iio: imu: add BNO055 serdev driver

Add a serdev driver for communicating to a BNO055 IMU via serial bus, and
enable the BNO055 core driver to work in this scenario.

Signed-off-by: Andrea Merello <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Cameron <[email protected]>

Author: andreamerello

drivers/iio/imu/bno055/Kconfig

@@ -2,3 +2,13 @@
 
 config BOSCH_BNO055
 	tristate
+
+config BOSCH_BNO055_SERIAL
+	tristate "Bosch BNO055 attached via UART"
+	depends on SERIAL_DEV_BUS
+	select BOSCH_BNO055
+	help
+	  Enable this to support Bosch BNO055 IMUs attached via UART.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bno055_sl.

drivers/iio/imu/bno055/Makefile

@@ -1,3 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_BOSCH_BNO055) += bno055.o
+obj-$(CONFIG_BOSCH_BNO055_SERIAL) += bno055_ser.o
+bno055_ser-y := bno055_ser_core.o
+# define_trace.h needs to know how to find our header
+CFLAGS_bno055_ser_trace.o := -I$(src)
+bno055_ser-$(CONFIG_TRACING) += bno055_ser_trace.o