From patchwork Tue Jan 12 15:24:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ahmad Fatoum X-Patchwork-Id: 12013773 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 B1FEBC433E0 for ; Tue, 12 Jan 2021 15:26:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5ABF623130 for ; Tue, 12 Jan 2021 15:26:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729960AbhALP0z (ORCPT ); Tue, 12 Jan 2021 10:26:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728583AbhALP0z (ORCPT ); Tue, 12 Jan 2021 10:26:55 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 12B09C061575 for ; Tue, 12 Jan 2021 07:26:15 -0800 (PST) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kzLYQ-0005FN-Rg; Tue, 12 Jan 2021 16:25:54 +0100 Received: from afa by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1kzLYM-0005St-Si; Tue, 12 Jan 2021 16:25:50 +0100 From: Ahmad Fatoum To: Jonathan Cameron , Lars-Peter Clausen , Peter Meerwald-Stadler , Maxime Coquelin , Alexandre Torgue , Fabrice Gasnier , Olivier Moysan Cc: kernel@pengutronix.de, Thomas Gleixner , Lucas Stach , Holger Assmann , Ahmad Fatoum , linux-iio@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] iio: adc: stm32-adc: fix erroneous handling of spurious IRQs Date: Tue, 12 Jan 2021 16:24:42 +0100 Message-Id: <20210112152441.20665-1-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.30.0 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: afa@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-iio@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org 1c6c69525b40 ("genirq: Reject bogus threaded irq requests") makes sure that threaded IRQs either - have IRQF_ONESHOT set - don't have the default just return IRQ_WAKE_THREAD primary handler This is necessary because level-triggered interrupts need to be masked, either at device or irqchip, to avoid an interrupt storm. For spurious interrupts, the STM32 ADC driver still does this bogus request though: - It doesn't set IRQF_ONESHOT - Its primary handler just returns IRQ_WAKE_THREAD if the interrupt is unexpected, i.e. !(status & enabled_mask) - stm32mp151.dtsi describes the ADC interrupt as level-triggered Fix this by setting IRQF_ONESHOT to have the irqchip mask the IRQ until the IRQ thread has finished. IRQF_ONESHOT also has the effect that the primary handler is no longer forced into a thread. This makes the issue with spurious interrupts interrupts disappear when reading the ADC on a threadirqs=1 kernel. This used to result in following kernel error message: iio iio:device1: Unexpected IRQ: IER=0x00000000, ISR=0x0000100e or iio iio:device1: Unexpected IRQ: IER=0x00000004, ISR=0x0000100a But with this patch applied (or threaded IRQs disabled), this no longer occurs. Cc: Lucas Stach Reported-by: Holger Assmann Fixes: 695e2f5c289b ("iio: adc: stm32-adc: fix a regression when using dma and irq") Signed-off-by: Ahmad Fatoum --- drivers/iio/adc/stm32-adc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index c067c994dae2..7e0e21c79ac8 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -1910,7 +1910,7 @@ static int stm32_adc_probe(struct platform_device *pdev) ret = devm_request_threaded_irq(&pdev->dev, adc->irq, stm32_adc_isr, stm32_adc_threaded_isr, - 0, pdev->name, indio_dev); + IRQF_ONESHOT, pdev->name, indio_dev); if (ret) { dev_err(&pdev->dev, "failed to request IRQ\n"); return ret;