diff --git a/src/main/drivers/compass_ak8963.c b/src/main/drivers/compass_ak8963.c
index fb280f8ae3..584b8a00a8 100644
--- a/src/main/drivers/compass_ak8963.c
+++ b/src/main/drivers/compass_ak8963.c
@@ -42,9 +42,6 @@
 #include "accgyro_spi_mpu9250.h"
 #include "compass_ak8963.h"
 
-void ak8963Init(void);
-bool ak8963Read(int16_t *magData);
-
 // This sensor is available in MPU-9250.
 
 // AK8963, mag sensor address
@@ -110,7 +107,7 @@ typedef enum {
 
 static queuedReadState_t queuedRead = { false, 0, 0};
 
-bool ak8963SensorRead(uint8_t addr_, uint8_t reg_, uint8_t len_, uint8_t *buf)
+static bool ak8963SensorRead(uint8_t addr_, uint8_t reg_, uint8_t len_, uint8_t *buf)
 {
     verifympu9250WriteRegister(MPU_RA_I2C_SLV0_ADDR, addr_ | READ_FLAG);   // set I2C slave address for read
     verifympu9250WriteRegister(MPU_RA_I2C_SLV0_REG, reg_);                 // set I2C slave register
@@ -122,7 +119,7 @@ bool ak8963SensorRead(uint8_t addr_, uint8_t reg_, uint8_t len_, uint8_t *buf)
     return true;
 }
 
-bool ak8963SensorWrite(uint8_t addr_, uint8_t reg_, uint8_t data)
+static bool ak8963SensorWrite(uint8_t addr_, uint8_t reg_, uint8_t data)
 {
     verifympu9250WriteRegister(MPU_RA_I2C_SLV0_ADDR, addr_);               // set I2C slave address for write
     verifympu9250WriteRegister(MPU_RA_I2C_SLV0_REG, reg_);                 // set I2C slave register
@@ -131,7 +128,7 @@ bool ak8963SensorWrite(uint8_t addr_, uint8_t reg_, uint8_t data)
     return true;
 }
 
-bool ak8963SensorStartRead(uint8_t addr_, uint8_t reg_, uint8_t len_)
+static bool ak8963SensorStartRead(uint8_t addr_, uint8_t reg_, uint8_t len_)
 {
     if (queuedRead.waiting) {
         return false;
@@ -166,7 +163,7 @@ static uint32_t ak8963SensorQueuedReadTimeRemaining(void)
     return timeRemaining;
 }
 
-bool ak8963SensorCompleteRead(uint8_t *buf)
+static bool ak8963SensorCompleteRead(uint8_t *buf)
 {
     uint32_t timeRemaining = ak8963SensorQueuedReadTimeRemaining();
 
@@ -180,47 +177,18 @@ bool ak8963SensorCompleteRead(uint8_t *buf)
     return true;
 }
 #else
-bool ak8963SensorRead(uint8_t addr_, uint8_t reg_, uint8_t len, uint8_t* buf)
+static bool ak8963SensorRead(uint8_t addr_, uint8_t reg_, uint8_t len, uint8_t* buf)
 {
     return i2cRead(MAG_I2C_INSTANCE, addr_, reg_, len, buf);
 }
 
-bool ak8963SensorWrite(uint8_t addr_, uint8_t reg_, uint8_t data)
+static bool ak8963SensorWrite(uint8_t addr_, uint8_t reg_, uint8_t data)
 {
     return i2cWrite(MAG_I2C_INSTANCE, addr_, reg_, data);
 }
 #endif
 
-bool ak8963Detect(magDev_t *mag)
-{
-    uint8_t sig = 0;
-
-#if defined(USE_SPI) && defined(MPU9250_SPI_INSTANCE)
-    // initialze I2C master via SPI bus (MPU9250)
-
-    verifympu9250WriteRegister(MPU_RA_INT_PIN_CFG, 0x10);               // INT_ANYRD_2CLEAR
-    delay(10);
-
-    verifympu9250WriteRegister(MPU_RA_I2C_MST_CTRL, 0x0D);              // I2C multi-master / 400kHz
-    delay(10);
-
-    verifympu9250WriteRegister(MPU_RA_USER_CTRL, 0x30);                 // I2C master mode, SPI mode only
-    delay(10);
-#endif
-
-    // check for AK8963
-    bool ack = ak8963SensorRead(AK8963_MAG_I2C_ADDRESS, AK8963_MAG_REG_WHO_AM_I, 1, &sig);
-    if (ack && sig == AK8963_Device_ID) // 0x48 / 01001000 / 'H'
-    {
-        mag->init = ak8963Init;
-        mag->read = ak8963Read;
-
-        return true;
-    }
-    return false;
-}
-
-void ak8963Init()
+static void ak8963Init()
 {
     uint8_t calibration[3];
     uint8_t status;
@@ -253,7 +221,7 @@ void ak8963Init()
 #endif
 }
 
