Merge pull request #641 from presslab-us/backlight_fade_cb

Use callback for backlight fade

src/dev/esp32/esp32.cpp

@@ -110,6 +110,8 @@ Esp32Device::Esp32Device()
     _backlight_power  = 1;
     _backlight_level  = 255;
     _backlight_pin    = 255; // not TFT_BCKL because it is unknown at this stage
+    _backlight_pending = false;
+    _backlight_fading = false;
 
     /* fill unique identifier with wifi mac */
     byte mac[6];
@@ -241,6 +243,22 @@ const char* Esp32Device::get_hardware_id()
     return _hardware_id.c_str();
 }
 
+bool Esp32Device::cb_backlight(const ledc_cb_param_t *param, void *user_arg) {
+    reinterpret_cast<Esp32Device*>(user_arg)->end_backlight_fade();
+    return false;
+}
+
+void Esp32Device::end_backlight_fade()
+{
+    if (_backlight_pending) {
+        _backlight_pending = false;
+        _backlight_fading = false;
+        update_backlight(_backlight_fade);
+    } else {
+        _backlight_fading = false;
+    }
+}
+
 void Esp32Device::set_backlight_pin(uint8_t pin)
 {
     _backlight_pin = pin;
@@ -255,6 +273,8 @@ void Esp32Device::set_backlight_pin(uint8_t pin)
 #endif
         ledcAttachPin(pin, BACKLIGHT_CHANNEL);
         ledc_fade_func_install(0);
+        ledc_cbs_t cbs = {cb_backlight};
+        ledc_cb_register(LEDC_LOW_SPEED_MODE, (ledc_channel_t) BACKLIGHT_CHANNEL, &cbs, this);
         update_backlight(false);
     } else {
         LOG_VERBOSE(TAG_GUI, F("Backlight  : Pin not set"));
@@ -275,8 +295,7 @@ bool Esp32Device::get_backlight_invert()
 void Esp32Device::set_backlight_level(uint8_t level)
 {
     _backlight_level = level;
-    // update_backlight(true);
+    update_backlight(true);
-    update_backlight(false);
 }
 
 uint8_t Esp32Device::get_backlight_level()
@@ -287,8 +306,7 @@ uint8_t Esp32Device::get_backlight_level()
 void Esp32Device::set_backlight_power(bool power)
 {
     _backlight_power = power;
-    // update_backlight(true);
+    update_backlight(true);
-    update_backlight(false);
 }
 
 bool Esp32Device::get_backlight_power()
@@ -298,28 +316,36 @@ bool Esp32Device::get_backlight_power()
 
 void Esp32Device::update_backlight(bool fade)
 {
-    static uint32_t last_duty = 0;
     if(_backlight_pin < GPIO_NUM_MAX) {
 #if !defined(CONFIG_IDF_TARGET_ESP32S2)
         uint32_t duty = _backlight_power ? map(_backlight_level, 0, 255, 0, 1023) : 0;
         if(_backlight_invert) duty = 1023 - duty;
-        if(fade) {
+        if(_backlight_fading) {
-            ledcWrite(BACKLIGHT_CHANNEL, last_duty); // this will stop an in-progress fade
+            _backlight_fade = fade;
-            ledc_set_fade_time_and_start(LEDC_LOW_SPEED_MODE, (ledc_channel_t) BACKLIGHT_CHANNEL, duty, BACKLIGHT_FADEMS, LEDC_FADE_NO_WAIT);
+            _backlight_pending = true;
         } else {
-            ledcWrite(BACKLIGHT_CHANNEL, duty); // ledChannel and value
+            if(fade) {
+                _backlight_fading = true;
+                ledc_set_fade_time_and_start(LEDC_LOW_SPEED_MODE, (ledc_channel_t) BACKLIGHT_CHANNEL, duty, BACKLIGHT_FADEMS, LEDC_FADE_NO_WAIT);
+            } else {
+                ledcWrite(BACKLIGHT_CHANNEL, duty); // ledChannel and value
+            }
         }
 #else
         uint32_t duty = _backlight_power ? map(_backlight_level, 0, 255, 0, 1023) : 0;
         if(_backlight_invert) duty = 1023 - duty;
-        if(fade) {
+        if(_backlight_fading) {
-            ledcWrite(BACKLIGHT_CHANNEL, last_duty); // this will stop an in-progress fade
+            _backlight_fade = fade;
-            ledc_set_fade_time_and_start(LEDC_LOW_SPEED_MODE, (ledc_channel_t) BACKLIGHT_CHANNEL, duty, BACKLIGHT_FADEMS, LEDC_FADE_NO_WAIT);
+            _backlight_pending = true;
         } else {
-            ledcWrite(BACKLIGHT_CHANNEL, duty); // ledChannel and value
+            if(fade) {
+                _backlight_fading = true;
+                ledc_set_fade_time_and_start(LEDC_LOW_SPEED_MODE, (ledc_channel_t) BACKLIGHT_CHANNEL, duty, BACKLIGHT_FADEMS, LEDC_FADE_NO_WAIT);
+            } else {
+                ledcWrite(BACKLIGHT_CHANNEL, duty); // ledChannel and value
+            }
         }
 #endif
-        last_duty = duty;
     }
 
     // haspTft.tft.writecommand(0x53); // Write CTRL Display

src/dev/esp32/esp32.h

@@ -6,6 +6,7 @@
 
 #include "hasp_conf.h"
 #include "../device.h"
+#include "driver/ledc.h"
 
 #if defined(ESP32)
 
@@ -68,8 +69,13 @@ class Esp32Device : public BaseDevice {
     uint8_t _backlight_level;
     uint8_t _backlight_power;
     uint8_t _backlight_invert;
+    bool _backlight_pending;
+    bool _backlight_fading;
+    bool _backlight_fade;
 
     void update_backlight(bool fade);
+    static bool cb_backlight(const ledc_cb_param_t *param, void *user_arg);
+    void end_backlight_fade();
 };
 
 } // namespace dev