iio: imu: Add mpu9255 support to mpu6050 driver

Added support for the mpu9255 IMU to the mpu6050 driver. The
register map is the same as the other chips; the only driver
difference is the compatible string and the WHOAMI register
value.
Signed-off-by: Douglas Fischer <fischerdouglasc@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt

@@ -8,6 +8,7 @@ Required properties:
  		"invensense,mpu6500"
 		"invensense,mpu9150"
 		"invensense,mpu9250"
+		"invensense,mpu9255"
 		"invensense,icm20608"
  - reg : the I2C address of the sensor
  - interrupt-parent : should be the phandle for the interrupt controller

drivers/iio/imu/inv_mpu6050/inv_mpu_core.c

@@ -120,6 +120,12 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6500,
 		.config = &chip_config_6050,
 	},
+	{
+		.whoami = INV_MPU9255_WHOAMI_VALUE,
+		.name = "MPU9255",
+		.reg = &reg_set_6500,
+		.config = &chip_config_6050,
+	},
 	{
 		.whoami = INV_ICM20608_WHOAMI_VALUE,
 		.name = "ICM20608",

drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c

@@ -179,6 +179,7 @@ static const struct i2c_device_id inv_mpu_id[] = {
 	{"mpu6500", INV_MPU6500},
 	{"mpu9150", INV_MPU9150},
 	{"mpu9250", INV_MPU9250},
+	{"mpu9255", INV_MPU9255},
 	{"icm20608", INV_ICM20608},
 	{}
 };
@@ -202,6 +203,10 @@ static const struct of_device_id inv_of_match[] = {
 		.compatible = "invensense,mpu9250",
 		.data = (void *)INV_MPU9250
 	},
+	{
+		.compatible = "invensense,mpu9255",
+		.data = (void *)INV_MPU9255
+	},
 	{
 		.compatible = "invensense,icm20608",
 		.data = (void *)INV_ICM20608

drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h

@@ -74,6 +74,7 @@ enum inv_devices {
 	INV_MPU6000,
 	INV_MPU9150,
 	INV_MPU9250,
+	INV_MPU9255,
 	INV_ICM20608,
 	INV_NUM_PARTS
 };
@@ -232,6 +233,7 @@ struct inv_mpu6050_state {
 #define INV_MPU6500_WHOAMI_VALUE		0x70
 #define INV_MPU9150_WHOAMI_VALUE		0x68
 #define INV_MPU9250_WHOAMI_VALUE		0x71
+#define INV_MPU9255_WHOAMI_VALUE		0x73
 #define INV_ICM20608_WHOAMI_VALUE		0xAF
 
 /* scan element definition */

drivers/iio/imu/inv_mpu6050/inv_mpu_spi.c

@@ -83,6 +83,7 @@ static const struct spi_device_id inv_mpu_id[] = {
 	{"mpu6500", INV_MPU6500},
 	{"mpu9150", INV_MPU9150},
 	{"mpu9250", INV_MPU9250},
+	{"mpu9255", INV_MPU9255},
 	{"icm20608", INV_ICM20608},
 	{}
 };