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RIOT/drivers/lm75/lm75.c
Gunar Schorcht 312c31dce5 drivers: update to new I2C API
2021-11-29 06:35:25 +01:00

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/*
* Copyright (C) 2021 ML!PA Consulting GmbH
*
* 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_lm75
*
* @{
* @file
* @brief Driver for the LM75 temperature sensor.
*
* A general driver for the lm75 temperature sensor including support for the
* lm75a and tmp1075 sensors as well.
*
* @author Vitor Batista <vitor.batista@ml-pa.com>
*
* @}
*/
#include "board.h"
#include "lm75.h"
#include "lm75_regs.h"
#include "lm75_params.h"
#include "log.h"
#include "kernel_defines.h"
#include "periph/gpio.h"
#include <stdint.h>
#include <byteorder.h>
#include "xtimer.h"
#include "debug.h"
#define I2C_BUS dev->lm75_params.i2c_bus
#define I2C_ADDR dev->lm75_params.i2c_addr
#define LM75_CONFIG_SHUTDOWN_MODE 0x01
#define TMP1075_CONFIG_ONE_SHOT_MODE 0x81 /* also sets the shutdown register to 1 */
#if IS_ACTIVE(MODULE_LM75A)
lm75_properties_t lm75a_properties = {
.os_res = LM75A_OS_RES,
.os_mult = LM75A_OS_MULT,
.temp_res = LM75A_TEMP_RES,
.temp_mult = LM75A_TEMP_MULT,
.os_shift = LM75A_OS_SHIFT,
.temp_shift = LM75A_TEMP_SHIFT,
};
#endif
#if IS_ACTIVE(MODULE_TMP1075)
lm75_properties_t tmp1075_properties = {
.os_res = TMP1075_OS_RES,
.os_mult = TMP1075_OS_MULT,
.temp_res = TMP1075_TEMP_RES,
.temp_mult = TMP1075_TEMP_MULT,
.os_shift = TMP1075_OS_SHIFT,
.temp_shift = TMP1075_TEMP_SHIFT,
};
#endif
int lm75_init(lm75_t *dev, const lm75_params_t *params) {
dev->lm75_params = *params;
uint8_t config = (params->shutdown_mode) | (params->tm_mode << 1) \
| (params->polarity << 2) | (params->fault_q << 3);
i2c_acquire(I2C_BUS);
/* read the device ID register of the TMP1075 sensor to confirm it is a TMP1075 */
if (IS_USED(MODULE_TMP1075) && (dev->lm75_params.res == &tmp1075_properties)) {
uint16_t deid = 0;
if (i2c_read_regs(I2C_BUS, I2C_ADDR, TMP1075_DEVICE_ID_REG, &deid, 2, 0) != 0) {
LOG_ERROR("lm75: error reading device ID\n");
}
deid = (uint16_t)ntohs(deid);
/* checks if the device ID corresponds to the TMP1075 sensor
* and extends the parameter configuration if so */
if (deid == 0x7500) {
DEBUG("lm75: device is a TMP1075\n");
config |= (params->conv_rate_reg << 5);
}
else {
LOG_ERROR("lm75: device ID Register doesnt match");
i2c_release(I2C_BUS);
return LM75_ERROR;
}
}
else if (IS_USED(MODULE_LM75A) && (dev->lm75_params.res == &lm75a_properties)) {
DEBUG("lm75: device is an LM75A\n");
}
else {
LOG_ERROR("lm75: device not supported\n");
i2c_release(I2C_BUS);
return LM75_ERROR;
}
/* write the config byte into the configuration register */
if (i2c_write_reg(I2C_BUS, I2C_ADDR, LM75_CONF_REG, config, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR_I2C;
}
i2c_release(I2C_BUS);
return LM75_SUCCESS;
}
int lm75_get_temperature_raw(lm75_t *dev, int *temperature) {
int16_t temp;
i2c_acquire(I2C_BUS);
/* read the temperature register */
if (i2c_read_regs(I2C_BUS, I2C_ADDR, LM75_TEMP_REG, &temp, 2, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR_I2C;
}
i2c_release(I2C_BUS);
/* since the value is read in big endian, it must be converted to little endian
* then it must be multiplied by its resolution
* and then shifted so only the correct number of bits is used */
