iio: imu: bmi160: added mount-matrix support

Add mount-matrix binding support. As chip could have different orientations
a mount matrix support is needed to correctly translate these differences.
Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/bmi160/bmi160.h

@@ -9,6 +9,7 @@ struct bmi160_data {
 	struct regmap *regmap;
 	struct iio_trigger *trig;
 	struct regulator_bulk_data supplies[2];
+	struct iio_mount_matrix orientation;
 };
 
 extern const struct regmap_config bmi160_regmap_config;

drivers/iio/imu/bmi160/bmi160_core.c

@@ -110,6 +110,7 @@
 		.storagebits = 16,				\
 		.endianness = IIO_LE,				\
 	},							\
+	.ext_info = bmi160_ext_info,				\
 }
 
 /* scan indexes follow DATA register order */
@@ -265,6 +266,20 @@ static const struct  bmi160_odr_item bmi160_odr_table[] = {
 	},
 };
 
+static const struct iio_mount_matrix *
+bmi160_get_mount_matrix(const struct iio_dev *indio_dev,
+			const struct iio_chan_spec *chan)
+{
+	struct bmi160_data *data = iio_priv(indio_dev);
+
+	return &data->orientation;
+}
+
+static const struct iio_chan_spec_ext_info bmi160_ext_info[] = {
+	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, bmi160_get_mount_matrix),
+	{ }
+};
+
 static const struct iio_chan_spec bmi160_channels[] = {
 	BMI160_CHANNEL(IIO_ACCEL, X, BMI160_SCAN_ACCEL_X),
 	BMI160_CHANNEL(IIO_ACCEL, Y, BMI160_SCAN_ACCEL_Y),
@@ -839,6 +854,11 @@ int bmi160_core_probe(struct device *dev, struct regmap *regmap,
 		return ret;
 	}
 
+	ret = iio_read_mount_matrix(dev, "mount-matrix",
+				    &data->orientation);
+	if (ret)
+		return ret;
+
 	ret = bmi160_chip_init(data, use_spi);
 	if (ret)
 		return ret;