linux-kernel - [PATCH v5 4/5] iio: adc: ad7768-1: refactor ad7768_write

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Message-ID: <3c3122b60ace1c69b46fbd341c029ff7bd1cbd17.1765900411.git.Jonathan.Santos@analog.com>
Date: Wed, 17 Dec 2025 02:52:56 -0300
From: Jonathan Santos <Jonathan.Santos@...log.com>
To: <linux-iio@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC: Jonathan Santos <Jonathan.Santos@...log.com>, <lars@...afoo.de>,
        <Michael.Hennerich@...log.com>, <jic23@...nel.org>,
        <dlechner@...libre.com>, <nuno.sa@...log.com>, <andy@...nel.org>,
        <robh@...nel.org>, <krzk+dt@...nel.org>, <conor+dt@...nel.org>,
        <jonath4nns@...il.com>
Subject: [PATCH v5 4/5] iio: adc: ad7768-1: refactor ad7768_write_raw()

Squash __ad7768_write_raw() back to ad7768_write_raw() to allow the
addition of new attributes without requiring a direct mode claim.

Signed-off-by: Jonathan Santos <Jonathan.Santos@...log.com>
---
v5 Changes:
* new patch suggested by Jonathan Cameron to allow attributes without 
  the direct mode claim, necessary for fixing the deadlock issue reported
  in v4.
---
 drivers/iio/adc/ad7768-1.c | 50 ++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 24 deletions(-)

diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index 89b0ca8f584c..bd4b2e090c5b 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -742,6 +742,19 @@ static int ad7768_get_filter_type_attr(struct iio_dev *dev,
 	return ad7768_filter_regval_to_type[FIELD_GET(mask, mode)];
 }
 
+static int ad7768_update_dec_rate(struct iio_dev *dev, unsigned int dec_rate)
+{
+	struct ad7768_state *st = iio_priv(dev);
+	int ret;
+
+	ret = ad7768_configure_dig_fil(dev, st->filter_type, dec_rate);
+	if (ret)
+		return ret;
+
+	/* Update sampling frequency */
+	return ad7768_set_freq(st, st->samp_freq);
+}
+
 static const struct iio_enum ad7768_filter_type_iio_enum = {
 	.items = ad7768_filter_enum,
 	.num_items = ARRAY_SIZE(ad7768_filter_enum),
@@ -867,44 +880,33 @@ static int ad7768_read_avail(struct iio_dev *indio_dev,
 	}
 }
 
-static int __ad7768_write_raw(struct iio_dev *indio_dev,
-			      struct iio_chan_spec const *chan,
-			      int val, int val2, long info)
+static int ad7768_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val, int val2, long info)
 {
 	struct ad7768_state *st = iio_priv(indio_dev);
 	int ret;
 
 	switch (info) {
 	case IIO_CHAN_INFO_SAMP_FREQ:
-		return ad7768_set_freq(st, val);
+		if (!iio_device_claim_direct(indio_dev))
+			return -EBUSY;
 
+		ret = ad7768_set_freq(st, val);
+		iio_device_release_direct(indio_dev);
+		return ret;
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
-		ret = ad7768_configure_dig_fil(indio_dev, st->filter_type, val);
-		if (ret)
-			return ret;
+		if (!iio_device_claim_direct(indio_dev))
+			return -EBUSY;
 
-		/* Update sampling frequency */
-		return ad7768_set_freq(st, st->samp_freq);
+		ret = ad7768_update_dec_rate(indio_dev, val);
+		iio_device_release_direct(indio_dev);
+		return ret;
 	default:
 		return -EINVAL;
 	}
 }
 
-static int ad7768_write_raw(struct iio_dev *indio_dev,
-			    struct iio_chan_spec const *chan,
-			    int val, int val2, long info)
-{
-	int ret;
-
-	if (!iio_device_claim_direct(indio_dev))
-		return -EBUSY;
-
-	ret = __ad7768_write_raw(indio_dev, chan, val, val2, info);
-	iio_device_release_direct(indio_dev);
-
-	return ret;
-}
-
 static int ad7768_read_label(struct iio_dev *indio_dev,
 	const struct iio_chan_spec *chan, char *label)
 {
-- 
2.34.1