From 7523bac4f4b3b09b0f0ba651ad79f0bbe13d8884 Mon Sep 17 00:00:00 2001
From: Rob Riggs <rob@pangalactic.org>
Date: Wed, 19 Sep 2018 22:38:18 -0500
Subject: [PATCH] Start work on power saving modes.

---
 TNC/PowerMode.cpp | 52 +++++++++++++++++++++++++++++++++++++++++++++++
 TNC/PowerMode.h   | 16 +++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 TNC/PowerMode.cpp
 create mode 100644 TNC/PowerMode.h

diff --git a/TNC/PowerMode.cpp b/TNC/PowerMode.cpp
new file mode 100644
index 0000000..f5a63aa
--- /dev/null
+++ b/TNC/PowerMode.cpp
@@ -0,0 +1,52 @@
+// Copyright 2018 Rob Riggs <rob@mobilinkd.com>
+// All rights reserved.
+
+#include "main.h"
+#include "PowerMode.h"
+#include "stm32l4xx_hal.h"
+
+#include <stdint.h>
+
+volatile PowerMode power_mode{PowerMode::RUN};
+PowerMode previous_mode{PowerMode::RUN};        // Always start in RUN mode.
+
+/**
+ * Handle state transitions here.  Valid transitions are from RUN to any mode,
+ * LPRUN to any mode, SLEEP to LPRUN or STOP, and STOP to LPRUN or SLEEP.
+ *
+ * If moving from RUN to any SLEEP or STOP, we assume the upper layers have
+ * already disconnected the connection, either bu
+ *
+ * @param ulExpectedIdleTime
+ */
+extern "C" void PreSleepProcessing(uint32_t *ulExpectedIdleTime)
+{
+    switch (power_mode)
+    {
+    case PowerMode::RUN:
+        break;
+    case PowerMode::LPRUN:
+        if (previous_mode != power_mode);
+        break;
+    case PowerMode::SLEEP:
+        break;
+    case PowerMode::STOP:
+        break;
+    }
+}
+
+extern "C" void PostSleepProcessing(uint32_t *ulExpectedIdleTime)
+{
+    switch (power_mode)
+    {
+    case PowerMode::RUN:
+        break;
+    case PowerMode::LPRUN:
+        break;
+    case PowerMode::SLEEP:
+        break;
+    case PowerMode::STOP:
+        break;
+    }
+}
+
diff --git a/TNC/PowerMode.h b/TNC/PowerMode.h
new file mode 100644
index 0000000..22666f9
--- /dev/null
+++ b/TNC/PowerMode.h
@@ -0,0 +1,16 @@
+// Copyright 2018 Rob Riggs <rob@mobilinkd.com>
+// All rights reserved.
+
+#ifndef TNC_POWERMODE_H_
+#define TNC_POWERMODE_H_
+
+enum class PowerMode {
+    RUN,        // Power on, connected.
+    LPRUN,      // Power on, not connected.
+    SLEEP,      // Power off, USB connected.
+    STOP        // Power off, no USB connection.
+};
+
+extern volatile PowerMode power_mode;
+
+#endif // TNC_POWERMODE_H_