-bool ak8963Read(int16_t *magData)
+static bool ak8963Read(int16_t *magData)
 {
     bool ack = false;
     uint8_t buf[7];
@@ -339,3 +307,32 @@ restart:
     return ak8963SensorWrite(AK8963_MAG_I2C_ADDRESS, AK8963_MAG_REG_CNTL, CNTL_MODE_ONCE); // start reading again
 #endif
 }
+
+bool ak8963Detect(magDev_t *mag)
+{
+    uint8_t sig = 0;
+
+#if defined(USE_SPI) && defined(MPU9250_SPI_INSTANCE)
+    // initialze I2C master via SPI bus (MPU9250)
+
+    verifympu9250WriteRegister(MPU_RA_INT_PIN_CFG, 0x10);               // INT_ANYRD_2CLEAR
+    delay(10);
+
+    verifympu9250WriteRegister(MPU_RA_I2C_MST_CTRL, 0x0D);              // I2C multi-master / 400kHz
+    delay(10);
+
+    verifympu9250WriteRegister(MPU_RA_USER_CTRL, 0x30);                 // I2C master mode, SPI mode only
+    delay(10);
+#endif
+
+    // check for AK8963
+    bool ack = ak8963SensorRead(AK8963_MAG_I2C_ADDRESS, AK8963_MAG_REG_WHO_AM_I, 1, &sig);
+    if (ack && sig == AK8963_Device_ID) // 0x48 / 01001000 / 'H'
+    {
+        mag->init = ak8963Init;
+        mag->read = ak8963Read;
+
+        return true;
+    }
+    return false;
+}
diff --git a/src/main/drivers/compass_ak8975.c b/src/main/drivers/compass_ak8975.c
index 579c7118cb..0d8fe1192e 100644
--- a/src/main/drivers/compass_ak8975.c
+++ b/src/main/drivers/compass_ak8975.c
@@ -37,9 +37,6 @@
 
 #include "compass_ak8975.h"
 
-void ak8975Init(void);
-bool ak8975Read(int16_t *magData);
-
 // This sensor is available in MPU-9150.
 
 // AK8975, mag sensor address
@@ -60,25 +57,11 @@ bool ak8975Read(int16_t *magData);
 #define AK8975_MAG_REG_CNTL         0x0a
 #define AK8975_MAG_REG_ASCT         0x0c // self test
 
-bool ak8975Detect(magDev_t *mag)
-{
-    uint8_t sig = 0;
-    bool ack = i2cRead(MAG_I2C_INSTANCE, AK8975_MAG_I2C_ADDRESS, AK8975_MAG_REG_WHO_AM_I, 1, &sig);
-
-    if (!ack || sig != 'H') // 0x48 / 01001000 / 'H'
-        return false;
-
-    mag->init = ak8975Init;
-    mag->read = ak8975Read;
-
-    return true;
-}
-
 #define AK8975A_ASAX 0x10 // Fuse ROM x-axis sensitivity adjustment value
 #define AK8975A_ASAY 0x11 // Fuse ROM y-axis sensitivity adjustment value
 #define AK8975A_ASAZ 0x12 // Fuse ROM z-axis sensitivity adjustment value
 
-void ak8975Init()
+static void ak8975Init()
 {
     uint8_t buffer[3];
     uint8_t status;
@@ -108,7 +91,7 @@ void ak8975Init()
 #define BIT_STATUS2_REG_DATA_ERROR              (1 << 2)
 #define BIT_STATUS2_REG_MAG_SENSOR_OVERFLOW     (1 << 3)
 
