iio: test: rework Kconfig to support modules

Rework the IIO test Kconfig to support building KUnit tests as modules.
This lets users execute tests at runtime in addition to the usual
tools/testing/kunit/kunit.py script.

Signed-off-by: Liam Beguin <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/test/Kconfig

···
 
 # Keep in alphabetical order
 config IIO_RESCALE_KUNIT_TEST
-	bool "Test IIO rescale conversion functions"
-	depends on KUNIT=y && IIO_RESCALE=y
+	tristate "Test IIO rescale conversion functions" if !KUNIT_ALL_TESTS
+	depends on KUNIT && IIO_RESCALE
 	default KUNIT_ALL_TESTS
 	help
-	  If you want to run tests on the iio-rescale code say Y here.
+	  Build unit tests for the iio-rescale code.
 
-	  This takes advantage of ARCH=um to run tests and should be used by
-	  developers to tests their changes to the rescaling logic.
+	  For more information on KUnit and unit tests in general, please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.
 
 config IIO_FORMAT_KUNIT_TEST
-        bool "Test IIO formatting functions"
-        depends on KUNIT=y
+	tristate "Test IIO formatting functions" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  build unit tests for the IIO formatting functions.
+
+	  For more information on KUnit and unit tests in general, please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.