*temperature = (int16_t)ntohs(temp) * dev->lm75_params.res->temp_res \
>> dev->lm75_params.res->temp_shift;
return LM75_SUCCESS;
}
int lm75_get_temperature(lm75_t *dev, int *temperature) {
if (lm75_get_temperature_raw(dev, temperature) != 0) {
return LM75_ERROR;
}
/* if the device's resolution is lower than mºC convert the temp to mºC */
if (dev->lm75_params.res->temp_mult < 1000) {
*temperature *= 1000 / dev->lm75_params.res->temp_mult;
}
/* if the device's resolution is greater than mºC
* truncates the device's values lower than the mºC range */
else if (dev->lm75_params.res->temp_mult > 1000) {
*temperature /= dev->lm75_params.res->temp_mult / 1000;
}
return LM75_SUCCESS;
}
int lm75_set_temp_limits(lm75_t *dev, int temp_hyst, int temp_os, gpio_cb_t cb, void *arg) {
/* Check if the OS alert pin is valid */
if (!gpio_is_valid(dev->lm75_params.gpio_alarm)) {
return LM75_ERROR;
}
/* Enable OS interrupt */
if (gpio_init_int(dev->lm75_params.gpio_alarm, GPIO_IN, \
dev->lm75_params.polarity ? GPIO_FALLING : GPIO_RISING, cb, arg) != 0) {
return LM75_ERROR;
}
if (temp_hyst >= temp_os) {
LOG_ERROR("lm75: THYST must be lower than TOS\n");
return LM75_ERROR;
}
int16_t temp_hyst_short, temp_os_short;
/* getting into the correct precision value in units of 10 */
temp_hyst = (temp_hyst * dev->lm75_params.res->os_mult) / 1000;
temp_os = (temp_os * dev->lm75_params.res->os_mult) / 1000;
/* temp must first be converted to 16 bit format, and sampled to its resolution
* then shifted by the number of unused bits and finally reversed
* into little endian for writing into the register.
* NOTE: values smaller than the resolution steps are truncated */
temp_hyst_short = (int16_t) (temp_hyst / dev->lm75_params.res->os_res);
temp_hyst_short = temp_hyst_short << dev->lm75_params.res->os_shift;
temp_hyst_short = ntohs(temp_hyst_short);
temp_os_short = (int16_t) (temp_os / dev->lm75_params.res->os_res);
temp_os_short = temp_os_short << dev->lm75_params.res->os_shift;
temp_os_short = ntohs(temp_os_short);
i2c_acquire(I2C_BUS);
if (i2c_write_regs(I2C_BUS, I2C_ADDR, LM75_THYST_REG, &temp_hyst_short, 2, 0) != 0) {
i2c_release(I2C_BUS);
LOG_ERROR("lm75: ERROR wrtiting Hyst temp\n");
return LM75_ERROR_I2C;
}
if (i2c_write_regs(I2C_BUS, I2C_ADDR, LM75_TOS_REG, &temp_os_short, 2, 0) != 0) {
i2c_release(I2C_BUS);
LOG_ERROR("lm75: ERROR writing OS temp\n");
return LM75_ERROR_I2C;
}
i2c_release(I2C_BUS);
return LM75_SUCCESS;
}
int lm75_get_os_temp(lm75_t *dev, int *temperature) {
int16_t temp;
i2c_acquire(I2C_BUS);
/* read the temperature register */
if (i2c_read_regs(I2C_BUS, I2C_ADDR, LM75_TOS_REG, &temp, 2, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR_I2C;
}
i2c_release(I2C_BUS);
/* since the value is read in big endian, it must be converted into little endian
* then it must be multiplied by its resolution
* and then shifted by the number of unused bits that must be discarded */
*temperature = (int16_t)ntohs(temp) * dev->lm75_params.res->os_res \
>> dev->lm75_params.res->os_shift;
return LM75_SUCCESS;
}
int lm75_get_hyst_temp(lm75_t *dev, int *temperature) {
int16_t temp;
i2c_acquire(I2C_BUS);
/* read the temperature register */
if (i2c_read_regs(I2C_BUS, I2C_ADDR, LM75_THYST_REG, &temp, 2, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR_I2C;
}
