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/*
* (C) Copyright 2007
* 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 sensor, int reg)
{
int dlen;
uchar 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;
}
/*
* Calculate sensor address and register.
*/
sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate LM73 addr */
/*
* Now try to read the register.
*/
if (i2c_read(sensor, reg, 1, data, dlen) != 0)
return -1;
/*
* Handle 2 byte result.
*/
if (2 == dlen)
return ((int)((short)data[1] + (((short)data[0]) << 8)));
return (int)data[0];
} /* dtt_read() */
int dtt_write(int sensor, int reg, int val)
{
int dlen;
uchar data[2];
/*
* Validate 'reg' param and handle register size
*/
switch (reg) {
case DTT_CONFIG:
case DTT_CONTROL:
dlen = 1;
data[0] = (char)(val & 0xff);
break;
case DTT_TEMP_HIGH:
case DTT_TEMP_LOW:
dlen = 2;
data[0] = (char)((val >> 8) & 0xff); /* MSB first */
data[1] = (char)(val & 0xff);
break;
default:
return -1;
}
/*
* Calculate sensor address and register.
*/
sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate LM73 addr */
/*
* Write value to register.
*/
return i2c_write(sensor, reg, 1, data, dlen) != 0;
} /* dtt_write() */
static int _dtt_init(int 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 (_dtt_init(sensors[i]) != 0)
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 sensor)
{
return (dtt_read(sensor, DTT_READ_TEMP) + 0x0040) >> 7;
} /* dtt_get_temp() */
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