Add idle->standby support when locked and no music

src/drivers/i2s_dac.cpp

@@ -91,9 +91,7 @@ I2SDac::I2SDac(IGpios* gpio, i2s_chan_handle_t i2s_handle)
   // Reset all registers back to their default values.
   wm8523::WriteRegister(wm8523::Register::kReset, 1);
   vTaskDelay(pdMS_TO_TICKS(10));
-
-  // Power up the charge pump.
-  wm8523::WriteRegister(wm8523::Register::kPsCtrl, 0b01);
+  wm8523::WriteRegister(wm8523::Register::kPsCtrl, 0b0);
 }
 
 I2SDac::~I2SDac() {
@@ -102,24 +100,28 @@ I2SDac::~I2SDac() {
 }
 
 auto I2SDac::Start() -> void {
+  // Ramp up the amplifier power supply.
   gpio_->WriteSync(IGpios::Pin::kAmplifierEnable, true);
+
+  // Wait for voltage to stabilise
   vTaskDelay(pdMS_TO_TICKS(1));
-  wm8523::WriteRegister(wm8523::Register::kPsCtrl, 0b10);
 
-  uint8_t zeroes[256]{0};
-  size_t bytes_loaded = 0;
-  esp_err_t res = ESP_OK;
-  do {
-    res = i2s_channel_preload_data(i2s_handle_, zeroes, 256, &bytes_loaded);
-  } while (bytes_loaded > 0 && res == ESP_OK);
+  // Ensure the DAC powers up to a muted state.
+  wm8523::WriteRegister(wm8523::Register::kPsCtrl, 0b10);
 
-  wm8523::WriteRegister(wm8523::Register::kPsCtrl, 0b11);
+  // Enable MCLK; this has the side effect of triggering the DAC's startup
+  // sequence.
   i2s_channel_enable(i2s_handle_);
+
+  // Wait for DAC output lines to stabilise
+  vTaskDelay(pdMS_TO_TICKS(1));
+
+  // FIXME: Pull the amp's EN pin here.
   i2s_active_ = true;
 }
 
 auto I2SDac::Stop() -> void {
-  wm8523::WriteRegister(wm8523::Register::kPsCtrl, 0b01);
+  wm8523::WriteRegister(wm8523::Register::kPsCtrl, 0b0);
   i2s_channel_disable(i2s_handle_);
 
   gpio_->WriteSync(IGpios::Pin::kAmplifierEnable, false);

src/drivers/include/touchwheel.hpp

@@ -35,6 +35,8 @@ class TouchWheel {
   auto Update() -> void;
   auto GetTouchWheelData() const -> TouchWheelData;
 
+  auto PowerDown() -> void;
+
  private:
   TouchWheelData data_;
 

src/drivers/touchwheel.cpp

@@ -22,6 +22,8 @@
 
 namespace drivers {
 
+// Touch wheel implementation using a Microchip AT42QT2120
+
 static const char* kTag = "TOUCHWHEEL";
 static const uint8_t kTouchWheelAddress = 0x1C;
 static const gpio_num_t kIntPin = GPIO_NUM_25;
@@ -121,4 +123,8 @@ TouchWheelData TouchWheel::GetTouchWheelData() const {
   return data_;
 }
 
+auto TouchWheel::PowerDown() -> void {
+  WriteRegister(LOW_POWER, 0);
+}
+
 }  // namespace drivers

src/system_fsm/CMakeLists.txt

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: GPL-3.0-only
 
 idf_component_register(
-  SRCS "system_fsm.cpp" "running.cpp" "booting.cpp"
+  SRCS "system_fsm.cpp" "running.cpp" "booting.cpp" "idle.cpp"
   INCLUDE_DIRS "include"
   REQUIRES "tinyfsm" "drivers" "database" "ui" "result" "events" "audio" "app_console")
 target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})

src/system_fsm/booting.cpp

@@ -94,13 +94,11 @@ auto Booting::exit() -> void {
 auto Booting::react(const BootComplete& ev) -> void {
   ESP_LOGI(kTag, "bootup completely successfully");
 
-  // It's possible that the SAMD is currently exposing the SD card as a USB
-  // device. Make sure we don't immediately try to claim it.
-  if (sSamd &&
-      sSamd->GetUsbStatus() == drivers::Samd::UsbStatus::kAttachedMounted) {
-    transit<Unmounted>();
+  if (sGpios->Get(drivers::Gpios::Pin::kKeyLock)) {
+    transit<Running>();
+  } else {
+    transit<Idle>();
   }
-  transit<Running>();
 }
 
