Add very basic usb msc ui

lua/settings.lua

@@ -275,6 +275,53 @@ local InputSettings = screen:new {
   end
 }
 
+local MassStorageSettings = screen:new {
+  createUi = function(self)
+    self.menu = SettingsScreen("USB Storage")
+    local version = require("version").samd()
+    if tonumber(version) < 2 then
+      self.menu.content:Label {
+        w = lvgl.PCT(100),
+        text = "Usb Mass Storage requires a SAMD21 firmware version >=2."
+      }
+      return
+    end
+
+    local enable_container = self.menu.content:Object {
+      flex = {
+        flex_direction = "row",
+        justify_content = "flex-start",
+        align_items = "content",
+        align_content = "flex-start",
+      },
+      w = lvgl.PCT(100),
+      h = lvgl.SIZE_CONTENT,
+      pad_bottom = 1,
+    }
+    enable_container:Label { text = "Enable", flex_grow = 1 }
+    local enable_sw = enable_container:Switch {}
+
+    local usb = require("usb")
+    local bind_switch = function()
+      if usb.msc_enabled:get() then
+        enable_sw:add_state(lvgl.STATE.CHECKED)
+      else
+        enable_sw:clear_state(lvgl.STATE.CHECKED)
+      end
+    end
+
+    enable_sw:onevent(lvgl.EVENT.VALUE_CHANGED, function()
+      usb.msc_enabled:set(enable_sw:enabled())
+      bind_switch()
+    end)
+
+    self.bindings = {
+      usb.msc_enabled:bind(bind_switch),
+    }
+  end,
+  canPop = true
+}
+
 local DatabaseSettings = screen:new {
   createUi = function(self)
     self.menu = SettingsScreen("Database")
@@ -352,6 +399,9 @@ return screen:new {
     submenu("Display", DisplaySettings)
     submenu("Input Method", InputSettings)
 
+    section("USB")
+    submenu("Storage", MassStorageSettings)
+
     section("System")
     submenu("Database", DatabaseSettings)
     submenu("Firmware", FirmwareSettings)

src/system_fsm/idle.cpp

@@ -13,6 +13,7 @@
 
 #include "audio_fsm.hpp"
 #include "event_queue.hpp"
+#include "samd.hpp"
 #include "storage.hpp"
 #include "system_events.hpp"
 #include "system_fsm.hpp"
@@ -40,7 +41,7 @@ void Idle::entry() {
   events::Audio().Dispatch(OnIdle{});
   events::Ui().Dispatch(OnIdle{});
 
-  sIdleTimeout = xTimerCreate("idle_timeout", kTicksBeforeSleep, false, NULL,
+  sIdleTimeout = xTimerCreate("idle_timeout", kTicksBeforeSleep, true, NULL,
                               timer_callback);
   xTimerStart(sIdleTimeout, portMAX_DELAY);
 }
@@ -63,6 +64,13 @@ void Idle::react(const internal::IdleTimeout& ev) {
     transit<Running>();
     return;
   }
+  auto s = static_cast<int>(sServices->samd().GetUsbStatus());
+  ESP_LOGI(kTag, "usb status is %i", s);
+  if (sServices->samd().GetUsbStatus() != drivers::Samd::UsbStatus::kDetached) {
+    // Stay powered on if we're plugged in, in order to charge faster, sync
+    // files, flash updates, etc.
+    return;
+  }
   ESP_LOGI(kTag, "system shutting down");
 
   // FIXME: It would be neater to just free a bunch of our pointers, deinit the

src/system_fsm/running.cpp

@@ -41,7 +41,11 @@ void Running::entry() {
     sUnmountTimer = xTimerCreate("unmount_timeout", kTicksBeforeUnmount, false,
                                  NULL, timer_callback);
   }
-  mountStorage();
+  // Only mount our storage immediately if we know it's not currently in use
+  // by the SAMD.
+  if (!sServices->samd().UsbMassStorage()) {
+    mountStorage();
+  }
 }
 
 void Running::exit() {

src/ui/include/ui_fsm.hpp

@@ -132,6 +132,8 @@ class UiState : public tinyfsm::Fsm<UiState> {
   static lua::Property sLockSwitch;
 
   static lua::Property sDatabaseUpdating;
+
+  static lua::Property sUsbMassStorageEnabled;
 };
 
 namespace states {

src/ui/ui_fsm.cpp

@@ -285,6 +285,17 @@ lua::Property UiState::sLockSwitch{false};
 
 lua::Property UiState::sDatabaseUpdating{false};
 
+lua::Property UiState::sUsbMassStorageEnabled{
+    false, [](const lua::LuaValue& val) {
+      if (!std::holds_alternative<bool>(val)) {
+        return false;
+      }
+      bool enable = std::get<bool>(val);
+      // FIXME: Check for system busy.
+      events::System().Dispatch(system_fsm::SamdUsbMscChanged{.en = enable});
+      return true;
+    }};
+
 auto UiState::InitBootSplash(drivers::IGpios& gpios, drivers::NvsStorage& nvs)
     -> bool {
   // Init LVGL first, since the display driver registers itself with LVGL.
@@ -553,6 +564,10 @@ void Lua::entry() {
     registry.AddPropertyModule("database", {
                                                {"updating", &sDatabaseUpdating},
                                            });
+    registry.AddPropertyModule("usb",
+                               {
+                                   {"msc_enabled", &sUsbMassStorageEnabled},
+                               });
 
     auto bt = sServices->bluetooth();
     sBluetoothEnabled.Update(bt.IsEnabled());