Kernel: Add mixer support to IHDA

This has not been tested as I don't have any hardware with mixers on
output paths :P

kernel/include/kernel/Audio/HDAudio/Definitions.h

@@ -65,6 +65,7 @@ namespace Kernel::HDAudio
 		};
 
 		BAN::Optional<Amplifier> output_amplifier;
+		BAN::Optional<Amplifier> input_amplifier;
 
 		BAN::Vector<uint16_t> connections;
 	};

kernel/kernel/Audio/HDAudio/AudioFunctionGroup.cpp

@@ -342,6 +342,7 @@ namespace Kernel
 			{
 				using HDAudio::AFGWidget;
 				case AFGWidget::Type::OutputConverter:
+				case AFGWidget::Type::Mixer:
 				case AFGWidget::Type::PinComplex:
 					break;
 				default:
@@ -363,7 +364,7 @@ namespace Kernel
 			}));
 
 			// set connection index
-			if (i + 1 < path.size() && path[i]->connections.size() > 1)
+			if (i + 1 < path.size() && path[i]->connections.size() > 1 && path[i]->type != HDAudio::AFGWidget::Type::Mixer)
 			{
 				uint8_t index = 0;
 				for (; index < path[i]->connections.size(); index++)
@@ -419,6 +420,25 @@ namespace Kernel
 					}));
 					break;
 
+				case AFGWidget::Type::Mixer:
+					if (path[i]->input_amplifier.has_value())
+					{
+						for (size_t idx = 0; idx < path[i]->connections.size(); idx++)
+						{
+							const uint8_t step = (path[i]->connections[idx] == path[i + 1]->id)
+								? path[i]->input_amplifier->offset
+								: 0b1'0000000;
+							const uint32_t volume = 0b0'1'1'1'0000'0'0000000 | (idx << 8) | step;
+							TRY(m_controller->send_command({
+								.data = static_cast<uint8_t>(volume & 0xFF),
+								.command = static_cast<uint16_t>(0x300 | (volume >> 8)),
+								.node_index = path[i]->id,
+								.codec_address = m_cid,
+							}));
+						}
+					}
+					break;
+
 				case AFGWidget::Type::PinComplex:
 					// enable output and H-Phn
 					TRY(m_controller->send_command({
@@ -504,6 +524,7 @@ namespace Kernel
 				using HDAudio::AFGWidget;
 
 				case AFGWidget::Type::OutputConverter:
+				case AFGWidget::Type::Mixer:
 					break;
 
 				case AFGWidget::Type::PinComplex:

kernel/kernel/Audio/HDAudio/Controller.cpp

@@ -333,6 +333,20 @@ namespace Kernel
 			};
 		}
 
+		if (const uint32_t in_amp_cap = send_command_or_zero(0xF00, 0x0D))
+		{
+			const uint8_t offset    = (in_amp_cap >>  0) & 0x7F;
+			const uint8_t num_steps = (in_amp_cap >>  8) & 0x7F;
+			const uint8_t step_size = (in_amp_cap >> 16) & 0x7F;
+			const bool    mute      = (in_amp_cap >> 31);
+			result.input_amplifier = HDAudio::AFGWidget::Amplifier {
+				.offset = offset,
+				.num_steps = num_steps,
+				.step_size = step_size,
+				.mute = mute,
+			};
+		}
+
 		const uint8_t connection_info = send_command_or_zero(0xF00, 0x0E);
 		const uint8_t conn_width = (connection_info & 0x80) ? 2 : 1;
 		const uint8_t conn_count = connection_info & 0x3F;