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Wed, 03 Jun 2026 03:20:11 -0700 (PDT) Date: Wed, 3 Jun 2026 13:20:08 +0300 From: Dan Carpenter To: Andy Shevchenko Cc: Taha Narimani , jic23@kernel.org, lars@metafoo.de, Michael.Hennerich@analog.com, gregkh@linuxfoundation.org, dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org, linux-iio@vger.kernel.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] staging: iio: adc: ad7816: Use devm_gpiod_get_optional() for busy GPIO Message-ID: References: <20260603123333.5608-1-tahanarimani3443@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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