make zero value useful for configuration

Author: soypat

examples/mpu6050/main.go

@@ -13,10 +13,8 @@ func main() {
 
 	mpuDevice := mpu6050.New(machine.I2C0, mpu6050.DefaultAddress)
 
-	err := mpuDevice.Configure(mpu6050.Config{
-		AccelRange: mpu6050.ACCEL_RANGE_16,
-		GyroRange:  mpu6050.GYRO_RANGE_2000,
-	})
+	// Configure the device with default configuration.
+	err := mpuDevice.Configure(mpu6050.Config{})
 	if err != nil {
 		panic(err.Error())
 	}

mpu6050/mpu6050.go

@@ -167,12 +167,13 @@ func (p *Device) setRangeGyro(gyroRange RangeGyro) (err error) {
 		p.gRange = 500
 	case RangeGyro1000:
 		p.gRange = 1000
-	case RangeGyro2000:
+	case RangeGyro2000, rangeGyroDefault:
+		gyroRange = RangeGyro2000
 		p.gRange = 2000
 	default:
 		return errInvalidRangeGyro
 	}
-	return p.writeMasked(_GYRO_CONFIG, _G_FS_SEL, uint8(gyroRange)<<_G_FS_SHIFT)
+	return p.writeMasked(_GYRO_CONFIG, _G_FS_SEL, uint8(gyroRange-1)<<_G_FS_SHIFT)
 }
 
 // setRangeAccel configures the full scale range of the accelerometer.
@@ -187,12 +188,13 @@ func (p *Device) setRangeAccel(accRange RangeAccel) (err error) {
 		p.aRange = 4
 	case RangeAccel8:
 		p.aRange = 8
-	case RangeAccel16:
+	case RangeAccel16, rangeAccelDefault:
+		accRange = RangeAccel16
 		p.aRange = 16
 	default:
 		return errInvalidRangeAccel
 	}
-	return p.writeMasked(_ACCEL_CONFIG, _AFS_SEL, uint8(accRange)<<_AFS_SHIFT)
+	return p.writeMasked(_ACCEL_CONFIG, _AFS_SEL, uint8(accRange-1)<<_AFS_SHIFT)
 }
 
 // Sleep sets the sleep bit on the power managment 1 field.
@@ -218,12 +220,3 @@ func b2u8(b bool) byte {
 	}
 	return 0
 }
-
-func DefaultConfig() Config {
-	return Config{
-		AccelRange:  RangeAccel16,
-		GyroRange:   RangeGyro2000,
-		sampleRatio: 0, // TODO add const values.
-		clkSel:      0,
-	}
-}

mpu6050/registers.go

@@ -41,8 +41,9 @@ const (
 
 // Gyroscope ranges for Init configuration
 const (
+	rangeGyroDefault = iota
 	// 250°/s
-	RangeGyro250 RangeGyro = iota
+	RangeGyro250
 	// 500°/s
 	RangeGyro500
 	// 1000°/s
@@ -53,8 +54,9 @@ const (
 
 // Accelerometer ranges for Init configuration
 const (
+	rangeAccelDefault RangeAccel = iota
 	// 2g
-	RangeAccel2 RangeAccel = iota
+	RangeAccel2
 	// 4g
 	RangeAccel4
 	// 8g