staging: iio: ad2s1200: Improve readability with be16_to_cpup

The manual states that the data is contained in the upper 12 bits
of the 16 bits read by spi. The code that extracts these 12 bits
is correct for both be and le machines, but this is not clear
from a first glance.

To improve readability the relevant expressions are replaced
with equivalent expressions that use be16_to_cpup.
Signed-off-by: David Veenstra <davidjulianveenstra@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/resolver/ad2s1200.c

@@ -38,7 +38,7 @@ struct ad2s1200_state {
 	struct spi_device *sdev;
 	int sample;
 	int rdvel;
-	u8 rx[2] ____cacheline_aligned;
+	__be16 rx ____cacheline_aligned;
 };
 
 static int ad2s1200_read_raw(struct iio_dev *indio_dev,
@@ -49,7 +49,6 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
 {
 	struct ad2s1200_state *st = iio_priv(indio_dev);
 	int ret = 0;
-	s16 vel;
 
 	mutex_lock(&st->lock);
 	gpio_set_value(st->sample, 0);
@@ -59,7 +58,7 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
 	gpio_set_value(st->sample, 1);
 	gpio_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
 
-	ret = spi_read(st->sdev, st->rx, 2);
+	ret = spi_read(st->sdev, &st->rx, 2);
 	if (ret < 0) {
 		mutex_unlock(&st->lock);
 		return ret;
@@ -67,12 +66,10 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
 
 	switch (chan->type) {
 	case IIO_ANGL:
-		*val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
+		*val = be16_to_cpup(&st->rx) >> 4;
 		break;
 	case IIO_ANGL_VEL:
-		vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
-		vel = sign_extend32(vel, 11);
-		*val = vel;
+		*val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11);
 		break;
 	default:
 		mutex_unlock(&st->lock);