/* * (C) Copyright 2001 * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com. * * See file CREDITS for list of people who contributed to this * project. * * 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 DS1621 Digital Thermometer and Thermostat. */ #include <common.h> #if !defined(CFG_EEPROM_PAGE_WRITE_ENABLE) || \ (CFG_EEPROM_PAGE_WRITE_BITS < 1) # error "CFG_EEPROM_PAGE_WRITE_ENABLE must be defined and CFG_EEPROM_PAGE_WRITE_BITS must be greater than 1 to use CONFIG_DTT_DS1621" #endif #include <i2c.h> #include <dtt.h> /* * Device code */ #define DTT_I2C_DEV_CODE 0x48 /* Dallas Semi's DS1621 */ #define DTT_READ_TEMP 0xAA #define DTT_READ_COUNTER 0xA8 #define DTT_READ_SLOPE 0xA9 #define DTT_WRITE_START_CONV 0xEE #define DTT_WRITE_STOP_CONV 0x22 #define DTT_TEMP_HIGH 0xA1 #define DTT_TEMP_LOW 0xA2 #define DTT_CONFIG 0xAC 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 ds1621*/ /* * Prepare to handle 2 byte result. */ if ((reg == DTT_READ_TEMP) || (reg == DTT_TEMP_HIGH) || (reg == DTT_TEMP_LOW)) 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]; } /* dtt_read() */ 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_HIGH) || (reg == DTT_TEMP_LOW)) { dlen = 2; data[0] = (char)((val >> 8) & 0xff); /* MSB first */ data[1] = (char)(val & 0xff); } else if ((reg == DTT_WRITE_START_CONV) || (reg == DTT_WRITE_STOP_CONV)) { dlen = 0; data[0] = (char)0; data[1] = (char)0; } 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; } /* dtt_write() */ 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_HIGH, 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_LOW, val) != 0) return 1; udelay(50000); /* Max 50ms */ /* * Setup configuraton register * * Clear THF & TLF, Reserved = 1, Polarity = Active Low, One Shot = YES * * We run in polled mode, since there isn't any way to know if this * lousy device is ready to provide temperature readings on power up. */ val = 0x9; if (dtt_write(sensor, DTT_CONFIG, val) != 0) return 1; udelay(50000); /* Max 50ms */ return 0; } /* _dtt_init() */ 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); } /* dtt_init() */ int dtt_get_temp(int sensor) { int i; /* * Start a conversion, may take up to 1 second. */ dtt_write(sensor, DTT_WRITE_START_CONV, 0); for (i = 0; i <= 10; i++) { udelay(100000); if (dtt_read(sensor, DTT_CONFIG) & 0x80) break; } return (dtt_read(sensor, DTT_READ_TEMP) / 256); } /* dtt_get_temp() */