[PATCH] docs: dt: writing-schema: Describe validating one DTB

[Krzysztof Kozlowski]

Running DT schema validation with `dtbs_check` is time consuming thus we
also have ability to check only one DTB target like:

  make -j8 DT_SCHEMA_FILES=gpio CHECK_DTBS=y qcom/sm8450-hdk.dtb

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
---
 Documentation/devicetree/bindings/writing-schema.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/writing-schema.rst b/Documentation/devicetree/bindings/writing-schema.rst
index eb8ced400c7e..6dea741c5962 100644
--- a/Documentation/devicetree/bindings/writing-schema.rst
+++ b/Documentation/devicetree/bindings/writing-schema.rst
@@ -222,6 +222,10 @@ separated by ':'.
     make dt_binding_check DT_SCHEMA_FILES=/gpio/
     make dtbs_check DT_SCHEMA_FILES=trivial-devices.yaml
 
+Validation of one DT source by providing Makefile target::
+
+    make CHECK_DTBS=y target.dtb
+    make DT_SCHEMA_FILES=xxx.yaml CHECK_DTBS=y target.dtb
 
 json-schema Resources
 ---------------------
-- 
2.43.0