-bool ak8975Read(int16_t *magData)
+static bool ak8975Read(int16_t *magData)
 {
     bool ack;
     uint8_t status;
@@ -142,4 +125,18 @@ bool ak8975Read(int16_t *magData)
     i2cWrite(MAG_I2C_INSTANCE, AK8975_MAG_I2C_ADDRESS, AK8975_MAG_REG_CNTL, 0x01); // start reading again
     return true;
 }
+
+bool ak8975Detect(magDev_t *mag)
+{
+    uint8_t sig = 0;
+    bool ack = i2cRead(MAG_I2C_INSTANCE, AK8975_MAG_I2C_ADDRESS, AK8975_MAG_REG_WHO_AM_I, 1, &sig);
+
+    if (!ack || sig != 'H') // 0x48 / 01001000 / 'H'
+        return false;
+
+    mag->init = ak8975Init;
+    mag->read = ak8975Read;
+
+    return true;
+}
 #endif
diff --git a/src/main/drivers/compass_hmc5883l.c b/src/main/drivers/compass_hmc5883l.c
index d4e802597b..e96af8526b 100644
--- a/src/main/drivers/compass_hmc5883l.c
+++ b/src/main/drivers/compass_hmc5883l.c
@@ -41,9 +41,6 @@
 
 #include "compass_hmc5883l.h"
 
-void hmc5883lInit(void);
-bool hmc5883lRead(int16_t *magData);
-
 //#define DEBUG_MAG_DATA_READY_INTERRUPT
 
 // HMC5883L, default address 0x1E
@@ -129,7 +126,7 @@ static const hmc5883Config_t *hmc5883Config = NULL;
 static IO_t intIO;
 static extiCallbackRec_t hmc5883_extiCallbackRec;
 
-void hmc5883_extiHandler(extiCallbackRec_t* cb)
+static void hmc5883_extiHandler(extiCallbackRec_t* cb)
 {
     UNUSED(cb);
 #ifdef DEBUG_MAG_DATA_READY_INTERRUPT
@@ -170,23 +167,24 @@ static void hmc5883lConfigureDataReadyInterruptHandling(void)
 #endif
 }
 
-bool hmc5883lDetect(magDev_t* mag, const hmc5883Config_t *hmc5883ConfigToUse)
+static bool hmc5883lRead(int16_t *magData)
 {
-    hmc5883Config = hmc5883ConfigToUse;
+    uint8_t buf[6];
 
-    uint8_t sig = 0;
-    bool ack = i2cRead(MAG_I2C_INSTANCE, MAG_ADDRESS, 0x0A, 1, &sig);
-
-    if (!ack || sig != 'H')
+    bool ack = i2cRead(MAG_I2C_INSTANCE, MAG_ADDRESS, MAG_DATA_REGISTER, 6, buf);
+    if (!ack) {
         return false;
-
-    mag->init = hmc5883lInit;
-    mag->read = hmc5883lRead;
+    }
+    // During calibration, magGain is 1.0, so the read returns normal non-calibrated values.
+    // After calibration is done, magGain is set to calculated gain values.
+    magData[X] = (int16_t)(buf[0] << 8 | buf[1]) * magGain[X];
+    magData[Z] = (int16_t)(buf[2] << 8 | buf[3]) * magGain[Z];
+    magData[Y] = (int16_t)(buf[4] << 8 | buf[5]) * magGain[Y];
 
     return true;
 }
 
-void hmc5883lInit(void)
+static void hmc5883lInit(void)
 {
     int16_t magADC[3];
     int i;
@@ -258,19 +256,18 @@ void hmc5883lInit(void)
     hmc5883lConfigureDataReadyInterruptHandling();
 }
 
-bool hmc5883lRead(int16_t *magData)
+bool hmc5883lDetect(magDev_t* mag, const hmc5883Config_t *hmc5883ConfigToUse)
 {
-    uint8_t buf[6];
+    hmc5883Config = hmc5883ConfigToUse;
 
-    bool ack = i2cRead(MAG_I2C_INSTANCE, MAG_ADDRESS, MAG_DATA_REGISTER, 6, buf);
-    if (!ack) {
+    uint8_t sig = 0;
+    bool ack = i2cRead(MAG_I2C_INSTANCE, MAG_ADDRESS, 0x0A, 1, &sig);
+
+    if (!ack || sig != 'H')
         return false;
-    }
-    // During calibration, magGain is 1.0, so the read returns normal non-calibrated values.
-    // After calibration is done, magGain is set to calculated gain values.
-    magData[X] = (int16_t)(buf[0] << 8 | buf[1]) * magGain[X];
-    magData[Z] = (int16_t)(buf[2] << 8 | buf[3]) * magGain[Z];
-    magData[Y] = (int16_t)(buf[4] << 8 | buf[5]) * magGain[Y];
+
+    mag->init = hmc5883lInit;
+    mag->read = hmc5883lRead;
 
     return true;
 }