156 lines
3.2 KiB
C
156 lines
3.2 KiB
C
/*
|
|
* (C) Copyright 2001
|
|
* Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*/
|
|
|
|
/*
|
|
* Dallas Semiconductor's DS1621/1631 Digital Thermometer and Thermostat.
|
|
*/
|
|
|
|
#include <common.h>
|
|
#include <i2c.h>
|
|
#include <dtt.h>
|
|
|
|
/*
|
|
* Device code
|
|
*/
|
|
#define DTT_I2C_DEV_CODE 0x48 /* Dallas Semi's DS1621 */
|
|
#define DTT_READ_TEMP 0xAA
|
|
#define DTT_READ_COUNTER 0xA8
|
|
#define DTT_READ_SLOPE 0xA9
|
|
#define DTT_WRITE_START_CONV 0xEE
|
|
#define DTT_WRITE_STOP_CONV 0x22
|
|
#define DTT_TEMP_HIGH 0xA1
|
|
#define DTT_TEMP_LOW 0xA2
|
|
#define DTT_CONFIG 0xAC
|
|
|
|
/*
|
|
* Config register bits
|
|
*/
|
|
#define DTT_CONFIG_1SHOT 0x01
|
|
#define DTT_CONFIG_POLARITY 0x02
|
|
#define DTT_CONFIG_R0 0x04 /* ds1631 only */
|
|
#define DTT_CONFIG_R1 0x08 /* ds1631 only */
|
|
#define DTT_CONFIG_NVB 0x10
|
|
#define DTT_CONFIG_TLF 0x20
|
|
#define DTT_CONFIG_THF 0x40
|
|
#define DTT_CONFIG_DONE 0x80
|
|
|
|
|
|
int dtt_read(int sensor, int reg)
|
|
{
|
|
int dlen;
|
|
uchar data[2];
|
|
|
|
/* Calculate sensor address and command */
|
|
sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* Calculate addr of ds1621*/
|
|
|
|
/* Prepare to handle 2 byte result */
|
|
switch(reg) {
|
|
case DTT_READ_TEMP:
|
|
case DTT_TEMP_HIGH:
|
|
case DTT_TEMP_LOW:
|
|
dlen = 2;
|
|
break;
|
|
default:
|
|
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 (short)((data[0] << 8) | data[1]);
|
|
|
|
return (int)data[0];
|
|
}
|
|
|
|
|
|
int dtt_write(int sensor, int reg, int val)
|
|
{
|
|
int dlen;
|
|
uchar data[2];
|
|
|
|
/* Calculate sensor address and register */
|
|
sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);
|
|
|
|
/* Handle various data sizes. */
|
|
switch(reg) {
|
|
case DTT_READ_TEMP:
|
|
case DTT_TEMP_HIGH:
|
|
case DTT_TEMP_LOW:
|
|
dlen = 2;
|
|
data[0] = (char)((val >> 8) & 0xff); /* MSB first */
|
|
data[1] = (char)(val & 0xff);
|
|
break;
|
|
case DTT_WRITE_START_CONV:
|
|
case DTT_WRITE_STOP_CONV:
|
|
dlen = 0;
|
|
data[0] = (char)0;
|
|
data[1] = (char)0;
|
|
break;
|
|
default:
|
|
dlen = 1;
|
|
data[0] = (char)(val & 0xff);
|
|
}
|
|
|
|
/* Write value to device */
|
|
if (i2c_write(sensor, reg, 1, data, dlen) != 0)
|
|
return 1;
|
|
|
|
/* Poll NV memory busy bit in case write was to register stored in EEPROM */
|
|
while(i2c_reg_read(sensor, DTT_CONFIG) & DTT_CONFIG_NVB)
|
|
;
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
int dtt_init_one(int sensor)
|
|
{
|
|
int val;
|
|
|
|
/* Setup High Temp */
|
|
val = ((CONFIG_SYS_DTT_MAX_TEMP * 2) << 7) & 0xff80;
|
|
if (dtt_write(sensor, DTT_TEMP_HIGH, val) != 0)
|
|
return 1;
|
|
|
|
/* Setup Low Temp - hysteresis */
|
|
val = (((CONFIG_SYS_DTT_MAX_TEMP - CONFIG_SYS_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
|
|
if (dtt_write(sensor, DTT_TEMP_LOW, val) != 0)
|
|
return 1;
|
|
|
|
/*
|
|
* Setup configuraton register
|
|
*
|
|
* Clear THF & TLF, Reserved = 1, Polarity = Active Low, One Shot = YES
|
|
*
|
|
* We run in polled mode, since there isn't any way to know if this
|
|
* lousy device is ready to provide temperature readings on power up.
|
|
*/
|
|
val = 0x9;
|
|
if (dtt_write(sensor, DTT_CONFIG, val) != 0)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dtt_get_temp(int sensor)
|
|
{
|
|
int i;
|
|
|
|
/* Start a conversion, may take up to 1 second. */
|
|
dtt_write(sensor, DTT_WRITE_START_CONV, 0);
|
|
for (i = 0; i <= 10; i++) {
|
|
udelay(100000);
|
|
if (dtt_read(sensor, DTT_CONFIG) & DTT_CONFIG_DONE)
|
|
break;
|
|
}
|
|
|
|
return (dtt_read(sensor, DTT_READ_TEMP) / 256);
|
|
}
|