From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B3885221739; Sat, 25 Jul 2026 22:24:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785018280; cv=none; b=QOIFM8yYE8Oqe/vYJrXIqVtD2ZhQGGSpKfKNWM1Nn9FsxL9qApcFMOzkIjTks9CKcE/taGKWjUeP1ukoJAUb0bMhmNM3L2F9eMFIsXcZ2J8b7SeLO1tcUWShrcweuGEoz5G4isymJKUIQ7p8ioyaC+M8CQ4yVwN6j6KaHPtw9Vw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785018280; c=relaxed/simple; bh=1lg2B1+hqw5WTlOpRbq+F9KuDJQGNbN1kQw25jbR7Bg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BIrXs7gNEJncC0js5aYHpn4GFrhtoqYFdqhHuxe0UaZWvYQHuloOI948whl9+l8a7B8zl/akXvdDWRiTagv4+ucVzOvJ9/ybXeMYkLQjd18jr7zte/fdjXr8yGky6nDA67WjHvHr4GSbpDlNkwCJFvEW5cG3XRx/C5VRef0nHK0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WhTqN5JR; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WhTqN5JR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 335701F000E9; Sat, 25 Jul 2026 22:24:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785018279; bh=zI1Fz0os6qWy4FslM9JiAI8M6Xs9T908N+pSWxJAf5I=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=WhTqN5JR4hfhwCUKAoPirjZ6f5SnxTfXW2Kbgv9dG2LA9dAcm7YEpKM/ce8dt1qJD AlCTGZIQhu/bm2T7pfUVtYYp1GkaKjqVYK1w+sZSJb+lrGvo+8DlCbDe7ydb9HuwXf fYXZP1guI+4E46ojgFVKjDly7gKLka2SCf0LFnh+BeFfWky28V9cG02FNo76xGWvXs w2eRzFT20ecxO3l1b0qg+ifYvmGYwJzJ0oxtSSUaUizio2Uk91WvhX6XF8aCHfxTDX l5w/Nxn6Ip0AVQNVDYJ08sNS34ThOyo0r6MnXoBZaQZMSgNiTUPYrTkPz2O6m0c4Co fMGtCAdJHiylg== Date: Sat, 25 Jul 2026 23:24:32 +0100 From: Jonathan Cameron To: Rodrigo Alencar via B4 Relay Cc: rodrigo.alencar@analog.com, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-hardening@vger.kernel.org, Lars-Peter Clausen , Michael Hennerich , David Lechner , Andy Shevchenko , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Philipp Zabel , Jonathan Corbet , Shuah Khan , Kees Cook , "Gustavo A. R. Silva" Subject: Re: [PATCH v9 08/17] iio: core: add hierarchical channel relationships Message-ID: <20260725232432.7a0d4292@jic23-huawei> In-Reply-To: <20260722-ad9910-iio-driver-v9-8-459d1df5ac56@analog.com> References: <20260722-ad9910-iio-driver-v9-0-459d1df5ac56@analog.com> <20260722-ad9910-iio-driver-v9-8-459d1df5ac56@analog.com> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.52; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 22 Jul 2026 16:50:17 +0100 Rodrigo Alencar via B4 Relay wrote: > From: Rodrigo Alencar > > Add parent-child relationship between iio channels by creating a parent > pointer field in iio_chan_spec struct and exposing a sysfs attribute that > returns the parent channel prefix. > > Signed-off-by: Rodrigo Alencar Hi Rodrigo. One small thing below Jonathan > --- > drivers/iio/industrialio-core.c | 40 ++++++++++++++++++++++++++++++++++++++++ > include/linux/iio/iio.h | 5 +++++ > 2 files changed, 45 insertions(+) > > diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c > index aa9d6474edd9..f7e3048354b9 100644 > --- a/drivers/iio/industrialio-core.c > +++ b/drivers/iio/industrialio-core.c > @@ -856,6 +856,22 @@ static ssize_t iio_read_channel_label(struct device *dev, > to_iio_dev_attr(attr)->c, buf); > } > > +static ssize_t iio_read_channel_parent(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + const struct iio_chan_spec *chan = to_iio_dev_attr(attr)->c->parent; > + ssize_t len; > + > + len = __iio_chan_prefix_emit(dev, chan, IIO_SEPARATE, buf, PAGE_SIZE); > + if (len < 0) > + return len; > + > + buf[len++] = '\n'; Use sysfs_emit_at() for this rather than a direct write. I'd rather not have to think about what happens if __iio_chan_prefix_emit() returns exactly PAGE_SIZE(). > + > + return len; > +} > +