From mboxrd@z Thu Jan 1 00:00:00 1970 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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 2CA71C10F11 for ; Wed, 24 Apr 2019 17:23:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE1EB205ED for ; Wed, 24 Apr 2019 17:23:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556126633; bh=lXmPmFari3fcUIko0tqOMsfK9GVESnB74N8MQ7XFwyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FkhhcwWuYNbFxKFOFI2d4Lt5uemt+R2XdFh2oq5bo/dH4CWa0sM1uIKN/qz9qqPDU ANAgXFK7333BC+AgwAcdl34K9MsJtyDAfbYclBBTobogoCM7ZZrvRb9NeGzo66YD9i MukuRvs3thrq8fUykcp2VVpLQnNAy0ldmW9T4CLk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389780AbfDXRXv (ORCPT ); Wed, 24 Apr 2019 13:23:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:49538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389461AbfDXRXt (ORCPT ); Wed, 24 Apr 2019 13:23:49 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B270B21904; Wed, 24 Apr 2019 17:23:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556126629; bh=lXmPmFari3fcUIko0tqOMsfK9GVESnB74N8MQ7XFwyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MeqzOQyIOXDpFOChVVELGcKu9GVeIpJ186jDfbqIMPT9NzuX+RxG8KKbHNJGFcLL7 Nqmmv2oM+eECzaTyLelHM0m+j4nEZyhl2oQCgLIsGQ9+Rl5M7u1Gojn1I/L73BErKC f1BBdCahdo+mV5TgyhGAOBXjgUhnumlEu4TAYYRo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Georg Ottinger , Ludovic Desroches , Stable@vger.kernel.org, Jonathan Cameron Subject: [PATCH 4.4 151/168] iio: adc: at91: disable adc channel interrupt in timeout case Date: Wed, 24 Apr 2019 19:09:55 +0200 Message-Id: <20190424170932.128459149@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170923.452349382@linuxfoundation.org> References: <20190424170923.452349382@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Georg Ottinger commit 09c6bdee51183a575bf7546890c8c137a75a2b44 upstream. Having a brief look at at91_adc_read_raw() it is obvious that in the case of a timeout the setting of AT91_ADC_CHDR and AT91_ADC_IDR registers is omitted. If 2 different channels are queried we can end up with a situation where two interrupts are enabled, but only one interrupt is cleared in the interrupt handler. Resulting in a interrupt loop and a system hang. Signed-off-by: Georg Ottinger Acked-by: Ludovic Desroches Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/adc/at91_adc.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) --- a/drivers/iio/adc/at91_adc.c +++ b/drivers/iio/adc/at91_adc.c @@ -702,23 +702,29 @@ static int at91_adc_read_raw(struct iio_ ret = wait_event_interruptible_timeout(st->wq_data_avail, st->done, msecs_to_jiffies(1000)); - if (ret == 0) - ret = -ETIMEDOUT; - if (ret < 0) { - mutex_unlock(&st->lock); - return ret; - } - - *val = st->last_value; + /* Disable interrupts, regardless if adc conversion was + * successful or not + */ at91_adc_writel(st, AT91_ADC_CHDR, AT91_ADC_CH(chan->channel)); at91_adc_writel(st, AT91_ADC_IDR, BIT(chan->channel)); - st->last_value = 0; - st->done = false; + if (ret > 0) { + /* a valid conversion took place */ + *val = st->last_value; + st->last_value = 0; + st->done = false; + ret = IIO_VAL_INT; + } else if (ret == 0) { + /* conversion timeout */ + dev_err(&idev->dev, "ADC Channel %d timeout.\n", + chan->channel); + ret = -ETIMEDOUT; + } + mutex_unlock(&st->lock); - return IIO_VAL_INT; + return ret; case IIO_CHAN_INFO_SCALE: *val = st->vref_mv;