Merge 1d0df29b2c into 3a0d673df4

When turning off the screen, if there is no actual app loaded (i.e. we
are still in the Launcher, Notifications, QuickSettings, or Settings
screens) we should just reload the Clock app directly.

src/components/brightness/BrightnessController.cpp

@@ -2,38 +2,138 @@
 #include <hal/nrf_gpio.h>
 #include "displayapp/screens/Symbols.h"
 #include "drivers/PinMap.h"
+#include <libraries/delay/nrf_delay.h>
 using namespace Pinetime::Controllers;
 
+namespace {
+  // reinterpret_cast is not constexpr so this is the best we can do
+  static NRF_RTC_Type* const RTC = reinterpret_cast<NRF_RTC_Type*>(NRF_RTC2_BASE);
+}
+
 void BrightnessController::Init() {
   nrf_gpio_cfg_output(PinMap::LcdBacklightLow);
   nrf_gpio_cfg_output(PinMap::LcdBacklightMedium);
   nrf_gpio_cfg_output(PinMap::LcdBacklightHigh);
+
+  nrf_gpio_pin_clear(PinMap::LcdBacklightLow);
+  nrf_gpio_pin_clear(PinMap::LcdBacklightMedium);
+  nrf_gpio_pin_clear(PinMap::LcdBacklightHigh);
+
+  static_assert(timerFrequency == 32768, "Change the prescaler below");
+  RTC->PRESCALER = 0;
+  // CC1 switches the backlight on (pin transitions from high to low) and resets the counter to 0
+  RTC->CC[1] = timerPeriod;
+  // Enable compare events for CC0,CC1
+  RTC->EVTEN = 0b0000'0000'0000'0011'0000'0000'0000'0000;
+  // Disable all interrupts
+  RTC->INTENCLR = 0b0000'0000'0000'1111'0000'0000'0000'0011;
   Set(level);
 }
 
+void BrightnessController::ApplyBrightness(uint16_t rawBrightness) {
+  // The classic off, low, medium, high brightnesses are at {0, timerPeriod, timerPeriod*2, timerPeriod*3}
+  // These brightness levels do not use PWM: they only set/clear the corresponding pins
+  // Any brightness level between the above levels is achieved with efficient RTC based PWM on the next pin up
+  // E.g 2.5*timerPeriod corresponds to medium brightness with 50% PWM on the high pin
+  // Note: Raw brightness does not necessarily correspond to a linear perceived brightness
+
+  uint8_t pin;
+  if (rawBrightness > 2 * timerPeriod) {
+    rawBrightness -= 2 * timerPeriod;
+    pin = PinMap::LcdBacklightHigh;
+  } else if (rawBrightness > timerPeriod) {
+    rawBrightness -= timerPeriod;
+    pin = PinMap::LcdBacklightMedium;
+  } else {
+    pin = PinMap::LcdBacklightLow;
+  }
+  if (rawBrightness == timerPeriod || rawBrightness == 0) {
+    if (lastPin != UNSET) {
+      RTC->TASKS_STOP = 1;
+      nrf_delay_us(rtcStopTime);
+      nrf_ppi_channel_disable(ppiBacklightOff);
+      nrf_ppi_channel_disable(ppiBacklightOn);
+      nrfx_gpiote_out_uninit(lastPin);
+      nrf_gpio_cfg_output(lastPin);
+    }
+    lastPin = UNSET;
+    if (rawBrightness == 0) {
+      nrf_gpio_pin_set(pin);
+    } else {
+      nrf_gpio_pin_clear(pin);
+    }
+  } else {
+    // If the pin on which we are doing PWM is changing
+    // Disable old PWM channel (if exists) and set up new one
+    if (lastPin != pin) {
+      if (lastPin != UNSET) {
+        RTC->TASKS_STOP = 1;
+        nrf_delay_us(rtcStopTime);
+        nrf_ppi_channel_disable(ppiBacklightOff);
+        nrf_ppi_channel_disable(ppiBacklightOn);
+        nrfx_gpiote_out_uninit(lastPin);
+        nrf_gpio_cfg_output(lastPin);
+      }
+      nrfx_gpiote_out_config_t gpioteCfg = {.action = NRF_GPIOTE_POLARITY_TOGGLE,
+                                            .init_state = NRF_GPIOTE_INITIAL_VALUE_LOW,
+                                            .task_pin = true};
+      APP_ERROR_CHECK(nrfx_gpiote_out_init(pin, &gpioteCfg));
+      nrfx_gpiote_out_task_enable(pin);
+      nrf_ppi_channel_endpoint_setup(ppiBacklightOff,
+                                     reinterpret_cast<uint32_t>(&RTC->EVENTS_COMPARE[0]),
+                                     nrfx_gpiote_out_task_addr_get(pin));
+      nrf_ppi_channel_endpoint_setup(ppiBacklightOn,
+                                     reinterpret_cast<uint32_t>(&RTC->EVENTS_COMPARE[1]),
+                                     nrfx_gpiote_out_task_addr_get(pin));
+      nrf_ppi_fork_endpoint_setup(ppiBacklightOn, reinterpret_cast<uint32_t>(&RTC->TASKS_CLEAR));
+      nrf_ppi_channel_enable(ppiBacklightOff);
+      nrf_ppi_channel_enable(ppiBacklightOn);
+    } else {
+      // If the pin used for PWM isn't changing, we only need to set the pin state to the initial value (low)
+      RTC->TASKS_STOP = 1;
+      nrf_delay_us(rtcStopTime);
+      // Due to errata 20,179 and the intricacies of RTC timing, keep it simple: override the pin state
+      nrfx_gpiote_out_task_force(pin, false);
+    }
+    // CC0 switches the backlight off (pin transitions from low to high)
+    RTC->CC[0] = rawBrightness;
+    RTC->TASKS_CLEAR = 1;
+    RTC->TASKS_START = 1;
+    lastPin = pin;
+  }
+  switch (pin) {
+    case PinMap::LcdBacklightHigh:
+      nrf_gpio_pin_clear(PinMap::LcdBacklightLow);
+      nrf_gpio_pin_clear(PinMap::LcdBacklightMedium);
+      break;
+    case PinMap::LcdBacklightMedium:
+      nrf_gpio_pin_clear(PinMap::LcdBacklightLow);
+      nrf_gpio_pin_set(PinMap::LcdBacklightHigh);
+      break;
+    case PinMap::LcdBacklightLow:
+      nrf_gpio_pin_set(PinMap::LcdBacklightMedium);
+      nrf_gpio_pin_set(PinMap::LcdBacklightHigh);
+  }
+}
+
 void BrightnessController::Set(BrightnessController::Levels level) {
   this->level = level;
   switch (level) {
     default:
     case Levels::High:
-      nrf_gpio_pin_clear(PinMap::LcdBacklightLow);
-      nrf_gpio_pin_clear(PinMap::LcdBacklightMedium);
-      nrf_gpio_pin_clear(PinMap::LcdBacklightHigh);
+      ApplyBrightness(3 * timerPeriod);
       break;
     case Levels::Medium:
-      nrf_gpio_pin_clear(PinMap::LcdBacklightLow);
-      nrf_gpio_pin_clear(PinMap::LcdBacklightMedium);
-      nrf_gpio_pin_set(PinMap::LcdBacklightHigh);
+      ApplyBrightness(2 * timerPeriod);
       break;
     case Levels::Low:
-      nrf_gpio_pin_clear(PinMap::LcdBacklightLow);
-      nrf_gpio_pin_set(PinMap::LcdBacklightMedium);
-      nrf_gpio_pin_set(PinMap::LcdBacklightHigh);
+      ApplyBrightness(timerPeriod);
+      break;
+    case Levels::AlwaysOn:
+      ApplyBrightness(timerPeriod / 10);
       break;
     case Levels::Off:
-      nrf_gpio_pin_set(PinMap::LcdBacklightLow);
-      nrf_gpio_pin_set(PinMap::LcdBacklightMedium);
-      nrf_gpio_pin_set(PinMap::LcdBacklightHigh);
+      ApplyBrightness(0);
       break;
   }
 }

