diff options
Diffstat (limited to 'dtt')
| -rw-r--r-- | dtt/Makefile | 2 | ||||
| -rw-r--r-- | dtt/ds1775.c | 156 |
2 files changed, 157 insertions, 1 deletions
diff --git a/dtt/Makefile b/dtt/Makefile index e6cb128..c6a670a 100644 --- a/dtt/Makefile +++ b/dtt/Makefile @@ -30,7 +30,7 @@ include $(TOPDIR)/config.mk LIB = $(obj)libdtt.a -COBJS = lm75.o ds1621.o adm1021.o lm81.o +COBJS = lm75.o ds1621.o adm1021.o lm81.o ds1775.o SRCS := $(COBJS:.o=.c) OBJS := $(addprefix $(obj),$(COBJS)) diff --git a/dtt/ds1775.c b/dtt/ds1775.c new file mode 100644 index 0000000..e44cee3 --- /dev/null +++ b/dtt/ds1775.c @@ -0,0 +1,156 @@ +/* + * 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> + +#ifdef CONFIG_DTT_DS1775 +#include <i2c.h> +#include <dtt.h> + +#define DTT_I2C_DEV_CODE 0x49 /* Dallas Semi's DS1775 device code */ + +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; +} + + +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_OS, 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_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_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); +} + + +int dtt_get_temp(int sensor) +{ + return (dtt_read(sensor, DTT_READ_TEMP) / 256); +} + + +#endif /* CONFIG_DTT_DS1775 */ |