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Diffstat (limited to 'dtt/lm75.c')
| -rw-r--r-- | dtt/lm75.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/dtt/lm75.c b/dtt/lm75.c new file mode 100644 index 0000000..9930a8b --- /dev/null +++ b/dtt/lm75.c @@ -0,0 +1,181 @@ +/* + * (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> + +#ifdef CONFIG_DTT_LM75 +#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_LM75" +#endif + +#include <i2c.h> +#include <dtt.h> + + +/* + * Device code + */ +#define DTT_I2C_DEV_CODE 0x48 /* ON Semi's LM75 device */ + +int dtt_read(int sensor, int reg) +{ + 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); /* calculate address of lm75 */ + + /* + * 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); /* calculate address of lm75 */ + + /* + * 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() */ + + +static int _dtt_init(int sensor) +{ + int val; + + /* + * Setup TSET ( trip point ) register + */ + val = ((CFG_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 = (((CFG_DTT_MAX_TEMP - CFG_DTT_HYSTERESIS) * 2) << 7) & 0xff80; + if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0) + return 1; + + /* + * Setup configuraton register + */ + /* config = 6 sample integration, int mode, active low, and enable */ + val = 0x18; + if (dtt_write(sensor, DTT_CONFIG, val) != 0) + return 1; + + return 0; +} /* _dtt_init() */ + + +int dtt_init (void) +{ + int i; + unsigned char sensors[] = CONFIG_DTT_SENSORS; + const char *const header = "DTT: "; + + for (i = 0; i < sizeof(sensors); i++) { + if (_dtt_init(sensors[i]) != 0) + printf("%s%d FAILED INIT\n", header, i+1); + else + printf("%s%d is %i C\n", header, i+1, + dtt_get_temp(sensors[i])); + } + + return (0); +} /* dtt_init() */ + +int dtt_get_temp(int sensor) +{ + return (dtt_read(sensor, DTT_READ_TEMP) / 256); +} /* dtt_get_temp() */ + +#endif /* CONFIG_DTT_LM75 */ + |