/* * (C) Copyright 2001 * Bill Hunter, Wave 7 Optics, williamhunter@mediaone.net * * 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 */ /* * On Semiconductor's LM75 Temperature Sensor */ #include <common.h> #include <i2c.h> #include <dtt.h> /* * Device code */ #if defined(CONFIG_SYS_I2C_DTT_ADDR) #define DTT_I2C_DEV_CODE CONFIG_SYS_I2C_DTT_ADDR #else #define DTT_I2C_DEV_CODE 0x48 /* ON Semi's LM75 device */ #endif #define DTT_READ_TEMP 0x0 #define DTT_CONFIG 0x1 #define DTT_TEMP_HYST 0x2 #define DTT_TEMP_SET 0x3 int dtt_read(int sensor, int reg) { int dlen; uchar data[2]; #ifdef CONFIG_DTT_AD7414 /* * On AD7414 the first value upon bootup is not read correctly. * This is most likely because of the 800ms update time of the * temp register in normal update mode. To get current values * each time we issue the "dtt" command including upon powerup * we switch into one-short mode. * * Issue one-shot mode command */ dtt_write(sensor, DTT_CONFIG, 0x64); #endif /* Validate 'reg' param */ if((reg < 0) || (reg > 3)) return -1; /* Calculate sensor address and register. */ sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* Prepare to handle 2 byte result. */ if ((reg == DTT_READ_TEMP) || (reg == DTT_TEMP_HYST) || (reg == DTT_TEMP_SET)) 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]; /* Validate 'reg' param */ if ((reg < 0) || (reg > 3)) return 1; /* Calculate sensor address and register. */ sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* Handle 2 byte values. */ if ((reg == DTT_READ_TEMP) || (reg == DTT_TEMP_HYST) || (reg == DTT_TEMP_SET)) { 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 register. */ if (i2c_write(sensor, reg, 1, data, dlen) != 0) return 1; return 0; } /* dtt_write() */ int dtt_init_one(int sensor) { int val; /* Setup TSET ( trip point ) register */ val = ((CONFIG_SYS_DTT_MAX_TEMP * 2) << 7) & 0xff80; /* trip */ if (dtt_write(sensor, DTT_TEMP_SET, val) != 0) return 1; /* Setup THYST ( untrip point ) register - 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; /* Setup configuraton register */ #ifdef CONFIG_DTT_AD7414 /* config = alert active low and disabled */ val = 0x60; #else /* config = 6 sample integration, int mode, active low, and enable */ val = 0x18; #endif if (dtt_write(sensor, DTT_CONFIG, val) != 0) return 1; return 0; } /* dtt_init_one() */ int dtt_get_temp(int sensor) { int const ret = dtt_read(sensor, DTT_READ_TEMP); if (ret < 0) { printf("DTT temperature read failed.\n"); return 0; } return (int)((int16_t) ret / 256); } /* dtt_get_temp() */