From patchwork Fri Oct 15 08:14:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 12560593 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8AEE4C433EF for ; Fri, 15 Oct 2021 08:16:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 761A0610D2 for ; Fri, 15 Oct 2021 08:16:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237214AbhJOIS6 (ORCPT ); Fri, 15 Oct 2021 04:18:58 -0400 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:55945 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237000AbhJOISF (ORCPT ); Fri, 15 Oct 2021 04:18:05 -0400 Received: (Authenticated sender: miquel.raynal@bootlin.com) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id 30A452000D; Fri, 15 Oct 2021 08:15:57 +0000 (UTC) From: Miquel Raynal To: Jonathan Cameron , Lee Jones , linux-iio@vger.kernel.org, linux-omap@vger.kernel.org, Thomas Petazzoni , Ryan Barnett , linux-kernel@vger.kernel.org Cc: Miquel Raynal , Jonathan Cameron Subject: [PATCH v6 38/48] iio: adc: ti_am335x_adc: Wait the idle state to avoid stalls Date: Fri, 15 Oct 2021 10:14:56 +0200 Message-Id: <20211015081506.933180-39-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211015081506.933180-1-miquel.raynal@bootlin.com> References: <20211015081506.933180-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-omap@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 1cc2efbb2875..0a4d66a541ed 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 * 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 | @@ -446,12 +461,12 @@ 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; @@ -461,6 +476,11 @@ 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); @@ -508,7 +528,7 @@ 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 = {