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From:   Olivier Moysan <olivier.moysan@foss.st.com>
To:     Rob Herring <robh+dt@kernel.org>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Olivier Moysan <olivier.moysan@foss.st.com>
CC:     <linux-arm-kernel@lists.infradead.org>,
        <linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <devicetree@vger.kernel.org>
Subject: [PATCH v4 1/8] iio: adc: stm32-adc: fix channel sampling time init
Date:   Wed, 12 Oct 2022 16:21:58 +0200
Message-ID: <20221012142205.13041-2-olivier.moysan@foss.st.com>
In-Reply-To: <20221012142205.13041-1-olivier.moysan@foss.st.com>
References: <20221012142205.13041-1-olivier.moysan@foss.st.com>
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Fix channel init for ADC generic channel bindings.
In generic channel initialization, stm32_adc_smpr_init() is called to
initialize channel sampling time. The "st,min-sample-time-ns" property
is an optional property. If it is not defined, stm32_adc_smpr_init() is
currently skipped.
However stm32_adc_smpr_init() must always be called, to force a minimum
sampling time for the internal channels, as the minimum sampling time is
known. Make stm32_adc_smpr_init() call unconditional.

Fixes: 796e5d0b1e9b ("iio: adc: stm32-adc: use generic binding for sample-time")
Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
---
 drivers/iio/adc/stm32-adc.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 6256977eb7f7..3cda529f081d 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -2086,18 +2086,19 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
 		stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
 					vin[1], scan_index, differential);
 
+		val = 0;
 		ret = fwnode_property_read_u32(child, "st,min-sample-time-ns", &val);
 		/* st,min-sample-time-ns is optional */
-		if (!ret) {
-			stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
-			if (differential)
-				stm32_adc_smpr_init(adc, vin[1], val);
-		} else if (ret != -EINVAL) {
+		if (ret && ret != -EINVAL) {
 			dev_err(&indio_dev->dev, "Invalid st,min-sample-time-ns property %d\n",
 				ret);
 			goto err;
 		}
 
+		stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
+		if (differential)
+			stm32_adc_smpr_init(adc, vin[1], val);
+
 		scan_index++;
 	}
 
-- 
2.25.1