Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 | /* * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ /* * Dallas Semiconductor's DS1775 Digital Thermometer and Thermostat */ #include <common.h> #ifdef CONFIG_DTT_DS1775 #include <i2c.h> #include <dtt.h> #define DTT_I2C_DEV_CODE 0x49 /* Dallas Semi's DS1775 device code */ int dtt_read(int sensor, int reg) { int dlen; uchar data[2]; /* * Calculate sensor address and command */ sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* Calculate addr of ds1775 */ /* * Prepare to handle 2 byte result */ if ((reg == DTT_READ_TEMP) || (reg == DTT_TEMP_OS) || (reg == DTT_TEMP_HYST)) dlen = 2; else dlen = 1; /* * Now try to read the register */ if (i2c_read(sensor, reg, 1, data, dlen) != 0) return 1; /* * Handle 2 byte result */ if (dlen == 2) return ((int)((short)data[1] + (((short)data[0]) << 8))); return (int) data[0]; } int dtt_write(int sensor, int reg, int val) { int dlen; uchar data[2]; /* * Calculate sensor address and register */ sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* * Handle various data sizes */ if ((reg == DTT_READ_TEMP) || (reg == DTT_TEMP_OS) || (reg == DTT_TEMP_HYST)) { dlen = 2; data[0] = (char)((val >> 8) & 0xff); /* MSB first */ data[1] = (char)(val & 0xff); } else { dlen = 1; data[0] = (char)(val & 0xff); } /* * Write value to device */ if (i2c_write(sensor, reg, 1, data, dlen) != 0) return 1; return 0; } static int _dtt_init(int sensor) { int val; /* * Setup High Temp */ val = ((CFG_DTT_MAX_TEMP * 2) << 7) & 0xff80; if (dtt_write(sensor, DTT_TEMP_OS, val) != 0) return 1; udelay(50000); /* Max 50ms */ /* * Setup Low Temp - hysteresis */ val = (((CFG_DTT_MAX_TEMP - CFG_DTT_HYSTERESIS) * 2) << 7) & 0xff80; if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0) return 1; udelay(50000); /* Max 50ms */ /* * Setup configuraton register * * Fault Tolerance limits 4, Thermometer resolution bits is 9, * Polarity = Active Low,continuous conversion mode, Thermostat * mode is interrupt mode */ val = 0xa; if (dtt_write(sensor, DTT_CONFIG, val) != 0) return 1; udelay(50000); /* Max 50ms */ return 0; } int dtt_init (void) { int i; unsigned char sensors[] = CONFIG_DTT_SENSORS; for (i = 0; i < sizeof(sensors); i++) { if (_dtt_init(sensors[i]) != 0) printf("DTT%d: FAILED\n", i+1); else printf("DTT%d: %i C\n", i+1, dtt_get_temp(sensors[i])); } return (0); } int dtt_get_temp(int sensor) { return (dtt_read(sensor, DTT_READ_TEMP) / 256); } #endif /* CONFIG_DTT_DS1775 */ |