ADS1115: skip negative values.

Makefile

@@ -23,6 +23,8 @@ LIB_INSTALL_DIR ?= $(PREFIX)/lib
 INC_INSTALL_DIR ?= $(PREFIX)/include/lib$(TARGET_FILE)
 
 INCLUDES := inc
+INCLUDES += $(PREFIX)/include/
+INCLUDES += $(EXTRA_INC)
 
 ifneq "$(findstring $(MAKECMDGOALS), build_unit_test exec_unit_test coverage)" ""
 INCLUDES += test/inc
@@ -51,7 +53,7 @@ UNIT_TEST_TARGET = $(BIN_DIR)/$(UNIT_TEST_SRC_DIR)/$(TARGET_FILE)
 
 THIS_MAKEFILE := $(lastword $(MAKEFILE_LIST))
 
-.PHONY: all install uninstall clean
+.PHONY: all install uninstall clean distclean
 all: $(STATIC_LIB) $(DYNAMIC_LIB)
 
 install: all
@@ -76,6 +78,9 @@ clean:
 	rm -f $(OBJ_DIR)/*.gcda $(OBJ_DIR)/*.gcno
 	rm -fr $(COVERAGE_DIR)
 
+distclean:
+	rm -fr $(BIN_DIR) $(OBJ_DIR) $(LIB_DIR) $(COVERAGE_DIR)
+
 .PHONY: coverage
 coverage: _cov_genhtml
 	$(eval COVERAGE:=$(shell grep 'lines' .coverage.tmp | egrep -o '[0-9]+.[0-9]+%'))

inc/ads1115.h

@@ -2,7 +2,7 @@
 #define __ADS1115__
 
 #include <stdint.h>
-#include <libi2c_bb/i2c_bb.h>
+#include <libi2c_bb/i2c.h>
 
 struct ads1115_dev {
     struct i2c_bb *i2c_dev;

src/ads1115.c

@@ -11,6 +11,7 @@
 #define BUF_SIZE        3
 #define VPS             6.144 / 32768.0
 
+// cppcheck-suppress unusedFunction
 int ads1115_open(const struct ads1115_dev *ads1115)
 {
     int res;
@@ -28,6 +29,7 @@ int ads1115_open(const struct ads1115_dev *ads1115)
     return 0;
 }
 
+// cppcheck-suppress unusedFunction
 int ads1115_close(const struct ads1115_dev *ads1115)
 {
     assert(NULL != ads1115);
@@ -35,6 +37,7 @@ int ads1115_close(const struct ads1115_dev *ads1115)
     return i2c_close(ads1115->i2c_dev);
 }
 
+// cppcheck-suppress unusedFunction
 int ads1115_start_conversation(const struct ads1115_dev *ads1115)
 {
     int res;
@@ -61,6 +64,7 @@ int ads1115_start_conversation(const struct ads1115_dev *ads1115)
     return 0;
 }
 
+// cppcheck-suppress unusedFunction
 int ads1115_read_conversation_result(const struct ads1115_dev *ads1115,
                                      struct ads1115_conversation_result *result)
 {
@@ -94,6 +98,9 @@ int ads1115_read_conversation_result(const struct ads1115_dev *ads1115,
         return res;
     }
     result->raw = buffer[0] << 8 | buffer[1];
+    if(result->raw & 0x8000) {
+        result->raw = 0;
+    }
     result->voltage = result->raw * VPS;
 
     return 0;