iio: magnetometer: add a driver for Voltafield AF8133J magnetometer

AF8133J is a simple I2C-connected magnetometer, without interrupts.

Add a simple IIO driver for it.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Dalton Durst <dalton@ubports.com>
Signed-off-by: Shoji Keita <awaittrot@shjk.jp>
Co-developed-by: Ondrej Jirman <megi@xff.cz>
Signed-off-by: Ondrej Jirman <megi@xff.cz>
Reviewed-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Tested-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Link: https://lore.kernel.org/r/20240222011341.3232645-4-megi@xff.czSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/magnetometer/Kconfig

@@ -6,6 +6,18 @@
 
 menu "Magnetometer sensors"
 
+config AF8133J
+	tristate "Voltafield AF8133J 3-Axis Magnetometer"
+	depends on I2C
+	depends on OF
+	select REGMAP_I2C
+	help
+	  Say yes here to build support for Voltafield AF8133J I2C-based
+	  3-axis magnetometer chip.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called af8133j.
+
 config AK8974
 	tristate "Asahi Kasei AK8974 3-Axis Magnetometer"
 	depends on I2C

drivers/iio/magnetometer/Makefile

@@ -4,6 +4,7 @@
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_AF8133J)	+= af8133j.o
 obj-$(CONFIG_AK8974)	+= ak8974.o
 obj-$(CONFIG_AK8975)	+= ak8975.o
 obj-$(CONFIG_BMC150_MAGN) += bmc150_magn.o