[Buildroot] [PATCH v2 4/5] package/hidapi: make the hidraw backend optional

[Tomas Mudrunka <tomas.mudrunka@gmail.com>]

The hidraw backend is the only part of hidapi that needs udev (for
libudev); the libusb backend only needs libusb. Make the hidraw backend
optional through a new BR2_PACKAGE_HIDAPI_HIDRAW option, available
when a udev provider is enabled and enabled by default, so existing
configurations are unchanged.

This allows hidapi (libhidapi-libusb) to be used on small systems
without udev. The BR2_USE_MMU dependency, which was only needed for
udev, is dropped from hidapi.

All in-tree users of hidapi, except libmanette, can use either backend
(they look up hidapi-hidraw and hidapi-libusb, or load either library
at runtime). libmanette only looks up hidapi-hidraw.pc, so make it
select BR2_PACKAGE_HIDAPI_HIDRAW.

Signed-off-by: Tomas Mudrunka <tomas.mudrunka@gmail.com>
---
 package/hidapi/Config.in     | 23 ++++++++++++++++++-----
 package/hidapi/hidapi.mk     | 10 ++++++++--
 package/libmanette/Config.in |  3 ++-
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/package/hidapi/Config.in b/package/hidapi/Config.in
index 72ae32a6d8..aec90e9501 100644
--- a/package/hidapi/Config.in
+++ b/package/hidapi/Config.in
@@ -1,9 +1,7 @@
 config BR2_PACKAGE_HIDAPI
 	bool "hidapi"
-	depends on BR2_PACKAGE_HAS_UDEV
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL
 	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_9 # libusb
-	depends on BR2_USE_MMU # udev
 	depends on BR2_USE_WCHAR # wcsdup()
 	select BR2_PACKAGE_LIBUSB
 	select BR2_PACKAGE_LIBICONV if !BR2_ENABLE_LOCALE
@@ -14,11 +12,26 @@ config BR2_PACKAGE_HIDAPI
 	  to interface with USB and Bluetooth HID-Class devices on
 	  Windows, Linux, and Mac OS X.
 
+	  The libusb backend (libhidapi-libusb) is always built.
+
 	  http://github.com/libusb/hidapi/
 
-comment "hidapi needs udev /dev management and a toolchain w/ NPTL, gcc >= 4.9, wchar"
-	depends on BR2_USE_MMU
+if BR2_PACKAGE_HIDAPI
+
+config BR2_PACKAGE_HIDAPI_HIDRAW
+	bool "hidraw backend"
+	default y
+	depends on BR2_PACKAGE_HAS_UDEV
+	help
+	  Build the hidraw backend (libhidapi-hidraw), which uses the
+	  kernel hidraw interface and needs libudev.
+
+comment "hidraw backend needs udev /dev management"
+	depends on !BR2_PACKAGE_HAS_UDEV
+
+endif
+
+comment "hidapi needs a toolchain w/ NPTL, gcc >= 4.9, wchar"
 	depends on !BR2_TOOLCHAIN_HAS_THREADS_NPTL || \
-		!BR2_PACKAGE_HAS_UDEV || \
 		!BR2_TOOLCHAIN_GCC_AT_LEAST_4_9 || \
 		!BR2_USE_WCHAR
diff --git a/package/hidapi/hidapi.mk b/package/hidapi/hidapi.mk
index 5f0c482a95..884912f175 100644
--- a/package/hidapi/hidapi.mk
+++ b/package/hidapi/hidapi.mk
@@ -10,14 +10,20 @@ HIDAPI_INSTALL_STAGING = YES
 HIDAPI_LICENSE = GPL-3.0 or BSD-3-Clause or HIDAPI license
 HIDAPI_LICENSE_FILES = LICENSE.txt LICENSE-gpl3.txt LICENSE-bsd.txt LICENSE-orig.txt
 
-HIDAPI_DEPENDENCIES = libusb udev
+HIDAPI_DEPENDENCIES = libusb
 
 HIDAPI_CONF_OPTS = \
-	-DHIDAPI_WITH_HIDRAW=ON \
 	-DHIDAPI_WITH_LIBUSB=ON \
 	-DHIDAPI_WITH_TESTS=OFF \
 	-DHIDAPI_BUILD_HIDTEST=OFF
 
+ifeq ($(BR2_PACKAGE_HIDAPI_HIDRAW),y)
+HIDAPI_CONF_OPTS += -DHIDAPI_WITH_HIDRAW=ON
+HIDAPI_DEPENDENCIES += udev
+else
+HIDAPI_CONF_OPTS += -DHIDAPI_WITH_HIDRAW=OFF
+endif
+
 ifeq ($(BR2_PACKAGE_LIBICONV),y)
 HIDAPI_DEPENDENCIES += libiconv
 endif
diff --git a/package/libmanette/Config.in b/package/libmanette/Config.in
index 0f3a5a7bb0..9377f35a42 100644
--- a/package/libmanette/Config.in
+++ b/package/libmanette/Config.in
@@ -2,11 +2,12 @@ config BR2_PACKAGE_LIBMANETTE
 	bool "libmanette"
 	depends on BR2_USE_MMU # libglib2, hidapi
 	depends on BR2_USE_WCHAR # libglib2, hidapi
-	depends on BR2_PACKAGE_HAS_UDEV # hidapi
+	depends on BR2_PACKAGE_HAS_UDEV # hidapi-hidraw
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL # hidapi
 	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_16
 	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_9 # hidapi -> libusb
 	select BR2_PACKAGE_HIDAPI
+	select BR2_PACKAGE_HIDAPI_HIDRAW # needs hidapi-hidraw.pc
 	select BR2_PACKAGE_LIBEVDEV
 	select BR2_PACKAGE_LIBGLIB2
 	select BR2_PACKAGE_LIBGUDEV
-- 
2.56.1

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