From patchwork Tue Apr 4 14:11:59 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: 13200265 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 A0F6FC6FD1D for ; Tue, 4 Apr 2023 14:12:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235693AbjDDOMQ (ORCPT ); Tue, 4 Apr 2023 10:12:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235594AbjDDOML (ORCPT ); Tue, 4 Apr 2023 10:12:11 -0400 Received: from mail-yw1-x112c.google.com (mail-yw1-x112c.google.com [IPv6:2607:f8b0:4864:20::112c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D9EE4206 for ; Tue, 4 Apr 2023 07:12:08 -0700 (PDT) Received: by mail-yw1-x112c.google.com with SMTP id 00721157ae682-5463fa0c2bfso285263817b3.1 for ; Tue, 04 Apr 2023 07:12:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1680617527; 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=ntJEhFvPVyRwKjpX84wW6Nzwfs8RwaisnK/y3HB3QZI=; b=q4242DFwPstTgqf5Ui1GWU4QZfjJwo8dqlFgpBF1Y0R5XPVUd4yDM1Rzwf894WOFVJ 6e1xj/rMw0ZCFRKA4dzd8FtEjKCAJKd6Qon1yqC1BVmUvacoqdHv7+1ZA50uPczq6yup ewQPrYZMCzQ5ARCh8e1iMvQevFSngbCEVU+5SyRPiku+75PNHrzPh1IojCQYIGqiqD1l qE+0Z/99iGSfJgZWPwC+IqgGydOYuLRrU7F8bV3EvVZweZ98dWmbWTfzDc6KRrzE+H82 0MgfvhI9qRyAQ8Z5FZ5+0BxfvgWHFKYZ9SauqRu/mXORNcWHCWoWsxjG0+Wuz/1wEAAV eV1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680617527; 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=ntJEhFvPVyRwKjpX84wW6Nzwfs8RwaisnK/y3HB3QZI=; b=0DSo1oHcgSy/FAKMH9nUBqlYeB1rMFncUTRBFTxiyv79cPKmMbbFwRsjv8nxL6MACU LM/YRuOvyyENKVXgyQlBiNAcGeUwazFX7hjE6n0vKebAhwGfYnij/YBE0X3liJVzTaz3 gNUS9oJ2uuj8/wrhSHCX6G2tGbnbQ/dbIMRzdxM/EtaMa8BgYqcrRk9yoi6NarMXzO13 o4RGSwmVMEduzJGs4bL5pLBL1ZmaoTxppzJgp10/O7l9GOaGii1ahZfPeTLTCPL5fhSS RHPx196ghZi/6C/u61PXumpLvJv8CzbgSb+QuHwSsGjwvuilreQpK+L64Y0SWxSVEM7W 5g8g== X-Gm-Message-State: AAQBX9fjFLFPA/34CgxhI/zPsnq6+ziNV/zq1vfRm0sPKRy16O8oduFq Kkzz32mjQyjGazPk5kJEZWw/xQ== X-Google-Smtp-Source: AKy350Ydsp7NUvBJDlQJTdMtriZo5hMFkAr3fDz46ScNCXgyl5gdZJVc8UmA8llIPFg0FVx1L4dy0A== X-Received: by 2002:a0d:d88d:0:b0:541:8909:eb5a with SMTP id a135-20020a0dd88d000000b005418909eb5amr2368089ywe.18.1680617527339; Tue, 04 Apr 2023 07:12:07 -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 d195-20020a811dcc000000b00545a08184d8sm3202750ywd.104.2023.04.04.07.12.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Apr 2023 07:12:06 -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 v4 2/5] iio: addac: stx104: Fix race condition when converting analog-to-digital Date: Tue, 4 Apr 2023 10:11:59 -0400 Message-Id: <2ae5e40eed5006ca735e4c12181a9ff5ced65547.1680564468.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 --- 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 */