src/components/brightness/BrightnessController.h

@@ -2,11 +2,14 @@
 
 #include <cstdint>
 
+#include "nrf_ppi.h"
+#include "nrfx_gpiote.h"
+
 namespace Pinetime {
   namespace Controllers {
     class BrightnessController {
     public:
-      enum class Levels { Off, Low, Medium, High };
+      enum class Levels { Off, AlwaysOn, Low, Medium, High };
       void Init();
 
       void Set(Levels level);
@@ -20,6 +23,25 @@ namespace Pinetime {
 
     private:
       Levels level = Levels::High;
+      static constexpr uint8_t UNSET = UINT8_MAX;
+      uint8_t lastPin = UNSET;
+      // Maximum time (μs) it takes for the RTC to fully stop
+      static constexpr uint8_t rtcStopTime = 46;
+      // Frequency of timer used for PWM (Hz)
+      static constexpr uint16_t timerFrequency = 32768;
+      // Backlight PWM frequency (Hz)
+      static constexpr uint16_t pwmFreq = 1000;
+      // Wraparound point in timer ticks
+      // Defines the number of brightness levels between each pin
+      static constexpr uint16_t timerPeriod = timerFrequency / pwmFreq;
+      // Warning: nimble reserves some PPIs
+      // https://github.com/InfiniTimeOrg/InfiniTime/blob/034d83fe6baf1ab3875a34f8cee387e24410a824/src/libs/mynewt-nimble/nimble/drivers/nrf52/src/ble_phy.c#L53
+      // SpiMaster uses PPI 0 for an erratum workaround
+      // Channel 1, 2 should be free to use
+      static constexpr nrf_ppi_channel_t ppiBacklightOn = NRF_PPI_CHANNEL1;
+      static constexpr nrf_ppi_channel_t ppiBacklightOff = NRF_PPI_CHANNEL2;
+
+      void ApplyBrightness(uint16_t val);
     };
   }
 }

src/components/settings/Settings.h

@@ -214,6 +214,21 @@ namespace Pinetime {
         return settings.screenTimeOut;
       };
 
+      bool GetAlwaysOnDisplay() const {
+        return settings.alwaysOnDisplay && GetNotificationStatus() != Notification::Sleep;
+      };
+
+      void SetAlwaysOnDisplaySetting(bool state) {
+        if (state != settings.alwaysOnDisplay) {
+          settingsChanged = true;
+        }
+        settings.alwaysOnDisplay = state;
+      }
+
+      bool GetAlwaysOnDisplaySetting() const {
+        return settings.alwaysOnDisplay;
+      }
+
       void SetShakeThreshold(uint16_t thresh) {
         if (settings.shakeWakeThreshold != thresh) {
           settings.shakeWakeThreshold = thresh;
@@ -286,13 +301,15 @@ namespace Pinetime {
     private:
       Pinetime::Controllers::FS& fs;
 
