drivers: minimize additional I2C retries

src/drivers/barometer/lps22hb/LPS22HB_I2C.cpp

@@ -72,20 +72,18 @@ int LPS22HB_I2C::probe()
 {
 	uint8_t id = 0;
 
-	_retries = 10;
-
 	if (read(WHO_AM_I, &id, 1)) {
 		DEVICE_DEBUG("read_reg fail");
 		return -EIO;
 	}
 
-	_retries = 2;
-
 	if (id != LPS22HB_ID_WHO_AM_I) {
 		DEVICE_DEBUG("ID byte mismatch (%02x != %02x)", LPS22HB_ID_WHO_AM_I, id);
 		return -EIO;
 	}
 
+	_retries = 1;
+
 	return PX4_OK;
 }
 

src/drivers/barometer/lps25h/lps25h_i2c.cpp

@@ -71,20 +71,18 @@ int LPS25H_I2C::probe()
 {
 	uint8_t id;
 
-	_retries = 10;
-
 	if (read(ADDR_WHO_AM_I, &id, 1)) {
 		DEVICE_DEBUG("read_reg fail");
 		return -EIO;
 	}
 
-	_retries = 2;
-
 	if (id != ID_WHO_AM_I) {
 		DEVICE_DEBUG("ID byte mismatch (%02x != %02x)", ID_WHO_AM_I, id);
 		return -EIO;
 	}
 
+	_retries = 1;
+
 	return OK;
 }
 

src/drivers/barometer/mpl3115a2/MPL3115A2.cpp

@@ -85,18 +85,15 @@ int MPL3115A2::init()
 
 int MPL3115A2::probe()
 {
-	_retries = 10;
 	uint8_t whoami = 0;
 
 	if ((RegisterRead(MPL3115A2_REG_WHO_AM_I, &whoami) > 0) && (whoami == MPL3115A2_WHO_AM_I)) {
-		/*
-		 * Disable retries; we may enable them selectively in some cases,
-		 * but the device gets confused if we retry some of the commands.
-		 */
-		_retries = 0;
+
 		return PX4_OK;
 	}
 
+	_retries = 1;
+
 	return -EIO;
 }
 
@@ -198,11 +195,6 @@ int MPL3115A2::measure()
 	// Send the command to read the ADC for P and T.
 	unsigned addr = (MPL3115A2_CTRL_REG1 << 8) | MPL3115A2_CTRL_TRIGGER;
 
-	/*
-	 * Disable retries on this command; we can't know whether failure
-	 * means the device did or did not see the command.
-	 */
-	_retries = 0;
 	int ret = RegisterWrite((addr >> 8) & 0xff, addr & 0xff);
 
 	if (ret == -EIO) {

src/drivers/barometer/ms5611/ms5611_i2c.cpp

@@ -141,18 +141,14 @@ MS5611_I2C::ioctl(unsigned operation, unsigned &arg)
 int
 MS5611_I2C::probe()
 {
-	_retries = 10;
-
 	if ((PX4_OK == _probe_address(MS5611_ADDRESS_1)) ||
 	    (PX4_OK == _probe_address(MS5611_ADDRESS_2))) {
-		/*
-		 * Disable retries; we may enable them selectively in some cases,
-		 * but the device gets confused if we retry some of the commands.
-		 */
-		_retries = 0;
+
 		return PX4_OK;
 	}
 
+	_retries = 1;
+
 	return -EIO;
 }
 
@@ -183,7 +179,7 @@ MS5611_I2C::_reset()
 	int		result;
 
 	/* bump the retry count */
-	_retries = 10;
+	_retries = 3;
 	result = transfer(&cmd, 1, nullptr, 0);
 	_retries = old_retrycount;
 
@@ -193,12 +189,6 @@ MS5611_I2C::_reset()
 int
 MS5611_I2C::_measure(unsigned addr)
 {
-	/*
-	 * Disable retries on this command; we can't know whether failure
-	 * means the device did or did not see the command.
-	 */
-	_retries = 0;
-
 	uint8_t cmd = addr;
 	return transfer(&cmd, 1, nullptr, 0);
 }