diff options
Diffstat (limited to 'u-boot/drivers/hwmon/ds1621.c')
| -rw-r--r-- | u-boot/drivers/hwmon/ds1621.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/u-boot/drivers/hwmon/ds1621.c b/u-boot/drivers/hwmon/ds1621.c new file mode 100644 index 0000000..5a2ea62 --- /dev/null +++ b/u-boot/drivers/hwmon/ds1621.c @@ -0,0 +1,188 @@ +/* + * (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 DS1621/1631 Digital Thermometer and Thermostat. + */ + +#include <common.h> +#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 + +/* + * Config register bits + */ +#define DTT_CONFIG_1SHOT 0x01 +#define DTT_CONFIG_POLARITY 0x02 +#define DTT_CONFIG_R0 0x04 /* ds1631 only */ +#define DTT_CONFIG_R1 0x08 /* ds1631 only */ +#define DTT_CONFIG_NVB 0x10 +#define DTT_CONFIG_TLF 0x20 +#define DTT_CONFIG_THF 0x40 +#define DTT_CONFIG_DONE 0x80 + + +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 */ + switch(reg) { + case DTT_READ_TEMP: + case DTT_TEMP_HIGH: + case DTT_TEMP_LOW: + dlen = 2; + break; + default: + 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 (short)((data[0] << 8) | data[1]); + + 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. */ + switch(reg) { + case DTT_READ_TEMP: + case DTT_TEMP_HIGH: + case DTT_TEMP_LOW: + dlen = 2; + data[0] = (char)((val >> 8) & 0xff); /* MSB first */ + data[1] = (char)(val & 0xff); + break; + case DTT_WRITE_START_CONV: + case DTT_WRITE_STOP_CONV: + dlen = 0; + data[0] = (char)0; + data[1] = (char)0; + break; + default: + dlen = 1; + data[0] = (char)(val & 0xff); + } + + /* Write value to device */ + if (i2c_write(sensor, reg, 1, data, dlen) != 0) + return 1; + + /* Poll NV memory busy bit in case write was to register stored in EEPROM */ + while(i2c_reg_read(sensor, DTT_CONFIG) & DTT_CONFIG_NVB) + ; + + return 0; +} + + +static int _dtt_init(int sensor) +{ + int val; + + /* Setup High Temp */ + val = ((CONFIG_SYS_DTT_MAX_TEMP * 2) << 7) & 0xff80; + if (dtt_write(sensor, DTT_TEMP_HIGH, val) != 0) + return 1; + + /* Setup Low Temp - hysteresis */ + val = (((CONFIG_SYS_DTT_MAX_TEMP - CONFIG_SYS_DTT_HYSTERESIS) * 2) << 7) & 0xff80; + if (dtt_write(sensor, DTT_TEMP_LOW, val) != 0) + return 1; + + /* + * 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; + + 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) +{ + 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) & DTT_CONFIG_DONE) + break; + } + + return (dtt_read(sensor, DTT_READ_TEMP) / 256); +} |