ds620.c
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/*
* DS620 DTT support
*
* (C) Copyright 2014 3ADEV <http://www.3adev.com>
* Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Dallas Semiconductor's DS1621/1631 Digital Thermometer and Thermostat.
*/
#include <common.h>
#include <i2c.h>
#include <dtt.h>
/*
* Device code
*/
#define DTT_I2C_DEV_CODE 0x48
#define DTT_START_CONVERT 0x51
#define DTT_TEMP 0xAA
#define DTT_CONFIG 0xAC
/*
* Config register MSB bits
*/
#define DTT_CONFIG_1SHOT 0x01
#define DTT_CONFIG_AUTOC 0x02
#define DTT_CONFIG_R0 0x04 /* always 1 */
#define DTT_CONFIG_R1 0x08 /* always 1 */
#define DTT_CONFIG_TLF 0x10
#define DTT_CONFIG_THF 0x20
#define DTT_CONFIG_NVB 0x40
#define DTT_CONFIG_DONE 0x80
#define CHIP(sensor) (DTT_I2C_DEV_CODE + (sensor & 0x07))
int dtt_init_one(int sensor)
{
uint8_t config = DTT_CONFIG_1SHOT
| DTT_CONFIG_R0
| DTT_CONFIG_R1;
return i2c_write(CHIP(sensor), DTT_CONFIG, 1, &config, 1);
}
int dtt_get_temp(int sensor)
{
uint8_t status;
uint8_t temp[2];
/* Start a conversion, may take up to 1 second. */
i2c_write(CHIP(sensor), DTT_START_CONVERT, 1, NULL, 0);
do {
if (i2c_read(CHIP(sensor), DTT_CONFIG, 1, &status, 1))
/* bail out if I2C error */
status |= DTT_CONFIG_DONE;
} while (!(status & DTT_CONFIG_DONE));
if (i2c_read(CHIP(sensor), DTT_TEMP, 1, temp, 2))
/* bail out if I2C error */
return -274; /* below absolute zero == error */
return ((int16_t)(temp[1] | (temp[0] << 8))) >> 7;
}