main: add support for disabling postfilters

README.md

@@ -70,6 +70,8 @@ The scope of this setting is per TCP session.
 | `pid <0/1> integral_max <value>` | Set integral upper bound                            |
 | `s-h`                            | Show Steinhart-Hart equation parameters             |
 | `s-h <0/1> <t/b/r0> <value>`     | Set Steinhart-Hart parameter for a channel          |
+| `postfilter`                     | Show postfilter settings                            |
+| `postfilter <0/1> off`           | Disable postfilter                                  |
 | `postfilter <0/1> rate <rate>`   | Set postfilter output data rate                     |
 | `load`                           | Restore configuration from EEPROM                   |
 | `save`                           | Save configuration to EEPROM                        |

src/command_parser.rs

@@ -164,7 +164,7 @@ pub enum Command {
     },
     PostFilter {
         channel: usize,
-        rate: f32,
+        rate: Option<f32>,
     },
 }
 
@@ -392,16 +392,24 @@ fn postfilter(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
             |input| {
                 let (input, channel) = channel(input)?;
                 let (input, _) = whitespace(input)?;
+                alt((
+                    value(Ok(Command::PostFilter {
+                        channel,
+                        rate: None,
+                    }), tag("off")),
+                    move |input| {
                         let (input, _) = tag("rate")(input)?;
                         let (input, _) = whitespace(input)?;
                         let (input, rate) = float(input)?;
                         let result = rate
                             .map(|rate| Command::PostFilter {
                                 channel,
-                        rate: rate as f32,
+                                rate: Some(rate as f32),
                             });
                         Ok((input, result))
                     }
+                ))(input)
+            }
         ),
         value(Ok(Command::Show(ShowCommand::PostFilter)), end)
     ))(input)
@@ -570,12 +578,27 @@ mod test {
         }));
     }
 
+    #[test]
+    fn parse_postfilter() {
+        let command = Command::parse(b"postfilter");
+        assert_eq!(command, Ok(Command::Show(ShowCommand::PostFilter)));
+    }
+
+    #[test]
+    fn parse_postfilter_off() {
+        let command = Command::parse(b"postfilter 1 off");
+        assert_eq!(command, Ok(Command::PostFilter {
+            channel: 1,
+            rate: None,
+        }));
+    }
+
     #[test]
     fn parse_postfilter_rate() {
         let command = Command::parse(b"postfilter 0 rate 21");
         assert_eq!(command, Ok(Command::PostFilter {
             channel: 0,
-            rate: 21.0,
+            rate: Some(21.0),
         }));
     }
 

src/main.rs

@@ -308,7 +308,7 @@ fn main() -> ! {
                                             }
                                             None => {
                                                 let _ = writeln!(
-                                                    socket, "channel {}: no postfilter",
+                                                    socket, "channel {}: postfilter disabled",
                                                     channel
                                                 );
                                             }
@@ -421,7 +421,14 @@ fn main() -> ! {
                                     }
                                     let _ = writeln!(socket, "Steinhart-Hart equation parameter updated");
                                 }
-                                Command::PostFilter { channel, rate } => {
+                                Command::PostFilter { channel, rate: None } => {
+                                    channels.adc.set_postfilter(channel as u8, None).unwrap();
+                                    let _ = writeln!(
+                                        socket, "channel {}: postfilter disabled",
+                                        channel
+                                    );
+                                }
+                                Command::PostFilter { channel, rate: Some(rate) } => {
                                     let filter = ad7172::PostFilter::closest(rate);
                                     match filter {
                                         Some(filter) => {