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