From f0c35148847132276941aedcb38a398c26599104 Mon Sep 17 00:00:00 2001
From: Thomas Klaehn <tkl@blackfinn.de>
Date: Mon, 29 Jul 2019 10:18:14 +0100
Subject: [PATCH] ADS1115: skip negative values.

---
 Makefile      | 12 ++++++++----
 inc/ads1115.h |  2 +-
 src/ads1115.c |  7 +++++++
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 567b25d..bea57a1 100644
--- a/Makefile
+++ b/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
@@ -35,7 +37,9 @@ C_FLAGS += -fpic
 
 C_FLAGS += -O0 -g -Wall -Wextra -Werror
 CPP_FLAGS += $(addprefix -I, $(INCLUDES))
-CHECK_FLAGS = --enable=all --template=gcc --error-exitcode=1 --suppress=missingIncludeSystem --inline-suppr $(C_SRCS)
+
+CHECK_FLAGS = $(addprefix -I,$(filter-out $(PREFIX)/include/,$(INCLUDES)))
+CHECK_FLAGS += --enable=all --template=gcc --error-exitcode=1 --suppress=missingIncludeSystem --inline-suppr --force
 
 C_SRCS = $(wildcard $(SRC_DIR)/*.c)
 C_OBJS = $(patsubst $(SRC_DIR)%,$(OBJ_DIR)%,$(patsubst %.c,%.o,$(C_SRCS)))
@@ -62,8 +66,8 @@ install: all
 	install -m 0644 inc/* $(INC_INSTALL_DIR)
 
 uninstall:
-	rm -f $(LIB_INSTALL_DIR)/$(STATIC_LIB)
-	rm -f $(LIB_INSTALL_DIR)/$(DYNAMIC_LIB)
+	rm -f $(LIB_INSTALL_DIR)/$(STATIC_LIB_FILE)
+	rm -f $(LIB_INSTALL_DIR)/$(DYNAMIC_LIB_FILE)
 	rm -f $(addprefix $(INC_INSTALL_DIR)/,$(shell ls inc))
 	rm -rf $(INC_INSTALL_DIR)
 
@@ -104,7 +108,7 @@ exec_unit_test: $(UNIT_TEST_TARGET)
 
 .PHONY: check
 check: $(C_SRCS)
-	$(CHECK) $(CPP_FLAGS) $(CHECK_FLAGS) $(C_SRCS)
+	$(CHECK) $(CHECK_FLAGS) $(C_SRCS)
 
 $(UNIT_TEST_TARGET): $(UNIT_TEST_OBJS) $(THIS_MAKEFILE)
 	@mkdir -p $(BIN_DIR)/$(UNIT_TEST_SRC_DIR)
diff --git a/inc/ads1115.h b/inc/ads1115.h
index 1c89d60..97b2710 100644
--- a/inc/ads1115.h
+++ b/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;
diff --git a/src/ads1115.c b/src/ads1115.c
index 762be90..d96c143 100644
--- a/src/ads1115.c
+++ b/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;