/* * 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> #include <i2c.h> #include <dtt.h> #define DTT_I2C_DEV_CODE CONFIG_SYS_I2C_DTT_ADDR /* Dallas Semi's DS1775 device code */ #define DTT_READ_TEMP 0x0 #define DTT_CONFIG 0x1 #define DTT_TEMP_HYST 0x2 #define DTT_TEMP_OS 0x3 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; } int dtt_init_one(int sensor) { int val; /* * Setup High Temp */ val = ((CONFIG_SYS_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 = (((CONFIG_SYS_DTT_MAX_TEMP - CONFIG_SYS_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_get_temp(int sensor) { return (dtt_read(sensor, DTT_READ_TEMP) / 256); }