Signed-off-by: Egor Savkin <es@m-labs.hk>

@@ -579,2 +593,4 @@
     max_i_pos: PwmSummaryField<ElectricCurrent>,
     max_i_neg: PwmSummaryField<ElectricCurrent>,
+    tacho: f64,
+    fan: f64,

@@ -481,6 +493,8 @@ impl Channels {
             max_v: (self.get_max_v(channel), ElectricPotential::new::<volt>(5.0)).into(),
             max_i_pos: self.get_max_i_pos(channel).into(),
             max_i_neg: self.get_max_i_neg(channel).into(),
+            tacho: self.get_pwm(0, PwmPin::Tacho),

@@ -315,0 +322,4 @@
+            fan.into_alternate(),
+        );
+        let (mut tacho, mut fan) = Timer::new(tim8, &clocks).pwm(channels, freq);
+        init_pwm_pin(&mut tacho);

@@ -185,2 +194,4 @@
 
                 let instant = Instant::from_millis(i64::from(timer::now()));
+                let tacho_input = tacho.check_interrupt();
+                tacho.clear_interrupt_pending_bit();

@@ -187,0 +199,4 @@
+                    tacho_cnt += 1;
+                }
+
+                let epoch = instant.millis >> 10;

@@ -172,1 +174,4 @@
 
+    tacho.make_interrupt_source(&mut dp.SYSCFG.constrain());
+    tacho.trigger_on_edge(&mut dp.EXTI, Edge::Rising);
+    tacho.enable_interrupt(&mut dp.EXTI);

@@ -474,3 +482,3 @@
     }
 
-    fn pwm_summary(&mut self, channel: usize) -> PwmSummary {
+    fn pwm_summary(&mut self, channel: usize, tacho: u32) -> PwmSummary {

@@ -488,3 +498,3 @@
         let mut summaries = Vec::<_, U2>::new();
         for channel in 0..CHANNELS {
-            let _ = summaries.push(self.pwm_summary(channel));
+            let _ = summaries.push(self.pwm_summary(channel, tacho));

@@ -342,12 +342,16 @@ impl Channels {
                 get(&self.pwm.max_i_neg0),
             (0, PwmPin::MaxV) =>
                 get(&self.pwm.max_v0),
+            (0, PwmPin::Fan) =>

@@ -272,0 +275,4 @@
+## Fan control
+
+Fan control is available for the thermostat revisions with integrated fan system. For this purpose two commands are available:
+1. `fan` - show fan stats: `fan_pwm`, `tacho`, `abs_max_tec_i`, `auto_mode`. Please note that `tacho` shows *approximate* value, which

@@ -70,3 +70,3 @@
           rustPlatform.rust.rustc
           rustPlatform.rust.cargo
-          openocd dfu-util
+          openocd dfu-util gcc-arm-embedded-10

@@ -272,0 +279,4 @@
+linearly correlates with the actual fan speed.
+2. `fan <value>` - set the fan power with the value from `0` to `100`. Since there is no hardware way to disable the fan,
+`0` value is used for enabling automatic fan control mode, which correlates with the square of the TEC's current. 
+Values from `1` to `100` are used for setting the power from minimum to maximum respectively.

@@ -24,3 +26,4 @@
 pub const R_SENSE: f64 = 0.05;
 // DAC chip outputs 0-5v, which is then passed through a resistor dividor to provide 0-3v range
 const DAC_OUT_V_MAX: f64 = 3.0;
+const MAX_TEC_I: f64 = 3.0; // as stated in the schemes

@@ -337,2 +366,4 @@
             (_, PwmPin::ISet) =>
                 panic!("i_set is no pwm pin"),
+            (_, PwmPin::Fan) =>
+                get(&self.pwm.fan),

@@ -454,6 +500,7 @@ impl Channels {
             tec_i,
             tec_u_meas: self.get_tec_v(channel),
             pid_output,
+            hwrev: self.hw_rev

