drivers: minimize additional I2C retries

src/drivers/magnetometer/hmc5883/hmc5883_i2c.cpp

@@ -72,7 +72,7 @@ int HMC5883_I2C::probe()
 {
 	uint8_t data[3] = {0, 0, 0};
 
-	_retries = 10;
+	_retries = 1;
 
 	if (read(ADDR_ID_A, &data[0], 1) ||
 	    read(ADDR_ID_B, &data[1], 1) ||
@@ -81,8 +81,6 @@ int HMC5883_I2C::probe()
 		return -EIO;
 	}
 
-	_retries = 2;
-
 	if ((data[0] != ID_A_WHO_AM_I) ||
 	    (data[1] != ID_B_WHO_AM_I) ||
 	    (data[2] != ID_C_WHO_AM_I)) {

src/drivers/magnetometer/isentek/ist8308/IST8308.cpp

@@ -86,12 +86,11 @@ void IST8308::print_status()
 
 int IST8308::probe()
 {
-	_retries = 2;
-
 	for (int retry = 0; retry < 3; retry++) {
 		const uint8_t WAI = RegisterRead(Register::WAI);
 
 		if (WAI == Device_ID) {
+			_retries = 1;
 			return PX4_OK;
 
 		} else {

src/drivers/magnetometer/lis2mdl/lis2mdl_i2c.cpp

@@ -86,15 +86,13 @@ LIS2MDL_I2C::probe()
 {
 	uint8_t data = 0;
 
-	_retries = 10;
+	_retries = 1;
 
 	if (read(ADDR_WHO_AM_I, &data, 1)) {
 		DEVICE_DEBUG("read_reg fail");
 		return -EIO;
 	}
 
-	_retries = 2;
-
 	if (data != ID_WHO_AM_I) {
 		DEVICE_DEBUG("LIS2MDL bad ID: %02x", data);
 		return -EIO;

src/drivers/magnetometer/lis3mdl/lis3mdl_i2c.cpp

@@ -85,20 +85,18 @@ int LIS3MDL_I2C::probe()
 {
 	uint8_t data = 0;
 
-	_retries = 10;
-
 	if (read(ADDR_WHO_AM_I, &data, 1)) {
 		DEVICE_DEBUG("read_reg fail");
 		return -EIO;
 	}
 
-	_retries = 2;
-
 	if (data != ID_WHO_AM_I) {
 		DEVICE_DEBUG("LIS3MDL bad ID: %02x", data);
 		return -EIO;
 	}
 
+	_retries = 1;
+
 	return OK;
 }
 

src/drivers/magnetometer/rm3100/rm3100_i2c.cpp

@@ -84,20 +84,18 @@ int RM3100_I2C::probe()
 {
 	uint8_t data = 0;
 
-	_retries = 10;
-
 	if (read(ADDR_REVID, &data, 1)) {
 		DEVICE_DEBUG("RM3100 read_reg fail");
 		return -EIO;
 	}
 
-	_retries = 2;
-
 	if (data != RM3100_REVID) {
 		DEVICE_DEBUG("RM3100 bad ID: %02x", data);
 		return -EIO;
 	}
 
+	_retries = 1;
+
 	return OK;
 }