doc: move Makefile to doc folder

Move the top-level Makefile to the documentation folder as it is only
used for documentation.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

.github/workflows/doc-build.yml

@@ -56,7 +56,7 @@ jobs:
     - name: build-docs
       run: |
         source zephyr-env.sh
-        make htmldocs
+        make -C doc htmldocs
         tar cvf htmldocs.tar --directory=./doc/_build html
 
     - name: upload-build

.github/workflows/doc-publish.yml

@@ -79,7 +79,7 @@ jobs:
         DOC_TAG: ${{ steps.tag.outputs.TYPE }}
       run: |
         source zephyr-env.sh
-        make DOC_TAG=${DOC_TAG} htmldocs
+        make DOC_TAG=${DOC_TAG} -C doc htmldocs
 
     - name: check-warns
       run: |

doc/Makefile

@@ -2,7 +2,7 @@
 # Top level makefile for documentation build
 #
 
-BUILDDIR ?= doc/_build
+BUILDDIR ?= _build
 DOC_TAG ?= development
 SPHINXOPTS ?= -q
 KCONFIG_TURBO_MODE ?= 0
@@ -22,7 +22,7 @@ htmldocs pdfdocs doxygen: configure
 # needed
 .PHONY: configure
 configure:
-	cmake -GNinja  -B${BUILDDIR} -Sdoc/ -DDOC_TAG=${DOC_TAG} \
+	cmake -GNinja -B${BUILDDIR} -S. -DDOC_TAG=${DOC_TAG} \
 		-DSPHINXOPTS=${SPHINXOPTS} \
 		-DKCONFIG_TURBO_MODE=${KCONFIG_TURBO_MODE}
 

doc/README.rst

@@ -180,13 +180,13 @@ of the build folder and run ``cmake`` and then ``ninja`` again.
 
    If you add or remove a file from the documentation, you need to re-run CMake.
 
-On Unix platforms a convenience :zephyr_file:`Makefile` at the root folder
+On Unix platforms a convenience :zephyr_file:`Makefile` at the ``doc`` folder
 of the Zephyr repository can be used to build the documentation directly from
 there:
 
 .. code-block:: console
 
-   cd ~/zephyr
+   cd ~/zephyr/doc
 
    # To generate HTML output
    make htmldocs