drivers/hwmon/lm73.c

   1 /*
   2  * (C) Copyright 2007
   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  * 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  * National Semiconductor LM73 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 0x48   /* National Semi's LM73 device */
  41
  42 int dtt_read(int sensor, int reg)
  43 {
  44         int dlen;
  45         uchar data[2];
  46
  47         /*
  48          * Validate 'reg' param and get register size.
  49          */
  50         switch (reg) {
  51         case DTT_CONFIG:
  52         case DTT_CONTROL:
  53                 dlen = 1;
  54                 break;
  55         case DTT_READ_TEMP:
  56         case DTT_TEMP_HIGH:
  57         case DTT_TEMP_LOW:
  58         case DTT_ID:
  59                 dlen = 2;
  60                 break;
  61         default:
  62                 return -1;
  63         }
  64         /*
  65          * Calculate sensor address and register.
  66          */
  67         sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);    /* calculate LM73 addr */
  68         /*
  69          * Now try to read the register.
  70          */
  71         if (i2c_read(sensor, reg, 1, data, dlen) != 0)
  72                 return -1;
  73         /*
  74          * Handle 2 byte result.
  75          */
  76         if (2 == dlen)
  77                 return ((int)((short)data[1] + (((short)data[0]) << 8)));
  78
  79         return (int)data[0];
  80 } /* dtt_read() */
  81
  82 int dtt_write(int sensor, int reg, int val)
  83 {
  84         int dlen;
  85         uchar data[2];
  86
  87         /*
  88          * Validate 'reg' param and handle register size
  89          */
  90         switch (reg) {
  91         case DTT_CONFIG:
  92         case DTT_CONTROL:
  93                 dlen = 1;
  94                 data[0] = (char)(val & 0xff);
  95                 break;
  96         case DTT_TEMP_HIGH:
  97         case DTT_TEMP_LOW:
  98                 dlen = 2;
  99                 data[0] = (char)((val >> 8) & 0xff);    /* MSB first */
 100                 data[1] = (char)(val & 0xff);
 101                 break;
 102         default:
 103                 return -1;
 104         }
 105         /*
 106          * Calculate sensor address and register.
 107          */
 108         sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);    /* calculate LM73 addr */
 109         /*
 110          * Write value to register.
 111          */
 112         return i2c_write(sensor, reg, 1, data, dlen) != 0;
 113 } /* dtt_write() */
 114
 115 static int _dtt_init(int sensor)
 116 {
 117         int val;
 118
 119         /*
 120          * Validate the Identification register
 121          */
 122         if (0x0190 != dtt_read(sensor, DTT_ID))
 123                 return 1;
 124         /*
 125          * Setup THIGH (upper-limit) and TLOW (lower-limit) registers
 126          */
 127         val = CFG_DTT_MAX_TEMP << 7;
 128         if (dtt_write(sensor, DTT_TEMP_HIGH, val))
 129                 return 1;
 130
 131         val = CFG_DTT_MIN_TEMP << 7;
 132         if (dtt_write(sensor, DTT_TEMP_LOW, val))
 133                 return 1;
 134         /*
 135          * Setup configuraton register
 136          */
 137         /* config = alert active low, disabled, and reset */
 138         val = 0x64;
 139         if (dtt_write(sensor, DTT_CONFIG, val))
 140                 return 1;
 141         /*
 142          * Setup control/status register
 143          */
 144         /* control = temp resolution 0.25C */
 145         val = 0x00;
 146         if (dtt_write(sensor, DTT_CONTROL, val))
 147                 return 1;
 148
 149         dtt_read(sensor, DTT_CONTROL);  /* clear temperature flags */
 150         return 0;
 151 } /* _dtt_init() */
 152
 153 int dtt_init(void)
 154 {
 155         int i;
 156         unsigned char sensors[] = CONFIG_DTT_SENSORS;
 157         const char *const header = "DTT:   ";
 158
 159         for (i = 0; i < sizeof(sensors); i++) {
 160                 if (_dtt_init(sensors[i]) != 0)
 161                         printf("%s%d FAILED INIT\n", header, i + 1);
 162                 else
 163                         printf("%s%d is %i C\n", header, i + 1,
 164                                dtt_get_temp(sensors[i]));
 165         }
 166         return 0;
 167 } /* dtt_init() */
 168
 169 int dtt_get_temp(int sensor)
 170 {
 171         return (dtt_read(sensor, DTT_READ_TEMP) + 0x0040) >> 7;
 172 } /* dtt_get_temp() */