i2c_release(I2C_BUS);
*temperature = (int16_t)ntohs(temp) * dev->lm75_params.res->os_res \
>> dev->lm75_params.res->os_shift;
return LM75_SUCCESS;
}
int lm75_get_os_pin(lm75_t *dev, bool *os_pin_state) {
if (!gpio_is_valid(dev->lm75_params.gpio_alarm)) {
LOG_ERROR("lm75: OS alert pin not connected or defined\n");
return LM75_ERROR;
}
*os_pin_state = !!gpio_read(dev->lm75_params.gpio_alarm) == dev->lm75_params.polarity;
return LM75_SUCCESS;
}
int lm75_poweroff(lm75_t *dev) {
i2c_acquire(I2C_BUS);
uint8_t config;
if (i2c_read_reg(I2C_BUS, I2C_ADDR, LM75_CONF_REG, &config, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR;
}
/* sets every register to 0 except the shutdown reg and sees if it is active */
if ((config & LM75_CONFIG_SHUTDOWN_MODE) != 0) {
LOG_ERROR("lm75: device already in shutdown mode\n");
i2c_release(I2C_BUS);
return LM75_SUCCESS;
}
/* set the shutdown register to 1 (shutdown mode) and keeps every other intact */
config |= LM75_CONFIG_SHUTDOWN_MODE;
if (i2c_write_reg(I2C_BUS, I2C_ADDR, LM75_CONF_REG, config, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR;
}
i2c_release(I2C_BUS);
return LM75_SUCCESS;
}
int lm75_poweron(lm75_t *dev) {
i2c_acquire(I2C_BUS);
uint8_t config;
if (i2c_read_reg(I2C_BUS, I2C_ADDR, LM75_CONF_REG, &config, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR;
}
/* sets every reg to 0 except the shutdown register and sees if it is active */
if ((config & LM75_CONFIG_SHUTDOWN_MODE) == 0) {
LOG_INFO("lm75: device is already awake\n");
i2c_release(I2C_BUS);
return LM75_SUCCESS;
}
/* set the shutdown bit to 0 (continuous conversion mode) and keep every other reg intact */
config &= ~LM75_CONFIG_SHUTDOWN_MODE;
if (i2c_write_reg(I2C_BUS, I2C_ADDR, LM75_CONF_REG, config, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR;
}
i2c_release(I2C_BUS);
return LM75_SUCCESS;
}
/* Performs a single temperature conversion from shutdown mode and goes back into shutdown */
int tmp1075_one_shot(lm75_t *dev) {
if (!IS_USED(MODULE_TMP1075) && (dev->lm75_params.res != &tmp1075_properties)) {
LOG_ERROR("lm75: device incompatible with the one shot conversion function\n");
return LM75_ERROR;
}
else {
i2c_acquire(I2C_BUS);
uint8_t config;
if (i2c_read_reg(I2C_BUS, I2C_ADDR, LM75_CONF_REG, &config, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR;
}
/* set the shutdown and one shot mode bits to 1 and keep every other register intact */
config |= TMP1075_CONFIG_ONE_SHOT_MODE;
if (i2c_write_reg(I2C_BUS, I2C_ADDR, LM75_CONF_REG, config, 0) != 0) {
i2c_release(I2C_BUS);
return LM75_ERROR;
}
i2c_release(I2C_BUS);
}
return LM75_SUCCESS;
}
int lm75_low_power_mode(lm75_t *dev, uint16_t interval) {
if (IS_USED(MODULE_TMP1075) && (dev->lm75_params.res == &tmp1075_properties)) {
if (tmp1075_one_shot(dev) != 0) {
return LM75_ERROR;
}
xtimer_msleep(interval);
}
else {
if (lm75_poweron(dev) != 0) {
return LM75_ERROR;
}
/* this is required to ensure the temp register updates for followup readings
* otherwise the temperature register will have outdated and possibly bogus values */
if (interval < dev->lm75_params.conv_rate) {
xtimer_msleep(dev->lm75_params.conv_rate);
}
else {
xtimer_msleep(interval);
}
if (lm75_poweroff(dev) != 0) {
return LM75_ERROR;
}
}
return LM75_SUCCESS;
}
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