did something

vendor/periph.io/x/host/v3/distro/devtree.go

@@ -0,0 +1,84 @@
+// Copyright 2016 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 distro
+
+import (
+	"encoding/binary"
+	"os"
+)
+
+// DTModel returns platform model info from the Linux device tree (/proc/device-tree/model), and
+// returns "unknown" on non-linux systems or if the file is missing.
+func DTModel() string {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if dtModel == "" {
+		dtModel = "<unknown>"
+		if isLinux {
+			dtModel = makeDTModelLinux()
+		}
+	}
+	return dtModel
+}
+
+// DTCompatible returns platform compatibility info from the Linux device tree
+// (/proc/device-tree/compatible), and returns []{"unknown"} on non-linux systems or if the file is
+// missing.
+func DTCompatible() []string {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if dtCompatible == nil {
+		dtCompatible = []string{}
+		if isLinux {
+			dtCompatible = makeDTCompatible()
+		}
+	}
+	return dtCompatible
+}
+
+// DTRevision returns the device revision (e.g. a02082 for the Raspberry Pi 3)
+// from the Linux device tree, or 0 if the file is missing or malformed.
+func DTRevision() uint32 {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if dtRevisionRead {
+		return dtRevision
+	}
+	dtRevisionRead = true
+	if b, _ := os.ReadFile("/proc/device-tree/system/linux,revision"); len(b) >= 4 {
+		dtRevision = binary.BigEndian.Uint32(b[:4])
+	}
+	return dtRevision
+}
+
+//
+
+var (
+	dtModel        string   // cached /proc/device-tree/model
+	dtCompatible   []string // cached /proc/device-tree/compatible
+	dtRevision     uint32   // cached /proc/device-tree/system/linux,revision
+	dtRevisionRead bool
+)
+
+func makeDTModelLinux() string {
+	// Read model from device tree.
+	if bytes, err := readFile("/proc/device-tree/model"); err == nil {
+		if model := splitNull(bytes); len(model) > 0 {
+			return model[0]
+		}
+	}
+	return "<unknown>"
+}
+
+func makeDTCompatible() []string {
+	// Read compatible from device tree.
+	if bytes, err := readFile("/proc/device-tree/compatible"); err == nil {
+		return splitNull(bytes)
+	}
+	return []string{}
+}