1 files changed, 52 insertions, 0 deletions
diff --git a/tmp117/src/id.rs b/tmp117/src/id.rs
new file mode 100644
index 0000000..e1fcc8b
--- /dev/null
+++ b/tmp117/src/id.rs
@@ -0,0 +1,52 @@
+pub struct Identity {
+    pub device_id: u16,
+
+    pub revision_number: u8,
+}
+
+impl From<u16> for Identity {
+    fn from(register: u16) -> Self {
+        let device_id = register & 0x0FFF;
+        let revision_number = ((register >> 12) & 0xF) as u8;
+        Self {
+            device_id,
+            revision_number,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_identity_from_known_device_id() {
+        let identity = Identity::from(0x0117);
+        assert_eq!(identity.device_id, 0x117);
+        assert_eq!(identity.revision_number, 0);
+    }
+
+    #[test]
+    fn test_identity_device_id_masked() {
+        // bits 11:0 are device ID
+        let identity = Identity::from(0x0FFF);
+        assert_eq!(identity.device_id, 0x0FFF);
+        assert_eq!(identity.revision_number, 0);
+    }
+
+    #[test]
+    fn test_identity_revision_number_extracted() {
+        // bits 15:12 are revision
+        let identity = Identity::from(0x1000);
+        assert_eq!(identity.device_id, 0x000);
+        assert_eq!(identity.revision_number, 1);
+    }
+
+    #[test]
+    fn test_identity_both_fields() {
+        // revision = 0xA, device_id = 0x117
+        let identity = Identity::from(0xA117);
+        assert_eq!(identity.device_id, 0x117);
+        assert_eq!(identity.revision_number, 0xA);
+    }
+}