Add monitor brightness support

src/lib.rs

@@ -17,9 +17,15 @@ enum Command {
     Monitor((usize, MonitorCommand)),
 }
 
+#[derive(Debug)]
+pub enum MonitorBrightnessCmd {
+    Absolute(u8),
+    Relative(i8),
+}
+
 #[derive(Debug)]
 pub enum MonitorCommand {
-    Brightness(u8),
+    Brightness(MonitorBrightnessCmd),
     Input(u8),
 }
 
@@ -51,17 +57,42 @@ fn run_i2c(idx: usize, mut dev: I2cDeviceDdc, command_channel: Receiver<MonitorC
             }
         }
         event!(Level::INFO, monitor_index = idx, ?cmd, "Sending DDC comand");
-        if let Err(e) = match cmd {
+        if let Err(e) = handle_monitor_cmd(&cmd, &mut dev) {
-            MonitorCommand::Brightness(b) => dev.set_vcp_feature(cmd.vcp(), b.into()),
-            // Hack - add 15 to align with DELL monitors
-            MonitorCommand::Input(i) => dev.set_vcp_feature(cmd.vcp(), (i + 15).into()),
-        } {
             event!(Level::WARN, err = %e, "Error sending DDC command");
         }
         last_sent_command.insert(cmd.cmd_str(), Some(Instant::now()));
     }
 }
 
+fn handle_monitor_cmd(cmd: &MonitorCommand, dev: &mut I2cDeviceDdc) -> StdError<()> {
+    match cmd {
+        MonitorCommand::Brightness(MonitorBrightnessCmd::Absolute(b)) => {
+            event!(Level::INFO, brightness = b, "Setting monitor brightness");
+            dev.set_vcp_feature(cmd.vcp(), (*b).into())
+                .map_err(|e| e.into())
+        }
+        MonitorCommand::Brightness(MonitorBrightnessCmd::Relative(b)) => {
+            let current = dev.get_vcp_feature(cmd.vcp())?;
+            let (current, max) = (current.value(), current.maximum());
+            event!(Level::INFO, current, max, "Got brightness of monitor");
+            if max != 100 {
+                return Err(format!("Expected maximum brightness to be 100, got {}", max).into());
+            }
+            let mut new = current.saturating_add_signed(*b as i16);
+            // Clamp to 0-100
+            if new > 100 {
+                new = 100;
+            }
+            event!(Level::INFO, brightness = new, "Setting monitor brightness");
+            dev.set_vcp_feature(cmd.vcp(), new).map_err(|e| e.into())
+        }
+        // Hack - add 15 to align with DELL monitors
+        MonitorCommand::Input(i) => dev
+            .set_vcp_feature(cmd.vcp(), (i + 15).into())
+            .map_err(|e| e.into()),
+    }
+}
+
 pub fn main() -> StdError<()> {
     event!(Level::INFO, "Starting");
     let displays = I2cDeviceEnumerator::new().unwrap().collect::<Vec<_>>();

src/mqtt.rs

@@ -1,4 +1,4 @@
-use crate::{handle_cmd, Command, MonitorCommand, StdError};
+use crate::{handle_cmd, Command, MonitorBrightnessCmd, MonitorCommand, StdError};
 use rumqttc::mqttbytes::v4::Packet;
 use rumqttc::{Client, Event, MqttOptions, QoS};
 use std::env;
@@ -8,6 +8,7 @@ use tracing::{event, Level};
 
 pub fn run_mqtt(txes: &Vec<Sender<MonitorCommand>>) -> StdError<()> {
     let client_id = env::var("MQTT_CLIENT_ID").unwrap_or("ddcmqtt".into());
+    let topic_prefix = env::var("MQTT_TOPIC_PREFIX").unwrap_or("ddcmqtt".into());
     let mqtt_host = env::var("MQTT_HOST").unwrap_or("localhost".into());
     let mqtt_port = env::var("MQTT_PORT")
         .unwrap_or("1883".into())
@@ -24,7 +25,7 @@ pub fn run_mqtt(txes: &Vec<Sender<MonitorCommand>>) -> StdError<()> {
     mqttoptions.set_keep_alive(Duration::from_secs(5));
 
     let (mut client, mut connection) = Client::new(mqttoptions, 10);
-    client.subscribe("ddcmqtt/#", QoS::AtMostOnce)?;
+    client.subscribe([&topic_prefix, "#"].join("/"), QoS::AtMostOnce)?;
 
     event!(Level::INFO, mqtt_host, mqtt_port, "Running MQTT client");
 
@@ -40,7 +41,7 @@ pub fn run_mqtt(txes: &Vec<Sender<MonitorCommand>>) -> StdError<()> {
                 );
                 continue;
             }
-            if topic[0] != "ddcmqtt" {
+            if topic[0] != topic_prefix {
                 event!(
                     Level::ERROR,
                     ?topic,
@@ -58,6 +59,18 @@ pub fn run_mqtt(txes: &Vec<Sender<MonitorCommand>>) -> StdError<()> {
                         &txes,
                     )?;
                 }
+                (Ok(idx), "brightness") => {
+                    let brightness = std::str::from_utf8(&p.payload)?;
+                    let cmd = if brightness.starts_with('+') | brightness.starts_with('-') {
+                        MonitorBrightnessCmd::Relative(brightness.parse::<i8>()?)
+                    } else {
+                        MonitorBrightnessCmd::Absolute(brightness.parse::<u8>()?)
+                    };
+                    handle_cmd(
+                        Command::Monitor((idx.into(), MonitorCommand::Brightness(cmd))),
+                        &txes,
+                    )?;
+                }
                 _ => {
                     event!(Level::ERROR, ?topic, "Unrecognised or invalid topic");
                     continue;

src/osc.rs

@@ -1,4 +1,4 @@
-use crate::{handle_cmd, Command, MonitorCommand, StdError};
+use crate::{handle_cmd, Command, MonitorBrightnessCmd, MonitorCommand, StdError};
 use rosc;
 use std::net::UdpSocket;
 use std::sync::mpsc::Sender;
@@ -36,9 +36,9 @@ fn osc_message_to_command(msg: rosc::OscMessage) -> StdError<Command> {
         ["monitor", idx, control] => {
             println!("Monitor {}, control {}, args {:?}", idx, control, msg.args);
             let command = match *control {
-                "brightness" => Some(MonitorCommand::Brightness(
+                "brightness" => Some(MonitorCommand::Brightness(MonitorBrightnessCmd::Absolute(
                     (msg.args[0].clone().float().unwrap() * 100.0) as u8,
-                )),
+                ))),
                 "input" => Some(MonitorCommand::Input(
                     (msg.args[0].clone().int().unwrap()) as u8,
                 )),