[Buildroot] [PATCH] libv4l: Add new package libv4l

[Thomas Petazzoni]

Hello Klaus,

Thanks for this new package. A couple of comments below.

On Fri,  4 Mar 2011 16:47:00 +0100
Klaus Schwarzkopf <schwarzkopf at sensortherm.de> wrote:

> --- /dev/null
> +++ b/package/libv4l/Config.in
> @@ -0,0 +1,10 @@
> +config BR2_PACKAGE_LIBV4L
> +	bool "libv4l"
> +	depends on BR2_LARGEFILE
> +	help
> +	  	libv4l is an accompanying collection of libraries that adds a thin abstraction layer on top of video4linux2 (V4L2) devices.
> +
> +		http://freshmeat.net/projects/libv4l

The help text indentation should be one tab + 2 spaces, and should be
wrapped at a reasonable length (~80 columns).

> +#############################################################
> +#
> +# libv4l
> +#
> +#############################################################
> +LIBV4L_VERSION = 0.8.1

Version 0.8.3 is the latest release. Any reason not to use it ?

> +LIBV4L_SOURCE = v4l-utils-$(LIBV4L_VERSION).tar.bz2
> +LIBV4L_SITE = http://linuxtv.org/downloads/v4l-utils/
> +LIBV4L_INSTALL_STAGING = YES
> +LIBV4L_INSTALL_TARGET = YES

> +LIBV4L_CONF_OPT = --enable-shared \
> +		  --enable-static \

Since you're using the GENTARGETS infrastructure, this line is useless.

> +
> +define LIBV4L_BUILD_CMDS
> + 	#$(MAKE) CC=$(TARGET_CC) LD=$(TARGET_LD) -C $(@D) all

Comment, remove.

> +	$(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D)/lib PREFIX=/usr LINKTYPE=static
> +	$(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D)/lib PREFIX=/usr 

static linking is only needed when BR2_PREFER_STATIC_LIB is used. So
something like :

LIBV4L_MAKE_OPTS = PREFIX=/usr
ifeq ($(BR2_PREFER_STATIC_LIB),y)
LIBV4L_MAKE_OPTS += LINKTYPE=static
endif

define LIBV4L_BUILD_CMDS
	$(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D)/lib $(LIBV4AL_MAKE_OPTS)
endif

Moreover, why do you build only the library ? There are some utilities
in utils/ that may be interesting to build (not all of them, since at
least one of them depends on Qt, and we don't want libv4l to depend on
Qt). You could add a sub-option "Install libv4l utils" to be able to
selectively install or not the libv4l utilities.

> +#CFLAGS=-DO_LARGEFILE=0400000

Comment, remove.

> +endef
> +
> +define LIBV4L_INSTALL_STAGING_CMDS
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4l1/libv4l1.a $(STAGING_DIR)/usr/lib/libv4l1.a
> + 	$(INSTALL) -D -m 0644 $(@D)/lib/include/libv4l1.h $(STAGING_DIR)/usr/include/libv4l1.h
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4l1/libv4l1.so* $(STAGING_DIR)/usr/lib
> +
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4l2/libv4l2.a $(STAGING_DIR)/usr/lib/libv4l2.a
> + 	$(INSTALL) -D -m 0644 $(@D)/lib/include/libv4l2.h $(STAGING_DIR)/usr/include/libv4l2.h
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4l2/libv4l2.so* $(STAGING_DIR)/usr/lib
> +
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4lconvert/libv4lconvert.a $(STAGING_DIR)/usr/lib/libv4l2.a
> + 	$(INSTALL) -D -m 0644 $(@D)/lib/include/libv4lconvert.h $(STAGING_DIR)/usr/include/libv4lconvert.h
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4lconvert/libv4lconvert.so* $(STAGING_DIR)/usr/lib
> +endef
> +
> +define LIBV4L_INSTALL_TARGET_CMDS
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4l1/libv4l1.so* $(TARGET_DIR)/usr/lib
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4l2/libv4l2.so* $(TARGET_DIR)/usr/lib
> + 	$(INSTALL) -D -m 0755 $(@D)/lib/libv4lconvert/libv4lconvert.so* $(TARGET_DIR)/usr/lib
> +endef

Why don't you use the "make install" target here ? The libv4l Makefile
supports the $(DESTDIR) variable, so something like:

define LIBV4L_INSTALL_STAGING_CMDS
	$(MAKE) -C $(@D) DESTDIR=$(STAGING_DIR) PREFIX=/usr install
endif

define LIBV4L_INSTALL_TARGET_CMDS
	$(MAKE) -C $(@D) DESTDIR=$(TARGET_DIR) PREFIX=/usr install
endif

should work.

> +$(eval $(call GENTARGETS,package,libv4l))
> +#$(eval $(call AUTOTARGETS,package,libv4l))

Comment, remove.

Regards!

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com