sx126x: Driver for Semtech sx126x radio modules and optional RF Switch.

This first version of the driver has been tested with STM32WL SoC,
	which embeddeds SX1262 radio on the same die.

examples/sx126x/rfswitch/wl55jc.go

@@ -0,0 +1,55 @@
+//go:build nucleowl55jc
+// +build nucleowl55jc
+
+/*
+ Nucleo WL55JC1
+ RFSwitch
+
++-----------+---------+------------+------------+
+|           | FE_CTRL1 |  FE_CTRL2 |   FE_CTRL3 |
+|           |   (PC4)  |   (PC5)   |     (PC3)  |
++-----------+----------+-----------+------------+
+|  TX_HP    |   LOW    |   HIGH    |    HIGH    |
+|  TX_LP    |   HIGH   |   HIGH    |    HIGH    |
+|  RX       |   HIGH   |   LOW     |    HIGH    |
++-----------+----------+-----------+------------+
+*/
+package rfswitch
+
+import (
+	"machine"
+
+	"tinygo.org/x/drivers/sx126x"
+)
+
+type CustomSwitch struct {
+}
+
+func (s CustomSwitch) InitRFSwitch() {
+	machine.PC4.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	machine.PC5.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	machine.PC3.Configure(machine.PinConfig{Mode: machine.PinOutput})
+}
+
+func (s CustomSwitch) SetRfSwitchMode(mode int) error {
+	switch mode {
+
+	case sx126x.RFSWITCH_TX_HP:
+		machine.PC4.Set(false)
+		machine.PC5.Set(true)
+		machine.PC3.Set(true)
+
+	case sx126x.RFSWITCH_TX_LP:
+		machine.PC4.Set(true)
+		machine.PC5.Set(true)
+		machine.PC3.Set(true)
+
+	case sx126x.RFSWITCH_RX:
+		machine.PC4.Set(true)
+		machine.PC5.Set(false)
+		machine.PC3.Set(true)
+
+	}
+	return nil
+
+}