Fix SSD1306 post-setup brightness control (#1090)

* Fix post-setup brightness control

* Add turn_on() and turn_off() methods

* Added is_on() method

* Set brightness later in setup()

* Use clamp() for brightness validation

esphome/components/ssd1306_base/__init__.py

@@ -41,7 +41,7 @@ def setup_ssd1036(var, config):
         reset = yield cg.gpio_pin_expression(config[CONF_RESET_PIN])
         cg.add(var.set_reset_pin(reset))
     if CONF_BRIGHTNESS in config:
-        cg.add(var.set_brightness(config[CONF_BRIGHTNESS]))
+        cg.add(var.init_brightness(config[CONF_BRIGHTNESS]))
     if CONF_EXTERNAL_VCC in config:
         cg.add(var.set_external_vcc(config[CONF_EXTERNAL_VCC]))
     if CONF_LAMBDA in config:

esphome/components/ssd1306_base/ssd1306_base.cpp

@@ -5,7 +5,11 @@
 namespace esphome {
 namespace ssd1306_base {
 
-static const char *TAG = "sd1306";
+static const char *TAG = "ssd1306";
+
+static const uint8_t BLACK = 0;
+static const uint8_t WHITE = 1;
+static const uint8_t SSD1306_MAX_CONTRAST = 255;
 
 static const uint8_t SSD1306_COMMAND_DISPLAY_OFF = 0xAE;
 static const uint8_t SSD1306_COMMAND_DISPLAY_ON = 0xAF;
@@ -69,27 +73,6 @@ void SSD1306::setup() {
       break;
   }
 
-  this->command(SSD1306_COMMAND_SET_CONTRAST);
-  switch (this->model_) {
-    case SSD1306_MODEL_128_32:
-    case SH1106_MODEL_128_32:
-      this->command(0x8F);
-      break;
-    case SSD1306_MODEL_128_64:
-    case SH1106_MODEL_128_64:
-    case SSD1306_MODEL_64_48:
-    case SH1106_MODEL_64_48:
-      this->command(int(255 * (this->brightness_)));
-      break;
-    case SSD1306_MODEL_96_16:
-    case SH1106_MODEL_96_16:
-      if (this->external_vcc_)
-        this->command(0x10);
-      else
-        this->command(0xAF);
-      break;
-  }
-
   this->command(SSD1306_COMMAND_SET_PRE_CHARGE);
   if (this->external_vcc_)
     this->command(0x22);
@@ -104,7 +87,12 @@ void SSD1306::setup() {
 
   this->command(SSD1306_COMMAND_DEACTIVATE_SCROLL);
 
-  this->command(SSD1306_COMMAND_DISPLAY_ON);
+  set_brightness(this->brightness_);
+
+  this->fill(BLACK);  // clear display - ensures we do not see garbage at power-on
+  this->display();    // ...write buffer, which actually clears the display's memory
+
+  this->turn_on();
 }
 void SSD1306::display() {
   if (this->is_sh1106_()) {
@@ -140,6 +128,22 @@ void SSD1306::update() {
   this->do_update_();
   this->display();
 }
+void SSD1306::set_brightness(float brightness) {
+  // validation
+  this->brightness_ = clamp(brightness, 0, 1);
+  // now write the new brightness level to the display
+  this->command(SSD1306_COMMAND_SET_CONTRAST);
+  this->command(int(SSD1306_MAX_CONTRAST * (this->brightness_)));
+}
+bool SSD1306::is_on() { return this->is_on_; }
+void SSD1306::turn_on() {
+  this->command(SSD1306_COMMAND_DISPLAY_ON);
+  this->is_on_ = true;
+}
+void SSD1306::turn_off() {
+  this->command(SSD1306_COMMAND_DISPLAY_OFF);
+  this->is_on_ = false;
+}
 int SSD1306::get_height_internal() {
   switch (this->model_) {
     case SSD1306_MODEL_128_32:
@@ -178,7 +182,6 @@ int SSD1306::get_width_internal() {
 size_t SSD1306::get_buffer_length_() {
   return size_t(this->get_width_internal()) * size_t(this->get_height_internal()) / 8u;
 }
-
 void HOT SSD1306::draw_absolute_pixel_internal(int x, int y, Color color) {
   if (x >= this->get_width_internal() || x < 0 || y >= this->get_height_internal() || y < 0)
     return;

esphome/components/ssd1306_base/ssd1306_base.h

@@ -29,8 +29,11 @@ class SSD1306 : public PollingComponent, public display::DisplayBuffer {
   void set_model(SSD1306Model model) { this->model_ = model; }
   void set_reset_pin(GPIOPin *reset_pin) { this->reset_pin_ = reset_pin; }
   void set_external_vcc(bool external_vcc) { this->external_vcc_ = external_vcc; }
-  void set_brightness(float brightness) { this->brightness_ = brightness; }
+  void init_brightness(float brightness) { this->brightness_ = brightness; }
-
+  void set_brightness(float brightness);
+  bool is_on();
+  void turn_on();
+  void turn_off();
   float get_setup_priority() const override { return setup_priority::PROCESSOR; }
   void fill(Color color) override;
 
@@ -51,6 +54,7 @@ class SSD1306 : public PollingComponent, public display::DisplayBuffer {
   SSD1306Model model_{SSD1306_MODEL_128_64};
   GPIOPin *reset_pin_{nullptr};
   bool external_vcc_{false};
+  bool is_on_{false};
   float brightness_{1.0};
 };