rust: Add some initial information to README.md

Signed-off-by: Siddharth Chandrasekaran <[email protected]>

rust/README.md

@@ -1,18 +1,59 @@
 # OSDP Rust library
 
-This crate is a rust wrapper for the C library [LibOSDP][1].
+This crate is a rust wrapper for [LibOSDP][1] - the most popular open source
+library for creating OSDP devices. See github.cobm/goToMain/liosdp for more
+information.
+
+## Features
+
+  - Supports secure channel communication (AES-128)
+  - Can be used to setup a PD or CP mode of operation
+  - Most OSDP specified commands and replies are supported (see [doc][3])
 
 ## Usage
 
-TODO
+To add libosdp to your rust project do:
+
+```
+cargo add libosdp
+```
+
+### Control Panel:
+
+A simplified CP implementation:
+
+```
+let pd_info = PdInfo::new(...);
+let mut cp = ControlPanel::new(&mut pd_info)?;
+cp.set_event_callback(|pd, event| {
+    println!("Received event from {pd}: {:?}", event);
+});
+loop {
+    cp.refresh();
+    cp.send_command(0, OsdpCommand::new(...));
+}
+```
 
-### Control panel
+See [examples][2] for a working implementation.
 
-TODO
+### Peripheral Device:
 
-### Peripheral device
+A simplified PD implementation:
 
-TODO
+```
+let pd_info = PdInfo::new(...);
+let mut pd = PeripheralDevice::new(&mut pd_info)?;
+pd.set_command_callback(|cmd| {
+    println!("Received command {:?}", cmd);
+});
+loop {
+    pd.refresh();
+    cp.notify_event(OsdpEvent::new(...));
+}
+```
 
+See [examples][2] for a working implementation.
 
-1: https://github.cobm/goToMain/liosdp
+1: https://github.cobm/goToMain/liosdp
+2: https://github.com/goToMain/libosdp/blob/master/rust/examples
+3: https://libosdp.sidcha.dev/protocol/commands-and-replies