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wdenkc6097192002-11-03 00:24:07 +00001/*
2 * (C) Copyright 2001
3 * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
4 *
5 * See file CREDITS for list of people who contributed to this
6 * project.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA
22 */
23
24/*
Peter Tyserc3e5fa02010-09-29 13:46:17 -050025 * Dallas Semiconductor's DS1621/1631 Digital Thermometer and Thermostat.
wdenkc6097192002-11-03 00:24:07 +000026 */
27
28#include <common.h>
wdenkc6097192002-11-03 00:24:07 +000029#include <i2c.h>
30#include <dtt.h>
31
32/*
33 * Device code
34 */
Peter Tyser9a6c80b2010-09-29 13:46:18 -050035#define DTT_I2C_DEV_CODE 0x48 /* Dallas Semi's DS1621 */
Michal Simek6ecbb452008-07-11 11:50:53 +020036#define DTT_READ_TEMP 0xAA
37#define DTT_READ_COUNTER 0xA8
38#define DTT_READ_SLOPE 0xA9
39#define DTT_WRITE_START_CONV 0xEE
40#define DTT_WRITE_STOP_CONV 0x22
41#define DTT_TEMP_HIGH 0xA1
42#define DTT_TEMP_LOW 0xA2
43#define DTT_CONFIG 0xAC
wdenkc6097192002-11-03 00:24:07 +000044
Peter Tyserc3e5fa02010-09-29 13:46:17 -050045/*
46 * Config register bits
47 */
48#define DTT_CONFIG_1SHOT 0x01
49#define DTT_CONFIG_POLARITY 0x02
Peter Tyser9a6c80b2010-09-29 13:46:18 -050050#define DTT_CONFIG_R0 0x04 /* ds1631 only */
51#define DTT_CONFIG_R1 0x08 /* ds1631 only */
Peter Tyserc3e5fa02010-09-29 13:46:17 -050052#define DTT_CONFIG_NVB 0x10
53#define DTT_CONFIG_TLF 0x20
54#define DTT_CONFIG_THF 0x40
55#define DTT_CONFIG_DONE 0x80
56
57
wdenkc6097192002-11-03 00:24:07 +000058int dtt_read(int sensor, int reg)
59{
Peter Tyser9a6c80b2010-09-29 13:46:18 -050060 int dlen;
61 uchar data[2];
wdenkc6097192002-11-03 00:24:07 +000062
Peter Tyser9a6c80b2010-09-29 13:46:18 -050063 /* Calculate sensor address and command */
64 sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* Calculate addr of ds1621*/
wdenkc6097192002-11-03 00:24:07 +000065
Peter Tyser9a6c80b2010-09-29 13:46:18 -050066 /* Prepare to handle 2 byte result */
67 switch(reg) {
68 case DTT_READ_TEMP:
69 case DTT_TEMP_HIGH:
70 case DTT_TEMP_LOW:
71 dlen = 2;
72 break;
73 default:
74 dlen = 1;
75 }
wdenkc6097192002-11-03 00:24:07 +000076
Peter Tyser9a6c80b2010-09-29 13:46:18 -050077 /* Now try to read the register */
78 if (i2c_read(sensor, reg, 1, data, dlen) != 0)
79 return 1;
wdenkc6097192002-11-03 00:24:07 +000080
Peter Tyser9a6c80b2010-09-29 13:46:18 -050081 /* Handle 2 byte result */
82 if (dlen == 2)
Jeff Dischler7d85f1d2010-09-29 13:46:19 -050083 return (short)((data[0] << 8) | data[1]);
wdenkc6097192002-11-03 00:24:07 +000084
Peter Tyser9a6c80b2010-09-29 13:46:18 -050085 return (int)data[0];
86}
wdenkc6097192002-11-03 00:24:07 +000087
88
89int dtt_write(int sensor, int reg, int val)
90{
Peter Tyser9a6c80b2010-09-29 13:46:18 -050091 int dlen;
92 uchar data[2];
wdenkc6097192002-11-03 00:24:07 +000093
Peter Tyser9a6c80b2010-09-29 13:46:18 -050094 /* Calculate sensor address and register */
95 sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);
wdenkc6097192002-11-03 00:24:07 +000096
Peter Tyser9a6c80b2010-09-29 13:46:18 -050097 /* Handle various data sizes. */
98 switch(reg) {
99 case DTT_READ_TEMP:
100 case DTT_TEMP_HIGH:
101 case DTT_TEMP_LOW:
102 dlen = 2;
103 data[0] = (char)((val >> 8) & 0xff); /* MSB first */
