From 62ff08c6545794a9471ded7b147fc0cd384b4f46 Mon Sep 17 00:00:00 2001
From: Reimar <mail@reim.ar>
Date: Thu, 20 Mar 2025 08:25:46 +0100
Subject: [PATCH] Clean temperature code

---
 iot/main.c        |  6 +++---
 iot/temperature.c | 27 +++++++++++++++------------
 iot/temperature.h |  6 ++++--
 3 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/iot/main.c b/iot/main.c
index 06b99d6..8430bb3 100644
--- a/iot/main.c
+++ b/iot/main.c
@@ -10,12 +10,12 @@
 
 void *watch_temperature(void *arg)
 {
-	init_temperature();
+	temperature_handle_t temp_handle = init_temperature();
 
-	get_temperature();
+	get_temperature(temp_handle);
 
 	while (true) {
-		double temperature = get_temperature();
+		double temperature = get_temperature(temp_handle);
 
 		char *str = malloc(snprintf(NULL, 0, "%lf", temperature) + 1);
 		sprintf(str, "%lf", temperature);
diff --git a/iot/temperature.c b/iot/temperature.c
index 7f8348e..1719733 100644
--- a/iot/temperature.c
+++ b/iot/temperature.c
@@ -9,6 +9,8 @@
 #include <string.h>
 #include <sys/ioctl.h>
 
+#include "temperature.h"
+
 #define MPC9808_BUS	"/dev/i2c-2"
 #define MPC9808_ADR	0x18
 
@@ -21,14 +23,12 @@
 #define DEVID_REG  0x07
 #define RES_REG    0x08
 
-int file;
-
 uint8_t get_byte_in_integer(int num, int n)
 {
 	return (num >> (8*n)) & 0xff;
 }
 
-double get_temperature()
+double get_temperature(temperature_handle_t file)
 {
 	double temperature;
 	int32_t reg32;
@@ -51,9 +51,10 @@ double get_temperature()
 	return temperature;
 }
 
-void init_temperature(void)
+temperature_handle_t init_temperature(void)
 {
-	file = open(MPC9808_BUS, O_RDWR);
+	int file = open(MPC9808_BUS, O_RDWR);
+
 	if (file < 0) {
 		fprintf(stderr, "Error opening temperature sensor device (%s): %s\n", MPC9808_BUS, strerror(errno));
 		exit(1);
@@ -71,24 +72,26 @@ void init_temperature(void)
 	// Read manufactorer ID
 	reg32 = i2c_smbus_read_word_data(file, MANID_REG);
 
-	if ( reg32 < 0 ) {
+	if (reg32 < 0) {
 			fprintf(stderr, "ERROR: Read failed  on i2c bus register %d - %s\n",  MANID_REG,strerror(errno));
 			exit(1);
 	}
 	if (bswap_16(reg16poi[0]) != 0x0054) {
-			fprintf(stderr, "Manufactorer ID wrong is 0x%x should be 0x54\n",__bswap_16(reg16poi[0]));
-			exit(1);
+		fprintf(stderr, "Manufactorer ID wrong is 0x%x should be 0x54\n",__bswap_16(reg16poi[0]));
+		exit(1);
 	}
 
 	// Read device ID and revision
 	reg32 = i2c_smbus_read_word_data(file, DEVID_REG);
 	if (reg32 < 0) {
-			fprintf(stderr, "ERROR: Read failed  on i2c bus register %d - %s\n",  DEVID_REG,strerror(errno) );
-			exit(1);
+		fprintf(stderr, "ERROR: Read failed  on i2c bus register %d - %s\n",  DEVID_REG,strerror(errno) );
+		exit(1);
 	}
 	if (reg8poi[0] != 0x04) {
-			fprintf(stderr, "Manufactorer ID OK but device ID wrong is 0x%x should be 0x4\n",reg8poi[0]);
-			exit(1);
+		fprintf(stderr, "Manufactorer ID OK but device ID wrong is 0x%x should be 0x4\n",reg8poi[0]);
+		exit(1);
 	}
+
+	return file;
 }
 
diff --git a/iot/temperature.h b/iot/temperature.h
index 8bd0a39..e1f1471 100644
--- a/iot/temperature.h
+++ b/iot/temperature.h
@@ -1,4 +1,6 @@
-void init_temperature();
+typedef int temperature_handle_t;
 
-double get_temperature();
+temperature_handle_t init_temperature();
+
+double get_temperature(temperature_handle_t handle);