iio: imu: inv_icm42600: add gyroscope IIO device

Add IIO device for gyroscope sensor with data polling interface.
Attributes: raw, scale, sampling_frequency, calibbias.

Gyroscope in low noise mode.
Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/inv_icm42600/inv_icm42600.h

@@ -120,6 +120,8 @@ struct inv_icm42600_suspended {
  *  @orientation:	sensor chip orientation relative to main hardware.
  *  @conf:		chip sensors configurations.
  *  @suspended:		suspended sensors configuration.
+ *  @indio_gyro:	gyroscope IIO device.
+ *  @buffer:		data transfer buffer aligned for DMA.
  */
 struct inv_icm42600_state {
 	struct mutex lock;
@@ -131,6 +133,8 @@ struct inv_icm42600_state {
 	struct iio_mount_matrix orientation;
 	struct inv_icm42600_conf conf;
 	struct inv_icm42600_suspended suspended;
+	struct iio_dev *indio_gyro;
+	uint8_t buffer[2] ____cacheline_aligned;
 };
 
 /* Virtual register addresses: @bank on MSB (4 upper bits), @address on LSB */
@@ -369,4 +373,6 @@ int inv_icm42600_debugfs_reg(struct iio_dev *indio_dev, unsigned int reg,
 int inv_icm42600_core_probe(struct regmap *regmap, int chip,
 			    inv_icm42600_bus_setup bus_setup);
 
+struct iio_dev *inv_icm42600_gyro_init(struct inv_icm42600_state *st);
+
 #endif

drivers/iio/imu/inv_icm42600/inv_icm42600_core.c

@@ -509,6 +509,10 @@ int inv_icm42600_core_probe(struct regmap *regmap, int chip,
 	if (ret)
 		return ret;
 
+	st->indio_gyro = inv_icm42600_gyro_init(st);
+	if (IS_ERR(st->indio_gyro))
+		return PTR_ERR(st->indio_gyro);
+
 	/* setup runtime power management */
 	ret = pm_runtime_set_active(dev);
 	if (ret)