2 * This program is free software; you can redistribute it and/or
3 * modify it under the terms of the GNU General Public License as
4 * published by the Free Software Foundation; either version 2 of
5 * the License, or (at your option) any later version.
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
19 * Dallas Semiconductor's DS1775 Digital Thermometer and Thermostat
27 #define DTT_I2C_DEV_CODE CONFIG_SYS_I2C_DTT_ADDR /* Dallas Semi's DS1775 device code */
28 #define DTT_READ_TEMP 0x0
29 #define DTT_CONFIG 0x1
30 #define DTT_TEMP_HYST 0x2
31 #define DTT_TEMP_OS 0x3
33 int dtt_read(int sensor
, int reg
)
39 * Calculate sensor address and command
41 sensor
= DTT_I2C_DEV_CODE
+ (sensor
& 0x07); /* Calculate addr of ds1775 */
44 * Prepare to handle 2 byte result
46 if ((reg
== DTT_READ_TEMP
) ||
47 (reg
== DTT_TEMP_OS
) || (reg
== DTT_TEMP_HYST
))
53 * Now try to read the register
55 if (i2c_read(sensor
, reg
, 1, data
, dlen
) != 0)
59 * Handle 2 byte result
62 return ((int)((short)data
[1] + (((short)data
[0]) << 8)));
68 int dtt_write(int sensor
, int reg
, int val
)
74 * Calculate sensor address and register
76 sensor
= DTT_I2C_DEV_CODE
+ (sensor
& 0x07);
79 * Handle various data sizes
81 if ((reg
== DTT_READ_TEMP
) ||
82 (reg
== DTT_TEMP_OS
) || (reg
== DTT_TEMP_HYST
)) {
84 data
[0] = (char)((val
>> 8) & 0xff); /* MSB first */
85 data
[1] = (char)(val
& 0xff);
88 data
[0] = (char)(val
& 0xff);
92 * Write value to device
94 if (i2c_write(sensor
, reg
, 1, data
, dlen
) != 0)
101 static int _dtt_init(int sensor
)
108 val
= ((CONFIG_SYS_DTT_MAX_TEMP
* 2) << 7) & 0xff80;
109 if (dtt_write(sensor
, DTT_TEMP_OS
, val
) != 0)
111 udelay(50000); /* Max 50ms */
114 * Setup Low Temp - hysteresis
116 val
= (((CONFIG_SYS_DTT_MAX_TEMP
- CONFIG_SYS_DTT_HYSTERESIS
) * 2) << 7) & 0xff80;
117 if (dtt_write(sensor
, DTT_TEMP_HYST
, val
) != 0)
119 udelay(50000); /* Max 50ms */
122 * Setup configuraton register
124 * Fault Tolerance limits 4, Thermometer resolution bits is 9,
125 * Polarity = Active Low,continuous conversion mode, Thermostat
126 * mode is interrupt mode
129 if (dtt_write(sensor
, DTT_CONFIG
, val
) != 0)
131 udelay(50000); /* Max 50ms */
140 unsigned char sensors
[] = CONFIG_DTT_SENSORS
;
142 for (i
= 0; i
< sizeof(sensors
); i
++) {
143 if (_dtt_init(sensors
[i
]) != 0)
144 printf("DTT%d: FAILED\n", i
+1);
146 printf("DTT%d: %i C\n", i
+1, dtt_get_temp(sensors
[i
]));
153 int dtt_get_temp(int sensor
)
155 return (dtt_read(sensor
, DTT_READ_TEMP
) / 256);