[yocto] auto kernel version

[Trevor Woerner]

Hi,

Let's say I wanted to create a recipe to follow Linus' mainline or a recipe
to follow GregKH's staging-next. In those cases I wouldn't want to nail them
down with a version, I'd want to do AUTOREV. So I wouldn't put a version in
the recipe filename (linus-mainline.bb or gregkh-staging-next_git.bb).
But I can't seem to get away with not having some sort of version string
(LINUX_VERSION, PV) in the recipe itself. Is it not possible to extract a PV
or LINUX_VERSION automatically? Otherwise I'll need to update the recipe and
commit with every release (which isn't the end of the world, but adds to the
maintenance).

	SUMMARY = "GregKH's Staging-Next"
	SECTION = "kernel"
	LICENSE = "GPLv2"

	inherit kernel
	require recipes-kernel/linux/linux-dtb.inc

	LIC_FILES_CHKSUM = "file://COPYING;md5=d7810fab7487fb0aad327b76f1be7cd7"

	SRC_URI = "git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git;branch=staging-next"
	SRC_URI_append_rk3288 = " file://defconfig"
	SRC_URI_append_intel-corei7-64 = " file://defconfig"
	SRCREV = "${AUTOREV}"

	LINUX_VERSION = "4.11"
	PV = "${LINUX_VERSION}+git${SRCPV}"
	S = "${WORKDIR}/git"

	DEPENDS += "xz-native bc-native coreutils-native"