From patchwork Tue Oct 4 13:49:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Nuno Sa X-Patchwork-Id: 12998407 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A32ADC433F5 for ; Tue, 4 Oct 2022 13:50:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229867AbiJDNu3 (ORCPT ); Tue, 4 Oct 2022 09:50:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229781AbiJDNuZ (ORCPT ); Tue, 4 Oct 2022 09:50:25 -0400 Received: from mx0a-00128a01.pphosted.com (mx0a-00128a01.pphosted.com [148.163.135.77]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02FD92B25A for ; Tue, 4 Oct 2022 06:50:25 -0700 (PDT) Received: from pps.filterd (m0167088.ppops.net [127.0.0.1]) by mx0a-00128a01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 294AJj0u005490; Tue, 4 Oct 2022 09:49:41 -0400 Received: from nwd2mta3.analog.com ([137.71.173.56]) by mx0a-00128a01.pphosted.com (PPS) with ESMTPS id 3jxfd73npd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 04 Oct 2022 09:49:40 -0400 Received: from ASHBMBX8.ad.analog.com (ASHBMBX8.ad.analog.com [10.64.17.5]) by nwd2mta3.analog.com (8.14.7/8.14.7) with ESMTP id 294Dnbfl004154 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 4 Oct 2022 09:49:37 -0400 Received: from ASHBMBX9.ad.analog.com (10.64.17.10) by ASHBMBX8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.14; Tue, 4 Oct 2022 09:49:36 -0400 Received: from zeus.spd.analog.com (10.66.68.11) by ashbmbx9.ad.analog.com (10.64.17.10) with Microsoft SMTP Server id 15.2.986.14 via Frontend Transport; Tue, 4 Oct 2022 09:49:36 -0400 Received: from nsa.ad.analog.com ([10.44.3.52]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 294DlkVm032663; Tue, 4 Oct 2022 09:49:26 -0400 From: =?utf-8?q?Nuno_S=C3=A1?= To: , , , , CC: Heiko Stuebner , Martin Blumenstingl , Neil Armstrong , Shawn Guo , Lars-Peter Clausen , Jyoti Bhayana , Hans de Goede , Andriy Tryshnivskyy , Pengutronix Kernel Team , Miquel Raynal , Cixi Geng , Baolin Wang , Ciprian Regus , Fabio Estevam , =?utf-8?q?Nuno_S=C3=A1?= , Sascha Hauer , Alexandru Ardelean , Florian Boor , Michael Hennerich , Orson Zhai , Chen-Yu Tsai , Chunyan Zhang , Vladimir Zapolskiy , Andy Shevchenko , Jerome Brunet , Haibo Chen , Kevin Hilman , Jonathan Cameron Subject: [PATCH v2 15/16] iio: health: max30102: do not use internal iio_dev lock Date: Tue, 4 Oct 2022 15:49:08 +0200 Message-ID: <20221004134909.1692021-16-nuno.sa@analog.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221004134909.1692021-1-nuno.sa@analog.com> References: <20221004134909.1692021-1-nuno.sa@analog.com> MIME-Version: 1.0 X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-GUID: BdA7PqR-1AFDPhNVn-a5yd_q2TeJAau0 X-Proofpoint-ORIG-GUID: BdA7PqR-1AFDPhNVn-a5yd_q2TeJAau0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-10-04_06,2022-09-29_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 impostorscore=0 phishscore=0 suspectscore=0 lowpriorityscore=0 bulkscore=0 priorityscore=1501 mlxscore=0 mlxlogscore=999 clxscore=1015 spamscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210040089 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The pattern used in this device does not quite fit in the iio_device_claim_direct_mode() typical usage. In this case, we want to know if we are in buffered mode or not to know if the device is powered (buffer mode) or not. And depending on that max30102_get_temp() will power on the device if needed. Hence, in order to keep the same functionality, we try to: 1. Claim Buffered mode; 2: If 1) succeeds call max30102_get_temp() without powering on the device; 3: Release Buffered mode; 4: If 1) fails, Claim Direct mode; 5: If 4) succeeds call max30102_get_temp() with powering on the device; 6: Release Direct mode; 7: If 4) fails, goto to 1) and try again. This dance between buffered and direct mode is not particularly pretty (as well as the loop introduced by the goto statement) but it does allow us to get rid of the mlock usage while keeping the same behavior. Signed-off-by: Nuno Sá --- drivers/iio/health/max30102.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/iio/health/max30102.c b/drivers/iio/health/max30102.c index abbcef563807..b8b5ccf582fb 100644 --- a/drivers/iio/health/max30102.c +++ b/drivers/iio/health/max30102.c @@ -477,12 +477,23 @@ static int max30102_read_raw(struct iio_dev *indio_dev, * Temperature reading can only be acquired when not in * shutdown; leave shutdown briefly when buffer not running */ - mutex_lock(&indio_dev->mlock); - if (!iio_buffer_enabled(indio_dev)) +any_mode_retry: + if (iio_device_claim_buffer_mode(indio_dev)) { + /* + * This one is a *bit* hacky. If we cannot claim buffer + * mode, then try direct mode so that we make sure + * things cannot concurrently change. And we just keep + * trying until we get one of the modes... + */ + if (iio_device_claim_direct_mode(indio_dev)) + goto any_mode_retry; + ret = max30102_get_temp(data, val, true); - else + iio_device_release_direct_mode(indio_dev); + } else { ret = max30102_get_temp(data, val, false); - mutex_unlock(&indio_dev->mlock); + iio_device_release_buffer_mode(indio_dev); + } if (ret) return ret;