98 lines
2.5 KiB
C
98 lines
2.5 KiB
C
#include <linux/i2c-dev.h>
|
|
#include <i2c/smbus.h>
|
|
#include <stdint.h>
|
|
#include <fcntl.h>
|
|
#include <byteswap.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <errno.h>
|
|
#include <string.h>
|
|
#include <sys/ioctl.h>
|
|
|
|
#include "temperature.h"
|
|
|
|
#define MPC9808_BUS "/dev/i2c-2"
|
|
#define MPC9808_ADR 0x18
|
|
|
|
#define CONFIG_REG 0x01
|
|
#define TUPPER_REG 0x02
|
|
#define TLOWER_REG 0x03
|
|
#define TCRIT_REG 0x04
|
|
#define TA_REG 0x05
|
|
#define MANID_REG 0x06
|
|
#define DEVID_REG 0x07
|
|
#define RES_REG 0x08
|
|
|
|
uint8_t get_byte_in_integer(int num, int n)
|
|
{
|
|
return (num >> (8*n)) & 0xff;
|
|
}
|
|
|
|
double get_temperature(temperature_handle_t file)
|
|
{
|
|
double temperature;
|
|
int32_t reg32;
|
|
uint8_t temperatureUpper;
|
|
uint8_t temperatureLower;
|
|
|
|
reg32 = i2c_smbus_read_word_data(file, TA_REG);
|
|
reg32 = bswap_16(reg32); // swap to little endian
|
|
reg32 = reg32 & 0x1FFF; // clear unused flags
|
|
temperatureUpper = get_byte_in_integer(reg32, 1);
|
|
temperatureLower = get_byte_in_integer(reg32, 0);
|
|
|
|
if ((temperatureUpper & 0x10) == 0x10) {
|
|
temperatureUpper = temperatureUpper & 0x0F; // clear negative flag
|
|
temperature = 256.0 - (temperatureUpper * 16.0 + temperatureLower / 16.0);
|
|
} else {
|
|
temperature = (temperatureUpper * 16.0 + temperatureLower / 16.0);
|
|
}
|
|
|
|
return temperature;
|
|
}
|
|
|
|
temperature_handle_t init_temperature(void)
|
|
{
|
|
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);
|
|
}
|
|
|
|
if (ioctl(file, I2C_SLAVE, MPC9808_ADR) == -1) {
|
|
fprintf(stderr, "ERROR: setting address %d on i2c bus %s with ioctl() - %s", MPC9808_ADR, MPC9808_BUS, strerror(errno));
|
|
exit(1);
|
|
}
|
|
|
|
int32_t reg32;
|
|
uint16_t * const reg16poi = (uint16_t *) ®32;
|
|
uint8_t * const reg8poi = (uint8_t *) ®32;
|
|
|
|
// Read manufactorer ID
|
|
reg32 = i2c_smbus_read_word_data(file, MANID_REG);
|
|
|
|
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);
|
|
}
|
|
|
|
// 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);
|
|
}
|
|
if (reg8poi[0] != 0x04) {
|
|
fprintf(stderr, "Manufactorer ID OK but device ID wrong is 0x%x should be 0x4\n",reg8poi[0]);
|
|
exit(1);
|
|
}
|
|
|
|
return file;
|
|
}
|
|
|