Minor fixes to attr writes

rog-platform/src/macros.rs

@@ -85,6 +85,7 @@ macro_rules! get_attr_u8 {
     };
 }
 
+/// Most attributes expect `u8` as a char, so `1` should be written as `b'1'`.
 #[macro_export]
 macro_rules! set_attr_u8 {
     ($(#[$doc_comment:meta])? $attr_name:literal $item:ident) => {

rog-platform/src/platform.rs

@@ -76,25 +76,26 @@ pub enum GpuMode {
 }
 
 impl GpuMode {
-    pub fn to_mux(&self) -> u8 {
+    /// For writing to `gpu_mux_mode` attribute
+    pub fn to_mux_attr(&self) -> u8 {
         if *self == Self::Discrete {
-            return 0;
+            return b'0';
         }
-        1
+        b'1'
     }
 
-    pub fn to_dgpu(&self) -> u8 {
+    pub fn to_dgpu_attr(&self) -> u8 {
         if *self == Self::Integrated {
-            return 1;
+            return b'1';
         }
-        0
+        b'0'
     }
 
-    pub fn to_egpu(&self) -> u8 {
+    pub fn to_egpu_attr(&self) -> u8 {
         if *self == Self::Egpu {
-            return 1;
+            return b'1';
         }
-        0
+        b'0'
     }
 
     pub fn from_mux(num: u8) -> Self {