3 * Bill Hunter, Wave 7 Optics, williamhunter@mediaone.net
5 * See file CREDITS for list of people who contributed to this
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.
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.
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,
25 * On Semiconductor's LM75 Temperature Sensor
30 #ifdef CONFIG_DTT_LM75
31 #if !defined(CFG_EEPROM_PAGE_WRITE_ENABLE) || \
32 (CFG_EEPROM_PAGE_WRITE_BITS < 1)
33 # error "CFG_EEPROM_PAGE_WRITE_ENABLE must be defined and CFG_EEPROM_PAGE_WRITE_BITS must be greater than 1 to use CONFIG_DTT_LM75"
43 #define DTT_I2C_DEV_CODE 0x48 /* ON Semi's LM75 device */
45 int dtt_read(int sensor, int reg)
50 #ifdef CONFIG_DTT_AD7414
52 * On AD7414 the first value upon bootup is not read correctly.
53 * This is most likely because of the 800ms update time of the
54 * temp register in normal update mode. To get current values
55 * each time we issue the "dtt" command including upon powerup
56 * we switch into one-short mode.
58 * Issue one-shot mode command
60 dtt_write(sensor, DTT_CONFIG, 0x64);
64 * Validate 'reg' param
66 if((reg < 0) || (reg > 3))
70 * Calculate sensor address and register.
72 sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */
75 * Prepare to handle 2 byte result.
77 if ((reg == DTT_READ_TEMP) ||
78 (reg == DTT_TEMP_HYST) ||
79 (reg == DTT_TEMP_SET))
85 * Now try to read the register.
87 if (i2c_read(sensor, reg, 1, data, dlen) != 0)
91 * Handle 2 byte result.
94 return ((int)((short)data[1] + (((short)data[0]) << 8)));
101 int dtt_write(int sensor, int reg, int val)
107 * Validate 'reg' param
109 if ((reg < 0) || (reg > 3))
113 * Calculate sensor address and register.
115 sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */
118 * Handle 2 byte values.
120 if ((reg == DTT_READ_TEMP) ||
121 (reg == DTT_TEMP_HYST) ||
122 (reg == DTT_TEMP_SET)) {
124 data[0] = (char)((val >> 8) & 0xff); /* MSB first */
125 data[1] = (char)(val & 0xff);
128 data[0] = (char)(val & 0xff);
132 * Write value to register.
134 if (i2c_write(sensor, reg, 1, data, dlen) != 0)
141 static int _dtt_init(int sensor)
146 * Setup TSET ( trip point ) register
148 val = ((CFG_DTT_MAX_TEMP * 2) << 7) & 0xff80; /* trip */
149 if (dtt_write(sensor, DTT_TEMP_SET, val) != 0)
153 * Setup THYST ( untrip point ) register - Hysteresis
155 val = (((CFG_DTT_MAX_TEMP - CFG_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
156 if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0)
160 * Setup configuraton register
162 #ifdef CONFIG_DTT_AD7414
163 /* config = alert active low and disabled */
166 /* config = 6 sample integration, int mode, active low, and enable */
169 if (dtt_write(sensor, DTT_CONFIG, val) != 0)
179 unsigned char sensors[] = CONFIG_DTT_SENSORS;
180 const char *const header = "DTT: ";
182 for (i = 0; i < sizeof(sensors); i++) {
183 if (_dtt_init(sensors[i]) != 0)
184 printf("%s%d FAILED INIT\n", header, i+1);
186 printf("%s%d is %i C\n", header, i+1,
187 dtt_get_temp(sensors[i]));
193 int dtt_get_temp(int sensor)
195 int const ret = dtt_read(sensor, DTT_READ_TEMP);
198 printf("DTT temperature read failed.\n");
201 return (int)((int16_t) ret / 256);
202 } /* dtt_get_temp() */
204 #endif /* CONFIG_DTT_LM75 */