machine: add Device constant

This field contains the microcontroller name that we're compiling for,
or "generic" if we're not running on a microcontroller.

src/machine/machine.go

@@ -10,6 +10,13 @@ var (
 	ErrNoPinChangeChannel = errors.New("machine: no channel available for pin interrupt")
 )
 
+// Device is the running program's chip name, such as "ATSAMD51J19A" or
+// "nrf52840". It is not the same as the CPU name.
+//
+// The constant is some hardcoded default value if the program does not target a
+// particular chip but instead runs in WebAssembly for example.
+const Device = deviceName
+
 // PinMode sets the direction and pull mode of the pin. For example, PinOutput
 // sets the pin as an output and PinInputPullup sets the pin as an input with a
 // pull-up.

src/machine/machine_atsamd21.go

@@ -16,6 +16,8 @@ import (
 	"unsafe"
 )
 
+const deviceName = sam.Device
+
 const (
 	PinAnalog    PinMode = 1
 	PinSERCOM    PinMode = 2

src/machine/machine_atsamd51.go

@@ -16,6 +16,8 @@ import (
 	"unsafe"
 )
 
+const deviceName = sam.Device
+
 func CPUFrequency() uint32 {
 	return 120000000
 }

src/machine/machine_avr.go

@@ -8,6 +8,8 @@ import (
 	"unsafe"
 )
 
+const deviceName = avr.DEVICE
+
 const (
 	PinInput PinMode = iota
 	PinInputPullup

src/machine/machine_esp32.go

@@ -9,6 +9,8 @@ import (
 	"unsafe"
 )
 
+const deviceName = esp.Device
+
 const peripheralClock = 80000000 // 80MHz
 
 // CPUFrequency returns the current CPU frequency of the chip.

src/machine/machine_esp32c3.go

@@ -8,6 +8,8 @@ import (
 	"unsafe"
 )
 
+const deviceName = esp.Device
+
 // CPUFrequency returns the current CPU frequency of the chip.
 // Currently it is a fixed frequency but it may allow changing in the future.
 func CPUFrequency() uint32 {

src/machine/machine_esp8266.go

@@ -7,6 +7,8 @@ import (
 	"runtime/volatile"
 )
 
+const deviceName = esp.Device
+
 func CPUFrequency() uint32 {
 	return 80000000 // 80MHz
 }

src/machine/machine_fe310.go

@@ -8,6 +8,8 @@ import (
 	"unsafe"
 )
 
+const deviceName = sifive.Device
+
 func CPUFrequency() uint32 {
 	return 320000000 // 320MHz
 }

src/machine/machine_gameboyadvance.go

@@ -9,6 +9,10 @@ import (
 	"unsafe"
 )
 
+// Not sure what name to pick here. Not using ARM7TDMI because that's the CPU
+// name, not the device name.
+const deviceName = "GBA"
+
 // Interrupt numbers as used on the GameBoy Advance. Register them with
 // runtime/interrupt.New.
 const (

src/machine/machine_generic.go

@@ -4,6 +4,8 @@ package machine
 
 // Dummy machine package that calls out to external functions.
 
+const deviceName = "generic"
+
 var (
 	UART0 = &UART{0}
 	USB   = &UART{100}

src/machine/machine_k210.go

@@ -10,6 +10,8 @@ import (
 	"unsafe"
 )
 
+const deviceName = kendryte.Device
+
 func CPUFrequency() uint32 {
 	return 390000000
 }

src/machine/machine_mimxrt1062.go

@@ -11,6 +11,8 @@ import (
 
 // Peripheral abstraction layer for the MIMXRT1062
 
+const deviceName = nxp.Device
+
 func CPUFrequency() uint32 {
 	return 600000000
 }

src/machine/machine_nrf.go

@@ -13,6 +13,8 @@ var (
 	ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
 )
 
+const deviceName = nrf.Device
+
 const (
 	PinInput         PinMode = (nrf.GPIO_PIN_CNF_DIR_Input << nrf.GPIO_PIN_CNF_DIR_Pos) | (nrf.GPIO_PIN_CNF_INPUT_Connect << nrf.GPIO_PIN_CNF_INPUT_Pos)
 	PinInputPullup   PinMode = PinInput | (nrf.GPIO_PIN_CNF_PULL_Pullup << nrf.GPIO_PIN_CNF_PULL_Pos)

src/machine/machine_nxpmk66f18.go

@@ -37,6 +37,8 @@ import (
 	"unsafe"
 )
 
+const deviceName = nxp.Device
+
 const (
 	PinInput PinMode = iota
 	PinInputPullUp

src/machine/machine_rp2040.go

@@ -8,6 +8,8 @@ import (
 	"runtime/interrupt"
 )
 
+const deviceName = rp.Device
+
 const (
 	// GPIO pins
 	GPIO0  Pin = 0

src/machine/machine_stm32.go

@@ -2,6 +2,10 @@
 
 package machine
 
+import "device/stm32"
+
+const deviceName = stm32.Device
+
 // Peripheral abstraction layer for the stm32.
 
 const (