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/*
* (C) Copyright 2007-2008
* Larry Johnson, lrj@acm.org
*
* based on dtt/lm75.c which is ...
*
* (C) Copyright 2001
* Bill Hunter, Wave 7 Optics, williamhunter@mediaone.net
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* National Semiconductor LM73 Temperature Sensor
*/
#include <common.h>
#include <i2c.h>
#include <dtt.h>
/*
* Device code
*/
#define DTT_I2C_DEV_CODE 0x48 /* National Semi's LM73 device */
int dtt_read(int const sensor, int const reg)
{
int dlen;
uint8_t data[2];
/*
* Validate 'reg' param and get register size.
*/
switch (reg) {
case DTT_CONFIG:
case DTT_CONTROL:
dlen = 1;
break;
case DTT_READ_TEMP:
case DTT_TEMP_HIGH:
case DTT_TEMP_LOW:
case DTT_ID:
dlen = 2;
break;
default:
return -1;
}
/*
* Try to read the register at the calculated sensor address.
*/
if (0 !=
i2c_read(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data, dlen))
return -1;
/*
* Handle 2 byte result.
*/
if (2 == dlen)
return (int)((unsigned)data[0] << 8 | (unsigned)data[1]);
return (int)data[0];
} /* dtt_read() */
int dtt_write(int const sensor, int const reg, int const val)
{
int dlen;
uint8_t data[2];
/*
* Validate 'reg' param and handle register size
*/
switch (reg) {
case DTT_CONFIG:
case DTT_CONTROL:
dlen = 1;
data[0] = (uint8_t) val;
break;
case DTT_TEMP_HIGH:
case DTT_TEMP_LOW:
dlen = 2;
data[0] = (uint8_t) (val >> 8); /* MSB first */
data[1] = (uint8_t) val;
break;
default:
return -1;
}
/*
* Write value to register at the calculated sensor address.
*/
return 0 != i2c_write(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data,
dlen);
} /* dtt_write() */
static int _dtt_init(int const sensor)
{
int val;
/*
* Validate the Identification register
*/
if (0x0190 != dtt_read(sensor, DTT_ID))
return -1;
/*
* Setup THIGH (upper-limit) and TLOW (lower-limit) registers
*/
val = CFG_DTT_MAX_TEMP << 7;
if (dtt_write(sensor, DTT_TEMP_HIGH, val))
return -1;
val = CFG_DTT_MIN_TEMP << 7;
if (dtt_write(sensor, DTT_TEMP_LOW, val))
return -1;
/*
* Setup configuraton register
*/
/* config = alert active low, disabled, and reset */
val = 0x64;
if (dtt_write(sensor, DTT_CONFIG, val))
return -1;
/*
* Setup control/status register
*/
/* control = temp resolution 0.25C */
val = 0x00;
if (dtt_write(sensor, DTT_CONTROL, val))
return -1;
dtt_read(sensor, DTT_CONTROL); /* clear temperature flags */
return 0;
} /* _dtt_init() */
int dtt_init(void)
{
int i;
unsigned char sensors[] = CONFIG_DTT_SENSORS;
const char *const header = "DTT: ";
for (i = 0; i < sizeof(sensors); i++) {
if (0 != _dtt_init(sensors[i]))
printf("%s%d FAILED INIT\n", header, i + 1);
else
printf("%s%d is %i C\n", header, i + 1,
dtt_get_temp(sensors[i]));
}
return 0;
} /* dtt_init() */
int dtt_get_temp(int const sensor)
{
int const ret = dtt_read(sensor, DTT_READ_TEMP);
if (ret < 0) {
printf("DTT temperature read failed.\n");
return 0;
}
return (int)((int16_t) ret + 0x0040) >> 7;
} /* dtt_get_temp() */
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