gpiod-sysfs-proxy: new recipe

Many users are reluctant to use libgpiod instead of the deprecated
/sys/class/gpio interface. The gpiod-sysfs-proxy project aims at making
the transition easier by implementing a compatibility layer in
user-space using FUSE and python3-gpiod. This way we can eat the cookie
by disabling the sysfs ABI and have the users have it too by sticking to
their existing scripts.

The project itself is a very simple setuptools-based python package but
the recipe is quite complex due to comprehensive distro integration.

By default we use /run/gpio as mountpoint. For full backward
compatibility with the kernel interface, the user must explicitly add
the 'sys-class-mount' switch to PACKAGECONFIG. We do this because,
depending on whether CONFIG_GPIO_SYSFS Kconfig option is enabled,
/sys/class/gpio will either be non-empty or not exist at all. In the
latter case, we need to somehow create the /sys/class/gpio and, since
user-space is not allowed to mkdir() inside sysfs, we use overlayfs for
that. As this is rather non-standard, we want the user to be aware of
this.

We support both systemd and sys V init managers.

We also provide a ptest package which uses an external
gpio-sysfs-compat-tests script.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-filesystems/conf/layer.conf

@@ -16,3 +16,7 @@ LAYERVERSION_filesystems-layer = "1"
 LAYERDEPENDS_filesystems-layer = "core openembedded-layer networking-layer"
 
 LAYERSERIES_COMPAT_filesystems-layer = "styhead walnascar"
+
+BBFILES_DYNAMIC += " \
+    meta-python:${LAYERDIR}/dynamic-layers/meta-python/recipes-*/*/*.bb \
+"