On Wed, Feb 20, 2013 at 02:05:56PM -0700, Stephen Warren wrote: > From: Stephen Warren <swarren@xxxxxxxxxx> > > The recent dtc+cpp support allows header files and C pre-processor > defines/macros to be used when compiling device tree files. These > headers will typically define various constants that are part of the > device tree bindings. > > The original patch which set up the dtc+cpp include path only considered > using those headers from device tree files. However, they are also > useful for kernel code which needs to interpret the device tree. > > In both the DT files and the kernel, I'd like to include the DT-related > headers in the same way, for example, <dt-bindings/gpio/tegra-gpio.h>. > That will simplify any text which discusses the DT header locations. > > Creating a <dt-bindings/> for kernel source to use is as simple as > placing files into include/dt-bindings/. > > However, when compiling DT files, the include path should be restricted > so that only the dt-bindings path is available; arbitrary kernel headers > shouldn't be exposed. For this reason, create a specific include > directory for use by dtc+cpp, and symlink dt-bindings from there to the > actual location of include/dt-bindings/. For want of a better location, > place this "include chroot" into the existing dts/ directory. > > arch/*/boot/dts/include/dt-bindings -> ../../../../../dt-bindings ../../../../../include/dt-bindings And, I would expect only the headers that will actually be referenced by kernel should go into include/dt-bindings. There is no point to put headers that will not be included by kernel but only by dts files into there, and instead arch/arm/boot/dts/include should just be good enough for them. With this agreed ... > Cc: Shawn Guo <shawn.guo@xxxxxxxxxx> Acked-by: Shawn Guo <shawn.guo@xxxxxxxxxx> > Cc: Hiroshi Doyu <hdoyu@xxxxxxxxxx> > Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx> > --- > You can find an example of how this would be used at > git://nv-tegra.nvidia.com/user/swarren/linux-2.6 linux-next_common > (note: there's a bunch of other cruft in that branch too) > > arch/arm/boot/dts/include/dt-bindings | 1 + > scripts/Makefile.lib | 3 +-- > 2 files changed, 2 insertions(+), 2 deletions(-) > create mode 120000 arch/arm/boot/dts/include/dt-bindings > > diff --git a/arch/arm/boot/dts/include/dt-bindings b/arch/arm/boot/dts/include/dt-bindings > new file mode 120000 > index 0000000..08c00e4 > --- /dev/null > +++ b/arch/arm/boot/dts/include/dt-bindings > @@ -0,0 +1 @@ > +../../../../../include/dt-bindings > \ No newline at end of file > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > index 07125e6..d6c5036 100644 > --- a/scripts/Makefile.lib > +++ b/scripts/Makefile.lib > @@ -157,8 +157,7 @@ cpp_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \ > ld_flags = $(LDFLAGS) $(ldflags-y) > > dtc_cpp_flags = -Wp,-MD,$(depfile) -nostdinc \ > - -I$(srctree)/arch/$(SRCARCH)/boot/dts \ > - -I$(srctree)/arch/$(SRCARCH)/include/dts \ > + -I$(srctree)/arch/$(SRCARCH)/boot/dts/include \ > -undef -D__DTS__ > > # Finds the multi-part object the current object will be linked into > -- > 1.7.10.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
