From patchwork Mon Dec 28 12:51:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 353574 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=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 584FFC4332B for ; Mon, 28 Dec 2020 14:32:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B2902242A for ; Mon, 28 Dec 2020 14:32:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2503680AbgL1Obz (ORCPT ); Mon, 28 Dec 2020 09:31:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:38964 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2504401AbgL1ObY (ORCPT ); Mon, 28 Dec 2020 09:31:24 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A24ED207B2; Mon, 28 Dec 2020 14:31:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609165869; bh=W7pSCyKOlJXrAxmKWRx59qwpgcKSPHu8XN2FiSUblOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qYbNfi9nuik6GZ5HXiwI1QN3TnDFP7046TdSWH5NnNXsXy8Pfyn/xM/7HE42ayuP+ t80F5I89mCR5Uh4GUAvQFZ4/q5uA/t4VeeAFBi6g7IBRVrPE2d/n+UFHMlFoNNotEE jULyiS/AmaG4xV3xf/F6JAikMKWAZ3TBYwFzZTp0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lorenzo Bianconi , Stable@vger.kernel.org, Jonathan Cameron Subject: [PATCH 5.10 676/717] iio: imu: st_lsm6dsx: fix edge-trigger interrupts Date: Mon, 28 Dec 2020 13:51:14 +0100 Message-Id: <20201228125053.370159550@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Lorenzo Bianconi commit 3f9bce7a22a3f8ac9d885c9d75bc45569f24ac8b upstream. If we are using edge IRQs, new samples can arrive while processing current interrupt since there are no hw guarantees the irq line stays "low" long enough to properly detect the new interrupt. In this case the new sample will be missed. Polling FIFO status register in st_lsm6dsx_handler_thread routine allow us to read new samples even if the interrupt arrives while processing previous data and the timeslot where the line is "low" is too short to be properly detected. Fixes: 89ca88a7cdf2 ("iio: imu: st_lsm6dsx: support active-low interrupts") Fixes: 290a6ce11d93 ("iio: imu: add support to lsm6dsx driver") Signed-off-by: Lorenzo Bianconi Link: https://lore.kernel.org/r/5e93cda7dc1e665f5685c53ad8e9ea71dbae782d.1605378871.git.lorenzo@kernel.org Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c @@ -2255,19 +2255,35 @@ st_lsm6dsx_report_motion_event(struct st static irqreturn_t st_lsm6dsx_handler_thread(int irq, void *private) { struct st_lsm6dsx_hw *hw = private; + int fifo_len = 0, len; bool event; - int count; event = st_lsm6dsx_report_motion_event(hw); if (!hw->settings->fifo_ops.read_fifo) return event ? IRQ_HANDLED : IRQ_NONE; - mutex_lock(&hw->fifo_lock); - count = hw->settings->fifo_ops.read_fifo(hw); - mutex_unlock(&hw->fifo_lock); + /* + * If we are using edge IRQs, new samples can arrive while + * processing current interrupt since there are no hw + * guarantees the irq line stays "low" long enough to properly + * detect the new interrupt. In this case the new sample will + * be missed. + * Polling FIFO status register allow us to read new + * samples even if the interrupt arrives while processing + * previous data and the timeslot where the line is "low" is + * too short to be properly detected. + */ + do { + mutex_lock(&hw->fifo_lock); + len = hw->settings->fifo_ops.read_fifo(hw); + mutex_unlock(&hw->fifo_lock); - return count || event ? IRQ_HANDLED : IRQ_NONE; + if (len > 0) + fifo_len += len; + } while (len > 0); + + return fifo_len || event ? IRQ_HANDLED : IRQ_NONE; } static int st_lsm6dsx_irq_setup(struct st_lsm6dsx_hw *hw)