ads1115: Probe for reset value before init, do not spam console on device lost

src/drivers/adc/ads1115/ADS1115.cpp

@@ -39,7 +39,6 @@ int ADS1115::init()
 	int ret = I2C::init();
 
 	if (ret != PX4_OK) {
-		PX4_ERR("I2C init failed");
 		return ret;
 	}
 
@@ -61,6 +60,24 @@ int ADS1115::init()
 	return PX4_OK;
 }
 
+int ADS1115::probe()
+{
+	uint8_t buf[2] = {};
+	int ret = readReg(ADDRESSPOINTER_REG_CONFIG, buf, 2);
+
+	if (ret != PX4_OK) {
+		DEVICE_DEBUG("readReg failed (%i)", ret);
+		return ret;
+	}
+
+	if (buf[0] != CONFIG_RESET_VALUE_HIGH || buf[1] != CONFIG_RESET_VALUE_LOW) {
+		DEVICE_DEBUG("ADS1115 not found");
+		return PX4_ERROR;
+	}
+
+	return PX4_OK;
+}
+
 int ADS1115::setChannel(ADS1115::ChannelSelection ch)
 {
 	uint8_t buf[2] = {};

src/drivers/adc/ads1115/ADS1115.h

@@ -93,6 +93,9 @@
 #define CONFIG_LOW_COMP_QU_AFTER4    0x02
 #define CONFIG_LOW_COMP_QU_DISABLE    0x03
 
+#define CONFIG_RESET_VALUE_HIGH 0x85
+#define CONFIG_RESET_VALUE_LOW 0x83
+
 using namespace time_literals;
 
 /*
@@ -114,6 +117,8 @@ public:
 
 	void RunImpl();
 
+	int probe() override;
+
 protected:
 
 	void print_status() override;
@@ -132,6 +137,8 @@ private:
 
 	int     _channel_cycle_count{0};
 
+	bool    _reported_ready_last_cycle{false};
+
 	// ADS1115 logic part
 	enum ChannelSelection {
 		Invalid = -1, A0 = 0, A1, A2, A3

src/drivers/adc/ads1115/ads1115_main.cpp

@@ -80,6 +80,11 @@ void ADS1115::RunImpl()
 	_adc_report.timestamp = hrt_absolute_time();
 
 	if (isSampleReady()) { // whether ADS1115 is ready to be read or not
+		if (!_reported_ready_last_cycle) {
+			PX4_INFO("ADS1115: reported ready");
+			_reported_ready_last_cycle = true;
+		}
+
 		int16_t buf;
 		ADS1115::ChannelSelection ch = cycleMeasure(&buf);
 		++_channel_cycle_count;
@@ -118,7 +123,10 @@ void ADS1115::RunImpl()
 		}
 
 	} else {
-		PX4_WARN("ADS1115 not ready!");
+		if (_reported_ready_last_cycle) {
+			_reported_ready_last_cycle = false;
+			PX4_ERR("ADS1115: not ready. Device lost?");
+		}
 	}
 
 	perf_end(_cycle_perf);