GxEPD2-esphome/components/gxepd2/display.py

"""ESPHome display platform driving a GxEPD2 panel via a native chunked
refresh engine (see cycle_engine.h) instead of GxEPD2's own C++ classes.

Panels are selected via `model:`, each backed by a hand-written (later,
extracted) EpdPanelDescriptor - see panel_213_z98c.h / panel_426_gdeq0426t82.h
/ panel_583_gdeq0583t31.h. catalog.json/vendor/arduino_compat stay in the
tree as reference material for panels not yet ported to this engine.
"""

import re

import esphome.codegen as cg
import esphome.config_validation as cv
from esphome import pins
from esphome.components import display, font, spi
from esphome.const import (
    CONF_BUSY_PIN,
    CONF_CS_PIN,
    CONF_DC_PIN,
    CONF_ID,
    CONF_LAMBDA,
    CONF_MODEL,
    CONF_RESET_PIN,
    CONF_SPI_ID,
    Framework,
)
from esphome.types import ConfigType

CODEOWNERS = ["@zib"]
DEPENDENCIES = ["spi"]

# When true, the 1bpp (mono / BW+accent) draw path treats a *bright* color as
# ink and a *dark* color as background, instead of the literal RGB mapping
# (bright = white = blank). This exists only to ease conversion from
# ESPHome's LCD-rooted color model: its drawing primitives default to
# COLOR_ON = white, so with the literal mapping a default-color it.print()
# draws nothing. We can't tell a defaulted COLOR_ON from an explicit white
# (the default is compiled into the user's lambda as a constant), so the only
# lever is this wholesale mono inversion - the same thing waveshare_epaper
# bakes in. Default false (native, literal RGB); a future waveshare model
# alias will flip the *default* to true, but an explicit setting always wins.
# No effect on 2bpp/4bpp packed panels - there the palette maps literal RGB.
CONF_INVERT_MONO = "invert_mono"

# Optional font for the on-screen panel label test_pattern() draws (the model
# trailer, e.g. "GDEQ0583T31"). A normal ESPHome font:, so the builder can
# pull one from gfonts:// - no font, no label. See GxEPD2Display::test_pattern.
CONF_NAME_FONT = "name_font"

gxepd2_ns = cg.esphome_ns.namespace("gxepd2")
GxEPD2Display = gxepd2_ns.class_("GxEPD2Display", display.DisplayBuffer)

# model name -> (C++ descriptor global declared in the matching panel_*.h
# header - gxepd2_display.h includes them all, so no extra include wiring here;
# Good Display part number on the panel's silkscreen).
#
# The part number, not the GxEPD2 class name, is the source of truth for the
# on-screen label (see _panel_label / test_pattern): GxEPD2's older naming
# style drops the GDEx prefix and the 4-digit size - GxEPD2_213_Z98C is really
# GDEY0213Z98 - so the class name alone can't reconstruct what's on the tag.
MODELS = {
    "GxEPD2_213_Z98C": ("PANEL_213_Z98C", "GDEY0213Z98"),
    "GxEPD2_426_GDEQ0426T82": ("PANEL_426_GDEQ0426T82", "GDEQ0426T82"),
    "GxEPD2_583_GDEQ0583T31": ("PANEL_583_GDEQ0583T31", "GDEQ0583T31"),
    "GxEPD2_290c_GDEY029F51": ("PANEL_290C_GDEY029F51", "GDEY029F51"),
    "GxEPD2_579c_GDEY0579F51": ("PANEL_579C_GDEY0579F51", "GDEY0579F51"),
    # Debug variant: master half only, as if it were a self-contained
    # 396x272 panel - see panel_579c_gdey0579f51_master_only.h. Kept
    # around as a diagnostic tool, not the panel's real mode. Same physical
    # part as the full panel, so same label.
    "GxEPD2_579c_GDEY0579F51_MASTER_ONLY": ("PANEL_579C_GDEY0579F51_MASTER_ONLY", "GDEY0579F51"),
}


# Good Display part number -> shelf label: drop the 4-char GDEx series prefix,
# keeping just the size + type (GDEQ0583T31 -> 0583T31, GDEY0213Z98 ->
# 0213Z98). The GDEx series/generation letter encodes nothing we act on and
# costs scarce width on small panels; size stays encoded once, in the digits.
# Anything not starting with GDE<letter> is returned untouched.
def _panel_label(part: str) -> str:
    return re.sub(r"^GDE[A-Z]", "", part)

