drivers/hwmon/lm73.c

   1 /*
   2  * (C) Copyright 2007-2008
   3  * Larry Johnson, lrj@acm.org
   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  * National Semiconductor LM73 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 0x48   /* National Semi's LM73 device */
  25 #define DTT_READ_TEMP           0x0
  26 #define DTT_CONFIG              0x1
  27 #define DTT_TEMP_HIGH           0x2
  28 #define DTT_TEMP_LOW            0x3
  29 #define DTT_CONTROL             0x4
  30 #define DTT_ID                  0x7
  31
  32 int dtt_read(int const sensor, int const reg)
  33 {
  34         int dlen;
  35         uint8_t data[2];
  36
  37         /*
  38          * Validate 'reg' param and get register size.
  39          */
  40         switch (reg) {
  41         case DTT_CONFIG:
  42         case DTT_CONTROL:
  43                 dlen = 1;
  44                 break;
  45         case DTT_READ_TEMP:
  46         case DTT_TEMP_HIGH:
  47         case DTT_TEMP_LOW:
  48         case DTT_ID:
  49                 dlen = 2;
  50                 break;
  51         default:
  52                 return -1;
  53         }
  54         /*
  55          * Try to read the register at the calculated sensor address.
  56          */
  57         if (0 !=
  58             i2c_read(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data, dlen))
  59                 return -1;
  60         /*
  61          * Handle 2 byte result.
  62          */
  63         if (2 == dlen)
  64                 return (int)((unsigned)data[0] << 8 | (unsigned)data[1]);
  65
  66         return (int)data[0];
  67 } /* dtt_read() */
  68
  69 int dtt_write(int const sensor, int const reg, int const val)
  70 {
  71         int dlen;
  72         uint8_t data[2];
  73
  74         /*
  75          * Validate 'reg' param and handle register size
  76          */
  77         switch (reg) {
  78         case DTT_CONFIG:
  79         case DTT_CONTROL:
  80                 dlen = 1;
  81                 data[0] = (uint8_t) val;
  82                 break;
  83         case DTT_TEMP_HIGH:
  84         case DTT_TEMP_LOW:
  85                 dlen = 2;
  86                 data[0] = (uint8_t) (val >> 8); /* MSB first */
  87                 data[1] = (uint8_t) val;
  88                 break;
  89         default:
  90                 return -1;
  91         }
  92         /*
  93          * Write value to register at the calculated sensor address.
  94          */
  95         return 0 != i2c_write(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data,
  96                               dlen);
  97 } /* dtt_write() */
  98
  99 int dtt_init_one(int const sensor)
 100 {
 101         int val;
 102
 103         /*
 104          * Validate the Identification register
 105          */
 106         if (0x0190 != dtt_read(sensor, DTT_ID))
 107                 return -1;
 108         /*
 109          * Setup THIGH (upper-limit) and TLOW (lower-limit) registers
 110          */
 111         val = CONFIG_SYS_DTT_MAX_TEMP << 7;
 112         if (dtt_write(sensor, DTT_TEMP_HIGH, val))
 113                 return -1;
 114
 115         val = CONFIG_SYS_DTT_MIN_TEMP << 7;
 116         if (dtt_write(sensor, DTT_TEMP_LOW, val))
 117                 return -1;
 118         /*
 119          * Setup configuraton register
 120          */
 121         /* config = alert active low, disabled, and reset */
 122         val = 0x64;
 123         if (dtt_write(sensor, DTT_CONFIG, val))
 124                 return -1;
 125         /*
 126          * Setup control/status register
 127          */
 128         /* control = temp resolution 0.25C */
 129         val = 0x00;
 130         if (dtt_write(sensor, DTT_CONTROL, val))
 131                 return -1;
 132
 133         dtt_read(sensor, DTT_CONTROL);  /* clear temperature flags */
 134         return 0;
 135 } /* dtt_init_one() */
 136
 137 int dtt_get_temp(int const sensor)
 138 {
 139         int const ret = dtt_read(sensor, DTT_READ_TEMP);
 140
 141         if (ret < 0) {
 142                 printf("DTT temperature read failed.\n");
 143                 return 0;
 144         }
 145         return (int)((int16_t) ret + 0x0040) >> 7;
 146 } /* dtt_get_temp() */