From patchwork Thu Apr 6 14:40:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: William Breathitt Gray X-Patchwork-Id: 13203546 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 32678C77B6F for ; Thu, 6 Apr 2023 14:42:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239377AbjDFOma (ORCPT ); Thu, 6 Apr 2023 10:42:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236627AbjDFOmJ (ORCPT ); Thu, 6 Apr 2023 10:42:09 -0400 Received: from mail-oi1-x232.google.com (mail-oi1-x232.google.com [IPv6:2607:f8b0:4864:20::232]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73F8BB456 for ; Thu, 6 Apr 2023 07:40:35 -0700 (PDT) Received: by mail-oi1-x232.google.com with SMTP id w133so29220382oib.1 for ; Thu, 06 Apr 2023 07:40:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1680792034; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=/VAaI37UUMqujz98kbcVgbWBFxRUSTxumyIYUkuTwcc=; b=uJVnn/Jfr+TJwzOL9C4qjEv/Uo0+lzKmZ2RFC2vCBh+UeCVjgKNJpI3Mjs9o4xtWtC Kk5X4jO3NKGFNLq2fLzyVmA8etXFiLM/IX+RZ654JQ2GujskNzmlWXUyYKat5OIU+gGy +7xpaWVI0Y6X2O3kG/St+h0N8ofi/2Ml1jSm7fKbIxAoy1hzfsabAFTxoLjUV49pvUiE GW6R3Oc2rv/gtIM5fDbrA1yFeATw5BXz95Lat99blrO2FI4HHMLUcVRXlGhYKnJkoIuD GxJIWxIKuMToCHFe7ngjNaNigsoaHapTzN6pCUfS3IPwNFzTKAGhAfS9/3+Z5yWXgMqk 67mg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680792034; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=/VAaI37UUMqujz98kbcVgbWBFxRUSTxumyIYUkuTwcc=; b=mY5YYabvGVzMndb583MmS8BS8zozvpxt6sGI529iQgKfS7F9RSikMGPl9J7I3y07y6 /e7dw4AwUUzLtpurOp70HtQnFqaw8RJnXyuYE2VqmKrZ7CPxiHN0DOUOJ9hk7HfISu2D un0fA9ZlAtJjCy9O2qnrtMswD3y9LJ1kU6ICesr73bQPP6/I+o47lIknI3zVHap+PuOx ETf2HHrnXOlC8GjR3kmxq0Kgq9MgicikAe+nVAITLDn1574YqVISHGNINlXmqYZ4yxLQ om93H7oukRNYGyoztgOSiaGg4Jm94L2z+UnlGjqTvTzqRvjByHD8iJrNkADXipayYQ/q Hkng== X-Gm-Message-State: AAQBX9eCi5B/yMzzgErM0m+uLJ7qpvqvg4+jViA1QivzdDvcFjZ+ePgl wgXd3etPPgTYPC0A8kE9/U8GPQ== X-Google-Smtp-Source: AKy350b7bQVcppxgdKHQbyzF/mFoW8VEbJHgqp0obT7UjSjkp9f1/A810fJ2G0K0IFYxXUW5yw+PJw== X-Received: by 2002:a05:6808:1912:b0:387:1e85:d1ae with SMTP id bf18-20020a056808191200b003871e85d1aemr5819223oib.18.1680792034597; Thu, 06 Apr 2023 07:40:34 -0700 (PDT) Received: from fedora.attlocal.net (69-109-179-158.lightspeed.dybhfl.sbcglobal.net. [69.109.179.158]) by smtp.gmail.com with ESMTPSA id q7-20020acaf207000000b0037d7f4eb7e8sm726209oih.31.2023.04.06.07.40.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Apr 2023 07:40:34 -0700 (PDT) From: William Breathitt Gray To: Jonathan Cameron , Lars-Peter Clausen Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Andy Shevchenko , William Breathitt Gray Subject: [PATCH v5 2/6] iio: addac: stx104: Fix race condition when converting analog-to-digital Date: Thu, 6 Apr 2023 10:40:11 -0400 Message-Id: <2ae5e40eed5006ca735e4c12181a9ff5ced65547.1680790580.git.william.gray@linaro.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The ADC conversion procedure requires several device I/O operations performed in a particular sequence. If stx104_read_raw() is called concurrently, the ADC conversion procedure could be clobbered. Prevent such a race condition by utilizing a mutex. Fixes: 4075a283ae83 ("iio: stx104: Add IIO support for the ADC channels") Signed-off-by: William Breathitt Gray --- Changes in v5: none drivers/iio/addac/stx104.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/iio/addac/stx104.c b/drivers/iio/addac/stx104.c index 4239aafe42fc..8730b79e921c 100644 --- a/drivers/iio/addac/stx104.c +++ b/drivers/iio/addac/stx104.c @@ -117,6 +117,8 @@ static int stx104_read_raw(struct iio_dev *indio_dev, return IIO_VAL_INT; } + mutex_lock(&priv->lock); + /* select ADC channel */ iowrite8(chan->channel | (chan->channel << 4), ®->achan); @@ -127,6 +129,8 @@ static int stx104_read_raw(struct iio_dev *indio_dev, while (ioread8(®->cir_asr) & BIT(7)); *val = ioread16(®->ssr_ad); + + mutex_unlock(&priv->lock); return IIO_VAL_INT; case IIO_CHAN_INFO_OFFSET: /* get ADC bipolar/unipolar configuration */