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
  35 #ifdef CONFIG_DTT_LM81
  36 #if !defined(CFG_EEPROM_PAGE_WRITE_ENABLE) || \
  37         (CFG_EEPROM_PAGE_WRITE_BITS < 1)
  38 # error "CFG_EEPROM_PAGE_WRITE_ENABLE must be defined and CFG_EEPROM_PAGE_WRITE_BITS must be greater than  1 to use CONFIG_DTT_LM81"
  39 #endif
  40
  41 #include <i2c.h>
  42 #include <dtt.h>
  43
  44 /*
  45  * Device code
  46  */
  47 #define DTT_I2C_DEV_CODE 0x2c                   /* ON Semi's LM81 device */
  48
  49 int dtt_read(int sensor, int reg)
  50 {
  51     int dlen = 1;
  52     uchar data[2];
  53
  54     /*
  55      * Calculate sensor address and register.
  56      */
  57     sensor = DTT_I2C_DEV_CODE + (sensor & 0x03); /* calculate address of lm81 */
  58
  59     /*
  60      * Now try to read the register.
  61      */
  62     if (i2c_read(sensor, reg, 1, data, dlen) != 0)
  63         return -1;
  64
  65     return (int)data[0];
  66 } /* dtt_read() */
  67
  68
  69 int dtt_write(int sensor, int reg, int val)
  70 {
  71     uchar data;
  72
  73     /*
  74      * Calculate sensor address and register.
  75      */
  76     sensor = DTT_I2C_DEV_CODE + (sensor & 0x03); /* calculate address of lm81 */
  77
  78     data = (char)(val & 0xff);
  79
  80     /*
  81      * Write value to register.
  82      */
  83     if (i2c_write(sensor, reg, 1, &data, 1) != 0)
  84         return 1;
  85
  86     return 0;
  87 } /* dtt_write() */
  88
  89 #define DTT_MANU        0x3e
  90 #define DTT_REV         0x3f
  91 #define DTT_CONFIG      0x40
  92 #define DTT_ADR         0x48
  93
  94 static int _dtt_init(int sensor)
  95 {
  96         int     man;
  97         int     adr;
  98         int     rev;
  99
 100         if (dtt_write (sensor, DTT_CONFIG, 0x01) < 0)
 101                 return 1;
 102         /* The LM81 needs 400ms to get the correct values ... */
 103         udelay (400000);
 104         man = dtt_read (sensor, DTT_MANU);
 105         if (man != 0x01)
 106                 return 1;
 107         adr = dtt_read (sensor, DTT_ADR);
 108         if (adr < 0)
 109                 return 1;
 110         rev = dtt_read (sensor, DTT_REV);
 111         if (adr < 0)
 112                 return 1;
 113
 114         printf ("DTT:   Found LM81@%x Rev: %d\n", adr, rev);
 115         return 0;
 116 } /* _dtt_init() */
 117
 118
 119 int dtt_init (void)
 120 {
 121     int i;
 122     unsigned char sensors[] = CONFIG_DTT_SENSORS;
 123     const char *const header = "DTT:   ";
 124
 125     for (i = 0; i < sizeof(sensors); i++) {
 126         if (_dtt_init(sensors[i]) != 0)
 127             printf("%s%d FAILED INIT\n", header, i+1);
 128         else
 129             printf("%s%d is %i C\n", header, i+1,
 130                    dtt_get_temp(sensors[i]));
 131     }
 132
 133     return (0);
 134 } /* dtt_init() */
 135
 136 #define TEMP_FROM_REG(temp) \
 137    ((temp)<256?((((temp)&0x1fe) >> 1) * 10)      + ((temp) & 1) * 5:  \
 138                ((((temp)&0x1fe) >> 1) -255) * 10 - ((temp) & 1) * 5)  \
 139
 140 int dtt_get_temp(int sensor)
 141 {
 142         int val = dtt_read (sensor, DTT_READ_TEMP);
 143         int tmpcnf = dtt_read (sensor, DTT_CONFIG_TEMP);
 144
 145         return (TEMP_FROM_REG((val << 1) + ((tmpcnf & 0x80) >> 7))) / 10;
 146 } /* dtt_get_temp() */
 147
 148 #endif /* CONFIG_DTT_LM81 */