iio: adc: max1027: Separate the IRQ handler from the read logic

Create a max1027_read_scan() helper which will make clearer the future IRQ
handler updates (no functional change).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20210921115408.66711-12-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/max1027.c

@@ -440,22 +440,37 @@ static int max1027_set_cnvst_trigger_state(struct iio_trigger *trig, bool state)
 	return 0;
 }
 
-static irqreturn_t max1027_trigger_handler(int irq, void *private)
+static int max1027_read_scan(struct iio_dev *indio_dev)
 {
-	struct iio_poll_func *pf = private;
-	struct iio_dev *indio_dev = pf->indio_dev;
 	struct max1027_state *st = iio_priv(indio_dev);
 	unsigned int scanned_chans;
+	int ret;
 
 	scanned_chans = fls(*indio_dev->active_scan_mask) - 1;
 	if (*indio_dev->active_scan_mask & MAX1X27_SCAN_MASK_TEMP)
 		scanned_chans++;
 
 	/* fill buffer with all channel */
-	spi_read(st->spi, st->buffer, scanned_chans * 2);
+	ret = spi_read(st->spi, st->buffer, scanned_chans * 2);
+	if (ret < 0)
+		return ret;
 
 	iio_push_to_buffers(indio_dev, st->buffer);
 
+	return 0;
+}
+
+static irqreturn_t max1027_trigger_handler(int irq, void *private)
+{
+	struct iio_poll_func *pf = private;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	int ret;
+
+	ret = max1027_read_scan(indio_dev);
+	if (ret)
+		dev_err(&indio_dev->dev,
+			"Cannot read scanned values (%d)\n", ret);
+
 	iio_trigger_notify_done(indio_dev->trig);
 
 	return IRQ_HANDLED;