From e05a20af63e187c1d3a4d68007e962a34cd27b67 Mon Sep 17 00:00:00 2001
From: George Sexton <georges@mhsoftware.com>
Date: Fri, 20 Sep 2024 12:51:10 -0600
Subject: [PATCH] Issue #60, fix onewire not present, and hanging when it is.

---
 host_linux.go            |  1 +
 netlink/netlink_linux.go | 15 +++++++++++++++
 netlink/netlink_other.go |  4 ++++
 netlink/onewire.go       |  3 +++
 4 files changed, 23 insertions(+)

diff --git a/host_linux.go b/host_linux.go
index 5a729b99..a850466b 100644
--- a/host_linux.go
+++ b/host_linux.go
@@ -7,5 +7,6 @@ package host
 import (
 	// Make sure required drivers are registered.
 	_ "periph.io/x/host/v3/gpioioctl"
+	_ "periph.io/x/host/v3/netlink"
 	_ "periph.io/x/host/v3/sysfs"
 )
diff --git a/netlink/netlink_linux.go b/netlink/netlink_linux.go
index 76774c77..d60792b0 100644
--- a/netlink/netlink_linux.go
+++ b/netlink/netlink_linux.go
@@ -6,6 +6,7 @@ package netlink
 
 import (
 	"fmt"
+	"path/filepath"
 	"syscall"
 )
 
@@ -52,3 +53,17 @@ func (s *connSocket) close() error {
 	s.fd = 0
 	return syscall.Close(fd)
 }
+
+// isOneWireAvailable checks to see if the Linux onewire bus drivers are loaded.
+// It does this by looking for entries in the /sys/bus pseudo-filesystem.
+//
+// On a Raspberry Pi SBC, the onewire bus is enabled by creating entries in the
+// kernel config.txt file which is located in /boot, or /boot/firmware depending
+// on OS/kernel levels.
+func isOneWireAvailable() bool {
+	items, err := filepath.Glob("/sys/bus/w1/devices/*")
+	if err != nil || len(items) == 0 {
+		return false
+	}
+	return true
+}
diff --git a/netlink/netlink_other.go b/netlink/netlink_other.go
index bd0a2aee..6d2b0858 100644
--- a/netlink/netlink_other.go
+++ b/netlink/netlink_other.go
@@ -28,3 +28,7 @@ func (*connSocket) recv(_ []byte) (int, error) {
 func (*connSocket) close() error {
 	return errors.New("not implemented")
 }
+
+func isOneWireAvailable() bool {
+	return false
+}
diff --git a/netlink/onewire.go b/netlink/onewire.go
index 814fe8ca..c4c9b39b 100644
--- a/netlink/onewire.go
+++ b/netlink/onewire.go
@@ -463,6 +463,9 @@ func (d *driver1W) After() []string {
 }
 
 func (d *driver1W) Init() (bool, error) {
+	if !isOneWireAvailable() {
+		return false, errors.New("no onewire buses found")
+	}
 	s, err := newW1Socket()
 	if err != nil {
 		return false, fmt.Errorf("netlink-onewire: failed to open socket: %v", err)