ds1621.c
3.19 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
/*
* (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);
}