raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

This is a port of Pantelis Antoniou's v3 port that makes use of the
new upstreamed configfs support for binary attributes.

Original commit message:

Add a runtime interface to using configfs for generic device tree overlay
usage. With it its possible to use device tree overlays without having
to use a per-platform overlay manager.

Please see Documentation/devicetree/configfs-overlays.txt for more info.

Changes since v2:
- Removed ifdef CONFIG_OF_OVERLAY (since for now it's required)
- Created a documentation entry
- Slight rewording in Kconfig

Changes since v1:
- of_resolve() -> of_resolve_phandles().
Originally-signed-off-by: NPantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: NPhil Elwell <phil@raspberrypi.org>

DT configfs: Fix build errors on other platforms
Signed-off-by: NPhil Elwell <phil@raspberrypi.org>

DT configfs: fix build error

There is an error when compiling rpi-4.6.y branch:
  CC      drivers/of/configfs.o
drivers/of/configfs.c:291:21: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
   .default_groups = of_cfs_def_groups,
                     ^
drivers/of/configfs.c:291:21: note: (near initialization for 'of_cfs_subsys.su_group.default_groups.next')

The .default_groups is linked list since commit
1ae1602d.
This commit uses configfs_add_default_group to fix this problem.
Signed-off-by: NSlawomir Stepien <sst@poczta.fm>

configfs: New of_overlay API
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>