Atomic HRS reads (#1845)

- Combine the reading of all `HRS3300` registers into one I2C read so data is not partial
- Downsizes both HRS and ALS to 16bit as the sensor does not generate larger than
  16bit values in its current configuration
  - Increasing the resolution by 1 bit doubles the sensor acquisition time,
    since we are already at 10Hz we are never going to use a higher resolution
  - The PPG algorithm buffers for ALS/HRS are already 16bit anyway
- Remove functions for setting gain / drive that are unused throughout the codebase
- Calculate constants with constexpr

1 files changed, 6 insertions, 4 deletions

diff --git a/src/drivers/Hrs3300.h b/src/drivers/Hrs3300.h
index 8bbdc69a..6f721448 100644
--- a/src/drivers/Hrs3300.h
+++ b/src/drivers/Hrs3300.h
@@ -21,6 +21,11 @@ namespace Pinetime {
         Hgain = 0x17
       };
 
+      struct PackedHrsAls {
+        uint16_t hrs;
+        uint16_t als;
+      };
+
       Hrs3300(TwiMaster& twiMaster, uint8_t twiAddress);
       Hrs3300(const Hrs3300&) = delete;
       Hrs3300& operator=(const Hrs3300&) = delete;
@@ -30,10 +35,7 @@ namespace Pinetime {
       void Init();
       void Enable();
       void Disable();
-      uint32_t ReadHrs();
-      uint32_t ReadAls();
-      void SetGain(uint8_t gain);
-      void SetDrive(uint8_t drive);
+      PackedHrsAls ReadHrsAls();
 
     private:
       TwiMaster& twiMaster;