From patchwork Thu Sep 2 21:51:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 12472617 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,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 5FC24C433F5 for ; Thu, 2 Sep 2021 21:53:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4AFDF61151 for ; Thu, 2 Sep 2021 21:53:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347847AbhIBVyH (ORCPT ); Thu, 2 Sep 2021 17:54:07 -0400 Received: from relay10.mail.gandi.net ([217.70.178.230]:37657 "EHLO relay10.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347806AbhIBVx5 (ORCPT ); Thu, 2 Sep 2021 17:53:57 -0400 Received: (Authenticated sender: miquel.raynal@bootlin.com) by relay10.mail.gandi.net (Postfix) with ESMTPSA id 443B424000A; Thu, 2 Sep 2021 21:52:56 +0000 (UTC) From: Miquel Raynal To: Jonathan Cameron , Lars-Peter Clausen , Peter Meerwald-Stadler , Rob Herring , Dmitry Torokhov , Lee Jones , bcousson@baylibre.com, Tony Lindgren Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-input@vger.kernel.org, linux-omap@vger.kernel.org, Thomas Petazzoni , Vignesh Raghavendra , Lokesh Vutla , Tero Kristo , Ryan Barnett , Grygorii Strashko , Jason Reeder , Miquel Raynal , Jonathan Cameron Subject: [PATCH v2 36/46] iio: adc: ti_am335x_adc: Wait the idle state to avoid stalls Date: Thu, 2 Sep 2021 23:51:34 +0200 Message-Id: <20210902215144.507243-37-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210902215144.507243-1-miquel.raynal@bootlin.com> References: <20210902215144.507243-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org At least on a am4372, a simple: $ cat /sys/bus/iio/devices/iio\:deviceX/in_voltage*_raw can stall forever. It seems that it comes from the fact that the internal state machine does not have enough time to return to its idle state in this situation before receiving another request, leading to an internal stall. Add a tiadc_wait_idle() helper to ensure no new conversion is requested while the FSM is still busy. Signed-off-by: Miquel Raynal Acked-by: Jonathan Cameron --- drivers/iio/adc/ti_am335x_adc.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c index 25af90af16a3..2e86484409c3 100644 --- a/drivers/iio/adc/ti_am335x_adc.c +++ b/drivers/iio/adc/ti_am335x_adc.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -102,6 +103,15 @@ static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan) return 1 << adc_dev->channel_step[chan]; } +static int tiadc_wait_idle(struct tiadc_device *adc_dev) +{ + u32 val; + + return readl_poll_timeout(adc_dev->mfd_tscadc->tscadc_base + REG_ADCFSM, + val, !(val & SEQ_STATUS), 10, + IDLE_TIMEOUT_MS * 1000 * adc_dev->channels); +} + static void tiadc_step_config(struct iio_dev *indio_dev) { struct tiadc_device *adc_dev = iio_priv(indio_dev); @@ -295,6 +305,11 @@ static int tiadc_buffer_preenable(struct iio_dev *indio_dev) { struct tiadc_device *adc_dev = iio_priv(indio_dev); int i, fifo1count; + int ret; + + ret = tiadc_wait_idle(adc_dev); + if (ret) + return ret; tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN | @@ -454,12 +469,12 @@ static int tiadc_read_raw(struct iio_dev *indio_dev, int *val, int *val2, long mask) { struct tiadc_device *adc_dev = iio_priv(indio_dev); - int ret = IIO_VAL_INT; int i, map_val; unsigned int fifo1count, read, stepid; bool found = false; u32 step_en; unsigned long timeout; + int ret; if (iio_buffer_enabled(indio_dev)) return -EBUSY; @@ -469,6 +484,11 @@ static int tiadc_read_raw(struct iio_dev *indio_dev, return -EINVAL; mutex_lock(&adc_dev->fifo1_lock); + + ret = tiadc_wait_idle(adc_dev); + if (ret) + goto err_unlock; + fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); while (fifo1count--) tiadc_readl(adc_dev, REG_FIFO1); @@ -516,7 +536,7 @@ static int tiadc_read_raw(struct iio_dev *indio_dev, err_unlock: mutex_unlock(&adc_dev->fifo1_lock); - return ret; + return ret ? ret : IIO_VAL_INT; } static const struct iio_info tiadc_info = {