From patchwork Wed Aug 3 10:28:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudiu Beznea X-Patchwork-Id: 595148 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 592BDC3F6B0 for ; Wed, 3 Aug 2022 10:26:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237788AbiHCK05 (ORCPT ); Wed, 3 Aug 2022 06:26:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237687AbiHCK04 (ORCPT ); Wed, 3 Aug 2022 06:26:56 -0400 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3326120BE1; Wed, 3 Aug 2022 03:26:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1659522412; x=1691058412; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=pSIzxMNIlBjvvm8G+s2ESA2q3nUg2ihYeM/Z3C6vBKE=; b=DONmtz9ICGPL08b4EDFOnJxRbLW8UZ6Xi2l7dz12dMM2ro9hsYmx3+NU 0ba0JoKSIxKa7RyIu9J10IiGBNWryxCFjBoCmyDtHOitFFN+Ajw8UoNMY EopAJf/kryRKMIbZAAYKfYIFiIX8n/bPWqgh/n5e2Yh1rXWNQMyTA6YGp 3lPBCKDowUiD2BzZT8dYBtmgoXt7J6muprONfpHRBORPb+hxaUzoNSZ5R d19To/1awe+t7Mu+Log8qRovqE0DW92Vpst3tJAeeNIMlqKhSOR6LIRl6 VbNbbgqIXwvZnbh2DXFXUvpEsDNnqxd1nmlVrBg5PIwHwpoLzU2uWceCj Q==; X-IronPort-AV: E=Sophos;i="5.93,214,1654585200"; d="scan'208";a="107364673" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa6.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 03 Aug 2022 03:26:47 -0700 Received: from chn-vm-ex03.mchp-main.com (10.10.85.151) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.17; Wed, 3 Aug 2022 03:26:47 -0700 Received: from localhost.localdomain (10.10.115.15) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server id 15.1.2375.28 via Frontend Transport; Wed, 3 Aug 2022 03:26:44 -0700 From: Claudiu Beznea To: , , , , , , CC: , , , , Claudiu Beznea Subject: [PATCH v3 03/19] iio: adc: at91-sama5d2_adc: lock around oversampling and sample freq Date: Wed, 3 Aug 2022 13:28:39 +0300 Message-ID: <20220803102855.2191070-4-claudiu.beznea@microchip.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20220803102855.2191070-1-claudiu.beznea@microchip.com> References: <20220803102855.2191070-1-claudiu.beznea@microchip.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org .read_raw()/.write_raw() could be called asynchronously from user space or other in kernel drivers. Without locking on st->lock these could be called asynchronously while there is a conversion in progress. Read will be harmless but changing registers while conversion is in progress may lead to inconsistent results. Thus, to avoid this lock st->lock. Fixes: 27e177190891 ("iio:adc:at91_adc8xx: introduce new atmel adc driver") Fixes: 6794e23fa3fe ("iio: adc: at91-sama5d2_adc: add support for oversampling resolution") Signed-off-by: Claudiu Beznea --- drivers/iio/adc/at91-sama5d2_adc.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c index 08d1f806c839..3734ddc82952 100644 --- a/drivers/iio/adc/at91-sama5d2_adc.c +++ b/drivers/iio/adc/at91-sama5d2_adc.c @@ -1542,10 +1542,10 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev, ret = at91_adc_read_position(st, chan->channel, &tmp_val); *val = tmp_val; - mutex_unlock(&st->lock); - iio_device_release_direct_mode(indio_dev); if (ret > 0) ret = at91_adc_adjust_val_osr(st, val); + mutex_unlock(&st->lock); + iio_device_release_direct_mode(indio_dev); return ret; } @@ -1558,10 +1558,10 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev, ret = at91_adc_read_pressure(st, chan->channel, &tmp_val); *val = tmp_val; - mutex_unlock(&st->lock); - iio_device_release_direct_mode(indio_dev); if (ret > 0) ret = at91_adc_adjust_val_osr(st, val); + mutex_unlock(&st->lock); + iio_device_release_direct_mode(indio_dev); return ret; } @@ -1650,16 +1650,20 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev, /* if no change, optimize out */ if (val == st->oversampling_ratio) return 0; + mutex_lock(&st->lock); st->oversampling_ratio = val; /* update ratio */ at91_adc_config_emr(st); + mutex_unlock(&st->lock); return 0; case IIO_CHAN_INFO_SAMP_FREQ: if (val < st->soc_info.min_sample_rate || val > st->soc_info.max_sample_rate) return -EINVAL; + mutex_lock(&st->lock); at91_adc_setup_samp_freq(indio_dev, val); + mutex_unlock(&st->lock); return 0; default: return -EINVAL;