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, most 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 -> ../../../../../include/dt-bindings Some headers used by device tree files may not be useful to the kernel; they may be used simply to aid in constructing the DT file (e.g. macros to create a node), but not define any information that the kernel needs to share. These may be placed directly into arch/*/boot/dts/ along with the DT files themselves. Cc: Hiroshi Doyu <hdoyu@xxxxxxxxxx> Acked-by: Michal Marek <mmarek@xxxxxxx> Acked-by: Shawn Guo <shawn.guo@xxxxxxxxxx> Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx> --- Grant, Rob, This is a pre-requisite for people to convert their *.dts files to use cpp, and hence is likely to be useful for a number of ARM subarch trees. Perhaps this patch can be placed into a standalone topic branch in the DT repo so we can all merge it. Assuming this patch is OK, I would also repost the patches that create common headers defining IRQ, and GPIO flags, which would place files into the new include/dt-bindings directory. v2: * Leave arch/*/boot/dts in dtc include path, for any headers that are only included by *.dts and don't need to be shared by the kernel. * Fix pathname in commit description. --- arch/arm/boot/dts/include/dt-bindings | 1 + scripts/Makefile.lib | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) 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..af35521 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -158,7 +158,7 @@ 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
