From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) (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 7D47A35AC2A; Mon, 2 Mar 2026 13:13:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.20 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772457210; cv=none; b=Jd1LpSp4uv5p52rWII6Sr/wClcM9KCBywPSezrWGXGIMxhwcHXqmLmdcFVpP5fLX9PaaRgLYfwA6Za0civF5VvFXkERZcrDMtWi4Hd6ZH++g8kjtYgPGEi34F3DjEPTu10dPJ5/5FBF9Wk5kh+e7KP+EUU5rpDwESbcaPpgtxtY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772457210; c=relaxed/simple; bh=jonLXlS3nkJ67zur7OggV7pwpTPklMSO4m7JNHmfVvg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=laINji1x19tdXrvbqjwE1Wem94VXYXhQeIPA2eHI6NN4bw7brosmdEpPI4OH+kP2nAGfRrqerQoFWaBwyJpxO55ig6ewwsHlgbrDT4nIeA4JfEwRAQinx0ksGdkaSGwBWr91w16V3A5oc1qB0wZ+gTX8qTQUcqGH2bJuEQTodTg= 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=ExN7Exy7; arc=none smtp.client-ip=198.175.65.20 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="ExN7Exy7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1772457210; x=1803993210; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=jonLXlS3nkJ67zur7OggV7pwpTPklMSO4m7JNHmfVvg=; b=ExN7Exy7bRfgq+PH6wdn7Nqq6uS6+iERhaHqJh1ov0tDx2rdvD7XlbKT I0l2njKl/XuFuWv7fHM86l6k792bT4P9RqaHfQGbU/dm0VAQ70S0QnW52 GgKJd/nME+WsL68DFqJkSms4JA13DrhHSqyAlzPrvkOJzSh/EqGWH37zy wR5wLmCY8Zr6k/uCa4aoPSi1QbaHRJJ7RwyDrvJmD5SRLjRffKGZm0rlS qiz7ITTkd0vT8E3j6ZUZkubyxWFi7Tp2hhWTwzsOXVNRM2zcw9nPvdmw0 EJ8zls+sp9DIfEkWMEFdEOqc+g+7zYSFx0kiJqESN7hPn5fYEbkOAq0Zg Q==; X-CSE-ConnectionGUID: YwmzzvaySDe99tXUiByj8w== X-CSE-MsgGUID: Ak9TJuHKT+yUY8kNnn3T7A== X-IronPort-AV: E=McAfee;i="6800,10657,11717"; a="73164808" X-IronPort-AV: E=Sophos;i="6.21,320,1763452800"; d="scan'208";a="73164808" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2026 05:13:29 -0800 X-CSE-ConnectionGUID: kl3y2uhUQVCTG/RwAofYGw== X-CSE-MsgGUID: d/MSyCDqT3+Ay17f3qohjQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,320,1763452800"; d="scan'208";a="214122539" Received: from dalessan-mobl3.ger.corp.intel.com (HELO localhost) ([10.245.244.52]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2026 05:13:26 -0800 Date: Mon, 2 Mar 2026 15:13:24 +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-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/4] iio: adc: ad799x: cache regulator voltages during probe Message-ID: References: <20260302130632.29144-1-architanant5@gmail.com> <20260302130632.29144-3-architanant5@gmail.com> Precedence: bulk X-Mailing-List: linux-iio@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: <20260302130632.29144-3-architanant5@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Mon, Mar 02, 2026 at 06:36:30PM +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. > > Cache the VCC and VREF voltages in the state structure during probe(). > This improves the performance of ad799x_read_raw() and removes the > dependency on the regulator pointers during fast-path reads. ... > + int vcc_uv; > + int vref_uv; _uV in both cases, please. It's a unit suffix. ... > case IIO_CHAN_INFO_SCALE: > if (st->vref) > - ret = regulator_get_voltage(st->vref); > + ret = st->vref_uv; > else > - ret = regulator_get_voltage(st->reg); > + ret = st->vcc_uv; > if (ret < 0) > return ret; Isn't it a dead check now? -- With Best Regards, Andy Shevchenko