iio: gyro: st_gyro: Support mount matrix

Add support to read and present the mounting matrix on ST gyroscopes.

Cc: Denis Ciocca <denis.ciocca@st.com>
Cc: Daniel Drake <drake@endlessm.com>
Cc: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210518230722.522446-5-linus.walleij@linaro.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/gyro/st_gyro_core.c

@@ -37,19 +37,36 @@
 #define ST_GYRO_FS_AVL_500DPS			500
 #define ST_GYRO_FS_AVL_2000DPS			2000
 
+static const struct iio_mount_matrix *
+st_gyro_get_mount_matrix(const struct iio_dev *indio_dev,
+			 const struct iio_chan_spec *chan)
+{
+	struct st_sensor_data *gdata = iio_priv(indio_dev);
+
+	return &gdata->mount_matrix;
+}
+
+static const struct iio_chan_spec_ext_info st_gyro_mount_matrix_ext_info[] = {
+	IIO_MOUNT_MATRIX(IIO_SHARED_BY_ALL, st_gyro_get_mount_matrix),
+	{ }
+};
+
 static const struct iio_chan_spec st_gyro_16bit_channels[] = {
-	ST_SENSORS_LSM_CHANNELS(IIO_ANGL_VEL,
+	ST_SENSORS_LSM_CHANNELS_EXT(IIO_ANGL_VEL,
 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 			ST_SENSORS_SCAN_X, 1, IIO_MOD_X, 's', IIO_LE, 16, 16,
-			ST_GYRO_DEFAULT_OUT_X_L_ADDR),
-	ST_SENSORS_LSM_CHANNELS(IIO_ANGL_VEL,
+			ST_GYRO_DEFAULT_OUT_X_L_ADDR,
+			st_gyro_mount_matrix_ext_info),
+	ST_SENSORS_LSM_CHANNELS_EXT(IIO_ANGL_VEL,
 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 			ST_SENSORS_SCAN_Y, 1, IIO_MOD_Y, 's', IIO_LE, 16, 16,
-			ST_GYRO_DEFAULT_OUT_Y_L_ADDR),
-	ST_SENSORS_LSM_CHANNELS(IIO_ANGL_VEL,
+			ST_GYRO_DEFAULT_OUT_Y_L_ADDR,
+			st_gyro_mount_matrix_ext_info),
+	ST_SENSORS_LSM_CHANNELS_EXT(IIO_ANGL_VEL,
 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 			ST_SENSORS_SCAN_Z, 1, IIO_MOD_Z, 's', IIO_LE, 16, 16,
-			ST_GYRO_DEFAULT_OUT_Z_L_ADDR),
+			ST_GYRO_DEFAULT_OUT_Z_L_ADDR,
+			st_gyro_mount_matrix_ext_info),
 	IIO_CHAN_SOFT_TIMESTAMP(3)
 };
 
@@ -479,6 +496,10 @@ int st_gyro_common_probe(struct iio_dev *indio_dev)
 	indio_dev->channels = gdata->sensor_settings->ch;
 	indio_dev->num_channels = ST_SENSORS_NUMBER_ALL_CHANNELS;
 
+	err = iio_read_mount_matrix(gdata->dev, &gdata->mount_matrix);
+	if (err)
+		return err;
+
 	gdata->current_fullscale = &gdata->sensor_settings->fs.fs_avl[0];
 	gdata->odr = gdata->sensor_settings->odr.odr_avl[0].hz;