did something

vendor/periph.io/x/conn/v3/gpio/func.go

@@ -0,0 +1,26 @@
+// Copyright 2018 The Periph Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package gpio
+
+import "periph.io/x/conn/v3/pin"
+
+// Well known pin functionality.
+const (
+	// Inputs
+	IN      pin.Func = "IN"      // Input
+	IN_HIGH pin.Func = "In/High" // Read high
+	IN_LOW  pin.Func = "In/Low"  // Read low
+
+	// Outputs
+	OUT      pin.Func = "OUT"      // Output, drive
+	OUT_OC   pin.Func = "OUT_OPEN" // Output, open collector/drain
+	OUT_HIGH pin.Func = "Out/High" // Drive high
+	OUT_LOW  pin.Func = "Out/Low"  // Drive low; open collector low
+
+	FLOAT pin.Func = "FLOAT" // Input float or Output open collector high
+
+	CLK pin.Func = "CLK" // Clock is a subset of a PWM, with a 50% duty cycle
+	PWM pin.Func = "PWM" // Pulse Width Modulation, which is a clock with variable duty cycle
+)