micropython.mk

# CircuitPython user C module glue for LVGL and its generated bindings.
#
# CircuitPython builds user C modules the way MicroPython does, so this
# directory can be handed to any CircuitPython port's make as is, with no
# patches to CircuitPython's own tree:
#
#   make -C ports/unix USER_C_MODULES=/path/to/lvgl-circuitpython
#   make -C ports/raspberrypi BOARD=adafruit_feather_rp2040 CIRCUITPY_GIFIO=0 \
#       USER_C_MODULES=/path/to/lvgl-circuitpython
#
# On a board, CIRCUITPY_GIFIO=0 goes on the make line: LVGL links its own
# copy of the AnimatedGIF decoder (LV_USE_GIF in lvgl-bindings' lv_conf.h),
# and CircuitPython's gifio links another, so the two collide at link time.
# The unix port compiles no gifio and needs nothing.

LVCP_DIR := $(USERMOD_DIR)
# $(abspath) tidies ".." in the text without following symlinks, so look beside
# the real directory.
LVCP_REAL := $(realpath $(LVCP_DIR))

ifeq ($(wildcard $(TOP)/py/circuitpy_mpconfig.h),)
$(error lvgl-circuitpython is for CircuitPython builds; MicroPython builds use lvgl-micropython)
endif

ifeq ($(CIRCUITPY_GIFIO),1)
$(error lvgl-circuitpython: add CIRCUITPY_GIFIO=0 to the make line. LVGL links its own AnimatedGIF decoder, which collides with gifio's)
endif

# Where lvgl-bindings comes from, first match wins:
#   1. LV_BINDINGS_DIR, from make's command line or the environment;
#   2. an lvgl-bindings checkout beside this one (beside the directory this
#      one really is: a build that hands the module over through a symlink
#      still finds it);
#   3. the commit in LVGL_BINDINGS_COMMIT, fetched into .deps/ with only what
#      this module compiles (a clone on its own).
# The first two build the checkout as it is: if it isn't at the pinned commit,
# the build says so and carries on. Only the fetched copy must match the pin.
ifneq ($(strip $(LV_BINDINGS_DIR)),)
LV_BINDINGS_DIR := $(abspath $(LV_BINDINGS_DIR))
LVCP_BINDINGS_FROM := LV_BINDINGS_DIR
ifeq ($(wildcard $(LV_BINDINGS_DIR)/lv_conf.h),)
$(error lvgl-circuitpython: LV_BINDINGS_DIR=$(LV_BINDINGS_DIR) is not an lvgl-bindings checkout (no lv_conf.h))
endif
else ifneq ($(wildcard $(LVCP_REAL)/../lvgl-bindings/lv_conf.h),)
LV_BINDINGS_DIR := $(abspath $(LVCP_REAL)/../lvgl-bindings)
LVCP_BINDINGS_FROM := the lvgl-bindings beside lvgl-circuitpython
else
LV_BINDINGS_DIR := $(abspath $(LVCP_DIR)/.deps/lvgl-bindings)
LVCP_BINDINGS_FROM := pin
LVCP_FETCH := $(shell bash $(LVCP_DIR)/scripts/fetch_bindings.sh 1>&2; echo $$?)
ifeq ($(wildcard $(LV_BINDINGS_DIR)/lv_conf.h),)
$(error lvgl-circuitpython: fetching lvgl-bindings failed (scripts/fetch_bindings.sh exit $(LVCP_FETCH)); set LV_BINDINGS_DIR to an lvgl-bindings checkout)
endif
endif

LVGL_DIR := $(LV_BINDINGS_DIR)/lvgl
LVCP_C := $(LV_BINDINGS_DIR)/generated/lvgl_circuitpython.c
LVCP_H := $(LV_BINDINGS_DIR)/generated/lvgl_circuitpython.h
LV_BINDINGS_PIN := $(strip $(shell cat $(LVCP_DIR)/LVGL_BINDINGS_COMMIT 2>/dev/null))
ifeq ($(LV_BINDINGS_PIN),)
$(error Missing $(LVCP_DIR)/LVGL_BINDINGS_COMMIT)
endif
# 1 when the binding inputs are exactly the pinned commit's, with nothing
# uncommitted on top.
LV_BINDINGS_AT_PIN := $(shell \
	git -C $(LV_BINDINGS_DIR) cat-file -e $(LV_BINDINGS_PIN)^{commit} 2>/dev/null && \
	git -C $(LV_BINDINGS_DIR) diff --quiet $(LV_BINDINGS_PIN) -- generated/lvgl_circuitpython.c generated/lvgl_circuitpython.h lvgl lv_conf.h && \
	git -C $(LV_BINDINGS_DIR) diff --quiet -- generated/lvgl_circuitpython.c generated/lvgl_circuitpython.h lvgl lv_conf.h && echo 1)
ifeq ($(LV_BINDINGS_AT_PIN),)
ifeq ($(LVCP_BINDINGS_FROM),pin)
$(error $(LV_BINDINGS_DIR) does not match pinned binding inputs $(LV_BINDINGS_PIN); delete it and build again to refetch)
endif
LV_BINDINGS_HEAD := $(shell git -C $(LV_BINDINGS_DIR) describe --always --dirty --abbrev=12 2>/dev/null || echo "not a git checkout")
$(info lvgl-circuitpython: note: building lvgl-bindings from $(LV_BINDINGS_DIR) ($(LVCP_BINDINGS_FROM)) at $(LV_BINDINGS_HEAD),)
$(info whose generated binding, lvgl or lv_conf.h differ from LVGL_BINDINGS_COMMIT $(LV_BINDINGS_PIN). Building it as it is.)
endif
$(if $(wildcard $(LVCP_C)),,$(error $(LVCP_C) not found. Run $(LV_BINDINGS_DIR)/regenerate_all.sh --target circuitpython))
$(if $(wildcard $(LVCP_H)),,$(error $(LVCP_H) not found. Run $(LV_BINDINGS_DIR)/regenerate_all.sh --target circuitpython))

