Fix Waveshare 7.5v2 epaper screens are always powered on (esphome#5283)

esphome/components/waveshare_epaper/waveshare_epaper.cpp

@@ -1561,17 +1561,45 @@ void WaveshareEPaper7P5In::dump_config() {
   LOG_PIN("  Busy Pin: ", this->busy_pin_);
   LOG_UPDATE_INTERVAL(this);
 }
+bool WaveshareEPaper7P5InV2::wait_until_idle_() {
+  if (this->busy_pin_ == nullptr) {
+    return true;
+  }
+
+  const uint32_t start = millis();
+  while (this->busy_pin_->digital_read()) {
+    this->command(0x71);
+    if (millis() - start > this->idle_timeout_()) {
+      ESP_LOGE(TAG, "Timeout while displaying image!");
+      return false;
+    }
+    App.feed_wdt();
+    delay(10);
+  }
+  return true;
+}
 void WaveshareEPaper7P5InV2::initialize() {
   // COMMAND POWER SETTING
   this->command(0x01);
   this->data(0x07);
   this->data(0x07);
   this->data(0x3f);
   this->data(0x3f);
-  this->command(0x04);
+
+  // We don't want the display to be powered at this point
 
   delay(100);  // NOLINT
   this->wait_until_idle_();
+
+  // COMMAND VCOM AND DATA INTERVAL SETTING
+  this->command(0x50);
+  this->data(0x10);
+  this->data(0x07);
+
+  // COMMAND TCON SETTING
+  this->command(0x60);
+  this->data(0x22);
+
   // COMMAND PANEL SETTING
   this->command(0x00);
   this->data(0x1F);
@@ -1582,34 +1610,54 @@ void WaveshareEPaper7P5InV2::initialize() {
   this->data(0x20);
   this->data(0x01);
   this->data(0xE0);
-  // COMMAND ...?
+
+  // COMMAND DUAL SPI MM_EN, DUSPI_EN
   this->command(0x15);
   this->data(0x00);
-  // COMMAND VCOM AND DATA INTERVAL SETTING
-  this->command(0x50);
-  this->data(0x10);
-  this->data(0x07);
-  // COMMAND TCON SETTING
-  this->command(0x60);
-  this->data(0x22);
+
+  // COMMAND POWER DRIVER HAT DOWN
+  // This command will turn off booster, controller, source driver, gate driver, VCOM, and
+  // temperature sensor, but register data will be kept until VDD turned OFF or Deep Sleep Mode.
+  // Source/Gate/Border/VCOM will be released to floating.
+  this->command(0x02);
 }
 void HOT WaveshareEPaper7P5InV2::display() {
   uint32_t buf_len = this->get_buffer_length_();
+
+  // COMMAND POWER ON
+  ESP_LOGI(TAG, "Power on the display and hat");
+
+  // This command will turn on booster, controller, regulators, and temperature sensor will be
+  // activated for one-time sensing before enabling booster. When all voltages are ready, the
+  // BUSY_N signal will return to high.
+  this->command(0x04);
+  delay(200);  // NOLINT
+  this->wait_until_idle_();
+
   // COMMAND DATA START TRANSMISSION NEW DATA
   this->command(0x13);
   delay(2);
   for (uint32_t i = 0; i < buf_len; i++) {
     this->data(~(this->buffer_[i]));
   }
 
+  delay(100);  // NOLINT
+  this->wait_until_idle_();
+
   // COMMAND DISPLAY REFRESH
   this->command(0x12);
   delay(100);  // NOLINT
   this->wait_until_idle_();
+
+  ESP_LOGV(TAG, "Before command(0x02) (>> power off)");
+  this->command(0x02);
+  this->wait_until_idle_();
+  ESP_LOGV(TAG, "After command(0x02) (>> power off)");
 }
 
 int WaveshareEPaper7P5InV2::get_width_internal() { return 800; }
 int WaveshareEPaper7P5InV2::get_height_internal() { return 480; }
+uint32_t WaveshareEPaper7P5InV2::idle_timeout_() { return 10000; }
 void WaveshareEPaper7P5InV2::dump_config() {
   LOG_DISPLAY("", "Waveshare E-Paper", this);
   ESP_LOGCONFIG(TAG, "  Model: 7.5inV2rev2");

esphome/components/waveshare_epaper/waveshare_epaper.h

@@ -472,6 +472,8 @@ class WaveshareEPaper7P5InBC : public WaveshareEPaper {
 
 class WaveshareEPaper7P5InV2 : public WaveshareEPaper {
  public:
+  bool wait_until_idle_();
+
   void initialize() override;
 
   void display() override;
@@ -491,6 +493,8 @@ class WaveshareEPaper7P5InV2 : public WaveshareEPaper {
   int get_width_internal() override;
 
   int get_height_internal() override;
+
+  uint32_t idle_timeout_() override;
 };
 
 class WaveshareEPaper7P5InV2alt : public WaveshareEPaper7P5InV2 {