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 12:26:11PM +0300, Andy Shevchenko wrote:
> On Wed, Jun 03, 2026 at 12:33:33PM +0000, Taha Narimani wrote:
> > The driver currently utilizes devm_gpiod_get() for the 'busy' line,
> > which makes the GPIO mandatory. However, the busy pin is hardware-optional
> > depending on the specific board configuration.
> > 
> > Switch to devm_gpiod_get_optional() to allow boards that do not have
> > this pin wired up to still probe the driver successfully, and remove
> > the redundant conditional chip-ID check since the optional API handles
> > missing descriptors gracefully.
> 
> ...
> 
> > -	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.

> >  		while (gpiod_get_value(chip->busy_pin))
> >  			cpu_relax();
> >  	}

regards,
dan carpenter