[PATCH] iio: adc: ti-ads124s08: Add direct mode protection and refactor read channel logic

[Lucas Sobrinho <lucasmsobrinho@gmail.com>]

Add a call to iio_device_claim_direct() in the ads124s_read_raw() function
to ensure exclusive access to the device during direct mode reads.

Also refactor the channel read logic into a separate function.

Signed-off-by: Lucas Sobrinho <lucasmsobrinho@gmail.com>
Co-developed-by: Filipe Tressmann Velozo <filipetressmann@usp.br>
Signed-off-by: Filipe Tressmann Velozo <filipetressmann@usp.br>
---
 drivers/iio/adc/ti-ads124s08.c | 85 ++++++++++++++++------------------
 1 file changed, 40 insertions(+), 45 deletions(-)

diff --git a/drivers/iio/adc/ti-ads124s08.c b/drivers/iio/adc/ti-ads124s08.c
index 8ea1269f7..e1efe8865 100644
--- a/drivers/iio/adc/ti-ads124s08.c
+++ b/drivers/iio/adc/ti-ads124s08.c
@@ -219,6 +219,40 @@ static int ads124s_read(struct iio_dev *indio_dev)
 	return get_unaligned_be24(&priv->data[2]);
 }
 
+static int  ads124s_read_channel(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val)
+{
+	int ret = ads124s_write_reg(indio_dev, ADS124S08_INPUT_MUX, chan);
+
+	if (ret) {
+		dev_err(&priv->spi->dev, "Set ADC CH failed\n");
+		return ret;
+	}
+
+	ret = ads124s_write_cmd(indio_dev, ADS124S08_START_CONV);
+	if (ret) {
+		dev_err(&priv->spi->dev, "Start ADC conversions failed\n");
+		return ret;
+	}
+
+	ret = ads124s_read(indio_dev);
+	if (ret < 0) {
+		dev_err(&priv->spi->dev, "Read ADC failed\n");
+		return ret;
+	}
+
+	*val = ret;
+
+	ret = ads124s_write_cmd(indio_dev, ADS124S08_STOP_CONV);
+	if (ret) {
+		dev_err(&priv->spi->dev, "Stop conversions failed\n");
+		return ret;
+	}
+
+	return IIO_VAL_INT;
+}
+
 static int ads124s_read_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int *val, int *val2, long m)
@@ -226,44 +260,18 @@ static int ads124s_read_raw(struct iio_dev *indio_dev,
 	struct ads124s_private *priv = iio_priv(indio_dev);
 	int ret;
 
-	mutex_lock(&priv->lock);
 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
-		ret = ads124s_write_reg(indio_dev, ADS124S08_INPUT_MUX,
-					chan->channel);
-		if (ret) {
-			dev_err(&priv->spi->dev, "Set ADC CH failed\n");
-			goto out;
-		}
-
-		ret = ads124s_write_cmd(indio_dev, ADS124S08_START_CONV);
-		if (ret) {
-			dev_err(&priv->spi->dev, "Start conversions failed\n");
-			goto out;
-		}
-
-		ret = ads124s_read(indio_dev);
-		if (ret < 0) {
-			dev_err(&priv->spi->dev, "Read ADC failed\n");
-			goto out;
-		}
-
-		*val = ret;
-
-		ret = ads124s_write_cmd(indio_dev, ADS124S08_STOP_CONV);
-		if (ret) {
-			dev_err(&priv->spi->dev, "Stop conversions failed\n");
-			goto out;
-		}
-
-		ret = IIO_VAL_INT;
+		if (!iio_device_claim_direct(indio_dev))
+			return -EBUSY;
+
+		ret = ads124s_read_channel(indio_dev, chan->channel, val);
+		iio_device_release_direct(indio_dev);
 		break;
 	default:
 		ret = -EINVAL;
 		break;
 	}
-out:
-	mutex_unlock(&priv->lock);
 	return ret;
 }
 
@@ -280,20 +288,7 @@ static irqreturn_t ads124s_trigger_handler(int irq, void *p)
 	int ret;
 
 	iio_for_each_active_channel(indio_dev, scan_index) {
-		ret = ads124s_write_reg(indio_dev, ADS124S08_INPUT_MUX,
-					scan_index);
-		if (ret)
-			dev_err(&priv->spi->dev, "Set ADC CH failed\n");
-
-		ret = ads124s_write_cmd(indio_dev, ADS124S08_START_CONV);
-		if (ret)
-			dev_err(&priv->spi->dev, "Start ADC conversions failed\n");
-
-		priv->buffer[j] = ads124s_read(indio_dev);
-		ret = ads124s_write_cmd(indio_dev, ADS124S08_STOP_CONV);
-		if (ret)
-			dev_err(&priv->spi->dev, "Stop ADC conversions failed\n");
-
+		ads124s_read_channel(indio_dev, chan->channel, &(priv->buffer[j]));
 		j++;
 	}
 
-- 
2.49.0