jc42.c
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/*
* Copyright (C) 2017 Koen Zandberg
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup drivers_jc42
* @{
*
* @file
* @brief Device driver implementation for the JEDEC jc42.4 compliant temperature sensors
*
* @author Koen Zandberg <koen@bergzand.net>
*
* @}
*/
#include "periph/i2c.h"
#include "byteorder.h"
#include "jc42.h"
#include "jc42_internal.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
static int jc42_get_register(const jc42_t* dev, uint8_t reg, uint16_t* data)
{
i2c_acquire(dev->i2c);
if (i2c_read_regs(dev->i2c, dev->addr, reg, data, 2) <= 0) {
DEBUG("[jc42] Problem reading register 0x%x\n", reg);
i2c_release(dev->i2c);
return JC42_NODEV;
}
i2c_release(dev->i2c);
return JC42_OK;
}
static int jc42_set_register(const jc42_t* dev, uint8_t reg, uint16_t* data)
{
i2c_acquire(dev->i2c);
if (i2c_write_regs(dev->i2c, dev->addr, reg, data, 2) <= 0) {
DEBUG("[jc42] Problem writing to register 0x%x\n", reg);
i2c_release(dev->i2c);
return JC42_NODEV;
}
i2c_release(dev->i2c);
return JC42_OK;
}
int jc42_get_config(const jc42_t* dev, uint16_t* data)
{
return jc42_get_register(dev, JC42_REG_CONFIG, data);
}
int jc42_set_config(const jc42_t* dev, uint16_t data)
{
return jc42_set_register(dev, JC42_REG_CONFIG, &data);
}
int jc42_get_temperature(const jc42_t* dev, int16_t* temperature)
{
struct { signed int x:12;} s;
uint16_t tmp;
/* Read temperature */
if (jc42_get_register(dev, JC42_REG_TEMP, &tmp) != 0) {
return JC42_NODEV;
}
tmp = ntohs(tmp);
/* Convert fixed point to uint16_t */
*temperature = ((s.x = tmp)*100)>>4;
return JC42_OK;
}
int jc42_init(jc42_t* dev, const jc42_params_t* params)
{
uint16_t config;
dev->i2c = params->i2c;
dev->addr = params->addr;
i2c_acquire(dev->i2c);
if (i2c_init_master(dev->i2c, params->speed) != 0) {
DEBUG("[jc42] Problem initializing I2C master\n");
i2c_release(dev->i2c);
return JC42_NOI2C;
}
i2c_release(dev->i2c);
/* Poll the device, fail if unavailable */
if (jc42_get_config(dev, &config) != 0) {
return JC42_NODEV;
}
DEBUG("[jc42] Config: 0x%x\n", config);
return JC42_OK;
}