-      static constexpr uint32_t settingsVersion = 0x0007;
+      static constexpr uint32_t settingsVersion = 0x0008;
 
       struct SettingsData {
         uint32_t version = settingsVersion;
         uint32_t stepsGoal = 10000;
         uint32_t screenTimeOut = 15000;
 
+        bool alwaysOnDisplay = false;
+
         ClockType clockType = ClockType::H24;
         WeatherFormat weatherFormat = WeatherFormat::Metric;
         Notification notificationStatus = Notification::On;

src/displayapp/DisplayApp.cpp

@@ -81,7 +81,8 @@ DisplayApp::DisplayApp(Drivers::St7789& lcd,
                        Pinetime::Controllers::AlarmController& alarmController,
                        Pinetime::Controllers::BrightnessController& brightnessController,
                        Pinetime::Controllers::TouchHandler& touchHandler,
-                       Pinetime::Controllers::FS& filesystem)
+                       Pinetime::Controllers::FS& filesystem,
+                       Pinetime::Drivers::SpiNorFlash& spiNorFlash)
   : lcd {lcd},
     touchPanel {touchPanel},
     batteryController {batteryController},
@@ -97,6 +98,7 @@ DisplayApp::DisplayApp(Drivers::St7789& lcd,
     brightnessController {brightnessController},
     touchHandler {touchHandler},
     filesystem {filesystem},
+    spiNorFlash {spiNorFlash},
     lvgl {lcd, filesystem},
     timer(this, TimerCallback),
     controllers {batteryController,
@@ -154,6 +156,36 @@ void DisplayApp::InitHw() {
   lcd.Init();
 }
 
+TickType_t DisplayApp::CalculateSleepTime() {
+  TickType_t ticksElapsed = xTaskGetTickCount() - alwaysOnStartTime;
+  // Divide both the numerator and denominator by 8 to increase the number of ticks (frames) before the overflow tick is reached
+  TickType_t elapsedTarget = ROUNDED_DIV((configTICK_RATE_HZ / 8) * alwaysOnTickCount * alwaysOnRefreshPeriod, 1000 / 8);
+  // ROUNDED_DIV overflows when numerator + (denominator floordiv 2) > uint32 max
+  // in this case around 9 hours
+  constexpr TickType_t overflowTick = (UINT32_MAX - (1000 / 16)) / ((configTICK_RATE_HZ / 8) * alwaysOnRefreshPeriod);
+
+  // Assumptions
+
+  // Tick rate is multiple of 8
+  // Needed for division trick above
+  static_assert(configTICK_RATE_HZ % 8 == 0);
+
+  // Local tick count must always wraparound before the system tick count does
+  // As a static assert we can use 64 bit ints and therefore dodge overflows
+  // Always on overflow time (ms) < system tick overflow time (ms)
+  static_assert((uint64_t) overflowTick * (uint64_t) alwaysOnRefreshPeriod < (uint64_t) UINT32_MAX * 1000ULL / configTICK_RATE_HZ);
+
+  if (alwaysOnTickCount == overflowTick) {
+    alwaysOnTickCount = 0;
+    alwaysOnStartTime = xTaskGetTickCount();
+  }
+  if (elapsedTarget > ticksElapsed) {
+    return elapsedTarget - ticksElapsed;
+  } else {
+    return 0;
+  }
+}
+
 void DisplayApp::Refresh() {
   auto LoadPreviousScreen = [this]() {
     FullRefreshDirections returnDirection;
@@ -203,7 +235,29 @@ void DisplayApp::Refresh() {
   TickType_t queueTimeout;
   switch (state) {
     case States::Idle:
-      queueTimeout = portMAX_DELAY;
+      if (settingsController.GetAlwaysOnDisplay()) {
+        if (!currentScreen->IsRunning()) {
+          LoadPreviousScreen();
+        }
+        // Check we've slept long enough
+        // Might not be true if the loop received an event
+        // If not true, then wait that amount of time
+        queueTimeout = CalculateSleepTime();
+        if (queueTimeout == 0) {
+          // Only advance the tick count when LVGL is done
+          // Otherwise keep running the task handler while it still has things to draw
+          // Note: under high graphics load, LVGL will always have more work to do
+          if (lv_task_handler() > 0) {
+            // Drop frames that we've missed if drawing/event handling took way longer than expected
+            while (queueTimeout == 0) {
+              alwaysOnTickCount += 1;
+              queueTimeout = CalculateSleepTime();
+            }
+          };
+        }
+      } else {
+        queueTimeout = portMAX_DELAY;
+      }
       break;
     case States::Running:
       if (!currentScreen->IsRunning()) {
@@ -234,20 +288,39 @@ void DisplayApp::Refresh() {
       case Messages::DimScreen:
         DimScreen();
         break;
-      case Messages::RestoreBrightness:
-        RestoreBrightness();
-        break;
       case Messages::GoToSleep:
-        while (brightnessController.Level() != Controllers::BrightnessController::Levels::Off) {
+        while (brightnessController.Level() != Controllers::BrightnessController::Levels::Low) {
           brightnessController.Lower();
           vTaskDelay(100);
         }
-        lcd.Sleep();
+        // Don't actually turn off the display for AlwaysOn mode
+        if (settingsController.GetAlwaysOnDisplay()) {
+          brightnessController.Set(Controllers::BrightnessController::Levels::AlwaysOn);
+          lcd.LowPowerOn();
+          // Record idle entry time
+          alwaysOnTickCount = 0;
+          alwaysOnStartTime = xTaskGetTickCount();
+        } else {
+          brightnessController.Set(Controllers::BrightnessController::Levels::Off);
+          lcd.Sleep();
+          // Since the active screen is not really an app, go back to Clock.
+          if (currentApp == Apps::Launcher || currentApp == Apps::Notifications || currentApp == Apps::QuickSettings ||
+              currentApp == Apps::Settings) {
+            LoadScreen(Apps::Clock, DisplayApp::FullRefreshDirections::None);
+          }
+        }
         PushMessageToSystemTask(Pinetime::System::Messages::OnDisplayTaskSleeping);
         state = States::Idle;
         break;
+      case Messages::NotifyDeviceActivity:
+        lv_disp_trig_activity(nullptr);
+        break;
       case Messages::GoToRunning:
-        lcd.Wakeup();
+        if (settingsController.GetAlwaysOnDisplay()) {
+          lcd.LowPowerOff();
+        } else {
+          lcd.Wakeup();
+        }
         lv_disp_trig_activity(nullptr);
         ApplyBrightness();
         state = States::Running;
@@ -535,7 +608,8 @@ void DisplayApp::LoadScreen(Apps app, DisplayApp::FullRefreshDirections directio
                                                             bleController,
                                                             watchdog,
                                                             motionController,
-                                                            touchPanel);
+                                                            touchPanel,
+                                                            spiNorFlash);
       break;
     case Apps::FlashLight:
       currentScreen = std::make_unique<Screens::FlashLight>(*systemTask, brightnessController);

src/displayapp/DisplayApp.h

@@ -66,7 +66,8 @@ namespace Pinetime {
                  Pinetime::Controllers::AlarmController& alarmController,
                  Pinetime::Controllers::BrightnessController& brightnessController,
                  Pinetime::Controllers::TouchHandler& touchHandler,
-                 Pinetime::Controllers::FS& filesystem);
+                 Pinetime::Controllers::FS& filesystem,
+                 Pinetime::Drivers::SpiNorFlash& spiNorFlash);
       void Start(System::BootErrors error);
       void PushMessage(Display::Messages msg);
 
@@ -96,6 +97,7 @@ namespace Pinetime {
       Pinetime::Controllers::BrightnessController& brightnessController;
       Pinetime::Controllers::TouchHandler& touchHandler;
       Pinetime::Controllers::FS& filesystem;
+      Pinetime::Drivers::SpiNorFlash& spiNorFlash;
 
       Pinetime::Controllers::FirmwareValidator validator;
       Pinetime::Components::LittleVgl lvgl;
@@ -135,6 +137,13 @@ namespace Pinetime {
       Utility::StaticStack<FullRefreshDirections, returnAppStackSize> appStackDirections;
 
       bool isDimmed = false;
+
+      TickType_t CalculateSleepTime();
+      TickType_t alwaysOnTickCount;
+      TickType_t alwaysOnStartTime;
+      // If this is to be changed, make sure the actual always on refresh rate is changed
+      // by configuring the LCD refresh timings
+      static constexpr uint32_t alwaysOnRefreshPeriod = 500;
     };
   }
 }

src/displayapp/DisplayAppRecovery.cpp

@@ -24,7 +24,8 @@ DisplayApp::DisplayApp(Drivers::St7789& lcd,
                        Pinetime::Controllers::AlarmController& /*alarmController*/,
                        Pinetime::Controllers::BrightnessController& /*brightnessController*/,
                        Pinetime::Controllers::TouchHandler& /*touchHandler*/,
-                       Pinetime::Controllers::FS& /*filesystem*/)
+                       Pinetime::Controllers::FS& /*filesystem*/,
+                       Pinetime::Drivers::SpiNorFlash& /*spiNorFlash*/)
   : lcd {lcd}, bleController {bleController} {
 }
 

src/displayapp/DisplayAppRecovery.h

@@ -18,6 +18,7 @@ namespace Pinetime {
     class St7789;
     class Cst816S;
     class Watchdog;
+    class SpiNorFlash;
   }
 
   namespace Controllers {
@@ -59,7 +60,8 @@ namespace Pinetime {
                  Pinetime::Controllers::AlarmController& alarmController,
                  Pinetime::Controllers::BrightnessController& brightnessController,
                  Pinetime::Controllers::TouchHandler& touchHandler,
-                 Pinetime::Controllers::FS& filesystem);
+                 Pinetime::Controllers::FS& filesystem,
+                 Pinetime::Drivers::SpiNorFlash& spiNorFlash);
       void Start();
 
       void Start(Pinetime::System::BootErrors) {

src/displayapp/Messages.h

@@ -18,7 +18,7 @@ namespace Pinetime {
         TimerDone,
         BleFirmwareUpdateStarted,
         DimScreen,
-        RestoreBrightness,
+        NotifyDeviceActivity,
         ShowPairingKey,
         AlarmTriggered,
         Chime,

src/displayapp/screens/FlashLight.cpp

@@ -17,6 +17,7 @@ namespace {
 FlashLight::FlashLight(System::SystemTask& systemTask, Controllers::BrightnessController& brightnessController)
   : systemTask {systemTask}, brightnessController {brightnessController} {
 
