From patchwork Mon Dec 28 12:50:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 353190 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, USER_AGENT_GIT 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 D3E0EC433E9 for ; Mon, 28 Dec 2020 15:58:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 962E2224D2 for ; Mon, 28 Dec 2020 15:58:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393173AbgL1P5B (ORCPT ); Mon, 28 Dec 2020 10:57:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:35012 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389179AbgL1Ned (ORCPT ); Mon, 28 Dec 2020 08:34:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DEF5A2063A; Mon, 28 Dec 2020 13:33:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609162432; bh=/8ee/wHfIlJuwhmBcBGroCS0Ii8mapdb0sG6eD+PMmM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BHDEmNz46wwFgb3qLrWQPj/4n+lIa+Kyd8SiGLZNlYi/gndEiK7G0KVenrKra4xrL dZNdE0yKLYWLAZTZqfbAcuF+ahBKEjsuIbbLwnFrBjk8wRuR7r9864GdkqvjyprvHz 5aS3L77K0olrxX5es3N0bA0Ko/QH16dodglUBCYk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rostislav Lisovy , Ian Abbott Subject: [PATCH 4.19 285/346] staging: comedi: mf6x4: Fix AI end-of-conversion detection Date: Mon, 28 Dec 2020 13:50:04 +0100 Message-Id: <20201228124933.558111985@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124919.745526410@linuxfoundation.org> References: <20201228124919.745526410@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ian Abbott commit 56c90457ebfe9422496aac6ef3d3f0f0ea8b2ec2 upstream. I have had reports from two different people that attempts to read the analog input channels of the MF624 board fail with an `ETIMEDOUT` error. After triggering the conversion, the code calls `comedi_timeout()` with `mf6x4_ai_eoc()` as the callback function to check if the conversion is complete. The callback returns 0 if complete or `-EBUSY` if not yet complete. `comedi_timeout()` returns `-ETIMEDOUT` if it has not completed within a timeout period which is propagated as an error to the user application. The existing code considers the conversion to be complete when the EOLC bit is high. However, according to the user manuals for the MF624 and MF634 boards, this test is incorrect because EOLC is an active low signal that goes high when the conversion is triggered, and goes low when the conversion is complete. Fix the problem by inverting the test of the EOLC bit state. Fixes: 04b565021a83 ("comedi: Humusoft MF634 and MF624 DAQ cards driver") Cc: # v4.4+ Cc: Rostislav Lisovy Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20201207145806.4046-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/mf6x4.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/staging/comedi/drivers/mf6x4.c +++ b/drivers/staging/comedi/drivers/mf6x4.c @@ -112,8 +112,9 @@ static int mf6x4_ai_eoc(struct comedi_de struct mf6x4_private *devpriv = dev->private; unsigned int status; + /* EOLC goes low at end of conversion. */ status = ioread32(devpriv->gpioc_reg); - if (status & MF6X4_GPIOC_EOLC) + if ((status & MF6X4_GPIOC_EOLC) == 0) return 0; return -EBUSY; }