[PATCH 10/29] iio: adc: ad7192: Factor out core of ad7192_write_raw() to simplify error handling.

[Jonathan Cameron <jic23@kernel.org>]

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Factor out everything under the lock, use guard() for the mutex to
avoid need to manually unlock, and switch sense of matching checks
in loops to reduce indent.

There are some functional changes in here as well as the code
no longer updates the filter_freq_available if no change has
been made to the oversampling ratio.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Alisa-Dariana Roman <alisa.roman@analog.com>
---
 drivers/iio/adc/ad7192.c | 111 ++++++++++++++++++++-------------------
 1 file changed, 57 insertions(+), 54 deletions(-)

diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index e96a5ae92375..785429900da8 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -7,6 +7,7 @@
 
 #include <linux/interrupt.h>
 #include <linux/bitfield.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/device.h>
@@ -945,80 +946,82 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
-static int ad7192_write_raw(struct iio_dev *indio_dev,
-			    struct iio_chan_spec const *chan,
-			    int val,
-			    int val2,
-			    long mask)
+static int __ad7192_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int val,
+			      int val2,
+			      long mask)
 {
 	struct ad7192_state *st = iio_priv(indio_dev);
-	int ret, i, div;
+	int i, div;
 	unsigned int tmp;
 
-	ret = iio_device_claim_direct_mode(indio_dev);
-	if (ret)
-		return ret;
-
-	mutex_lock(&st->lock);
+	guard(mutex)(&st->lock);
 
 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
-		ret = -EINVAL;
-		for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
-			if (val2 == st->scale_avail[i][1]) {
-				ret = 0;
-				tmp = st->conf;
-				st->conf &= ~AD7192_CONF_GAIN_MASK;
-				st->conf |= FIELD_PREP(AD7192_CONF_GAIN_MASK, i);
-				if (tmp == st->conf)
-					break;
-				ad_sd_write_reg(&st->sd, AD7192_REG_CONF,
-						3, st->conf);
-				ad7192_calibrate_all(st);
-				break;
-			}
-		break;
-	case IIO_CHAN_INFO_SAMP_FREQ:
-		if (!val) {
-			ret = -EINVAL;
-			break;
+		for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++) {
+			if (val2 != st->scale_avail[i][1])
+				continue;
+
+			tmp = st->conf;
+			st->conf &= ~AD7192_CONF_GAIN_MASK;
+			st->conf |= FIELD_PREP(AD7192_CONF_GAIN_MASK, i);
+			if (tmp == st->conf)
+				return 0;
+			ad_sd_write_reg(&st->sd, AD7192_REG_CONF, 3, st->conf);
+			ad7192_calibrate_all(st);
+			return 0;
 		}
+		return -EINVAL;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (!val)
+			return -EINVAL;
 
 		div = st->fclk / (val * ad7192_get_f_order(st) * 1024);
-		if (div < 1 || div > 1023) {
-			ret = -EINVAL;
-			break;
-		}
+		if (div < 1 || div > 1023)
+			return -EINVAL;
 
 		st->mode &= ~AD7192_MODE_RATE_MASK;
 		st->mode |= FIELD_PREP(AD7192_MODE_RATE_MASK, div);
 		ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
 		ad7192_update_filter_freq_avail(st);
-		break;
+		return 0;
 	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
-		ret = ad7192_set_3db_filter_freq(st, val, val2 / 1000);
-		break;
+		return ad7192_set_3db_filter_freq(st, val, val2 / 1000);
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
-		ret = -EINVAL;
-		for (i = 0; i < ARRAY_SIZE(st->oversampling_ratio_avail); i++)
-			if (val == st->oversampling_ratio_avail[i]) {
-				ret = 0;
-				tmp = st->mode;
-				st->mode &= ~AD7192_MODE_AVG_MASK;
-				st->mode |= FIELD_PREP(AD7192_MODE_AVG_MASK, i);
-				if (tmp == st->mode)
-					break;
-				ad_sd_write_reg(&st->sd, AD7192_REG_MODE,
-						3, st->mode);
-				break;
-			}
-		ad7192_update_filter_freq_avail(st);
-		break;
+		for (i = 0; i < ARRAY_SIZE(st->oversampling_ratio_avail); i++) {
+			if (val != st->oversampling_ratio_avail[i])
+				continue;
+
+			tmp = st->mode;
+			st->mode &= ~AD7192_MODE_AVG_MASK;
+			st->mode |= FIELD_PREP(AD7192_MODE_AVG_MASK, i);
+			if (tmp == st->mode)
+				return 0;
+			ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
+			ad7192_update_filter_freq_avail(st);
+			return 0;
+		}
+		return -EINVAL;
 	default:
-		ret = -EINVAL;
+		return -EINVAL;
 	}
+}
+
+static int ad7192_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val,
+			    int val2,
+			    long mask)
+{
+	int ret;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
 
-	mutex_unlock(&st->lock);
+	ret = __ad7192_write_raw(indio_dev, chan, val, val2, mask);
 
 	iio_device_release_direct_mode(indio_dev);
 
-- 
2.48.1