@@ -63,6 +77,21 @@ impl Channels {
         channels
     }
 
+    fn detect_hw_rev(hwrev_pins: &HWRevPins) -> HWRev {

@@ -521,0 +589,4 @@
+
+    pub fn fan_ctrl(&mut self) {
+        if self.fan_auto && self.fan_available() {
+            let scaled_current = self.current_abs_max_tec_i() / MAX_TEC_I;

@@ -521,0 +590,4 @@
+    pub fn fan_ctrl(&mut self) {
+        if self.fan_auto && self.fan_available() {
+            let scaled_current = self.current_abs_max_tec_i() / MAX_TEC_I;
+            let pwm = max_by(scaled_current * scaled_current * MAX_FAN_PWM,

@@ -173,0 +181,4 @@
+        // option for the current version of stm32f4xx-hal,
+        // since tying the IC's PC8 with the PWM's PC9 to the same TIM8 is not supported,
+        // and therefore would require even more weirder and unsafe hacks.
+        // Also such hacks wouldn't guarantee it to be more precise.

@@ -345,0 +366,4 @@
+        Ok(Handler::Handled)
+    }
+
+    fn fan_coeff (socket: &mut TcpSocket, fan_ctrl: &mut FanCtrl, k_a: f64, k_b: f64, k_c: f64) -> Result<Handler, Error> {

@@ -272,0 +283,4 @@
+`0` value is used for enabling automatic fan control mode, which correlates with the square of the TEC's current. 
+Values from `1` to `100` are used for setting the power from minimum to maximum respectively.
+Please note that power doesn't correlate with the actual speed linearly.
+3. `fcurve <a> <b> <c>` - set coefficients of the controlling curve `a*x^2 + b*x + c`, where `x` is `abs_max_tec_i/MAX_TEC_I`, 

@@ -523,0 +567,4 @@
+    ))(input)?;
+
+    let result = match coeffs {
+        Some(coeffs) => Ok(Command::FanCoeff { k_a: coeffs.0, k_b: coeffs.1, k_c: coeffs.2 }),

@@ -0,0 +273,4 @@
+            FanStatus::OK => "Fan is OK".as_bytes(),
+            FanStatus::NotAvailable => "Fan is not available".as_bytes(),
+            FanStatus::Stalled => "Fan is stalled".as_bytes(),
+            FanStatus::LowSignal => "Fan is low signal".as_bytes(),

@@ -151,1 +153,4 @@
     }
+    // considered safe since `channels` is being mutated in a single thread,
+    // while mutex would be excessive
+    let mut fan_ctrl = FanCtrl::new(fan, tacho, unsafe{ &mut *channels.as_ptr() }, &mut dp.EXTI, &mut dp.SYSCFG.constrain());

@@ -0,0 +186,4 @@
+
+    fn init(&mut self, exti: &mut EXTI, syscfg: &mut SysCfg) {
+        // These lines do not cause NVIC to run the ISR,
+        // since the interrupt should be unmasked in the cortex_m::peripheral::NVIC.

@@ -0,0 +191,4 @@
+        // option for the current version of stm32f4xx-hal,
+        // since tying the IC's PC8 with the PWM's PC9 to the same TIM8 is not supported,
+        // and therefore would require even more weirder and unsafe hacks.
+        // Also such hacks wouldn't guarantee it to be more precise.

@@ -0,0 +190,4 @@
+        // Also using interrupt-related workaround is the best
+        // option for the current version of stm32f4xx-hal,
+        // since tying the IC's PC8 with the PWM's PC9 to the same TIM8 is not supported,
+        // and therefore would require even more weirder and unsafe hacks.

