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git.ipfire.org Git - people/ms/u-boot.git/blob - drivers/hwmon/ds1775.c
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
24 #ifdef CONFIG_DTT_DS1775
28 #define DTT_I2C_DEV_CODE CFG_I2C_DTT_ADDR /* Dallas Semi's DS1775 device code */
30 int dtt_read(int sensor
, int reg
)
36 * Calculate sensor address and command
38 sensor
= DTT_I2C_DEV_CODE
+ (sensor
& 0x07); /* Calculate addr of ds1775 */
41 * Prepare to handle 2 byte result
43 if ((reg
== DTT_READ_TEMP
) ||
44 (reg
== DTT_TEMP_OS
) || (reg
== DTT_TEMP_HYST
))
50 * Now try to read the register
52 if (i2c_read(sensor
, reg
, 1, data
, dlen
) != 0)
56 * Handle 2 byte result
59 return ((int)((short)data
[1] + (((short)data
[0]) << 8)));
65 int dtt_write(int sensor
, int reg
, int val
)
71 * Calculate sensor address and register
73 sensor
= DTT_I2C_DEV_CODE
+ (sensor
& 0x07);
76 * Handle various data sizes
78 if ((reg
== DTT_READ_TEMP
) ||
79 (reg
== DTT_TEMP_OS
) || (reg
== DTT_TEMP_HYST
)) {
81 data
[0] = (char)((val
>> 8) & 0xff); /* MSB first */
82 data
[1] = (char)(val
& 0xff);
85 data
[0] = (char)(val
& 0xff);
89 * Write value to device
91 if (i2c_write(sensor
, reg
, 1, data
, dlen
) != 0)
98 static int _dtt_init(int sensor
)
105 val
= ((CFG_DTT_MAX_TEMP
* 2) << 7) & 0xff80;
106 if (dtt_write(sensor
, DTT_TEMP_OS
, val
) != 0)
108 udelay(50000); /* Max 50ms */
111 * Setup Low Temp - hysteresis
113 val
= (((CFG_DTT_MAX_TEMP
- CFG_DTT_HYSTERESIS
) * 2) << 7) & 0xff80;
114 if (dtt_write(sensor
, DTT_TEMP_HYST
, val
) != 0)
116 udelay(50000); /* Max 50ms */
119 * Setup configuraton register
121 * Fault Tolerance limits 4, Thermometer resolution bits is 9,
122 * Polarity = Active Low,continuous conversion mode, Thermostat
123 * mode is interrupt mode
126 if (dtt_write(sensor
, DTT_CONFIG
, val
) != 0)
128 udelay(50000); /* Max 50ms */
137 unsigned char sensors
[] = CONFIG_DTT_SENSORS
;
139 for (i
= 0; i
< sizeof(sensors
); i
++) {
140 if (_dtt_init(sensors
[i
]) != 0)
141 printf("DTT%d: FAILED\n", i
+1);
143 printf("DTT%d: %i C\n", i
+1, dtt_get_temp(sensors
[i
]));
150 int dtt_get_temp(int sensor
)
152 return (dtt_read(sensor
, DTT_READ_TEMP
) / 256);
156 #endif /* CONFIG_DTT_DS1775 */