raspberrypi.git

			@@ -1,9 +1,9 @@
			/*********************************************************************************
			* Copyright: (C) 2018 LingYun IoT System Studio
			* Copyright: (C) 2022 LingYun IoT System Studio
			* All rights reserved.
			*
			* Filename: ds18b20.c
			* Description: This file is temperature sensor DS18B20 code
			* Description: This file is DS18B20 temperature sensor example source code.
			*
			* Version: 1.0.0(2018/10/14)
			* Author: Guo Wenxue <guowenxue@gmail.com>
			@@ -32,7 +32,7 @@
			return 1;
			}

			printf("DS19B20 get temperature: %f ℃\n", temp);
			printf("DS18B20 get temperature: %f 'C\n", temp);
			return 0;
			}

			@@ -45,15 +45,16 @@

			int ds18b20_get_temperature(float *temp)
			{
			char w1_path[50] = "/sys/bus/w1/devices/";
			const char *w1_path = "/sys/bus/w1/devices/";
			char ds_path[50];
			char chip[20];
			char buf[128];
			DIR *dirp;
			struct dirent *direntp;
			int fd =-1;
			char *ptr;
			float value;
			int found = 0;
			int rv = 0;

			if( !temp )
			{
			@@ -88,27 +89,28 @@
			}

			/* get DS18B20 sample file full path: /sys/bus/w1/devices/28-xxxx/w1_slave */
			strncat(w1_path, chip, sizeof(w1_path)-strlen(w1_path));
			strncat(w1_path, "/w1_slave", sizeof(w1_path)-strlen(w1_path));
			snprintf(ds_path, sizeof(ds_path), "%s/%s/w1_slave", w1_path, chip);

			/* open file /sys/bus/w1/devices/28-xxxx/w1_slave to get temperature */
			if( (fd=open(w1_path, O_RDONLY)) < 0 )
			if( (fd=open(ds_path, O_RDONLY)) < 0 )
			{
			printf("open %s error: %s\n", w1_path, strerror(errno));
			printf("open %s error: %s\n", ds_path, strerror(errno));
			return -4;
			}

			if(read(fd, buf, sizeof(buf)) < 0)
			{
			printf("read %s error: %s\n", w1_path, strerror(errno));
			return -5;
			printf("read %s error: %s\n", ds_path, strerror(errno));
			rv = -5;
			goto cleanup;
			}

			ptr = strstr(buf, "t=");
			if( !ptr )
			{
			printf("ERROR: Can not get temperature\n");
			return -6;
			rv = -6;
			goto cleanup;
			}

			ptr+=2;
			@@ -116,7 +118,7 @@
			/* convert string value to float value */
			*temp = atof(ptr)/1000;

			cleanup:
			close(fd);

			return 0;
			return rv;
			}