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/*
* (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
*/
/*
* On Semiconductor's LM75 Temperature Sensor
*/
#include <common.h>
#ifdef CONFIG_DTT_LM75
#if !defined(CFG_EEPROM_PAGE_WRITE_ENABLE) || \
(CFG_EEPROM_PAGE_WRITE_BITS < 1)
# error "CFG_EEPROM_PAGE_WRITE_ENABLE must be defined and CFG_EEPROM_PAGE_WRITE_BITS must be greater than 1 to use CONFIG_DTT_LM75"
#endif
#include <i2c.h>
#include <dtt.h>
/*
* Device code
*/
#define DTT_I2C_DEV_CODE 0x48 /* ON Semi's LM75 device */
int dtt_read(int sensor, int reg)
{
int dlen;
uchar data[2];
/*
* Validate 'reg' param
*/
if((reg < 0) || (reg > 3))
return -1;
/*
* Calculate sensor address and register.
*/
sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */
/*
* Prepare to handle 2 byte result.
*/
if ((reg == DTT_READ_TEMP) ||
(reg == DTT_TEMP_HYST) ||
(reg == DTT_TEMP_SET))
dlen = 2;
else
dlen = 1;
/*
* Now try to read the register.
*/
if (i2c_read(sensor, reg, 1, data, dlen) != 0)
return -1;
/*
* Handle 2 byte result.
*/
if (dlen == 2)
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
*/
if ((reg < 0) || (reg > 3))
return 1;
/*
* Calculate sensor address and register.
*/
sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */
/*
* Handle 2 byte values.
*/
if ((reg == DTT_READ_TEMP) ||
(reg == DTT_TEMP_HYST) ||
(reg == DTT_TEMP_SET)) {
dlen = 2;
data[0] = (char)((val >> 8) & 0xff); /* MSB first */
data[1] = (char)(val & 0xff);
} else {
dlen = 1;
data[0] = (char)(val & 0xff);
}
/*
* Write value to register.
*/
if (i2c_write(sensor, reg, 1, data, dlen) != 0)
return 1;
return 0;
} /* dtt_write() */
static int _dtt_init(int sensor)
{
int val;
/*
* Setup TSET ( trip point ) register
*/
val = ((CFG_DTT_MAX_TEMP * 2) << 7) & 0xff80; /* trip */
if (dtt_write(sensor, DTT_TEMP_SET, val) != 0)
return 1;
/*
* Setup THYST ( untrip point ) register - Hysteresis
*/
val = (((CFG_DTT_MAX_TEMP - CFG_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0)
return 1;
/*
* Setup configuraton register
*/
/* config = 6 sample integration, int mode, active low, and enable */
val = 0x18;
if (dtt_write(sensor, DTT_CONFIG, val) != 0)
return 1;
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) / 256);
} /* dtt_get_temp() */
#endif /* CONFIG_DTT_LM75 */
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