iio: sps30: add support for serial interface

Sensor has support for both i2c and serial communication interfaces.
Both offer very similar set of features. Minor differences don't impact
overall functionality like doing measurements, etc.

Support for i2c have already been added, this patch adds support
for the latter ie. serial interface.
Signed-off-by: Tomasz Duszynski <tomasz.duszynski@octakon.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -16485,6 +16485,7 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/chemical/sensirion,sps30.yaml
 F:	drivers/iio/chemical/sps30.c
 F:	drivers/iio/chemical/sps30_i2c.c
+F:	drivers/iio/chemical/sps30_serial.c
 
 SERIAL DEVICE BUS
 M:	Rob Herring <robh@kernel.org>

drivers/iio/chemical/Kconfig

@@ -148,6 +148,17 @@ config SPS30_I2C
 	  To compile this driver as a module, choose M here: the module will
 	  be called sps30_i2c.
 
+config SPS30_SERIAL
+	tristate "SPS30 particulate matter sensor serial driver"
+	depends on SERIAL_DEV_BUS
+	select SPS30
+	help
+	  Say Y here to build support for the Sensirion SPS30 serial interface
+	  driver.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called sps30_serial.
+
 config VZ89X
 	tristate "SGX Sensortech MiCS VZ89X VOC sensor"
 	depends on I2C

drivers/iio/chemical/Makefile

@@ -18,4 +18,5 @@ obj-$(CONFIG_SCD30_SERIAL) += scd30_serial.o
 obj-$(CONFIG_SENSIRION_SGP30)	+= sgp30.o
 obj-$(CONFIG_SPS30) += sps30.o
 obj-$(CONFIG_SPS30_I2C) += sps30_i2c.o
+obj-$(CONFIG_SPS30_SERIAL) += sps30_serial.o
 obj-$(CONFIG_VZ89X)		+= vz89x.o