chore: don't need double precision for fan power/tacho

Author: SanaaHamel

src/gatt/fan.cpp

@@ -92,11 +92,12 @@ void fan_power_set(BLE::Percentage8 power, sensors::Sensors const& sensors = sen
 
 }  // namespace
 
-double fan_rpm() {
+float fan_rpm() {
     return g_tachometer.revolutions_per_second() * 60;
 }
 
-double fan_power() {
+float fan_power() {
+    // NOLINTNEXTLINE(bugprone-narrowing-conversions, cppcoreguidelines-narrowing-conversions)
     return g_fan_power.value_or(0);
 }
 

src/gatt/fan.hpp

@@ -17,8 +17,8 @@ bool init();
 void disconnected(hci_con_handle_t);
 
 // Current fan power. [0, 100]
-double fan_power();
-double fan_rpm();
+float fan_power();
+float fan_rpm();
 
 void fan_power_override(BLE::Percentage8 power);  // `NOT_KNOWN` to clear override
 BLE::Percentage8 fan_power_override();

src/sensors/tachometer.hpp

@@ -48,7 +48,7 @@ struct Tachometer final : SensorPeriodic {
         this->pulses_per_revolution = pulses_per_revolution;
     }
 
-    [[nodiscard]] double revolutions_per_second() const {
+    [[nodiscard]] auto revolutions_per_second() const {
         return revolutions_per_second_;
     }
 
@@ -67,7 +67,8 @@ struct Tachometer final : SensorPeriodic {
         auto end = std::chrono::steady_clock::now();
 
         auto duration_sec =
-                std::chrono::duration_cast<std::chrono::duration<double, std::ratio<1>>>(end - begin);
+                std::chrono::duration_cast<std::chrono::duration<float, std::ratio<1>>>(end - begin);
+        // NOLINTNEXTLINE(bugprone-narrowing-conversions, cppcoreguidelines-narrowing-conversions)
         revolutions_per_second_ = pulses / duration_sec.count() / pulses_per_revolution;
 
         // printf("tachometer_measure dur=%f s cnt=%u rev-per-sec=%f rpm=%f\n", duration_sec.count(),
@@ -145,8 +146,8 @@ struct Tachometer final : SensorPeriodic {
 
     Pins::GPIOs pins;
     std::bitset<Pins::ALTERNATIVES_MAX> state;
-    uint pulses_per_revolution = 1;
-    double revolutions_per_second_ = 0;
+    uint32_t pulses_per_revolution = 1;
+    float revolutions_per_second_ = 0;
 };
 
 }  // namespace nevermore::sensors