 }  // namespace states

src/system_fsm/include/system_events.hpp

@@ -28,15 +28,7 @@ struct BootComplete : tinyfsm::Event {};
  */
 struct FatalError : tinyfsm::Event {};
 
-/*
- * Sent before unmounting the system storage. Storage will not be unmounted
- * until each reaction to this even has returned. FSMs should immediately cease
- * their usage of storage.
- *
- * May be emitted either by UiState in response to user action, or by SysState
- * as a part of either entering low-power standby or powering off.
- */
-struct StorageUnmountRequested : tinyfsm::Event {};
+struct OnIdle : tinyfsm::Event {};
 
 /*
  * Sent by SysState when the system storage has been successfully mounted.
@@ -64,15 +56,11 @@ struct ChargingStatusChanged : tinyfsm::Event {};
 
 namespace internal {
 
-/*
- * Sent when the actual unmount operation should be performed. Always dispatched
- * by SysState in response to StoragePrepareToUnmount.
- */
-struct ReadyToUnmount : tinyfsm::Event {};
-
 struct GpioInterrupt : tinyfsm::Event {};
 struct SamdInterrupt : tinyfsm::Event {};
 
+struct IdleTimeout : tinyfsm::Event {};
+
 }  // namespace internal
 
 }  // namespace system_fsm

src/system_fsm/include/system_fsm.hpp

@@ -22,6 +22,9 @@
 #include "tinyfsm.hpp"
 #include "touchwheel.hpp"
 
+#include "freertos/FreeRTOS.h"
+#include "freertos/timers.h"
+
 #include "system_events.hpp"
 #include "track_queue.hpp"
 
@@ -47,10 +50,10 @@ class SystemState : public tinyfsm::Fsm<SystemState> {
 
   virtual void react(const DisplayReady&) {}
   virtual void react(const BootComplete&) {}
-  virtual void react(const StorageUnmountRequested&) {}
-  virtual void react(const internal::ReadyToUnmount&) {}
   virtual void react(const StorageMounted&) {}
   virtual void react(const StorageError&) {}
+  virtual void react(const KeyLockChanged&) {}
+  virtual void react(const internal::IdleTimeout&) {}
 
  protected:
   static std::shared_ptr<drivers::Gpios> sGpios;
@@ -95,13 +98,24 @@ class Running : public SystemState {
   void entry() override;
   void exit() override;
 
-  void react(const StorageUnmountRequested&) override;
-  void react(const internal::ReadyToUnmount&) override;
+  void react(const KeyLockChanged&) override;
   void react(const StorageError&) override;
   using SystemState::react;
 };
 
-class Unmounted : public SystemState {};
+class Idle : public SystemState {
+ public:
+  void entry() override;
+  void exit() override;
+
+  void react(const KeyLockChanged&) override;
+  void react(const internal::IdleTimeout&) override;
+
+  using SystemState::react;
+
+ private:
+  TimerHandle_t sIdleTimeout;
+};
 
 /*
  * Something unrecoverably bad went wrong. Shows an error (if possible), awaits

src/system_fsm/running.cpp

@@ -67,17 +67,15 @@ void Running::exit() {
   sStorage.reset();
 }
 
-void Running::react(const StorageUnmountRequested& ev) {
-  events::System().Dispatch(internal::ReadyToUnmount{});
-}
-
-void Running::react(const internal::ReadyToUnmount& ev) {
-  transit<Unmounted>();
+void Running::react(const KeyLockChanged& ev) {
+  if (!ev.falling && audio::AudioState::is_in_state<audio::states::Standby>()) {
+    transit<Idle>();
+  }
 }
 
 void Running::react(const StorageError& ev) {
   ESP_LOGW(kTag, "error loading storage");
-  transit<Unmounted>();
+  // TODO.
 }
 
 }  // namespace states

src/ui/ui_fsm.cpp

@@ -10,6 +10,7 @@
 #include "core/lv_obj.h"
 #include "display.hpp"
 #include "event_queue.hpp"
+#include "gpios.hpp"
 #include "lvgl_task.hpp"
 #include "relative_wheel.hpp"
 #include "screen.hpp"
@@ -92,7 +93,7 @@ namespace states {
 
 void Splash::exit() {
   if (sDisplay != nullptr) {
-    sDisplay->SetDisplayOn(true);
+    sDisplay->SetDisplayOn(sIGpios->Get(drivers::IGpios::Pin::kKeyLock));
   }
 }