+  previousBrightnessLevel = brightnessController.Level();
   brightnessController.Set(Controllers::BrightnessController::Levels::Low);
 
   flashLight = lv_label_create(lv_scr_act(), nullptr);
@@ -52,6 +53,7 @@ FlashLight::FlashLight(System::SystemTask& systemTask, Controllers::BrightnessCo
 FlashLight::~FlashLight() {
   lv_obj_clean(lv_scr_act());
   lv_obj_set_style_local_bg_color(lv_scr_act(), LV_OBJ_PART_MAIN, LV_STATE_DEFAULT, LV_COLOR_BLACK);
+  brightnessController.Set(previousBrightnessLevel);
   systemTask.PushMessage(Pinetime::System::Messages::EnableSleeping);
 }
 

src/displayapp/screens/FlashLight.h

@@ -27,6 +27,7 @@ namespace Pinetime {
         Controllers::BrightnessController& brightnessController;
 
         Controllers::BrightnessController::Levels brightnessLevel = Controllers::BrightnessController::Levels::High;
+        Controllers::BrightnessController::Levels previousBrightnessLevel;
 
         lv_obj_t* flashLight;
         lv_obj_t* backgroundAction;

src/displayapp/screens/SystemInfo.cpp

@@ -38,7 +38,8 @@ SystemInfo::SystemInfo(Pinetime::Applications::DisplayApp* app,
                        const Pinetime::Controllers::Ble& bleController,
                        const Pinetime::Drivers::Watchdog& watchdog,
                        Pinetime::Controllers::MotionController& motionController,
-                       const Pinetime::Drivers::Cst816S& touchPanel)
+                       const Pinetime::Drivers::Cst816S& touchPanel,
+                       const Pinetime::Drivers::SpiNorFlash& spiNorFlash)
   : app {app},
     dateTimeController {dateTimeController},
     batteryController {batteryController},
@@ -47,6 +48,7 @@ SystemInfo::SystemInfo(Pinetime::Applications::DisplayApp* app,
     watchdog {watchdog},
     motionController {motionController},
     touchPanel {touchPanel},
+    spiNorFlash {spiNorFlash},
     screens {app,
              0,
              {[this]() -> std::unique_ptr<Screen> {
@@ -186,10 +188,12 @@ std::unique_ptr<Screen> SystemInfo::CreateScreen3() {
   lv_obj_t* label = lv_label_create(lv_scr_act(), nullptr);
   lv_label_set_recolor(label, true);
   const auto& bleAddr = bleController.Address();
+  auto spiFlashId = spiNorFlash.GetIdentification();
   lv_label_set_text_fmt(label,
                         "#808080 BLE MAC#\n"
-                        " %02x:%02x:%02x:%02x:%02x:%02x"
+                        " %02x:%02x:%02x:%02x:%02x:%02x\n"
                         "\n"
+                        "#808080 SPI Flash# %02x-%02x-%02x\n"
                         "\n"
                         "#808080 Memory heap#\n"
                         " #808080 Free# %d\n"
@@ -202,6 +206,9 @@ std::unique_ptr<Screen> SystemInfo::CreateScreen3() {
                         bleAddr[2],
                         bleAddr[1],
                         bleAddr[0],
+                        spiFlashId.manufacturer,
+                        spiFlashId.type,
+                        spiFlashId.density,
                         xPortGetFreeHeapSize(),
                         xPortGetMinimumEverFreeHeapSize(),
                         mallocFailedCount,

src/displayapp/screens/SystemInfo.h

@@ -29,7 +29,8 @@ namespace Pinetime {
                             const Pinetime::Controllers::Ble& bleController,
                             const Pinetime::Drivers::Watchdog& watchdog,
                             Pinetime::Controllers::MotionController& motionController,
-                            const Pinetime::Drivers::Cst816S& touchPanel);
+                            const Pinetime::Drivers::Cst816S& touchPanel,
+                            const Pinetime::Drivers::SpiNorFlash& spiNorFlash);
         ~SystemInfo() override;
         bool OnTouchEvent(TouchEvents event) override;
 
@@ -42,6 +43,7 @@ namespace Pinetime {
         const Pinetime::Drivers::Watchdog& watchdog;
         Pinetime::Controllers::MotionController& motionController;
         const Pinetime::Drivers::Cst816S& touchPanel;
+        const Pinetime::Drivers::SpiNorFlash& spiNorFlash;
 
         ScreenList<5> screens;
 

src/displayapp/screens/settings/SettingDisplay.cpp

@@ -9,10 +9,17 @@
 using namespace Pinetime::Applications::Screens;
 
 namespace {
-  void event_handler(lv_obj_t* obj, lv_event_t event) {
+  void TimeoutEventHandler(lv_obj_t* obj, lv_event_t event) {
     auto* screen = static_cast<SettingDisplay*>(obj->user_data);
     screen->UpdateSelected(obj, event);
   }
+
+  void AlwaysOnEventHandler(lv_obj_t* obj, lv_event_t event) {
+    if (event == LV_EVENT_VALUE_CHANGED) {
+      auto* screen = static_cast<SettingDisplay*>(obj->user_data);
+      screen->ToggleAlwaysOn();
+    }
+  }
 }
 
 constexpr std::array<uint16_t, 6> SettingDisplay::options;
@@ -49,13 +56,20 @@ SettingDisplay::SettingDisplay(Pinetime::Applications::DisplayApp* app, Pinetime
     snprintf(buffer, sizeof(buffer), "%2" PRIu16 "s", options[i] / 1000);
     lv_checkbox_set_text(cbOption[i], buffer);
     cbOption[i]->user_data = this;
-    lv_obj_set_event_cb(cbOption[i], event_handler);
+    lv_obj_set_event_cb(cbOption[i], TimeoutEventHandler);
     SetRadioButtonStyle(cbOption[i]);
 
