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/*
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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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