# LVGL itself. Its host backends (SDL, X11, Wayland, OpenGL ES, ...) need host
# libraries and are left out of board builds; on unix each compiles to nothing
# unless lv_conf.h turns it on.
LVCP_LVGL_SOURCES := $(shell find $(LVGL_DIR)/src -type f -name '*.c')
ifeq ($(findstring /ports/unix,$(abspath $(CURDIR))),)
LVCP_EXCLUDE_DIRS := \
	$(LVGL_DIR)/src/drivers/opengles \
	$(LVGL_DIR)/src/drivers/sdl \
	$(LVGL_DIR)/src/drivers/glfw \
	$(LVGL_DIR)/src/drivers/x11 \
	$(LVGL_DIR)/src/drivers/wayland \
	$(LVGL_DIR)/src/drivers/evdev \
	$(LVGL_DIR)/src/drivers/libinput \
	$(LVGL_DIR)/src/drivers/qnx \
	$(LVGL_DIR)/src/drivers/uefi \
	$(LVGL_DIR)/src/drivers/nuttx \
	$(LVGL_DIR)/src/drivers/windows \
	$(LVGL_DIR)/src/draw/opengles \
	$(LVGL_DIR)/src/libs/gltf
LVCP_LVGL_SOURCES := $(foreach s,$(LVCP_LVGL_SOURCES),$(if $(strip $(foreach d,$(LVCP_EXCLUDE_DIRS),$(findstring $(d)/,$(s)))),,$(s)))
endif

# LVGL has no MP_QSTR_* in it, so it goes in SRC_USERMOD_LIB_C, which py.mk
# compiles and links but never scans for qstrs. Scanning it would only cost
# time, and on espressif the scan's command line passes the kernel's limit.
SRC_USERMOD_LIB_C += $(LVCP_LVGL_SOURCES)

# The CircuitPython side: the module (registered with MP_REGISTER_MODULE in
# shared-bindings/lvgl/__init__.c), the generated bindings, LVGL's allocator on
# CircuitPython's heap, LVGL's JPEG decoder on CircuitPython's TJpgDec (a no-op
# without jpegio), and what an LVGL assertion does (safe mode, not a hang).
# These are scanned for qstrs.
LVCP_SPIKE := $(LVCP_DIR)/src/circuitpython_spike
LVCP_SOURCES := \
	$(LVCP_SPIKE)/shared-bindings/lvgl/__init__.c \
	$(LVCP_SPIKE)/shared-module/lvgl/__init__.c \
	$(LVCP_DIR)/src/lv_mem_core_circuitpython.c \
	$(LVCP_DIR)/src/lv_jpegio_decoder_circuitpython.c \
	$(LVCP_DIR)/src/lv_assert_circuitpython.c \
	$(LVCP_C)
SRC_USERMOD_C += $(LVCP_SOURCES)

# The spike includes "shared-bindings/lvgl/__init__.h"; CircuitPython's own
# -I$(TOP) comes first and has no lvgl/, so these resolve to the spike's.
# LV_CIRCUITPYTHON_BUILD picks the allocator above in lv_conf.h and leaves
# lvgl.init()/deinit() to the spike.
CFLAGS_USERMOD += -DLV_CIRCUITPYTHON_BUILD=1 -I$(LVCP_SPIKE) -I$(LV_BINDINGS_DIR) -I$(LVGL_DIR) -Wno-unused-function

# LVGL's bindings bring about 53 KB of qstrs. CircuitPython 11 keeps a ROM qstr
# pool's strings in one blob addressed by 16-bit offsets, 64 KB at most, which
# a board's own modules and LVGL together pass. Where CircuitPython has the
# MICROPY_QSTR_OFFSET_BYTES setting, four-byte offsets lift that limit for
# about two bytes of flash per qstr.
CFLAGS_USERMOD += -DMICROPY_QSTR_OFFSET_BYTES=4

# Upstream LVGL and the generated bindings trip warnings CircuitPython's ports
# make errors of, and the board ports append those -Werror flags after
# CFLAGS_USERMOD, so a module-wide -Wno-* would lose. A target-specific flag
# lands last, so they are turned off per object, for this module's objects
# only. -Wfloat-equal, -Wdouble-promotion and -Wcast-align are the board
# ports' (arc and chart compare floats directly); the rest are LVGL's style.
LVCP_OBJ_CFLAGS := -Wno-cast-align -Wno-nested-externs -Wno-unused-parameter \
	-Wno-sign-compare -Wno-missing-prototypes -Wno-old-style-definition \
	-Wno-float-conversion -Wno-double-promotion -Wno-shadow -Wno-type-limits \
	-Wno-suggest-attribute=format -Wno-float-equal -Wno-unused-const-variable \
	-Wno-unused-but-set-variable -Wno-unused-function -Wno-undef

# py.mk names a user module's object $(BUILD)/<module dir name>/<path inside
# it>.o, and a source outside the module (lvgl-bindings beside it)
# $(BUILD)/<absolute path>.o. Both spellings are declared.
LVCP_OBJ = $(BUILD)/$(patsubst $(LVCP_DIR)/%,$(notdir $(LVCP_DIR))/%,$(1)) $(BUILD)/$(1)
$(foreach _s,$(LVCP_LVGL_SOURCES) $(LVCP_SOURCES),\
	$(eval $(call LVCP_OBJ,$(_s:.c=.o)): CFLAGS += $(LVCP_OBJ_CFLAGS)))