iio: at91-sama5d2_adc: split at91_adc_current_chan_is_touch() helper

This change moves the logic to check if the current channel is the
touchscreen channel to a separate helper.
This reduces some code duplication, but the main intent is to re-use this
in the next patches.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Eugen Hristev <eugen.hristev@microchip.com>
Reviewed-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/at91-sama5d2_adc.c

@@ -874,6 +874,15 @@ static bool at91_adc_buffer_check_use_irq(struct iio_dev *indio,
 	return true;
 }
 
+static bool at91_adc_current_chan_is_touch(struct iio_dev *indio_dev)
+{
+	struct at91_adc_state *st = iio_priv(indio_dev);
+
+	return !!bitmap_subset(indio_dev->active_scan_mask,
+			       &st->touch_st.channels_bitmask,
+			       AT91_SAMA5D2_MAX_CHAN_IDX + 1);
+}
+
 static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
 {
 	int ret;
@@ -881,12 +890,9 @@ static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
 	struct at91_adc_state *st = iio_priv(indio_dev);
 
 	/* check if we are enabling triggered buffer or the touchscreen */
-	if (bitmap_subset(indio_dev->active_scan_mask,
-			  &st->touch_st.channels_bitmask,
-			  AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
-		/* touchscreen enabling */
+	if (at91_adc_current_chan_is_touch(indio_dev))
 		return at91_adc_configure_touch(st, true);
-	}
+
 	/* if we are not in triggered mode, we cannot enable the buffer. */
 	if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
 		return -EINVAL;
@@ -938,12 +944,9 @@ static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
 	u8 bit;
 
 	/* check if we are disabling triggered buffer or the touchscreen */
-	if (bitmap_subset(indio_dev->active_scan_mask,
-			  &st->touch_st.channels_bitmask,
-			  AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
-		/* touchscreen disable */
+	if (at91_adc_current_chan_is_touch(indio_dev))
 		return at91_adc_configure_touch(st, false);
-	}
+
 	/* if we are not in triggered mode, nothing to do here */
 	if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
 		return -EINVAL;
@@ -1937,14 +1940,10 @@ static __maybe_unused int at91_adc_resume(struct device *dev)
 		return 0;
 
 	/* check if we are enabling triggered buffer or the touchscreen */
-	if (bitmap_subset(indio_dev->active_scan_mask,
-			  &st->touch_st.channels_bitmask,
-			  AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
-		/* touchscreen enabling */
+	if (at91_adc_current_chan_is_touch(indio_dev))
 		return at91_adc_configure_touch(st, true);
-	} else {
+	else
 		return at91_adc_configure_trigger(st->trig, true);
-	}
 
 	/* not needed but more explicit */
 	return 0;