stm32: Allow a board to disable MICROPY_VFS_FAT.

ports/stm32/modmachine.c

@@ -181,6 +181,7 @@ STATIC mp_obj_t machine_info(size_t n_args, const mp_obj_t *args) {
 
     // free space on flash
     {
+        #if MICROPY_VFS_FAT
         for (mp_vfs_mount_t *vfs = MP_STATE_VM(vfs_mount_table); vfs != NULL; vfs = vfs->next) {
             if (strncmp("/flash", vfs->str, vfs->len) == 0) {
                 // assumes that it's a FatFs filesystem
@@ -191,6 +192,7 @@ STATIC mp_obj_t machine_info(size_t n_args, const mp_obj_t *args) {
                 break;
             }
         }
+        #endif
     }
 
     #if MICROPY_PY_THREAD

ports/stm32/moduos.c

@@ -82,10 +82,12 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(os_uname_obj, os_uname);
 /// \function sync()
 /// Sync all filesystems.
 STATIC mp_obj_t os_sync(void) {
+    #if MICROPY_VFS_FAT
     for (mp_vfs_mount_t *vfs = MP_STATE_VM(vfs_mount_table); vfs != NULL; vfs = vfs->next) {
         // this assumes that vfs->obj is fs_user_mount_t with block device functions
         disk_ioctl(MP_OBJ_TO_PTR(vfs->obj), CTRL_SYNC, NULL);
     }
+    #endif
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_0(mod_os_sync_obj, os_sync);
@@ -148,7 +150,9 @@ STATIC const mp_rom_map_elem_t os_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_dupterm), MP_ROM_PTR(&uos_dupterm_obj) },
     { MP_ROM_QSTR(MP_QSTR_mount), MP_ROM_PTR(&mp_vfs_mount_obj) },
     { MP_ROM_QSTR(MP_QSTR_umount), MP_ROM_PTR(&mp_vfs_umount_obj) },
+    #if MICROPY_VFS_FAT
     { MP_ROM_QSTR(MP_QSTR_VfsFat), MP_ROM_PTR(&mp_fat_vfs_type) },
+    #endif
 };
 
 STATIC MP_DEFINE_CONST_DICT(os_module_globals, os_module_globals_table);

ports/stm32/mpconfigport.h

@@ -76,7 +76,9 @@
 #define MICROPY_ENABLE_SCHEDULER    (1)
 #define MICROPY_SCHEDULER_DEPTH     (8)
 #define MICROPY_VFS                 (1)
+#ifndef MICROPY_VFS_FAT
 #define MICROPY_VFS_FAT             (1)
+#endif
 
 // control over Python builtins
 #define MICROPY_PY_FUNCTION_ATTRS   (1)
@@ -103,7 +105,7 @@
 #define MICROPY_PY_MATH_SPECIAL_FUNCTIONS (1)
 #define MICROPY_PY_CMATH            (1)
 #define MICROPY_PY_IO               (1)
-#define MICROPY_PY_IO_FILEIO        (1)
+#define MICROPY_PY_IO_FILEIO        (MICROPY_VFS_FAT) // because mp_type_fileio/textio point to fatfs impl
 #define MICROPY_PY_SYS_MAXSIZE      (1)
 #define MICROPY_PY_SYS_EXIT         (1)
 #define MICROPY_PY_SYS_STDFILES     (1)