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  * SPDX-License-Identifier:     GPL-2.0+
  11  */
  12
  13 /*
  14  * On Semiconductor's LM81 Temperature Sensor
  15  */
  16
  17 #include <common.h>
  18 #include <i2c.h>
  19 #include <dtt.h>
  20
  21 /*
  22  * Device code
  23  */
  24 #define DTT_I2C_DEV_CODE 0x2c                   /* ON Semi's LM81 device */
  25 #define DTT_READ_TEMP           0x27
  26 #define DTT_CONFIG_TEMP         0x4b
  27 #define DTT_TEMP_MAX            0x39
  28 #define DTT_TEMP_HYST           0x3a
  29 #define DTT_CONFIG              0x40
  30
  31 int dtt_read(int sensor, int reg)
  32 {
  33     int dlen = 1;
  34     uchar data[2];
  35
  36     /*
  37      * Calculate sensor address and register.
  38      */
  39     sensor = DTT_I2C_DEV_CODE + (sensor & 0x03); /* calculate address of lm81 */
  40
  41     /*
  42      * Now try to read the register.
  43      */
  44     if (i2c_read(sensor, reg, 1, data, dlen) != 0)
  45         return -1;
  46
  47     return (int)data[0];
  48 } /* dtt_read() */
  49
  50
  51 int dtt_write(int sensor, int reg, int val)
  52 {
  53     uchar data;
  54
  55     /*
  56      * Calculate sensor address and register.
  57      */
  58     sensor = DTT_I2C_DEV_CODE + (sensor & 0x03); /* calculate address of lm81 */
  59
  60     data = (char)(val & 0xff);
  61
  62     /*
  63      * Write value to register.
  64      */
  65     if (i2c_write(sensor, reg, 1, &data, 1) != 0)
  66         return 1;
  67
  68     return 0;
  69 } /* dtt_write() */
  70
  71 #define DTT_MANU        0x3e
  72 #define DTT_REV         0x3f
  73 #define DTT_CONFIG      0x40
  74 #define DTT_ADR         0x48
  75
  76 int dtt_init_one(int sensor)
  77 {
  78         int     man;
  79         int     adr;
  80         int     rev;
  81
  82         if (dtt_write (sensor, DTT_CONFIG, 0x01) < 0)
  83                 return 1;
  84         /* The LM81 needs 400ms to get the correct values ... */
  85         udelay (400000);
  86         man = dtt_read (sensor, DTT_MANU);
  87         if (man != 0x01)
  88                 return 1;
  89         adr = dtt_read (sensor, DTT_ADR);
  90         if (adr < 0)
  91                 return 1;
  92         rev = dtt_read (sensor, DTT_REV);
  93         if (adr < 0)
  94                 return 1;
  95
  96         debug ("DTT:   Found LM81@%x Rev: %d\n", adr, rev);
  97         return 0;
  98 } /* dtt_init_one() */
  99
 100
 101 #define TEMP_FROM_REG(temp) \
 102    ((temp)<256?((((temp)&0x1fe) >> 1) * 10)      + ((temp) & 1) * 5:  \
 103                ((((temp)&0x1fe) >> 1) -255) * 10 - ((temp) & 1) * 5)  \
 104
 105 int dtt_get_temp(int sensor)
 106 {
 107         int val = dtt_read (sensor, DTT_READ_TEMP);
 108         int tmpcnf = dtt_read (sensor, DTT_CONFIG_TEMP);
 109
 110         return (TEMP_FROM_REG((val << 1) + ((tmpcnf & 0x80) >> 7))) / 10;
 111 } /* dtt_get_temp() */