From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 169361509AB; Sun, 8 Sep 2024 12:26:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725798409; cv=none; b=B2Ns5CigvRN4Qf12lQvUCJg9i3oIsxDAxzAKkqwRx5m5hX+m8jXF+iLR3TfXMEuCRoJau3I4wjnik7O8El6c9SDNdRGIvFvP2hiSxfEU5gGeos42C7NxGNO9YDO29j+ypTnTdaVo6eyIaSaNafIchIsE/RGcweMlJT65qq/5qD0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725798409; c=relaxed/simple; bh=VAcsrFstzUOeCIGcnQ5KBqekKS17CdwXMYlisjyPJQ4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=QdhFtIeAB9RDAbqLgPjEgOKT+WRNY7ntjgsNdHLrnOziK0MZ3K+iEzN2HQuDlkTzA0srxAPwMIy+cLfDjXdPfElh62Bh/5eY/B16qjZb+1NysMFZal0igYv59kxsWPKZpz7NkBMAXhl8XNirnkPpShu+S5bNciRpoZQ4oJ9pogg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=niQ6mWLG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="niQ6mWLG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9939C4CEC3; Sun, 8 Sep 2024 12:26:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725798408; bh=VAcsrFstzUOeCIGcnQ5KBqekKS17CdwXMYlisjyPJQ4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=niQ6mWLGzsHB8u7kUzL1M9m5aUfJ4bChFO8ZO3nnPftaa3Ak+oYKbDDalzX8P0qUJ WGgTFycxhZu1+S51n3Wy2spFPyl/CVxSy4WQVn6p8tnGhqWfUDXl47YAUM6DQxMFRe IvavxhXlkCiXOJ36VUnQYPWyDljohSe00MOsPctmbKBfAz3S1qTr8WidrLT4KS9AIq 62ORDHh+/YIuDXiPLh4VSo56CtuAwcSP512abmU4fxPceaVx1eYRX2D+8udsrfmuKl fVatOOVhPbzufo6RL8qBz7A9dvpcCeIZ/hkPkbIU30aXyaJWYQ/iE/fpdCIXXZypj1 CAkFiSa5J5f9Q== Date: Sun, 8 Sep 2024 13:26:38 +0100 From: Jonathan Cameron To: David Lechner Cc: Angelo Dureghello , Lars-Peter Clausen , Michael Hennerich , Nuno =?UTF-8?B?U8Oh?= , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Olivier Moysan , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 9/9] iio: ABI: add DAC sysfs synchronous_mode parameter Message-ID: <20240908132638.6322be29@jic23-huawei> In-Reply-To: References: <20240905-wip-bl-ad3552r-axi-v0-iio-testing-v2-0-87d669674c00@baylibre.com> <20240905-wip-bl-ad3552r-axi-v0-iio-testing-v2-9-87d669674c00@baylibre.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: devicetree@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 Thu, 5 Sep 2024 14:14:37 -0500 David Lechner wrote: > On 9/5/24 10:17 AM, Angelo Dureghello wrote: > > From: Angelo Dureghello > > > > Some DACs as ad3552r need a synchronous mode setting, adding > > this parameter for ad3552r and for future use on other DACs, > > if needed. > > > > Signed-off-by: Angelo Dureghello > > --- > > Documentation/ABI/testing/sysfs-bus-iio-dac | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac b/Documentation/ABI/testing/sysfs-bus-iio-dac > > index 810eaac5533c..2f4960c79385 100644 > > --- a/Documentation/ABI/testing/sysfs-bus-iio-dac > > +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac > > @@ -59,3 +59,19 @@ Description: > > multiple predefined symbols. Each symbol corresponds to a different > > output, denoted as out_voltageY_rawN, where N is the integer value > > of the symbol. Writing an integer value N will select out_voltageY_rawN. > > + > > +What: /sys/bus/iio/devices/iio:deviceX/out_voltage_synchronous_mode > > +KernelVersion: 6.13 > > +Contact: linux-iio@vger.kernel.org > > +Description: > > + Arm or disarm a wait-for-synchronization flag. Arming this flag > > + means the DAC will wait for a synchronizatiopn signal on a > > + specific internal or external wired connection. I.e., there are > > + cases where multiple DACs IP are built in the same chip or fpga > > + design, and they need to start the data stream synchronized. > > + > > +What: /sys/bus/iio/devices/iio:deviceX/out_voltage_synchronous_mode_available > > +KernelVersion: 6.13 > > +Contact: linux-iio@vger.kernel.org > > +Description: > > + List of available values for synchronous_mode. > > > > Since this depends on how things are wired, it seems like this should be > something specified in the devicetree, not through sysfs attributes. > Agreed. Smells like a wiring thing given the description. Is there a case where it works either way and it is usecase dependent which choice makes sense? Superficially it seems likely if a board has this wired, there is little disadvantage in using it always. Jonathan >