From 5be48c81ef2958f9e1caaa5273f972f517bcd460 Mon Sep 17 00:00:00 2001
From: Vegard Storheil Eriksen <zyp@jvnv.net>
Date: Sat, 29 Sep 2012 17:01:07 +0200
Subject: Added USB volume control.

---
 main.cpp | 55 ++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 9 deletions(-)

diff --git a/main.cpp b/main.cpp
index 1cee450..13dac75 100644
--- a/main.cpp
+++ b/main.cpp
@@ -119,6 +119,9 @@ USB_otg usb(OTG_FS, dev_desc_p, conf_desc_p);
 class USB_Audio : public USB_class_driver {
 	private:
 		USB_generic& usb;
+		
+		enum ControlState {None, VolLeft, VolRight};
+		ControlState control_state;
 	
 	public:
 		USB_Audio(USB_generic& usbd) : usb(usbd) {
@@ -127,34 +130,52 @@ class USB_Audio : public USB_class_driver {
 	
 	protected:
 		virtual SetupStatus handle_setup(uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex, uint16_t wLength) {
+			control_state = ControlState::None;
+			
+			// GET_CUR
 			if(bmRequestType == 0xa1 && bRequest == 0x81) {
-				uint32_t nullw = 0;
-				usb.write(0, &nullw, wLength);
+				uint32_t res = 0;
+				usb.write(0, &res, wLength);
 				return SetupStatus::Ok;
 			}
 			
+			// GET_MIN
 			if(bmRequestType == 0xa1 && bRequest == 0x82) {
-				uint32_t nullw = 0;
-				usb.write(0, &nullw, wLength);
+				uint32_t res = 0;
+				usb.write(0, &res, wLength);
 				return SetupStatus::Ok;
 			}
 			
+			// GET_MAX
 			if(bmRequestType == 0xa1 && bRequest == 0x83) {
-				uint32_t nullw = 0;
-				usb.write(0, &nullw, wLength);
+				uint32_t res = 127;
+				usb.write(0, &res, wLength);
 				return SetupStatus::Ok;
 			}
 			
+			// GET_RES
 			if(bmRequestType == 0xa1 && bRequest == 0x84) {
-				uint32_t nullw = 0;
-				usb.write(0, &nullw, wLength);
+				uint32_t res = 1;
+				usb.write(0, &res, wLength);
 				return SetupStatus::Ok;
 			}
 			
+			// SET_CUR
 			if(bmRequestType == 0x21 && bRequest == 0x01) {
+				switch(wValue) {
+					case 0x0201:
+						control_state = ControlState::VolLeft;
+						break;
+					
+					case 0x0202:
+						control_state = ControlState::VolRight;
+						break;
+				}
+				
 				return SetupStatus::Ok;
 			}
 			
+			// SET_CUR
 			if(bmRequestType == 0x22 && bRequest == 0x01) {
 				return SetupStatus::Ok;
 			}
@@ -170,7 +191,23 @@ class USB_Audio : public USB_class_driver {
 		}
 		
 		virtual void handle_out(uint8_t ep, uint32_t len) {
-			if(ep == 0) {
+			if(ep == 0 && len > 0) {
+				uint32_t buf;
+				usb.read(0, &buf, len > 4 ? 4 : len);
+				
+				switch(control_state) {
+					case ControlState::VolLeft:
+						dac.set_volume(0, buf & 0xff);
+						break;
+					
+					case ControlState::VolRight:
+						dac.set_volume(1, buf & 0xff);
+						break;
+					
+					default:
+						break;
+				}
+				
 				usb.write(0, nullptr, 0);
 				
 			} else if(ep == 1) {
-- 
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