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Fri, 19 Dec 2025 06:45:39 -0800 (PST) Received: from [192.168.1.187] ([161.230.67.253]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47be26a81b6sm101968425e9.0.2025.12.19.06.45.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Dec 2025 06:45:39 -0800 (PST) Message-ID: <2c61d7f3e169ee5204f795784a686e46613b7aa8.camel@gmail.com> Subject: Re: [PATCH 2/2] iio: adc: ad9467: make iio backend optional From: Nuno =?ISO-8859-1?Q?S=E1?= To: Tomas Melin , Michael Hennerich , Nuno Sa , Lars-Peter Clausen , Jonathan Cameron , David Lechner , Andy Shevchenko Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Date: Fri, 19 Dec 2025 14:46:20 +0000 In-Reply-To: References: <20251216-b4-ad9467-optional-backend-v1-0-83e61531ef4d@vaisala.com> <20251216-b4-ad9467-optional-backend-v1-2-83e61531ef4d@vaisala.com> <88efd2784c9fce72e432a59a03472bb4441e975b.camel@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.2 Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2025-12-19 at 13:16 +0200, Tomas Melin wrote: >=20 > On 18/12/2025 15:49, Nuno S=C3=A1 wrote: > > On Tue, 2025-12-16 at 11:40 +0000, Tomas Melin wrote: > > > Not all users can or want to use the device with an iio-backend. > > > For these users, let the driver work in standalone mode, not coupled > > > to the backend or the services it provides. > > >=20 > > > Signed-off-by: Tomas Melin > > > --- > > > =C2=A0drivers/iio/adc/ad9467.c | 37 +++++++++++++++++++++++++--------= ---- > > > =C2=A01 file changed, 25 insertions(+), 12 deletions(-) > > >=20 > > > diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c > > > index 60fc3361b2689a4c38287c613ef93fe00338e5fa..37b8f88da6681d44f3fbb= b6c8c171ae7117b9090 > > > 100644 > > > --- a/drivers/iio/adc/ad9467.c > > > +++ b/drivers/iio/adc/ad9467.c > > > @@ -1000,6 +1000,9 @@ static int ad9467_update_scan_mode(struct iio_d= ev *indio_dev, > > > =C2=A0 unsigned int c; > > > =C2=A0 int ret; > > > =C2=A0 > > > + if (!st->back) > > > + return -EOPNOTSUPP; > > > + > >=20 > > Let's not add the buffering interface if we can't control it. > > Having it just to return error does not make sense to me. This means ye= t another info: > >=20 > > https://elixir.bootlin.com/linux/v6.18.1/source/drivers/iio/adc/ad9467.= c#L916 > >=20 >=20 > I agree, not having the scan_mode at all would be more clean. > But adding those different iio_info structs comes across as a bit messy. > Would it make sense to create that iio_info dynamically in the probe and > fill out the callbacks that are supported for the configuration we > encounter? I could try out something like that and see how it would look > like in practice. >=20 Hmm yeah, it's not just one more iio_info we need but 2. But maybe let's ke= ep it simple and remove the check in ad9467_update_scan_mode(). I mean, if I'm not missi= ng nothing,=20 if there's no buffer, there's no real way for userspace to reach that code = path. - Nuno S=C3=A1 >=20