[PATCH v6 2/2] docs: Integrate rustdoc generation into htmldocs

[Carlos Bilbao <carlos.bilbao@amd.com>]

Change target `make htmldocs` to combine RST Sphinx and the generation of
Rust documentation, when support is available.

Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
---
 Documentation/Makefile | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index bb73dcb5ed05..4111d0dd54d0 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -59,6 +59,10 @@ PAPEROPT_letter = -D latex_paper_size=letter
 KERNELDOC       = $(srctree)/scripts/kernel-doc
 KERNELDOC_CONF  = -D kerneldoc_srctree=$(srctree) -D kerneldoc_bin=$(KERNELDOC)
 ALLSPHINXOPTS   =  $(KERNELDOC_CONF) $(PAPEROPT_$(PAPER)) $(SPHINXOPTS)
+ifeq ($(CONFIG_RUST),y)
+# Let Sphinx know we will include rustdoc
+ALLSPHINXOPTS   +=  -t rustdoc
+endif
 # the i18n builder cannot share the environment and doctrees with the others
 I18NSPHINXOPTS  = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
 
@@ -94,6 +98,12 @@ quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)
 htmldocs:
 	@$(srctree)/scripts/sphinx-pre-install --version-check
 	@+$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,html,$(var),,$(var)))
+# If Rust support is available, add rustdoc generated contents.
+# If there are any, the errors from this make rustdoc will be displayed but
+# won't stop the execution of htmldocs
+ifeq ($(CONFIG_RUST),y)
+	$(Q)$(MAKE) rustdoc || true
+endif
 
 texinfodocs:
 	@$(srctree)/scripts/sphinx-pre-install --version-check
-- 
2.34.1