@@ -0,0 +230,4 @@
+    fn diagnose(&mut self) -> FanStatus {
+        if self.past_record & 0b11 == 0b11 {
+            FanStatus::OK
+        } else if self.past_record & 0xAAAAAAAAAAAAAAAA > 0 {

@@ -0,0 +201,4 @@
+    fn add_record(&mut self, value: u32) {
+        self.past_record = self.past_record << 2;
+        if value >= TACHO_LOW_THRESHOLD {
+            self.past_record += 0b11;

@@ -0,0 +199,4 @@
+
+    #[inline]
+    fn add_record(&mut self, value: u32) {
+        self.past_record = self.past_record << 2;

@@ -0,0 +29,4 @@
+const TACHO_LOW_THRESHOLD: u32 = 100;
+const DEFAULT_K_A: f64 = 1.0;
+const DEFAULT_K_B: f64 = 0.0;
+const DEFAULT_K_C: f64 = 0.04;

@@ -0,0 +200,4 @@
+    #[inline]
+    fn add_record(&mut self, value: u32) {
+        self.past_record = self.past_record << 2;
+        if value >= TACHO_LOW_THRESHOLD {

@@ -164,3 +165,3 @@
     }
 
-    fn show_ipv4 (socket: &mut TcpSocket, ipv4_config: &mut Ipv4Config) -> Result<Handler, Error> {
+    fn show_ipv4(socket: &mut TcpSocket, ipv4_config: &mut Ipv4Config) -> Result<Handler, Error> {

@@ -345,0 +345,4 @@
+    fn fan(socket: &mut TcpSocket, fan_pwm: Option<u32>, fan_ctrl: &mut FanCtrl) -> Result<Handler, Error> {
+        match fan_pwm {
+            Some(val) => {
+                fan_ctrl.set_auto_mode(val == 0);

@@ -272,0 +279,4 @@
+
+Fan control is available for the thermostat revisions with integrated fan system. For this purpose four commands are available:
+1. `fan` - show fan stats: `fan_pwm`, `abs_max_tec_i`, `auto_mode`, `k_a`, `k_b`, `k_c`.
+2. `fan auto` - enable auto speed controller mode, which correlates with the square of the TEC's current.

@@ -272,0 +285,4 @@
+4. `fcurve <a> <b> <c>` - set coefficients of the controlling curve `a*x^2 + b*x + c`, where `x` is `abs_max_tec_i/MAX_TEC_I`, 
+i.e. receives values from 0 to 1 linearly tied to the maximum current. The controlling curve should produce values from 0 to 1,
+as below and beyond values would be substituted by 0 and 1 respectively.
+5. `fcurve default` - restore fan curve settings to defaults: `a = 1.0, b = 0.0, c = 0.0`.

@@ -0,0 +17,4 @@
+const MAX_USER_FAN_PWM: f64 = 100.0;
+const MIN_USER_FAN_PWM: f64 = 1.0;
+const MAX_FAN_PWM: f64 = 1.0;
+// below this value, motor pulse signal is too weak

@@ -0,0 +96,4 @@
+        self.fan_auto = fan_auto;
+    }
+
+    #[inline]

@@ -0,0 +125,4 @@
+    fn get_pwm(&self) -> u32 {
+        let duty = self.fan.get_duty();
+        let max = self.fan.get_max_duty();
+        (Self::scale_number(duty as f64 / (max as f64), MIN_USER_FAN_PWM, MAX_USER_FAN_PWM, MIN_FAN_PWM, MAX_FAN_PWM) + 0.5) as u32

@@ -0,0 +161,4 @@
+    use super::*;
+
+    #[test]
+    fn test_scaler() {

@@ -179,3 +181,3 @@
                 let mut new_ipv4_config = None;
                 let instant = Instant::from_millis(i64::from(timer::now()));
-                let updated_channel = channels.poll_adc(instant);
+                let updated_channel = fan_ctrl.channels.poll_adc(instant);

@@ -521,3 +532,3 @@
 }
 
-type JsonBuffer = Vec<u8, U1024>;
+pub type JsonBuffer = Vec<u8, U1024>;

