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c609719b WD |
1 | /* |
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 | /* | |
25 | * Dallas Semiconductor's DS1621 Digital Thermometer and Thermostat. | |
26 | */ | |
27 | ||
28 | #include <common.h> | |
29 | ||
c609719b | 30 | #if !defined(CFG_EEPROM_PAGE_WRITE_ENABLE) || \ |
8bde7f77 | 31 | (CFG_EEPROM_PAGE_WRITE_BITS < 1) |
c609719b WD |
32 | # error "CFG_EEPROM_PAGE_WRITE_ENABLE must be defined and CFG_EEPROM_PAGE_WRITE_BITS must be greater than 1 to use CONFIG_DTT_DS1621" |
33 | #endif | |
34 | #include <i2c.h> | |
35 | #include <dtt.h> | |
36 | ||
37 | /* | |
38 | * Device code | |
39 | */ | |
40 | #define DTT_I2C_DEV_CODE 0x48 /* Dallas Semi's DS1621 */ | |
6ecbb45b MS |
41 | #define DTT_READ_TEMP 0xAA |
42 | #define DTT_READ_COUNTER 0xA8 | |
43 | #define DTT_READ_SLOPE 0xA9 | |
44 | #define DTT_WRITE_START_CONV 0xEE | |
45 | #define DTT_WRITE_STOP_CONV 0x22 | |
46 | #define DTT_TEMP_HIGH 0xA1 | |
47 | #define DTT_TEMP_LOW 0xA2 | |
48 | #define DTT_CONFIG 0xAC | |
c609719b WD |
49 | |
50 | int dtt_read(int sensor, int reg) | |
51 | { | |
52 | int dlen; | |
53 | uchar data[2]; | |
54 | ||
55 | /* | |
56 | * Calculate sensor address and command. | |
57 | * | |
58 | */ | |
59 | sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* Calculate addr of ds1621*/ | |
60 | ||
61 | /* | |
62 | * Prepare to handle 2 byte result. | |
63 | */ | |
64 | if ((reg == DTT_READ_TEMP) || | |
65 | (reg == DTT_TEMP_HIGH) || (reg == DTT_TEMP_LOW)) | |
66 | dlen = 2; | |
67 | else | |
68 | dlen = 1; | |
69 | ||
70 | /* | |
71 | * Now try to read the register. | |
72 | */ | |
73 | if (i2c_read(sensor, reg, 1, data, dlen) != 0) | |
74 | return 1; | |
75 | ||
76 | /* | |
77 | * Handle 2 byte result. | |
78 | */ | |
79 | if (dlen == 2) | |
80 | return ((int)((short)data[1] + (((short)data[0]) << 8))); | |
81 | ||
82 | return (int)data[0]; | |
83 | } /* dtt_read() */ | |
84 | ||
85 | ||
86 | int dtt_write(int sensor, int reg, int val) | |
87 | { | |
88 | int dlen; | |
89 | uchar data[2]; | |
90 | ||
91 | /* | |
92 | * Calculate sensor address and register. | |
93 | * | |
94 | */ | |
8564acf9 | 95 | sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); |
c609719b WD |
96 | |
97 | /* | |
98 | * Handle various data sizes. | |
99 | */ | |
100 | if ((reg == DTT_READ_TEMP) || | |
101 | (reg == DTT_TEMP_HIGH) || (reg == DTT_TEMP_LOW)) { | |
102 | dlen = 2; | |
103 | data[0] = (char)((val >> 8) & 0xff); /* MSB first */ | |
104 | data[1] = (char)(val & 0xff); | |
105 | } | |
106 | else if ((reg == DTT_WRITE_START_CONV) || (reg == DTT_WRITE_STOP_CONV)) { | |
107 | dlen = 0; | |
108 | data[0] = (char)0; | |
109 | data[1] = (char)0; | |
110 | } | |
111 | else { | |
112 | dlen = 1; | |
113 | data[0] = (char)(val & 0xff); | |
114 | } | |
115 | ||
116 | /* | |
117 | * Write value to device. | |
118 | */ | |
119 | if (i2c_write(sensor, reg, 1, data, dlen) != 0) | |
120 | return 1; | |
121 | ||
122 | return 0; | |
123 | } /* dtt_write() */ | |
124 | ||
125 | ||
126 | static int _dtt_init(int sensor) | |
127 | { | |
128 | int val; | |
129 | ||
130 | /* | |
131 | * Setup High Temp. | |
132 | */ | |
133 | val = ((CFG_DTT_MAX_TEMP * 2) << 7) & 0xff80; | |
134 | if (dtt_write(sensor, DTT_TEMP_HIGH, val) != 0) | |
135 | return 1; | |
136 | udelay(50000); /* Max 50ms */ | |
137 | ||
138 | /* | |
139 | * Setup Low Temp - hysteresis. | |
140 | */ | |
141 | val = (((CFG_DTT_MAX_TEMP - CFG_DTT_HYSTERESIS) * 2) << 7) & 0xff80; | |
142 | if (dtt_write(sensor, DTT_TEMP_LOW, val) != 0) | |
143 | return 1; | |
144 | udelay(50000); /* Max 50ms */ | |
145 | ||
146 | /* | |
147 | * Setup configuraton register | |
148 | * | |
149 | * Clear THF & TLF, Reserved = 1, Polarity = Active Low, One Shot = YES | |
150 | * | |
151 | * We run in polled mode, since there isn't any way to know if this | |
152 | * lousy device is ready to provide temperature readings on power up. | |
153 | */ | |
154 | val = 0x9; | |
155 | if (dtt_write(sensor, DTT_CONFIG, val) != 0) | |
156 | return 1; | |
157 | udelay(50000); /* Max 50ms */ | |
158 | ||
159 | return 0; | |
160 | } /* _dtt_init() */ | |
161 | ||
162 | ||
163 | int dtt_init (void) | |
164 | { | |
165 | int i; | |
166 | unsigned char sensors[] = CONFIG_DTT_SENSORS; | |
167 | ||
168 | for (i = 0; i < sizeof(sensors); i++) { | |
169 | if (_dtt_init(sensors[i]) != 0) | |
170 | printf("DTT%d: FAILED\n", i+1); | |
171 | else | |
172 | printf("DTT%d: %i C\n", i+1, dtt_get_temp(sensors[i])); | |
173 | } | |
174 | ||
175 | return (0); | |
176 | } /* dtt_init() */ | |
177 | ||
178 | ||
179 | int dtt_get_temp(int sensor) | |
180 | { | |
181 | int i; | |
182 | ||
183 | /* | |
184 | * Start a conversion, may take up to 1 second. | |
185 | */ | |
186 | dtt_write(sensor, DTT_WRITE_START_CONV, 0); | |
187 | for (i = 0; i <= 10; i++) { | |
188 | udelay(100000); | |
189 | if (dtt_read(sensor, DTT_CONFIG) & 0x80) | |
190 | break; | |
191 | } | |
192 | ||
193 | return (dtt_read(sensor, DTT_READ_TEMP) / 256); | |
194 | } /* dtt_get_temp() */ |