Reset the Elecrow's GT911 the way Elecrow's own V3.0 example does (0.2.96, firmware 0.2.82)

The 2 ms reset of ESPHome's expander support (0.2.81) left the chip silent: "Calibration error" with the PCA9557
answering at 0x18. A component of smart_display's (elecrow_touch_reset.h, setup priority 700: after the I2C bus,
before the GT911 driver) writes the expander as Elecrow's V3.0 ESPHome example does: every pin an output and low,
20 ms, the reset released, 100 ms, the interrupt line back to an input. The driver's reset and interrupt pins are gone.

components/smart_display/__init__.py

@@ -7,12 +7,16 @@ into a screen's YAML.
 
 `smart_display: partitions: 4mb_wide_slots` (firmware 0.2.79) builds with one of the partition tables of partitions.py
 instead of ESPHome's own: two update slots of 1,984 KB on a 4 MB ESP32-S3, which the Elecrow CrowPanel 7.0" needs.
+
+`smart_display: elecrow_touch_reset: {i2c_id: ..., address: 0x18}` (firmware 0.2.82) brings the GT911 of the Elecrow
+CrowPanel 7.0" V3.0 out of reset through its PCA9557 before the touch driver runs (elecrow_touch_reset.h).
 """
 import logging
 
 import esphome.codegen as cg
-from esphome.components import esp32
+from esphome.components import esp32, i2c
 import esphome.config_validation as cv
+from esphome.const import CONF_ID
 from esphome.core import CORE
 from esphome.helpers import write_file_if_changed
 
@@ -24,6 +28,10 @@ _LOGGER = logging.getLogger(__name__)
 
 CONF_LANGUAGE = "language"
 CONF_PARTITIONS = "partitions"
+CONF_ELECROW_TOUCH_RESET = "elecrow_touch_reset"
+
+elecrow_ns = cg.global_ns.namespace("elecrow")
+TouchReset = elecrow_ns.class_("TouchReset", cg.Component, i2c.I2CDevice)
 
 
 def _language(value):
@@ -36,6 +44,8 @@ def _language(value):
 CONFIG_SCHEMA = cv.Schema({
     cv.Optional(CONF_LANGUAGE, default="en"): _language,
     cv.Optional(CONF_PARTITIONS): cv.one_of(*partitions.TABLES, lower=True),
+    cv.Optional(CONF_ELECROW_TOUCH_RESET): cv.Schema({cv.GenerateID(): cv.declare_id(TouchReset)})
+    .extend(cv.COMPONENT_SCHEMA).extend(i2c.i2c_device_schema(0x18)),
 })
 
 
@@ -51,3 +61,9 @@ async def to_code(config):
         table = CORE.relative_build_path("smart_display_partitions.csv")
         write_file_if_changed(table, partitions.TABLES[config[CONF_PARTITIONS]])
         esp32.add_extra_build_file("partitions.csv", table)
+    if CONF_ELECROW_TOUCH_RESET in config:
+        conf = config[CONF_ELECROW_TOUCH_RESET]
+        reset = cg.new_Pvariable(conf[CONF_ID])
+        await cg.register_component(reset, conf)
+        await i2c.register_i2c_device(reset, conf)
+        cg.add_build_flag("-DESP_SCREENS_ELECROW_TOUCH_RESET=1")

components/smart_display/elecrow_touch_reset.h

@@ -0,0 +1,41 @@
+#pragma once
+// The GT911 of the Elecrow CrowPanel 7.0" V3.0 hangs on a PCA9557 I/O expander (I2C 0x18): IO0 is its reset, IO1 its
+// interrupt line, and it stays in reset until something drives them (firmware 0.2.82). This is Elecrow's own sequence
+// from their V3.0 ESPHome example, byte for byte: every expander pin an output and low (the reset held, the interrupt
+// line low so the chip takes address 0x5D), 20 ms, the reset released, 100 ms for the chip to come up, then the
+// interrupt line back to an input. It runs after the I2C bus is up and before the GT911 driver looks for the chip
+// (setup priority 700, between the bus's 1000 and the driver's 600), so the driver finds it at 0x5D. A V2.0 board
+// has no expander: the writes fail, the log says so, and the GT911 boots by its pull-up as before.
+//
+// Only the Elecrow's board file builds this (`smart_display: elecrow_touch_reset:`, which sets the flag), so the
+// header adds nothing to a CYD, which has no I2C at all.
+#if defined(ESP_SCREENS_ELECROW_TOUCH_RESET) && ESP_SCREENS_ELECROW_TOUCH_RESET
+#include "esphome/components/i2c/i2c.h"
+#include "esphome/core/component.h"
+#include "esphome/core/hal.h"
+#include "esphome/core/log.h"
+
+namespace elecrow {
+class TouchReset : public esphome::Component, public esphome::i2c::I2CDevice {
+ public:
+  float get_setup_priority() const override { return 700.0f; }
+  void setup() override {
+    auto write = [this](uint8_t reg, uint8_t value) {
+      const uint8_t data[2] = {reg, value};
+      return this->write(data, sizeof(data)) == esphome::i2c::ERROR_OK;
+    };
+    bool ok = write(0x03, 0x00);          // configuration: every pin an output
+    ok = write(0x01, 0x00) && ok;         // output: reset low, interrupt low (address 0x5D), the rest low
+    esphome::delay(20);
+    ok = write(0x01, 0x01) && ok;         // reset released, the interrupt line still low
+    esphome::delay(100);
+    ok = write(0x03, 0x02) && ok;         // the interrupt line an input again; the GT911 drives it from here
+    if (ok) {
+      ESP_LOGI("touch", "GT911 reset through the PCA9557 at 0x%02X", this->address_);
+    } else {
+      ESP_LOGW("touch", "No PCA9557 at 0x%02X: the GT911 was not reset (a V2.0 board boots it by its pull-up)", this->address_);
+    }
+  }
+};
+}  // namespace elecrow
+#endif