statd: add pwm fan support

Due to their nature we cannot read out the RPM of the pwm fans on the
BPi-R3.  But we can at least show it's alive, or steering out a signal
to the fan.

Signed-off-by: Joachim Wiberg <[email protected]>

Author: troglobit

src/statd/python/cli_pretty/cli_pretty.py

@@ -652,7 +652,20 @@ def get_formatted_value(self):
             else:
                 return f"{self.value} W"
 
+        # Handle PWM fan sensors (reported as "other" type with milli scale)
+        # PWM duty cycle is reported as percentage (0-100)
+        elif self.value_type == 'other' and self.value_scale == 'milli':
+            # Check if this is likely a PWM sensor based on description or name
+            name_lower = self.name.lower()
+            desc_lower = (self.description or "").lower()
+            if 'pwm' in desc_lower or 'fan' in name_lower or 'fan' in desc_lower:
+                percent = self.value / 1000.0
+                return f"{percent:.1f}%"
+            # Fall through for other "other" type sensors
+
         # For unknown sensor types, show raw value
+        if self.value_type in ['other', 'unknown']:
+            return f"{self.value}"
         else:
             return f"{self.value} {self.value_type}"
 

src/statd/python/yanger/ietf_hardware.py

@@ -297,7 +297,7 @@ def create_sensor(sensor_name, value, value_type, value_scale, label=None):
                     except (FileNotFoundError, ValueError, IOError):
                         continue
 
-                # Fan sensors
+                # Fan sensors (RPM from tachometer)
                 for fan_file in glob.glob(os.path.join(hwmon_path, "fan*_input")):
                     try:
                         sensor_num = os.path.basename(fan_file).split('_')[0].replace('fan', '')
@@ -314,6 +314,36 @@ def create_sensor(sensor_name, value, value_type, value_scale, label=None):
                     except (FileNotFoundError, ValueError, IOError):
                         continue
 
+                # PWM fan sensors (duty cycle percentage)
+                # Only add if no fan*_input exists for this device (avoid duplicates)
+                has_rpm_sensor = bool(glob.glob(os.path.join(hwmon_path, "fan*_input")))
+                if not has_rpm_sensor:
+                    for pwm_file in glob.glob(os.path.join(hwmon_path, "pwm[0-9]*")):
+                        # Skip pwm*_enable, pwm*_mode, etc. - only process pwm1, pwm2, etc.
+                        pwm_basename = os.path.basename(pwm_file)
+                        if not pwm_basename.replace('pwm', '').isdigit():
+                            continue
+                        try:
+                            sensor_num = pwm_basename.replace('pwm', '')
+                            pwm_raw = int(HOST.read(pwm_file).strip())
+                            # Convert PWM duty cycle (0-255) to percentage (0-100)
+                            # Note: Some devices are inverted (255=off, 0=max), but we report as-is
+                            # The value represents duty cycle, not necessarily fan speed
+                            # Use "other" value-type since PWM duty cycle isn't a standard IETF type
+                            value = int((pwm_raw / 255.0) * 100 * 1000)  # Convert to milli-percent (0-100000)
+                            label_file = os.path.join(hwmon_path, f"pwm{sensor_num}_label")
+                            raw_label = None
+                            if HOST.exists(label_file):
+                                raw_label = HOST.read(label_file).strip()
+                                label = normalize_sensor_name(raw_label)
+                                sensor_name = f"{base_name}-{label}"
+                            else:
+                                sensor_name = base_name if sensor_num == '1' else f"{base_name}{sensor_num}"
+                            # Use "PWM Fan" as description so it displays nicely in show hardware
+                            add_sensor(base_name, create_sensor(sensor_name, value, "other", "milli", raw_label or "PWM Fan"))
+                        except (FileNotFoundError, ValueError, IOError):
+                            continue
+
                 # Voltage sensors
                 for voltage_file in glob.glob(os.path.join(hwmon_path, "in*_input")):
                     try: