wip: enc28j60 driver.

embassy-net-enc28j60/src/traits.rs

@@ -0,0 +1,57 @@
+use core::ops::Range;
+
+pub(crate) trait OffsetSize {
+    fn offset(self) -> u8;
+    fn size(self) -> u8;
+}
+
+impl OffsetSize for u8 {
+    fn offset(self) -> u8 {
+        self
+    }
+
+    fn size(self) -> u8 {
+        1
+    }
+}
+
+impl OffsetSize for Range<u8> {
+    fn offset(self) -> u8 {
+        self.start
+    }
+
+    fn size(self) -> u8 {
+        self.end - self.start
+    }
+}
+
+pub(crate) trait U16Ext {
+    fn from_parts(low: u8, high: u8) -> Self;
+
+    fn low(self) -> u8;
+
+    fn high(self) -> u8;
+}
+
+impl U16Ext for u16 {
+    fn from_parts(low: u8, high: u8) -> u16 {
+        ((high as u16) << 8) + low as u16
+    }
+
+    fn low(self) -> u8 {
+        (self & 0xff) as u8
+    }
+
+    fn high(self) -> u8 {
+        (self >> 8) as u8
+    }
+}
+
+#[derive(Clone, Copy)]
+pub struct Mask;
+
+#[derive(Clone, Copy)]
+pub struct R;
+
+#[derive(Clone, Copy)]
+pub struct W;