Add const to set hwmon index

backend-rs/src/sys.rs

@@ -1,17 +1,19 @@
 use usdpl_back::api::files::*;
 
+const HWMON_INDEX: usize = 5;
+
 pub fn read_fan() -> Option<u64> {
-    read_single("/sys/class/hwmon/hwmon5/fan1_input").ok()
+    read_single(format!("/sys/class/hwmon/hwmon{}/fan1_input", HWMON_INDEX)).ok()
 }
 
 pub fn read_thermal_zone(index: u8) -> Option<u64> {
     read_single(format!("/sys/class/thermal/thermal_zone{}/temp", index)).ok()
 }
 
 pub fn write_fan_recalc(enabled: bool) -> Result<(), std::io::Error> {
-    write_single("/sys/class/hwmon/hwmon5/recalculate", enabled as u8)
+    write_single(format!("/sys/class/hwmon/hwmon{}/recalculate", HWMON_INDEX), enabled as u8)
 }
 
 pub fn write_fan_target(rpm: u64) -> Result<(), std::io::Error> {
-    write_single("/sys/class/hwmon/hwmon5/fan1_target", rpm)
+    write_single(format!("/sys/class/hwmon/hwmon{}/fan1_target", HWMON_INDEX), rpm)
 }