From patchwork Wed Aug 25 15:25:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 502615 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 F08AAC25AEB for ; Wed, 25 Aug 2021 15:35:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D50426109E for ; Wed, 25 Aug 2021 15:35:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242011AbhHYPfr (ORCPT ); Wed, 25 Aug 2021 11:35:47 -0400 Received: from mslow1.mail.gandi.net ([217.70.178.240]:54391 "EHLO mslow1.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241942AbhHYPfj (ORCPT ); Wed, 25 Aug 2021 11:35:39 -0400 Received: from relay6-d.mail.gandi.net (unknown [217.70.183.198]) by mslow1.mail.gandi.net (Postfix) with ESMTP id EBB9BCE0AE; Wed, 25 Aug 2021 15:26:55 +0000 (UTC) Received: (Authenticated sender: miquel.raynal@bootlin.com) by relay6-d.mail.gandi.net (Postfix) with ESMTPSA id 54735C0017; Wed, 25 Aug 2021 15:26:32 +0000 (UTC) From: Miquel Raynal To: Jonathan Cameron , Lars-Peter Clausen , Peter Meerwald-Stadler , Rob Herring , Lee Jones , bcousson@baylibre.com, Tony Lindgren , Tero Kristo , Michael Turquette , Stephen Boyd Cc: Thomas Petazzoni , "Ryan J . Barnett" , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-input@vger.kernel.org, linux-omap@vger.kernel.org, linux-clk@vger.kernel.org, Miquel Raynal Subject: [PATCH 35/40] iio: adc: ti_am335x_adc: Wait the idle state to avoid stalls Date: Wed, 25 Aug 2021 17:25:13 +0200 Message-Id: <20210825152518.379386-36-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210825152518.379386-1-miquel.raynal@bootlin.com> References: <20210825152518.379386-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org 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 ebf6326af60d..d4619fd6fd54 100644 --- a/drivers/iio/adc/ti_am335x_adc.c +++ b/drivers/iio/adc/ti_am335x_adc.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -94,6 +95,15 @@ 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); @@ -268,6 +278,11 @@ 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 | @@ -419,12 +434,12 @@ static int tiadc_read_raw(struct iio_dev *indio_dev, 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; @@ -434,6 +449,11 @@ 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); @@ -482,7 +502,7 @@ 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 = {