drivers/hwmon/lm81.c

   1 /*
   2  * (C) Copyright 2006
   3  * Heiko Schocher, DENX Software Enginnering <hs@denx.de>
   4  *
   5  * based on dtt/lm75.c which is ...
   6  *
   7  * (C) Copyright 2001
   8  * Bill Hunter,  Wave 7 Optics, williamhunter@mediaone.net
   9  *
  10  * See file CREDITS for list of people who contributed to this
  11  * project.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License as
  15  * published by the Free Software Foundation; either version 2 of
  16  * the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  26  * MA 02111-1307 USA
  27  */
  28
  29 /*
  30  * On Semiconductor's LM81 Temperature Sensor
  31  */
  32
  33 #include <common.h>
  34 #include <i2c.h>
  35 #include <dtt.h>
  36
  37 /*
  38  * Device code
  39  */
  40 #define DTT_I2C_DEV_CODE 0x2c                   /* ON Semi's LM81 device */
  41 #define DTT_READ_TEMP           0x27
  42 #define DTT_CONFIG_TEMP         0x4b
  43 #define DTT_TEMP_MAX            0x39
  44 #define DTT_TEMP_HYST           0x3a
  45 #define DTT_CONFIG              0x40
  46
  47 int dtt_read(int sensor, int reg)
  48 {
  49     int dlen = 1;
  50     uchar data[2];
  51
  52     /*
  53      * Calculate sensor address and register.
  54      */
  55     sensor = DTT_I2C_DEV_CODE + (sensor & 0x03); /* calculate address of lm81 */
  56
  57     /*
  58      * Now try to read the register.
  59      */
  60     if (i2c_read(sensor, reg, 1, data, dlen) != 0)
  61         return -1;
  62
  63     return (int)data[0];
  64 } /* dtt_read() */
  65
  66
  67 int dtt_write(int sensor, int reg, int val)
  68 {
  69     uchar data;
  70
  71     /*
  72      * Calculate sensor address and register.
  73      */
  74     sensor = DTT_I2C_DEV_CODE + (sensor & 0x03); /* calculate address of lm81 */
  75
  76     data = (char)(val & 0xff);
  77
  78     /*
  79      * Write value to register.
  80      */
  81     if (i2c_write(sensor, reg, 1, &data, 1) != 0)
  82         return 1;
  83
  84     return 0;
  85 } /* dtt_write() */
  86
  87 #define DTT_MANU        0x3e
  88 #define DTT_REV         0x3f
  89 #define DTT_CONFIG      0x40
  90 #define DTT_ADR         0x48
  91
  92 int dtt_init_one(int sensor)
  93 {
  94         int     man;
  95         int     adr;
  96         int     rev;
  97
  98         if (dtt_write (sensor, DTT_CONFIG, 0x01) < 0)
  99                 return 1;
 100         /* The LM81 needs 400ms to get the correct values ... */
 101         udelay (400000);
 102         man = dtt_read (sensor, DTT_MANU);
 103         if (man != 0x01)
 104                 return 1;
 105         adr = dtt_read (sensor, DTT_ADR);
 106         if (adr < 0)
 107                 return 1;
 108         rev = dtt_read (sensor, DTT_REV);
 109         if (adr < 0)
 110                 return 1;
 111
 112         debug ("DTT:   Found LM81@%x Rev: %d\n", adr, rev);
 113         return 0;
 114 } /* dtt_init_one() */
 115
 116
 117 #define TEMP_FROM_REG(temp) \
 118    ((temp)<256?((((temp)&0x1fe) >> 1) * 10)      + ((temp) & 1) * 5:  \
 119                ((((temp)&0x1fe) >> 1) -255) * 10 - ((temp) & 1) * 5)  \
 120
 121 int dtt_get_temp(int sensor)
 122 {
 123         int val = dtt_read (sensor, DTT_READ_TEMP);
 124         int tmpcnf = dtt_read (sensor, DTT_CONFIG_TEMP);
 125
 126         return (TEMP_FROM_REG((val << 1) + ((tmpcnf & 0x80) >> 7))) / 10;
 127 } /* dtt_get_temp() */