@@ -454,6 +458,7 @@ impl Channels {
             tec_i,
             tec_u_meas: self.get_tec_v(channel),
             pid_output,
+            hwrev: self.hwrev

@@ -0,0 +55,4 @@
+            fan,
+            available,
+            // do not enable auto mode by default,
+            // but allow to turn it on on customer's own risk

@@ -0,0 +145,4 @@
+        self.major == 2 && self.minor == 2
+    }
+
+    pub fn fan_auto_mode_available(&self) -> bool {

@@ -217,2 +228,3 @@
 
-        (pins, leds, eeprom, eth_pins, usb)
+        // According to `SUNON DC Brushless Fan & Blower(255-E)` catalogue p.36-37
+        // Model name: MF35101V1-1000U-G99

@@ -0,0 +129,4 @@
+    }
+}
+
+impl HWRev {

@@ -0,0 +13,4 @@
+pub type FanPin = PwmChannels<TIM8, pwm::C4>;
+
+// as stated in the schematics
+const MAX_TEC_I: f64 = 3.0;

@@ -0,0 +47,4 @@
+        let available = hwrev.fan_available();
+
+        if available {
+            fan.set_duty(0);

@@ -345,0 +352,4 @@
+        if fan_ctrl.is_default_auto() {
+            send_line(socket, b"{}");
+        } else {
+            send_line(socket, b"{ \"warning\": \"this fan doesn't have full PWM support. Use it on your own risk!\" }");

@@ -0,0 +28,4 @@
+        self.major == 2 && self.minor == 2
+    }
+
+    pub fn fan_default_auto(&self) -> bool {

@@ -0,0 +36,4 @@
+
+    pub fn summary(&self) -> Result<JsonBuffer, serde_json_core::ser::Error> {
+        serde_json_core::to_vec(&self)
+

@@ -0,0 +18,4 @@
+const MAX_USER_FAN_PWM: f32 = 100.0;
+const MIN_USER_FAN_PWM: f32 = 1.0;
+const MAX_FAN_PWM: f32 = 1.0;
+// below this value motor's autostart feature may fail

@@ -0,0 +23,4 @@
+
+const DEFAULT_K_A: f32 = 1.0;
+const DEFAULT_K_B: f32 = 0.0;
+const DEFAULT_K_C: f32 = 0.0;

@@ -0,0 +63,4 @@
+
+    pub fn cycle(&mut self, abs_max_tec_i: f32) {
+        self.abs_max_tec_i = abs_max_tec_i;
+        self.adjust_speed();

@@ -0,0 +83,4 @@
+        }
+    }
+
+    pub fn adjust_speed(&mut self) {

@@ -0,0 +122,4 @@
+        self.default_auto
+    }
+
+    fn scale_number(unscaled: f32, to_min: f32, to_max: f32, from_min: f32, from_max: f32) -> f32 {

@@ -218,1 +229,3 @@
-        (pins, leds, eeprom, eth_pins, usb)
+        // According to `SUNON DC Brushless Fan & Blower(255-E)` catalogue p.36-37
+        // model MF35101V1-1000U-G99 doesn't have a PWM wire, so it is advised to have
+        // higher frequency to have less audible noise.

@@ -0,0 +35,4 @@
+        let mut fan_ctrl = FanCtrl {
+            fan,
+            // do not enable auto mode by default,
+            // but allow to turn it on on user's own risk

@@ -345,0 +356,4 @@
+        if fan_ctrl.fan_pwm_recommended() {
+            send_line(socket, b"{}");
+        } else {
+            send_line(socket, b"{ \"warning\": \"this fan doesn't have full PWM support. Use it on your own risk!\" }");

@@ -345,0 +384,4 @@
+        if fan_ctrl.fan_pwm_recommended() {
+            send_line(socket, b"{}");
+        } else {
+            send_line(socket, b"{ \"warning\": \"this fan doesn't have full PWM support. Use it on your own risk!\" }");