From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) (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 646AD3DBD73; Wed, 18 Mar 2026 14:40:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.21 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773844859; cv=none; b=I7V473tnJ1em/nPdQ+MU7TPJZ17IPO1beICFpsvrw3aYn1aWcF1Ggh/ThpqSrXcq2SYBjX1iHiwIvTRXbN/mjen0dIQxr7z+2btvNllQy4UV/M3yoKsAUkoz5by+/+HW71wfwPRgKetx83JuR6nyoIeZ6VWV/aPOIJw9o945CTE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773844859; c=relaxed/simple; bh=qmx0FR4aJBmqTxYHrYV3jbj/vc9cdEQpEDxq1Me5jVo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IB/PWsyoWBpchl7BRR2jJU5uyvoVRjAQC/y8AURRYQX1ksFCOvTEU1k+TpEf8rwJ3+TuVYj7o9xIn1tw6HBHeqDdq1G26cah++9P1ForZCzZFZ09hA5kugQXrEXlqE9Dere2xMINru/EornrwRd9PE8PekUgaKfdwF9MNBiSHYk= 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=P72TJqJ1; arc=none smtp.client-ip=198.175.65.21 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="P72TJqJ1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1773844858; x=1805380858; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=qmx0FR4aJBmqTxYHrYV3jbj/vc9cdEQpEDxq1Me5jVo=; b=P72TJqJ1Tb876FQSD5EnigyTR5kFFJK74D1eEt/aMqpZJgvtwEfE02x3 wOH4YqtT/+uTln0/d6aTRwr9V+2H56o9rEkxY3Bnu0QX95FM/Mr3/NkwV tY9JGhkhu4yzCGKcNFqUOUdWNC0MwaJ467YdXm7xEjRgKOmedGgfy03+C oEHhDb9vf/RGMy7UeRifPGQv1WnHOGkku65Eed/1/X7OlP6reNuVtEqk+ WSnTrM2WSAiaS8iX/iAmGAzky1v1vE/4e9Mac/o2qIh+BRKgCl4FY9RSr ldLPsFQR1OYyhtiFfqRSlhnDLSgpAM7YwvUzf7qqADXAaBI+ZOtSoGptv w==; X-CSE-ConnectionGUID: UmOKgBEKTke4323hCXhsrA== X-CSE-MsgGUID: P8z9GNhtRCuX2uV5SV5oJA== X-IronPort-AV: E=McAfee;i="6800,10657,11733"; a="74788016" X-IronPort-AV: E=Sophos;i="6.23,127,1770624000"; d="scan'208";a="74788016" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2026 07:40:58 -0700 X-CSE-ConnectionGUID: 746yei+tR5eqBGnFtsSUIw== X-CSE-MsgGUID: PMR3fvouTBiGtIz3kS056A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,127,1770624000"; d="scan'208";a="245671427" Received: from pgcooper-mobl3.ger.corp.intel.com (HELO localhost) ([10.245.245.240]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2026 07:40:55 -0700 Date: Wed, 18 Mar 2026 16:40:53 +0200 From: Andy Shevchenko To: Archit Anant Cc: jic23@kernel.org, lars@metafoo.de, Michael.Hennerich@analog.com, dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org, linux-iio@vger.kernel.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 3/4] iio: adc: ad799x: cache regulator voltages during probe Message-ID: References: <20260318092715.42538-1-architanant5@gmail.com> <20260318092715.42538-4-architanant5@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260318092715.42538-4-architanant5@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Wed, Mar 18, 2026 at 02:57:14PM +0530, Archit Anant wrote: > Reading the regulator voltage via regulator_get_voltage() can be a slow > operation. Since the reference voltages for this ADC are not expected to > change at runtime, it is inefficient to query the regulator API every > time userspace reads the IIO_CHAN_INFO_SCALE attribute. > > Determine the active reference voltage (either VREF or VCC) during > probe() and cache it in the state structure. This improves the > performance of ad799x_read_raw() and removes the dependency on the > regulator pointers during fast-path reads. ... > case IIO_CHAN_INFO_SCALE: > - if (st->vref) > - ret = regulator_get_voltage(st->vref); > - else > - ret = regulator_get_voltage(st->reg); > - > - if (ret < 0) > - return ret; > - *val = ret / 1000; > + *val = st->vref_uV / MILLI; Not sure I understand properly this MILLI in conjunction with FRACTIONAL_LOG2 below. Is this simply millivolts? Then we have "(MICRO / MILLI)" pattern as of today to show that in a better way. > *val2 = chan->scan_type.realbits; > return IIO_VAL_FRACTIONAL_LOG2; -- With Best Regards, Andy Shevchenko