104 data[1] = (char)(val & 0xff);
105 break;
106 case DTT_WRITE_START_CONV:
107 case DTT_WRITE_STOP_CONV:
108 dlen = 0;
109 data[0] = (char)0;
110 data[1] = (char)0;
111 break;
112 default:
113 dlen = 1;
114 data[0] = (char)(val & 0xff);
115 }
wdenkc6097192002-11-03 00:24:07 +0000116
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500117 /* Write value to device */
118 if (i2c_write(sensor, reg, 1, data, dlen) != 0)
119 return 1;
wdenkc6097192002-11-03 00:24:07 +0000120
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500121 /* Poll NV memory busy bit in case write was to register stored in EEPROM */
122 while(i2c_reg_read(sensor, DTT_CONFIG) & DTT_CONFIG_NVB)
123 ;
Peter Tyserc3e5fa02010-09-29 13:46:17 -0500124
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500125 return 0;
126}
wdenkc6097192002-11-03 00:24:07 +0000127
128
129static int _dtt_init(int sensor)
130{
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500131 int val;
wdenkc6097192002-11-03 00:24:07 +0000132
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500133 /* Setup High Temp */
134 val = ((CONFIG_SYS_DTT_MAX_TEMP * 2) << 7) & 0xff80;
135 if (dtt_write(sensor, DTT_TEMP_HIGH, val) != 0)
136 return 1;
wdenkc6097192002-11-03 00:24:07 +0000137
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500138 /* Setup Low Temp - hysteresis */
139 val = (((CONFIG_SYS_DTT_MAX_TEMP - CONFIG_SYS_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
140 if (dtt_write(sensor, DTT_TEMP_LOW, val) != 0)
141 return 1;
wdenkc6097192002-11-03 00:24:07 +0000142
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500143 /*
144 * Setup configuraton register
145 *
146 * Clear THF & TLF, Reserved = 1, Polarity = Active Low, One Shot = YES
147 *
148 * We run in polled mode, since there isn't any way to know if this
149 * lousy device is ready to provide temperature readings on power up.
150 */
151 val = 0x9;
152 if (dtt_write(sensor, DTT_CONFIG, val) != 0)
153 return 1;
wdenkc6097192002-11-03 00:24:07 +0000154
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500155 return 0;
156}
wdenkc6097192002-11-03 00:24:07 +0000157
158
159int dtt_init (void)
160{
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500161 int i;
162 unsigned char sensors[] = CONFIG_DTT_SENSORS;
wdenkc6097192002-11-03 00:24:07 +0000163
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500164 for (i = 0; i < sizeof(sensors); i++) {
165 if (_dtt_init(sensors[i]) != 0)
166 printf("DTT%d: FAILED\n", i + 1);
167 else
168 printf("DTT%d: %i C\n", i + 1, dtt_get_temp(sensors[i]));
169 }
wdenkc6097192002-11-03 00:24:07 +0000170
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500171 return (0);
172}
wdenkc6097192002-11-03 00:24:07 +0000173
174
175int dtt_get_temp(int sensor)
176{
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500177 int i;
wdenkc6097192002-11-03 00:24:07 +0000178
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500179 /* Start a conversion, may take up to 1 second. */
180 dtt_write(sensor, DTT_WRITE_START_CONV, 0);
181 for (i = 0; i <= 10; i++) {
182 udelay(100000);
183 if (dtt_read(sensor, DTT_CONFIG) & DTT_CONFIG_DONE)
184 break;
185 }
wdenkc6097192002-11-03 00:24:07 +0000186
Peter Tyser9a6c80b2010-09-29 13:46:18 -0500187 return (dtt_read(sensor, DTT_READ_TEMP) / 256);
188}