     if (settingsController.GetScreenTimeOut() == options[i]) {
       lv_checkbox_set_checked(cbOption[i], true);
     }
   }
+
+  alwaysOnCheckbox = lv_checkbox_create(container1, nullptr);
+  lv_checkbox_set_text(alwaysOnCheckbox, "Always On");
+  lv_checkbox_set_checked(alwaysOnCheckbox, settingsController.GetAlwaysOnDisplaySetting());
+  lv_obj_add_state(alwaysOnCheckbox, LV_STATE_DEFAULT);
+  alwaysOnCheckbox->user_data = this;
+  lv_obj_set_event_cb(alwaysOnCheckbox, AlwaysOnEventHandler);
 }
 
 SettingDisplay::~SettingDisplay() {
@@ -63,6 +77,11 @@ SettingDisplay::~SettingDisplay() {
   settingsController.SaveSettings();
 }
 
+void SettingDisplay::ToggleAlwaysOn() {
+  settingsController.SetAlwaysOnDisplaySetting(!settingsController.GetAlwaysOnDisplaySetting());
+  lv_checkbox_set_checked(alwaysOnCheckbox, settingsController.GetAlwaysOnDisplaySetting());
+}
+
 void SettingDisplay::UpdateSelected(lv_obj_t* object, lv_event_t event) {
   if (event == LV_EVENT_CLICKED) {
     for (unsigned int i = 0; i < options.size(); i++) {

src/displayapp/screens/settings/SettingDisplay.h

@@ -18,6 +18,7 @@ namespace Pinetime {
         ~SettingDisplay() override;
 
         void UpdateSelected(lv_obj_t* object, lv_event_t event);
+        void ToggleAlwaysOn();
 
       private:
         DisplayApp* app;
@@ -25,6 +26,7 @@ namespace Pinetime {
 
         Controllers::Settings& settingsController;
         lv_obj_t* cbOption[options.size()];
+        lv_obj_t* alwaysOnCheckbox;
       };
     }
   }

src/drivers/SpiNorFlash.cpp

@@ -10,7 +10,7 @@ SpiNorFlash::SpiNorFlash(Spi& spi) : spi {spi} {
 }
 
 void SpiNorFlash::Init() {
-  device_id = ReadIdentificaion();
+  device_id = ReadIdentification();
   NRF_LOG_INFO("[SpiNorFlash] Manufacturer : %d, Memory type : %d, memory density : %d",
                device_id.manufacturer,
                device_id.type,
@@ -32,7 +32,7 @@ void SpiNorFlash::Wakeup() {
   uint8_t cmd[cmdSize] = {static_cast<uint8_t>(Commands::ReleaseFromDeepPowerDown), 0x01, 0x02, 0x03};
   uint8_t id = 0;
   spi.Read(reinterpret_cast<uint8_t*>(&cmd), cmdSize, &id, 1);
-  auto devId = device_id = ReadIdentificaion();
+  auto devId = device_id = ReadIdentification();
   if (devId.type != device_id.type) {
     NRF_LOG_INFO("[SpiNorFlash] ID on Wakeup: Failed");
   } else {
@@ -41,7 +41,7 @@ void SpiNorFlash::Wakeup() {
   NRF_LOG_INFO("[SpiNorFlash] Wakeup")
 }
 
-SpiNorFlash::Identification SpiNorFlash::ReadIdentificaion() {
+SpiNorFlash::Identification SpiNorFlash::ReadIdentification() {
   auto cmd = static_cast<uint8_t>(Commands::ReadIdentification);
   Identification identification;
   spi.Read(&cmd, 1, reinterpret_cast<uint8_t*>(&identification), sizeof(Identification));
@@ -145,3 +145,7 @@ void SpiNorFlash::Write(uint32_t address, const uint8_t* buffer, size_t size) {
     len -= toWrite;
   }
 }
+
+SpiNorFlash::Identification SpiNorFlash::GetIdentification() const {
+  return device_id;
+}

src/drivers/SpiNorFlash.h

@@ -20,7 +20,6 @@ namespace Pinetime {
         uint8_t density = 0;
       };
 
-      Identification ReadIdentificaion();
       uint8_t ReadStatusRegister();
       bool WriteInProgress();
       bool WriteEnabled();
@@ -33,6 +32,8 @@ namespace Pinetime {
       bool ProgramFailed();
       bool EraseFailed();
 
+      Identification GetIdentification() const;
+
       void Init();
       void Uninit();
 
@@ -40,6 +41,8 @@ namespace Pinetime {
       void Wakeup();
 
     private:
+      Identification ReadIdentification();
+
       enum class Commands : uint8_t {
         PageProgram = 0x02,
         Read = 0x03,

src/drivers/St7789.cpp

@@ -16,6 +16,7 @@ void St7789::Init() {
   nrf_gpio_pin_set(pinReset);
   HardwareReset();
   SoftwareReset();
+  Command2Enable();
   SleepOut();
   PixelFormat();
   MemoryDataAccessControl();
@@ -24,8 +25,13 @@ void St7789::Init() {
 #ifndef DRIVER_DISPLAY_MIRROR
   DisplayInversionOn();
 #endif
+  PorchSet();
+  FrameRateNormalSet();
+  IdleFrameRateOff();
   NormalModeOn();
   SetVdv();
+  PowerControl();
+  GateControl();
   DisplayOn();
 }
 
