Shevchenko wrote:
> > > On Wed, Jun 03, 2026 at 12:33:33PM +0000, Taha Narimani wrote:
> 
> ...
> 
> > > > -	if (chip->id == ID_AD7817) {
> > > > +	if (chip->busy_pin) {
> > > 
> > > If we get GPIO optional, this check wouldn't be necessary anymore as the below
> > > should return 0 IIRC in this case.
> > 
> > No, it's still necessary.  It can be NULL because of the CONFIG_
> > in which case, sure, gpiod_get_value() is a no-op.  But it can
> > also be NULL because of the device tree and in that case we need
> > the check to avoid a NULL pointer dereference.
> 
> Can you elaborate on the latter more? I fail to see that.
> What I see is that the function either implemented or not is NULL-aware.
> 

Ah, yes.  You're right.  The VALIDATE_DESC() macro has a return hiding
inside.  I hadn't seen that.

regards,
dan carpenter