From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-08.mail-europe.com (mail-08.mail-europe.com [57.129.93.249]) (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 CF5E740DFC6; Sun, 19 Apr 2026 14:30:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=57.129.93.249 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776609051; cv=none; b=p9DoU6+0LzSQeDoVAglT56UR5RZaXQ3FDXbyaTZaIenie+My3lxhTQ7NrkcrCBJDGdc/U9RahXOIev8XJItbMvmNbxHDF44YbmKszE1U6g0r+RM6x6EB88Yi4IeraxHRNE3Dvkk7TlpLZhl0Sj0AjQZRJ4fdnlaoZFChZ4+7sR8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776609051; c=relaxed/simple; bh=Q1mpSCTG654r0w7ql2ejT8xE3eizhsUmD5BNUQmv4hQ=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=gLF2AiJo4GzwJedTwvOMzFaLkr1jEGOxD0C9xjOU0k1aGa7QGLwgNbrUqjMOsBFT2CwliSQCU880XqX3iPyAsIV1UBuFKdf2w/vEgugOLZ7onjXJFw23aAc391RwgqoAr+65FL4uPNcle6qFAJNUgbj49DndCtnlbvYOGlygubI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pm.me; spf=pass smtp.mailfrom=pm.me; dkim=pass (2048-bit key) header.d=pm.me header.i=@pm.me header.b=rYPDPRTO; arc=none smtp.client-ip=57.129.93.249 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pm.me Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pm.me Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=pm.me header.i=@pm.me header.b="rYPDPRTO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail3; t=1776609033; x=1776868233; bh=3atv76sLcV52AAdzO4Ac2tNGwsLxK7EwiNOZghNVc8I=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=rYPDPRTOPNi8ZeottOcqGYmHhNjOzGQnw9Kr2J4c2f+1ohjftzlr9K7YFYOmSQzsc IXJY57U+fqrmyRRLdSZwmsuaiUbsYdHiArq4fIaAt5eKwbTJPQIvzfr9WqD4W5k9Uv UiTyrZpE13IBJSqL6CVYWbLrU+FYuuvs8tRChtAR7r8VNFh68cTh1rtBco9XpRQiHn bwGX0sDCeO92oeujXC0q8dz3ugYEcansS9yeCW1muJl32Z8qJE/PGuDc0oU0dkmhpz mzjdJoEg/psiQ6H7Aiib1gUDYnYa8w7TL7L4JF6A8gyZRKZaBu8AUICTkaM/ljmFWk jFlaEw3R7uFcA== Date: Sun, 19 Apr 2026 14:30:26 +0000 To: David Lechner , Hardik Phalet , Greg Kroah-Hartman From: Hardik Phalet Cc: Jonathan Cameron , =?utf-8?Q?Nuno_S=C3=A1?= , Andy Shevchenko , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Brigham Campbell , Shuah Khan , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev Subject: Re: [PATCH v2 3/4] staging: iio: magnetometer: Add QST QMC5883P driver Message-ID: In-Reply-To: <2d966423-52b5-4b8a-a4d1-0edcd93a841b@baylibre.com> References: <20260409210639.3197576-1-hardik.phalet@pm.me> <20260409210639.3197576-4-hardik.phalet@pm.me> <736964f9-1e93-47e7-80ca-1a89f239a353@baylibre.com> <2d966423-52b5-4b8a-a4d1-0edcd93a841b@baylibre.com> Feedback-ID: 166659585:user:proton X-Pm-Message-ID: a1c02fe2284ab6a62d3546f796002a7a07f0b6cb Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Mon Apr 13, 2026 at 12:22 AM IST, David Lechner wrote: > On 4/12/26 4:54 AM, Hardik Phalet wrote: >> On Sat Apr 11, 2026 at 1:32 AM IST, David Lechner wrote: >>> On 4/9/26 4:07 PM, Hardik Phalet wrote: >>> >>> This is a little bit much to review all in one patch. Could be nice >>> to split out power management to a separate patch. >>> > > ... > >>>> +static IIO_DEVICE_ATTR(downsampling_ratio, 0644, downsampling_ratio_s= how, >>>> +=09=09 downsampling_ratio_store, 0); >>>> +static IIO_CONST_ATTR(downsampling_ratio_available, "1 2 4 8"); >>> >>> As mentioned in the cover letter, we'd like to know more about what >>> this actually does. If there is a good reason it doesn't fit with >>> any existing filter attribute, then we'll need a patch to document >>> the sysfs ABI as well. >>> >> In the device datasheet, OSR2("Down sampling ratio") is mentioned like t= his: >> "Another filter is added for better noise performance; the depth can be >> adjusted through OSR2". OSR2's defintion is called "down sampling ratio" >> in a table. Nowhere else. I didn't know what attribute to map it to in >> this case. >> > I wonder if there is an application note or something that explains it > in more detail if the datasheet does not. > I could not find any mention of it, in an application note or otherwise. I cannot confirm what this does, unless I get an oscilloscope and figure it out. > We could always omit the feature if no one knows what it actually does. Yes that's what I am planning to do. Regards, Hardik