@@ -63,6 +69,17 @@ void St7789::SoftwareReset() {
   vTaskDelay(pdMS_TO_TICKS(125));
 }
 
+void St7789::Command2Enable() {
+  WriteCommand(static_cast<uint8_t>(Commands::Command2Enable));
+  constexpr uint8_t args[] = {
+    0x5a, // Constant
+    0x69, // Constant
+    0x02, // Constant
+    0x01, // Enable
+  };
+  WriteData(args, sizeof(args));
+}
+
 void St7789::SleepOut() {
   if (!sleepIn) {
     return;
@@ -127,10 +144,79 @@ void St7789::NormalModeOn() {
   WriteCommand(static_cast<uint8_t>(Commands::NormalModeOn));
 }
 
+void St7789::IdleModeOn() {
+  WriteCommand(static_cast<uint8_t>(Commands::IdleModeOn));
+}
+
+void St7789::IdleModeOff() {
+  WriteCommand(static_cast<uint8_t>(Commands::IdleModeOff));
+}
+
+void St7789::PorchSet() {
+  WriteCommand(static_cast<uint8_t>(Commands::Porch));
+  constexpr uint8_t args[] = {
+    0x02, // Normal mode front porch
+    0x03, // Normal mode back porch
+    0x01, // Porch control enable
+    0xed, // Idle mode front:back porch
+    0xed, // Partial mode front:back porch (partial mode unused but set anyway)
+  };
+  WriteData(args, sizeof(args));
+}
+
+void St7789::FrameRateNormalSet() {
+  WriteCommand(static_cast<uint8_t>(Commands::FrameRateNormal));
+  // Note that the datasheet table is imprecise - see formula below table
+  WriteData(0x0a);
+}
+
+void St7789::IdleFrameRateOn() {
+  WriteCommand(static_cast<uint8_t>(Commands::FrameRateIdle));
+  // According to the datasheet, these controls should apply only to partial/idle mode
+  // However they appear to apply to normal mode, so we have to enable/disable
+  // every time we enter/exit always on
+  // In testing this divider appears to actually be 16x?
+  constexpr uint8_t args[] = {
+    0x13, // Enable frame rate control for partial/idle mode, 8x frame divider
+    0x1e, // Idle mode frame rate
+    0x1e, // Partial mode frame rate (unused)
+  };
+  WriteData(args, sizeof(args));
+}
+
+void St7789::IdleFrameRateOff() {
+  WriteCommand(static_cast<uint8_t>(Commands::FrameRateIdle));
+  constexpr uint8_t args[] = {
+    0x00, // Disable frame rate control and divider
+    0x0a, // Idle mode frame rate (normal)
+    0x0a, // Partial mode frame rate (normal, unused)
+  };
+  WriteData(args, sizeof(args));
+}
+
 void St7789::DisplayOn() {
   WriteCommand(static_cast<uint8_t>(Commands::DisplayOn));
 }
 
+void St7789::PowerControl() {
+  WriteCommand(static_cast<uint8_t>(Commands::PowerControl1));
+  constexpr uint8_t args[] = {
+    0xa4, // Constant
+    0x00, // Lowest possible voltages
+  };
+  WriteData(args, sizeof(args));
+
+  WriteCommand(static_cast<uint8_t>(Commands::PowerControl2));
+  // Lowest possible boost circuit clocks
+  WriteData(0xb3);
+}
+
+void St7789::GateControl() {
+  WriteCommand(static_cast<uint8_t>(Commands::GateControl));
+  // Lowest possible VGL/VGH
+  WriteData(0x00);
+}
+
 void St7789::SetAddrWindow(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1) {
   WriteCommand(static_cast<uint8_t>(Commands::ColumnAddressSet));
   uint8_t colArgs[] = {
@@ -198,6 +284,18 @@ void St7789::HardwareReset() {
   vTaskDelay(pdMS_TO_TICKS(125));
 }
 
+void St7789::LowPowerOn() {
+  IdleModeOn();
+  IdleFrameRateOn();
+  NRF_LOG_INFO("[LCD] Low power mode");
+}
+
+void St7789::LowPowerOff() {
+  IdleModeOff();
+  IdleFrameRateOff();
+  NRF_LOG_INFO("[LCD] Normal power mode");
+}
+
 void St7789::Sleep() {
   SleepIn();
   nrf_gpio_cfg_default(pinDataCommand);

src/drivers/St7789.h

@@ -24,6 +24,8 @@ namespace Pinetime {
 
       void DrawBuffer(uint16_t x, uint16_t y, uint16_t width, uint16_t height, const uint8_t* data, size_t size);
 
+      void LowPowerOn();
+      void LowPowerOff();
       void Sleep();
       void Wakeup();
 
