From 3a36dfeccdedf02bb28ba4ed76b23a59ba33f88d Mon Sep 17 00:00:00 2001
From: Dennis Frett <dennis.frett@live.com>
Date: Tue, 6 Sep 2022 18:55:44 +0200
Subject: [PATCH] Add functionality to retrieve input source from MiniDSP
 2x4HD.

---
 MiniDSP.cpp | 33 ++++++++++++++++++++++++++++++++-
 MiniDSP.h   | 22 ++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/MiniDSP.cpp b/MiniDSP.cpp
index 359018ba..bc6102c0 100644
--- a/MiniDSP.cpp
+++ b/MiniDSP.cpp
@@ -24,6 +24,7 @@
 void MiniDSP::ParseHIDData(USBHID *hid __attribute__ ((unused)), bool is_rpt_id __attribute__ ((unused)), uint8_t len, uint8_t *buf) {
 
         constexpr uint8_t StatusInputCommand[] = {0x05, 0xFF, 0xDA};
+        constexpr uint8_t InputSourceInputCommand[] = {0x05, 0xFF, 0xD9};
 
         // Only care about valid data for the MiniDSP 2x4HD.
         if(HIDUniversal::VID != MINIDSP_VID || HIDUniversal::PID != MINIDSP_PID || len <= 4 || buf == nullptr)
@@ -52,6 +53,28 @@ void MiniDSP::ParseHIDData(USBHID *hid __attribute__ ((unused)), bool is_rpt_id
                 if(pFuncOnMutedChange != nullptr && mutedChanged)
                         pFuncOnMutedChange(muted);
         }
+
+
+        // Check if this is an input source update.
+        // First byte is the length, we ignore that for now.
+        if(memcmp(buf + 1, InputSourceInputCommand, sizeof (InputSourceInputCommand)) == 0) {
+
+                // Parse data.
+                // Response is of format [ length ] [ 0x05 0xFF 0xD9 ] [ source ].
+                const auto newInputSource = buf[sizeof (InputSourceInputCommand) + 1];
+
+                // Ensure we only interpret valid inputs.
+                if(newInputSource >= 0x00 && newInputSource <= 0x02){
+                        const auto inputSourceChanged = newInputSource != (char) inputSource;
+
+                        // Update values.
+                        inputSource = (InputSource) newInputSource;
+
+                        // Call callbacks.
+                        if(pFuncOnInputSourceChange != nullptr && inputSourceChanged)
+                                pFuncOnInputSourceChange(inputSource);
+                }
+        }
 };
 
 uint8_t MiniDSP::OnInitSuccessful() {
@@ -59,8 +82,9 @@ uint8_t MiniDSP::OnInitSuccessful() {
         if(HIDUniversal::VID != MINIDSP_VID || HIDUniversal::PID != MINIDSP_PID)
                 return 0;
 
-        // Request current status so we can initialize the values.
+        // Request current information so we can initialize the values.
         RequestStatus();
+        RequestInputSource();
 
         if(pFuncOnInit != nullptr)
                 pFuncOnInit();
@@ -109,3 +133,10 @@ void MiniDSP::RequestStatus() const {
 
         SendCommand(RequestStatusOutputCommand, sizeof (RequestStatusOutputCommand));
 }
+
+
+void MiniDSP::RequestInputSource() const {
+  uint8_t RequestInputSourceCommand[] = {0x05, 0xFF, 0xD9, 0x01};
+
+  SendCommand(RequestInputSourceCommand, sizeof(RequestInputSourceCommand));
+}
diff --git a/MiniDSP.h b/MiniDSP.h
index 442a8f39..499631ed 100644
--- a/MiniDSP.h
+++ b/MiniDSP.h
@@ -39,6 +39,13 @@
 class MiniDSP : public HIDUniversal {
 public:
 
+        enum class InputSource {
+                ANALOG = 0x00,
+                TOSLINK = 0x01,
+                USB = 0x02,
+                UNKNOWN = 0x03
+        };
+
         /**
          * Constructor for the MiniDSP class.
          * @param  p   Pointer to the USB class instance.
@@ -83,6 +90,14 @@ public:
                 pFuncOnMutedChange = funcOnMutedChange;
         }
 
+        /**
+         * Used to call your own function when the input source has changed.
+         * @param funcOnInputSourceChange Function to call.
+         */
+        void attachOnInputSourceChange(void (*funcOnInputSourceChange)(InputSource)) {
+                pFuncOnInputSourceChange = funcOnInputSourceChange;
+        }
+
         /**
          * Retrieve the current volume of the MiniDSP.
          * The volume is passed as an unsigned integer that represents twice the
@@ -159,6 +174,9 @@ private:
         void
         RequestStatus() const;
 
+        void
+        RequestInputSource() const;
+
         /**
          * Send the given MiniDSP command. This function will create a buffer
          * with the expected header and checksum and send it to the MiniDSP.
@@ -179,6 +197,9 @@ private:
         // Pointer to function called when muted status changes.
         void (*pFuncOnMutedChange)(bool) = nullptr;
 
+        // Pointer to function called when input source changes.
+        void (*pFuncOnInputSourceChange)(InputSource) = nullptr;
+
         // -----------------------------------------------------------------------------
 
         // MiniDSP state. Currently only volume and muted status are
@@ -188,4 +209,5 @@ private:
         // -dB value. Example: 19 represents -9.5dB.
         uint8_t volume = 0;
         bool muted = false;
+        InputSource inputSource = InputSource::UNKNOWN;
 };