CONFIG_SCHEMA = cv.All(
    display.FULL_DISPLAY_SCHEMA.extend(
        {
            cv.GenerateID(): cv.declare_id(GxEPD2Display),
            cv.GenerateID(CONF_SPI_ID): cv.use_id(spi.SPIComponent),
            cv.Required(CONF_MODEL): cv.one_of(*MODELS),
            cv.Required(CONF_CS_PIN): pins.gpio_output_pin_schema,
            cv.Required(CONF_DC_PIN): pins.gpio_output_pin_schema,
            cv.Optional(CONF_RESET_PIN): pins.gpio_output_pin_schema,
            cv.Optional(CONF_BUSY_PIN): pins.gpio_input_pin_schema,
            # No schema default: absence falls to the alias-derived default in
            # to_code() (just False today; true for a waveshare alias once that
            # lands), while an explicit value always wins.
            cv.Optional(CONF_INVERT_MONO): cv.boolean,
            cv.Optional(CONF_NAME_FONT): cv.use_id(font.Font),
        }
    ),
    # IDF-first, but the runtime C++ uses only framework-portable ESPHome
    # abstractions (spi::SPIDevice, GPIOPin, hal.h, RAMAllocator, ESP_LOG*) -
    # the old IDF-only gate was a leftover from the superseded FreeRTOS-task
    # design. ESP32-Arduino is a supported accommodation; ESP8266-Arduino
    # compiles too but is resolution-restricted at 1bpp and lacks the PSRAM
    # that >1bpp (color) panels need, so those fail allocation at runtime.
    cv.only_with_framework([Framework.ESP_IDF, Framework.ARDUINO]),
)


async def to_code(config: ConfigType) -> None:
    var = cg.new_Pvariable(config[CONF_ID])

    descriptor, part_number = MODELS[config[CONF_MODEL]]
    cg.add(var.set_descriptor(cg.RawExpression(f"&esphome::gxepd2::{descriptor}")))
    cg.add(var.set_cs_pin(await cg.gpio_pin_expression(config[CONF_CS_PIN])))
    cg.add(var.set_dc_pin(await cg.gpio_pin_expression(config[CONF_DC_PIN])))
    if reset_pin := config.get(CONF_RESET_PIN):
        cg.add(var.set_reset_pin(await cg.gpio_pin_expression(reset_pin)))
    if busy_pin := config.get(CONF_BUSY_PIN):
        cg.add(var.set_busy_pin(await cg.gpio_pin_expression(busy_pin)))

    spi_parent = await cg.get_variable(config[CONF_SPI_ID])
    cg.add(var.set_spi_parent(spi_parent))

    # Alias-derived default is just False for now; the waveshare-compat layer
    # will compute it from the (aliased) model. An explicit invert_mono wins.
    cg.add(var.set_invert_mono(config.get(CONF_INVERT_MONO, False)))

    # Panel label for test_pattern(): the Good Display part number in the
    # vendor's dashed silkscreen form (GDEQ-0583T31), so a tested panel shows
    # what it is on the shelf, not the GxEPD2 C++ class id.
    cg.add(var.set_model_name(_panel_label(part_number)))
    if name_font := config.get(CONF_NAME_FONT):
        cg.add(var.set_name_font(await cg.get_variable(name_font)))

    # display.register_display() only wires up `pages:` - a bare top-level
    # `lambda:` (what our CONFIG_SCHEMA actually supports) has to be
    # processed and attached via set_writer() by the platform itself, same
    # as every other display component's to_code() (see e.g. epaper_spi's
    # display.py). Missing this meant the configured lambda never ran at
    # all - the only thing ever drawn was auto_clear's default
    # fill(COLOR_OFF), which is why every real-hardware run came out solid
    # black regardless of any protocol-level change.
    if CONF_LAMBDA in config:
        lambda_ = await cg.process_lambda(config[CONF_LAMBDA], [(display.DisplayRef, "it")], return_type=cg.void)
        cg.add(var.set_writer(lambda_))

    await display.register_display(var, config)