iio: mma8452: Add support for the "mount-matrix" device property

Add support for the standard "mount-matrix" device property to
the mma8452 driver.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220208124336.511884-2-hdegoede@redhat.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/accel/mma8452.c

@@ -104,6 +104,7 @@
 struct mma8452_data {
 	struct i2c_client *client;
 	struct mutex lock;
+	struct iio_mount_matrix orientation;
 	u8 ctrl_reg1;
 	u8 data_cfg;
 	const struct mma_chip_info *chip_info;
@@ -1190,6 +1191,20 @@ static const struct attribute_group mma8452_event_attribute_group = {
 	.attrs = mma8452_event_attributes,
 };
 
+static const struct iio_mount_matrix *
+mma8452_get_mount_matrix(const struct iio_dev *indio_dev,
+			   const struct iio_chan_spec *chan)
+{
+	struct mma8452_data *data = iio_priv(indio_dev);
+
+	return &data->orientation;
+}
+
+static const struct iio_chan_spec_ext_info mma8452_ext_info[] = {
+	IIO_MOUNT_MATRIX(IIO_SHARED_BY_TYPE, mma8452_get_mount_matrix),
+	{ }
+};
+
 #define MMA8452_FREEFALL_CHANNEL(modifier) { \
 	.type = IIO_ACCEL, \
 	.modified = 1, \
@@ -1228,6 +1243,7 @@ static const struct attribute_group mma8452_event_attribute_group = {
 	}, \
 	.event_spec = mma8452_transient_event, \
 	.num_event_specs = ARRAY_SIZE(mma8452_transient_event), \
+	.ext_info = mma8452_ext_info, \
 }
 
 #define MMA8652_CHANNEL(axis, idx, bits) { \
@@ -1249,6 +1265,7 @@ static const struct attribute_group mma8452_event_attribute_group = {
 	}, \
 	.event_spec = mma8452_motion_event, \
 	.num_event_specs = ARRAY_SIZE(mma8452_motion_event), \
+	.ext_info = mma8452_ext_info, \
 }
 
 static const struct iio_chan_spec mma8451_channels[] = {
@@ -1546,6 +1563,10 @@ static int mma8452_probe(struct i2c_client *client,
 		return -ENODEV;
 	}
 
+	ret = iio_read_mount_matrix(&client->dev, &data->orientation);
+	if (ret)
+		return ret;
+
 	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
 	if (IS_ERR(data->vdd_reg))
 		return dev_err_probe(&client->dev, PTR_ERR(data->vdd_reg),