* [ptxdist] [PATCH v2 2/2] kernel: validate device trees against the DT schema
2026-08-31 13:11 [ptxdist] [PATCH v2 0/2] Run DT schema check on selected device trees Bruno Thomsen
2026-08-31 13:11 ` [ptxdist] [PATCH v2 1/2] host-system-python3: add dtschema Bruno Thomsen
@ 2026-08-31 13:11 ` Bruno Thomsen
1 sibling, 0 replies; 3+ messages in thread
From: Bruno Thomsen @ 2026-08-31 13:11 UTC (permalink / raw)
To: ptxdist; +Cc: Bruno Thomsen
Make it possible to do device tree validation on
dts/dtsi during development and preparation for
upstream.
Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
---
v1 -> v2 changed:
- Move complexity from kernel.make to ptxd_make_world_dtb
- KERNEL_DTB_CHECK_OPT conditional on KERNEL_DTB_CHECK
- Move KERNEL_DTB_CHECK inside 'if KERNEL_DTB'
- Clarify in help that schema problems are warnings
---
platforms/kernel.in | 25 ++++++++++++++++++++++
rules/kernel.make | 7 +++++++
rules/post/ptxd_make_world_dtb.make | 1 +
scripts/lib/ptxd_make_world_dtb.sh | 32 +++++++++++++++++++++++++++++
4 files changed, 65 insertions(+)
diff --git a/platforms/kernel.in b/platforms/kernel.in
index 2c6d906e8..36a4f3cf0 100644
--- a/platforms/kernel.in
+++ b/platforms/kernel.in
@@ -11,6 +11,8 @@ menuconfig KERNEL
select HOST_LZ4 if KERNEL_LZ4
select HOST_LIBKMOD if KERNEL_MODULES
select HOST_SYSTEM_BC
+ select HOST_SYSTEM_PYTHON3 if KERNEL_DTB_CHECK
+ select HOST_SYSTEM_PYTHON3_DTSCHEMA if KERNEL_DTB_CHECK
select HOST_OPENSSL if KERNEL_OPENSSL
select HOST_LIBELF if KERNEL_LIBELF
select HOST_BINDGEN_CLI if KERNEL_RUST
@@ -200,6 +202,29 @@ config KERNEL_DTS
is used as a search path for the device tree files specified
here. Multiple dts files can be specified, separated by spaces.
+config KERNEL_DTB_CHECK
+ bool
+ prompt "validate device trees against the DT schema"
+ help
+ Additionally build the device trees with the kernel build system
+ ('make CHECK_DTBS=y <board>.dtb') to validate them against the
+ device tree bindings in Documentation/devicetree/bindings.
+ Schema problems are reported as warnings, so they do not break
+ the build.
+
+ This requires the 'dtschema' python package on the build host and
+ it noticeably increases the build time of the kernel, because the
+ schema of all bindings must be processed first.
+
+ Only device trees that are part of the kernel tree can be checked,
+ because the make targets are relative to arch/<arch>/boot/dts.
+ Each file in KERNEL_DTS is looked up in KERNEL_DTS_PATH and the
+ first match inside the kernel tree is validated. Device trees
+ without such a match are skipped with a warning. So for device
+ trees in a vendor directory, that directory must be part of
+ KERNEL_DTS_PATH, e.g.
+ "${KERNEL_DIR}/arch/${GENERIC_KERNEL_ARCH}/boot/dts/ti/omap".
+
config KERNEL_DTS_SUPPORT_OVERLAYS
bool
diff --git a/rules/kernel.make b/rules/kernel.make
index af0dd3913..d32a0443c 100644
--- a/rules/kernel.make
+++ b/rules/kernel.make
@@ -282,6 +282,13 @@ KERNEL_INSTALL_OPT = \
$(KERNEL_BASE_OPT) \
modules_install
+ifdef PTXCONF_KERNEL_DTB_CHECK
+# validate the device trees while building them in world/dtb
+KERNEL_DTB_CHECK_OPT = \
+ $(KERNEL_SHARED_OPT) \
+ CHECK_DTBS=y
+endif
+
$(STATEDIR)/kernel.install:
@$(call targetinfo)
ifdef PTXCONF_KERNEL_MODULES_INSTALL
diff --git a/rules/post/ptxd_make_world_dtb.make b/rules/post/ptxd_make_world_dtb.make
index 37468c0be..81b237a87 100644
--- a/rules/post/ptxd_make_world_dtb.make
+++ b/rules/post/ptxd_make_world_dtb.make
@@ -10,6 +10,7 @@ world/dtb/env = \
$(call world/env, $(1)) \
pkg_dts_path="$($(1)_DTS_PATH)" \
pkg_dts="$($(1)_DTS)" \
+ pkg_dtb_check_opt="$(call ptx/escape,$($(1)_DTB_CHECK_OPT))" \
pkg_arch="$(GENERIC_KERNEL_ARCH)"
world/dtb = \
diff --git a/scripts/lib/ptxd_make_world_dtb.sh b/scripts/lib/ptxd_make_world_dtb.sh
index dea9268ff..22622b2ad 100644
--- a/scripts/lib/ptxd_make_world_dtb.sh
+++ b/scripts/lib/ptxd_make_world_dtb.sh
@@ -109,10 +109,13 @@ export -f ptxd_make_world_dtbo
ptxd_make_world_dtb() {
local dtb_deps_target dtb_source dtb_target
+ local dts_file dts_in_tree dtb_check_dtstree
+ local -a dtb_check_targets=()
ptxd_make_world_init || return
dtb_deps_target="${ptx_state_dir}/${pkg_stamp}"
+ dtb_check_dtstree="${pkg_kernel_dir:-${pkg_dir}}/arch/${pkg_arch}/boot/dts"
echo -e "\nBuilding device trees..."
@@ -128,7 +131,36 @@ ptxd_make_world_dtb() {
dtb_source="${ptxd_reply}"
dtb_target="${pkg_pkg_dir}/boot/$(basename ${dts_dts/%.dts/.dtb})"
+ #
+ # The dtb targets of the kernel build system are relative to
+ # arch/<arch>/boot/dts, so only device trees from the kernel tree
+ # can be validated.
+ #
+ if [ -n "${pkg_dtb_check_opt}" ]; then
+ dts_file=""
+ for dts_in_tree in "${ptxd_reply[@]}"; do
+ if [ "${dts_in_tree}" != "${dts_in_tree#${dtb_check_dtstree}/}" ]; then
+ dts_file="${dts_in_tree#${dtb_check_dtstree}/}"
+ break
+ fi
+ done
+ if [ -n "${dts_file}" ]; then
+ dtb_check_targets[${#dtb_check_targets[@]}]="${dts_file/%.dts/.dtb}"
+ else
+ ptxd_warning "Device tree '${dts_dts}' is not part of the kernel tree. Skipping validation."
+ fi
+ fi
+
ptxd_make_dtb || break
done
+
+ if [ ${#dtb_check_targets[@]} -ne 0 ]; then
+ echo -e "\nValidating device trees..."
+ ptxd_eval \
+ "${MAKE}" \
+ "${pkg_dtb_check_opt}" \
+ "${dtb_check_targets[@]}" ||
+ ptxd_bailout "Unable to validate device trees."
+ fi
}
export -f ptxd_make_world_dtb
--
2.55.0
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