From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (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 9B3A0125B9; Fri, 13 Jun 2025 12:47:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749818859; cv=none; b=RkK1uSObYIcQjTC2m4ZQlpHj31eFqt/v+HnE4MZcnJDx4n/TWqbSM8mOjNqza6OseAoWNnCU/LolMr5HPyR0pVnwhdsQV4QSquNNfBH37FB1QViSaKur9Ac3dUfQPUudAd7AAM+E/D6Ib+91NaEYAttqD8SmhNE60MeZ5kk7HzY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749818859; c=relaxed/simple; bh=5mk3F0ocPUMcuaVsmdoVLDWViyRIeQim/i1Xpz+fTFE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SsiNZGEePnRSNZM9hmD9mjE1zpVg1bH6do8DLsAl8IbNlE/vG39cKGzMon6K2JKcRKNvpwCf7CFTxkxo/KnGVxX4Z2sqnCvq8ShBi/8v2ys7D4KA/yOUNqIQ2me7FH91y0kd/s+hGoTC/0CBSnHvGeOFCoLq0MdjwZQiq1Qw9pc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=gXDWy6K5; arc=none smtp.client-ip=192.198.163.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="gXDWy6K5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1749818858; x=1781354858; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=5mk3F0ocPUMcuaVsmdoVLDWViyRIeQim/i1Xpz+fTFE=; b=gXDWy6K5S/leQU6FAT053Xhl/g4IKrgl9o4aLyKv6v49KsTR8uVIJ/HY jL+UHydzuObgivAlLn10ROMf4oOEWAIqGmaMkSubbLiUjxdIFkts7Obw+ bZ4kOem5sRq98FkGAfruyaSf3ZDkbL9ItRYdS6b30d5zYFTuXgTo3cTtK WyrWgf5EqWEGEMB1RxQbVAniCDbEflJkyjBz291n+9HJ1S7hdzHKDV6qt sJaFCu6XWQudmVGbygaickIn7Ke97NYC9QKF6cAXfrIc2RCMlssy+vJSR jS2wIhl6G/e1/e+ubeFihzTumpj/y80ckts4LEN8eSH0a30hTRE9lLyTt w==; X-CSE-ConnectionGUID: A61/o5loQBeivdkPV59+dA== X-CSE-MsgGUID: PbD5Ye+0S9S0jJDt2n1xcQ== X-IronPort-AV: E=McAfee;i="6800,10657,11463"; a="63386316" X-IronPort-AV: E=Sophos;i="6.16,233,1744095600"; d="scan'208";a="63386316" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jun 2025 05:47:37 -0700 X-CSE-ConnectionGUID: USdByUw8THa5lIoi+6/lmA== X-CSE-MsgGUID: +jwK5CYjQaqwZEctRuWepQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,233,1744095600"; d="scan'208";a="147721964" Received: from smile.fi.intel.com ([10.237.72.52]) by orviesa010.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jun 2025 05:47:33 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.98.2) (envelope-from ) id 1uQ3of-00000006FO3-3SxN; Fri, 13 Jun 2025 15:47:29 +0300 Date: Fri, 13 Jun 2025 15:47:29 +0300 From: Andy Shevchenko To: Jonathan Santos Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, andy@kernel.org, nuno.sa@analog.com, Michael.Hennerich@analog.com, marcelo.schmitt@analog.com, jic23@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, marcelo.schmitt1@gmail.com, linus.walleij@linaro.org, brgl@bgdev.pl, lgirdwood@gmail.com, broonie@kernel.org, jonath4nns@gmail.com, dlechner@baylibre.com Subject: Re: [PATCH v11 11/11] iio: adc: ad7768-1: add low pass -3dB cutoff attribute Message-ID: References: <804d66f1858014d7278aec3344d81c223661e878.1749569957.git.Jonathan.Santos@analog.com> 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-Disposition: inline In-Reply-To: <804d66f1858014d7278aec3344d81c223661e878.1749569957.git.Jonathan.Santos@analog.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Wed, Jun 11, 2025 at 08:52:03AM -0300, Jonathan Santos wrote: > Ad7768-1 has a different -3db frequency multiplier depending on > the filter type configured. The cutoff frequency also varies according > to the current ODR. > > Add a readonly low pass -3dB frequency cutoff attribute to clarify to > the user which bandwidth is being allowed depending on the filter > configurations. > +/* -3dB cutoff frequency multipliers (relative to ODR) for each filter type. */ > +static const int ad7768_filter_3db_odr_multiplier[] = { > + [AD7768_FILTER_SINC5] = 204, /* 0.204 */ > + [AD7768_FILTER_SINC3] = 262, /* 0.2617 */ > + [AD7768_FILTER_SINC3_REJ60] = 262, /* 0.2617 */ > + [AD7768_FILTER_WIDEBAND] = 433, /* 0.433 */ Just to be sure, is it 0.433 or 0.4333(3) actually? Sometimes datasheets have rounding that even may lead to problems (see TSC issues for some of the Intel CPUs in the past). That's behind my question. > +}; ... > + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: > + temp = st->samp_freq * ad7768_filter_3db_odr_multiplier[st->filter_type]; > + *val = DIV_ROUND_CLOSEST(temp, 1000); MILLI? KILO/ MICRO/MILLI? ...? -- With Best Regards, Andy Shevchenko