LXR uboot/drivers/hwmon/lm75.c

   1/*
   2 * (C) Copyright 2001
   3 * Bill Hunter,  Wave 7 Optics, williamhunter@mediaone.net
   4 *
   5 * See file CREDITS for list of people who contributed to this
   6 * project.
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License as
  10 * published by the Free Software Foundation; either version 2 of
  11 * the License, or (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21 * MA 02111-1307 USA
  22 */
  23
  24/*
  25 * On Semiconductor's LM75 Temperature Sensor
  26 */
  27
  28#include <common.h>
  29#include <i2c.h>
  30#include <dtt.h>
  31
  32/*
  33 * Device code
  34 */
  35#if defined(CONFIG_SYS_I2C_DTT_ADDR)
  36#define DTT_I2C_DEV_CODE CONFIG_SYS_I2C_DTT_ADDR
  37#else
  38#define DTT_I2C_DEV_CODE 0x48                   /* ON Semi's LM75 device */
  39#endif
  40#define DTT_READ_TEMP           0x0
  41#define DTT_CONFIG              0x1
  42#define DTT_TEMP_HYST           0x2
  43#define DTT_TEMP_SET            0x3
  44
  45int dtt_read(int sensor, int reg)
  46{
  47        int dlen;
  48        uchar data[2];
  49
  50#ifdef CONFIG_DTT_AD7414
  51        /*
  52         * On AD7414 the first value upon bootup is not read correctly.
  53         * This is most likely because of the 800ms update time of the
  54         * temp register in normal update mode. To get current values
  55         * each time we issue the "dtt" command including upon powerup
  56         * we switch into one-short mode.
  57         *
  58         * Issue one-shot mode command
  59         */
  60        dtt_write(sensor, DTT_CONFIG, 0x64);
  61#endif
  62
  63        /* Validate 'reg' param */
  64        if((reg < 0) || (reg > 3))
  65                return -1;
  66
  67        /* Calculate sensor address and register. */
  68        sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);
  69
  70        /* Prepare to handle 2 byte result. */
  71        if ((reg == DTT_READ_TEMP) ||
  72                (reg == DTT_TEMP_HYST) ||
  73                (reg == DTT_TEMP_SET))
  74                        dlen = 2;
  75        else
  76                dlen = 1;
  77
  78        /* Now try to read the register. */
  79        if (i2c_read(sensor, reg, 1, data, dlen) != 0)
  80                return -1;
  81
  82        /* Handle 2 byte result. */
  83        if (dlen == 2)
  84                return ((int)((short)data[1] + (((short)data[0]) << 8)));
  85
  86        return (int)data[0];
  87} /* dtt_read() */
  88
  89
  90int dtt_write(int sensor, int reg, int val)
  91{
  92        int dlen;
  93        uchar data[2];
  94
  95        /* Validate 'reg' param */
  96        if ((reg < 0) || (reg > 3))
  97                return 1;
  98
  99        /* Calculate sensor address and register. */
 100        sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);
 101
 102        /* Handle 2 byte values. */
 103        if ((reg == DTT_READ_TEMP) ||
 104                (reg == DTT_TEMP_HYST) ||
 105                (reg == DTT_TEMP_SET)) {
 106                        dlen = 2;
 107                data[0] = (char)((val >> 8) & 0xff);    /* MSB first */
 108                data[1] = (char)(val & 0xff);
 109        } else {
 110                dlen = 1;
 111                data[0] = (char)(val & 0xff);
 112        }
 113
 114        /* Write value to register. */
 115        if (i2c_write(sensor, reg, 1, data, dlen) != 0)
 116                return 1;
 117
 118        return 0;
 119} /* dtt_write() */
 120
 121
 122static int _dtt_init(int sensor)
 123{
 124        int val;
 125
 126        /* Setup TSET ( trip point ) register */
 127        val = ((CONFIG_SYS_DTT_MAX_TEMP * 2) << 7) & 0xff80; /* trip */
 128        if (dtt_write(sensor, DTT_TEMP_SET, val) != 0)
 129                return 1;
 130
 131        /* Setup THYST ( untrip point ) register - Hysteresis */
 132        val = (((CONFIG_SYS_DTT_MAX_TEMP - CONFIG_SYS_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
 133        if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0)
 134                return 1;
 135
 136        /* Setup configuraton register */
 137#ifdef CONFIG_DTT_AD7414
 138        /* config = alert active low and disabled */
 139        val = 0x60;
 140#else
 141        /* config = 6 sample integration, int mode, active low, and enable */
 142        val = 0x18;
 143#endif
 144        if (dtt_write(sensor, DTT_CONFIG, val) != 0)
 145                return 1;
 146
 147        return 0;
 148} /* _dtt_init() */
 149
 150
 151int dtt_init (void)
 152{
 153        int i;
 154        unsigned char sensors[] = CONFIG_DTT_SENSORS;
 155        const char *const header = "DTT:   ";
 156        int old_bus;
 157
 158        /* switch to correct I2C bus */
 159        old_bus = I2C_GET_BUS();
 160        I2C_SET_BUS(CONFIG_SYS_DTT_BUS_NUM);
 161
 162        for (i = 0; i < sizeof(sensors); i++) {
 163        if (_dtt_init(sensors[i]) != 0)
 164                printf("%s%d FAILED INIT\n", header, i+1);
 165        else
 166                printf("%s%d is %i C\n", header, i+1,
 167                dtt_get_temp(sensors[i]));
 168        }
 169        /* switch back to original I2C bus */
 170        I2C_SET_BUS(old_bus);
 171
 172        return (0);
 173} /* dtt_init() */
 174
 175int dtt_get_temp(int sensor)
 176{
 177        int const ret = dtt_read(sensor, DTT_READ_TEMP);
 178
 179        if (ret < 0) {
 180                printf("DTT temperature read failed.\n");
 181                return 0;
 182        }
 183        return (int)((int16_t) ret / 256);
 184} /* dtt_get_temp() */
 185