@@ -37,6 +39,7 @@ namespace Pinetime {
 
       void HardwareReset();
       void SoftwareReset();
+      void Command2Enable();
       void SleepOut();
       void EnsureSleepOutPostDelay();
       void SleepIn();
@@ -45,8 +48,16 @@ namespace Pinetime {
       void DisplayInversionOn();
       void NormalModeOn();
       void WriteToRam(const uint8_t* data, size_t size);
+      void IdleModeOn();
+      void IdleModeOff();
+      void FrameRateNormalSet();
+      void IdleFrameRateOff();
+      void IdleFrameRateOn();
       void DisplayOn();
       void DisplayOff();
+      void PowerControl();
+      void GateControl();
+      void PorchSet();
 
       void SetAddrWindow(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1);
       void SetVdv();
@@ -68,8 +79,17 @@ namespace Pinetime {
         MemoryDataAccessControl = 0x36,
         VerticalScrollDefinition = 0x33,
         VerticalScrollStartAddress = 0x37,
+        IdleModeOff = 0x38,
+        IdleModeOn = 0x39,
         PixelFormat = 0x3a,
+        FrameRateIdle = 0xb3,
+        FrameRateNormal = 0xc6,
         VdvSet = 0xc4,
+        Command2Enable = 0xdf,
+        PowerControl1 = 0xd0,
+        PowerControl2 = 0xe8,
+        GateControl = 0xb7,
+        Porch = 0xb2,
       };
       void WriteData(uint8_t data);
       void WriteData(const uint8_t* data, size_t size);

src/main.cpp

@@ -123,7 +123,8 @@ Pinetime::Applications::DisplayApp displayApp(lcd,
                                               alarmController,
                                               brightnessController,
                                               touchHandler,
-                                              fs);
+                                              fs,
+                                              spiNorFlash);
 
 Pinetime::System::SystemTask systemTask(spi,
                                         spiNorFlash,

src/systemtask/SystemTask.cpp

@@ -102,7 +102,9 @@ void SystemTask::Work() {
   watchdog.Setup(7, Drivers::Watchdog::SleepBehaviour::Run, Drivers::Watchdog::HaltBehaviour::Pause);
   watchdog.Start();
   NRF_LOG_INFO("Last reset reason : %s", Pinetime::Drivers::ResetReasonToString(watchdog.GetResetReason()));
-  APP_GPIOTE_INIT(2);
+  if (!nrfx_gpiote_is_init()) {
+    nrfx_gpiote_init();
+  }
 
   spi.Init();
   spiNorFlash.Init();
@@ -192,13 +194,16 @@ void SystemTask::Work() {
           if (!bleController.IsFirmwareUpdating()) {
             doNotGoToSleep = false;
           }
-          displayApp.PushMessage(Pinetime::Applications::Display::Messages::RestoreBrightness);
+          displayApp.PushMessage(Pinetime::Applications::Display::Messages::NotifyDeviceActivity);
           break;
         case Messages::DisableSleeping:
           doNotGoToSleep = true;
           break;
         case Messages::GoToRunning:
-          spi.Wakeup();
+          // SPI doesn't go to sleep for always on mode
+          if (!settingsController.GetAlwaysOnDisplay()) {
+            spi.Wakeup();
+          }
 
           // Double Tap needs the touch screen to be in normal mode
           if (!settingsController.isWakeUpModeOn(Pinetime::Controllers::Settings::WakeUpMode::DoubleTap)) {
@@ -240,7 +245,7 @@ void SystemTask::Work() {
           heartRateApp.PushMessage(Pinetime::Applications::HeartRateTask::Messages::GoToSleep);
           break;
         case Messages::OnNewTime:
-          displayApp.PushMessage(Pinetime::Applications::Display::Messages::RestoreBrightness);
+          displayApp.PushMessage(Pinetime::Applications::Display::Messages::NotifyDeviceActivity);
           displayApp.PushMessage(Pinetime::Applications::Display::Messages::UpdateDateTime);
           if (alarmController.State() == Controllers::AlarmController::AlarmState::Set) {
             alarmController.ScheduleAlarm();
@@ -251,7 +256,7 @@ void SystemTask::Work() {
             if (state == SystemTaskState::Sleeping) {
               GoToRunning();
             } else {
-              displayApp.PushMessage(Pinetime::Applications::Display::Messages::RestoreBrightness);
+              displayApp.PushMessage(Pinetime::Applications::Display::Messages::NotifyDeviceActivity);
             }
             displayApp.PushMessage(Pinetime::Applications::Display::Messages::NewNotification);
           }
@@ -263,7 +268,7 @@ void SystemTask::Work() {
           displayApp.PushMessage(Pinetime::Applications::Display::Messages::AlarmTriggered);
           break;
         case Messages::BleConnected:
-          displayApp.PushMessage(Pinetime::Applications::Display::Messages::RestoreBrightness);
+          displayApp.PushMessage(Pinetime::Applications::Display::Messages::NotifyDeviceActivity);
           isBleDiscoveryTimerRunning = true;
           bleDiscoveryTimer = 5;
           break;
@@ -323,7 +328,11 @@ void SystemTask::Work() {
             // if it's in sleep mode. Avoid bricked device by disabling sleep mode on these versions.
             spiNorFlash.Sleep();
           }
-          spi.Sleep();
+
+          // Must keep SPI awake when still updating the display for always on
+          if (!settingsController.GetAlwaysOnDisplay()) {
+            spi.Sleep();
+          }
 
           // Double Tap needs the touch screen to be in normal mode
           if (!settingsController.isWakeUpModeOn(Pinetime::Controllers::Settings::WakeUpMode::DoubleTap)) {
@@ -457,7 +466,7 @@ void SystemTask::HandleButtonAction(Controllers::ButtonActions action) {
     return;
   }
 
-  displayApp.PushMessage(Pinetime::Applications::Display::Messages::RestoreBrightness);
+  displayApp.PushMessage(Pinetime::Applications::Display::Messages::NotifyDeviceActivity);
 
   using Actions = Controllers::ButtonActions;