iio: add filter subfolder

Add filter subfolder for IIO devices that handle filter functionality.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/Kconfig

@@ -78,6 +78,7 @@ source "drivers/iio/chemical/Kconfig"
 source "drivers/iio/common/Kconfig"
 source "drivers/iio/dac/Kconfig"
 source "drivers/iio/dummy/Kconfig"
+source "drivers/iio/filter/Kconfig"
 source "drivers/iio/frequency/Kconfig"
 source "drivers/iio/gyro/Kconfig"
 source "drivers/iio/health/Kconfig"

drivers/iio/Makefile

@@ -25,6 +25,7 @@ obj-y += common/
 obj-y += dac/
 obj-y += dummy/
 obj-y += gyro/
+obj-y += filter/
 obj-y += frequency/
 obj-y += health/
 obj-y += humidity/

drivers/iio/filter/Kconfig

@@ -0,0 +1,8 @@
+#
+# Filter drivers
+#
+# When adding new entries keep the list in alphabetical order
+
+menu "Filters"
+
+endmenu

drivers/iio/filter/Makefile

@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for industrial I/O Filter drivers
+#
+
+# When adding new entries keep the list in alphabetical order