add SPI driver for semtech sx128x chips

sx128x/README.md

@@ -0,0 +1,7 @@
+# SX128x Radio
+Radio from Semtech in the 2.4 GHz band. This driver uses SPI to communicate with the radio instead of the alternative UART interface.
+
+## Supported Chips
+- [SX1280](https://www.semtech.com/products/wireless-rf/lora-connect/sx1280)
+- [SX1281](https://www.semtech.com/products/wireless-rf/lora-connect/sx1281) 
+

sx128x/commands.go

@@ -0,0 +1,52 @@
+package sx128x
+
+const (
+	// SX128X SPI commands
+	cmdGetStatus = uint8(0xC0)
+
+	// Register Access Operations
+	cmdWriteRegister = uint8(0x18)
+	cmdReadRegister  = uint8(0x19)
+
+	// Data Buffer Operations
+	cmdWriteBuffer = uint8(0x1A)
+	cmdReadBuffer  = uint8(0x1B)
+
+	// Radio Operation Modes
+	cmdSetSleep              = uint8(0x84)
+	cmdSetStandby            = uint8(0x80)
+	cmdSetFS                 = uint8(0xC1)
+	cmdSetTx                 = uint8(0x83)
+	cmdSetRx                 = uint8(0x82)
+	cmdSetRxDutyCycle        = uint8(0x94)
+	cmdSetLongPreamble       = uint8(0x9B)
+	cmdSetCAD                = uint8(0xC5)
+	cmdSetTxContinuousWave   = uint8(0xD1)
+	cmdSetContinuousPreamble = uint8(0xD2)
+	cmdSetAutoTx             = uint8(0x98)
+	cmdSetAutoFS             = uint8(0x9E)
+
+	// Radio Configuration
+	cmdSetPacketType        = uint8(0x8A)
+	cmdGetPacketType        = uint8(0x03)
+	cmdSetRFFrequency       = uint8(0x86)
+	cmdSetTxParams          = uint8(0x8E)
+	cmdSetCADParams         = uint8(0x88)
+	cmdSetBufferBaseAddress = uint8(0x8F)
+	cmdSetModulationParams  = uint8(0x8B)
+	cmdSetPacketParams      = uint8(0x8C)
+
+	// Communication Status Information
+	cmdGetRxBufferStatus = uint8(0x17)
+	cmdGetPacketStatus   = uint8(0x1D)
+	cmdGetRSSIInst       = uint8(0x1F)
+
+	// IRQ Handling
+	cmdSetDIOIRQParams = uint8(0x8D)
+	cmdGetIRQStatus    = uint8(0x15)
+	cmdClearIRQStatus  = uint8(0x97)
+
+	// Miscellaneous
+	cmdSetRegulatorMode = uint8(0x96)
+	cmdSetSaveContext   = uint8(0xD5)
+)