all: Remove third argument to MP_REGISTER_MODULE.

It's no longer needed because this macro is now processed after
preprocessing the source code via cpp (in the qstr extraction stage), which
means unused MP_REGISTER_MODULE's are filtered out by the preprocessor.

Signed-off-by: Damien George <damien@micropython.org>

3 files changed, 9 insertions, 12 deletions

diff --git a/docs/develop/cmodules.rst b/docs/develop/cmodules.rst
index 38225e868..143057f7f 100644
--- a/docs/develop/cmodules.rst
+++ b/docs/develop/cmodules.rst
@@ -221,23 +221,25 @@ as described above.
 If a module is not enabled by default then the corresponding C preprocessor macro
 must be enabled.  This macro name can be found by searching for the ``MP_REGISTER_MODULE``
 line in the module's source code (it usually appears at the end of the main source file).
-The third argument to ``MP_REGISTER_MODULE`` is the macro name, and this must be set
-to 1 using ``CFLAGS_EXTRA`` to make the module available.  If the third argument is just
-the number 1 then the module is enabled by default.
+This macro should be surrounded by a ``#if X`` / ``#endif`` pair, and the configuration
+option ``X`` must be set to 1 using ``CFLAGS_EXTRA`` to make the module available.  If
+there is no ``#if X`` / ``#endif`` pair then the module is enabled by default.
 
 For example, the ``examples/usercmodule/cexample`` module is enabled by default so
 has the following line in its source code:
 
   .. code-block:: c
 
-      MP_REGISTER_MODULE(MP_QSTR_cexample, example_user_cmodule, 1);
+      MP_REGISTER_MODULE(MP_QSTR_cexample, example_user_cmodule);
 
 Alternatively, to make this module disabled by default but selectable through
 a preprocessor configuration option, it would be:
 
   .. code-block:: c
 
-      MP_REGISTER_MODULE(MP_QSTR_cexample, example_user_cmodule, MODULE_CEXAMPLE_ENABLED);
+      #if MODULE_CEXAMPLE_ENABLED
+      MP_REGISTER_MODULE(MP_QSTR_cexample, example_user_cmodule);
+      #endif
 
 In this case the module is enabled by adding ``CFLAGS_EXTRA=-DMODULE_CEXAMPLE_ENABLED=1``
 to the ``make`` command, or editing ``mpconfigport.h`` or ``mpconfigboard.h`` to add
diff --git a/docs/develop/library.rst b/docs/develop/library.rst
index 47ea2dc8d..c2a86ea16 100644
--- a/docs/develop/library.rst
+++ b/docs/develop/library.rst
@@ -64,7 +64,7 @@ hypothetical new module ``subsystem`` in the file ``modsubsystem.c``:
        .globals = (mp_obj_dict_t *)&mp_module_subsystem_globals,
    };
 
-   MP_REGISTER_MODULE(MP_QSTR_subsystem, mp_module_subsystem, MICROPY_PY_SUBSYSTEM);
+   MP_REGISTER_MODULE(MP_QSTR_subsystem, mp_module_subsystem);
 
    #endif
 
diff --git a/docs/develop/porting.rst b/docs/develop/porting.rst
index d08fd74e4..bc25f47ed 100644
--- a/docs/develop/porting.rst
+++ b/docs/develop/porting.rst
@@ -280,12 +280,7 @@ To add a custom module like ``myport``, first add the module definition in a fil
        .globals = (mp_obj_dict_t *)&myport_module_globals,
    };
 
-   MP_REGISTER_MODULE(MP_QSTR_myport, myport_module, 1);
-
-Note: the "1" as the third argument in ``MP_REGISTER_MODULE`` enables this new module
-unconditionally. To allow it to be conditionally enabled, replace the "1" by
-``MICROPY_PY_MYPORT`` and then add ``#define MICROPY_PY_MYPORT (1)`` in ``mpconfigport.h``
-accordingly.
+   MP_REGISTER_MODULE(MP_QSTR_myport, myport_module);
 
 You will also need to edit the Makefile to add ``modmyport.c`` to the ``SRC_C`` list, and
 a new line adding the same file to ``SRC_QSTR`` (so qstrs are searched for in this new file),