/* * (C) Copyright 2007-2008 * Larry Johnson, lrj@acm.org * * based on dtt/lm75.c which is ... * * (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 */ /* * National Semiconductor LM73 Temperature Sensor */ #include <common.h> #include <i2c.h> #include <dtt.h> /* * Device code */ #define DTT_I2C_DEV_CODE 0x48 /* National Semi's LM73 device */ #define DTT_READ_TEMP 0x0 #define DTT_CONFIG 0x1 #define DTT_TEMP_HIGH 0x2 #define DTT_TEMP_LOW 0x3 #define DTT_CONTROL 0x4 #define DTT_ID 0x7 int dtt_read(int const sensor, int const reg) { int dlen; uint8_t data[2]; /* * Validate 'reg' param and get register size. */ switch (reg) { case DTT_CONFIG: case DTT_CONTROL: dlen = 1; break; case DTT_READ_TEMP: case DTT_TEMP_HIGH: case DTT_TEMP_LOW: case DTT_ID: dlen = 2; break; default: return -1; } /* * Try to read the register at the calculated sensor address. */ if (0 != i2c_read(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data, dlen)) return -1; /* * Handle 2 byte result. */ if (2 == dlen) return (int)((unsigned)data[0] << 8 | (unsigned)data[1]); return (int)data[0]; } /* dtt_read() */ int dtt_write(int const sensor, int const reg, int const val) { int dlen; uint8_t data[2]; /* * Validate 'reg' param and handle register size */ switch (reg) { case DTT_CONFIG: case DTT_CONTROL: dlen = 1; data[0] = (uint8_t) val; break; case DTT_TEMP_HIGH: case DTT_TEMP_LOW: dlen = 2; data[0] = (uint8_t) (val >> 8); /* MSB first */ data[1] = (uint8_t) val; break; default: return -1; } /* * Write value to register at the calculated sensor address. */ return 0 != i2c_write(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data, dlen); } /* dtt_write() */ int dtt_init_one(int const sensor) { int val; /* * Validate the Identification register */ if (0x0190 != dtt_read(sensor, DTT_ID)) return -1; /* * Setup THIGH (upper-limit) and TLOW (lower-limit) registers */ val = CONFIG_SYS_DTT_MAX_TEMP << 7; if (dtt_write(sensor, DTT_TEMP_HIGH, val)) return -1; val = CONFIG_SYS_DTT_MIN_TEMP << 7; if (dtt_write(sensor, DTT_TEMP_LOW, val)) return -1; /* * Setup configuraton register */ /* config = alert active low, disabled, and reset */ val = 0x64; if (dtt_write(sensor, DTT_CONFIG, val)) return -1; /* * Setup control/status register */ /* control = temp resolution 0.25C */ val = 0x00; if (dtt_write(sensor, DTT_CONTROL, val)) return -1; dtt_read(sensor, DTT_CONTROL); /* clear temperature flags */ return 0; } /* dtt_init_one() */ int dtt_get_temp(int const 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 + 0x0040) >> 7; } /* dtt_get_temp() */