From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A19CDC4320A for ; Sun, 1 Aug 2021 16:58:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84746610A5 for ; Sun, 1 Aug 2021 16:58:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229803AbhHAQ6q (ORCPT ); Sun, 1 Aug 2021 12:58:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:45920 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229575AbhHAQ6p (ORCPT ); Sun, 1 Aug 2021 12:58:45 -0400 Received: from jic23-huawei (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A7B3960EB5; Sun, 1 Aug 2021 16:58:31 +0000 (UTC) Date: Sun, 1 Aug 2021 18:01:11 +0100 From: Jonathan Cameron To: Guenter Roeck Cc: Andreas Klinger , devicetree@vger.kernel.org, linux-iio@vger.kernel.org, Rob Herring , Jonathan Cameron , Jiri Kosina , Chris Packham , Slawomir Stepien , Krzysztof Kozlowski , Alexandre Belloni , Vadim Pasternak , Alexandru Ardelean , linux-kernel@vger.kernel.org, Lars-Peter Clausen , Tomasz Duszynski Subject: Re: [PATCH 2/2] iio: chemical: Add driver support for sgp40 Message-ID: <20210801180111.28a1c4d1@jic23-huawei> In-Reply-To: <42e31edc-445c-06ac-dd3a-80db1b439996@roeck-us.net> References: <20210727163517.GA3468@arbad> <20210731173928.08d6812f@jic23-huawei> <42e31edc-445c-06ac-dd3a-80db1b439996@roeck-us.net> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 31 Jul 2021 11:06:25 -0700 Guenter Roeck wrote: > On 7/31/21 9:39 AM, Jonathan Cameron wrote: > > On Tue, 27 Jul 2021 18:35:19 +0200 > > Andreas Klinger wrote: > > > >> sgp40 is a gas sensor used for measuring the air quality. > >> > >> This driver is reading the raw resistance value which can be passed to > >> a userspace algorithm for further calculation. > >> > >> The raw value is also used to calculate an estimated absolute voc index > >> in the range from 0 to 500. For this purpose the raw_mean value of the > >> resistance for which the index value is 250 might be set up as a > >> calibration step. > >> > >> Compensation of relative humidity and temperature is supported and can > >> be used by writing to device attributes of the driver. > >> > >> There is a predecesor sensor type (sgp30) already existing. This driver > >> module was not extended because the new sensor is quite different in its > >> i2c telegrams. > >> > >> Signed-off-by: Andreas Klinger > > > > Hi Andreas, > > > > Non standard ABI in here, so we are missing documentation in Documentation/ABI/testing/sysfs-bus-iio-* > > > > Otherwise a few suggestions inline. > > > > Thanks, > > > > Jonathan > > > > > >> --- > [ ... ] > > >> +static int sgp40_read_raw(struct iio_dev *indio_dev, > >> + struct iio_chan_spec const *chan, int *val, > >> + int *val2, long mask) > >> +{ > >> + struct sgp40_data *data = iio_priv(indio_dev); > >> + int ret; > >> + u16 raw; > >> + int voc; > >> + > >> + switch (mask) { > >> + case IIO_CHAN_INFO_RAW: > >> + mutex_lock(&data->lock); > >> + ret = sgp40_measure_raw(data, &raw); > >> + if (ret) { > >> + mutex_unlock(&data->lock); > >> + return ret; > >> + } > >> + *val = raw; > >> + ret = IIO_VAL_INT; > >> + mutex_unlock(&data->lock); > >> + break; > >> + case IIO_CHAN_INFO_PROCESSED: > >> + mutex_lock(&data->lock); > >> + ret = sgp40_measure_raw(data, &raw); > >> + if (ret) { > >> + mutex_unlock(&data->lock); > >> + return ret; > >> + } > >> + ret = sgp40_calc_voc(data, raw, &voc); > >> + if (ret) { > >> + mutex_unlock(&data->lock); > >> + return ret; > >> + } > >> + *val = voc; > >> + ret = IIO_VAL_INT; > >> + mutex_unlock(&data->lock); > > > > You are holding the lock longer than needed - it would be good > > to reduce this, hopefully removing the need for unlocking separately > > in each of the error paths. > > > >> + break; > >> + default: > >> + return -EINVAL; > >> + } > >> + > >> + return ret; > > > > Drop this as you can't get here. > > > > Are you sure ? I see several "break;" above. Doh! In that case, return directly where it has break above so we don't need to go see if anything else happens in those paths. > > Guenter