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
  35 #ifdef CONFIG_DTT_LM73
  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_LM73"
  39 #endif
  40
  41 #include <i2c.h>
  42 #include <dtt.h>
  43
  44 /*
  45  * Device code
  46  */
  47 #define DTT_I2C_DEV_CODE 0x48   /* National Semi's LM73 device */
  48
  49 int dtt_read(int sensor, int reg)
  50 {
  51         int dlen;
  52         uchar data[2];
  53
  54         /*
  55          * Validate 'reg' param and get register size.
  56          */
  57         switch (reg) {
  58         case DTT_CONFIG:
  59         case DTT_CONTROL:
  60                 dlen = 1;
  61                 break;
  62         case DTT_READ_TEMP:
  63         case DTT_TEMP_HIGH:
  64         case DTT_TEMP_LOW:
  65         case DTT_ID:
  66                 dlen = 2;
  67                 break;
  68         default:
  69                 return -1;
  70         }
  71         /*
  72          * Calculate sensor address and register.
  73          */
  74         sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);    /* calculate LM73 addr */
  75         /*
  76          * Now try to read the register.
  77          */
  78         if (i2c_read(sensor, reg, 1, data, dlen) != 0)
  79                 return -1;
  80         /*
  81          * Handle 2 byte result.
  82          */
  83         if (2 == dlen)
  84                 return ((int)((short)data[1] + (((short)data[0]) << 8)));
  85
  86         return (int)data[0];
  87 } /* dtt_read() */
  88
  89 int dtt_write(int sensor, int reg, int val)
  90 {
  91         int dlen;
  92         uchar data[2];
  93
  94         /*
  95          * Validate 'reg' param and handle register size
  96          */
  97         switch (reg) {
  98         case DTT_CONFIG:
  99         case DTT_CONTROL:
 100                 dlen = 1;
 101                 data[0] = (char)(val & 0xff);
 102                 break;
 103         case DTT_TEMP_HIGH:
 104         case DTT_TEMP_LOW:
 105                 dlen = 2;
 106                 data[0] = (char)((val >> 8) & 0xff);    /* MSB first */
 107                 data[1] = (char)(val & 0xff);
 108                 break;
 109         default:
 110                 return -1;
 111         }
 112         /*
 113          * Calculate sensor address and register.
 114          */
 115         sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);    /* calculate LM73 addr */
 116         /*
 117          * Write value to register.
 118          */
 119         return i2c_write(sensor, reg, 1, data, dlen) != 0;
 120 } /* dtt_write() */
 121
 122 static int _dtt_init(int sensor)
 123 {
 124         int val;
 125
 126         /*
 127          * Validate the Identification register
 128          */
 129         if (0x0190 != dtt_read(sensor, DTT_ID))
 130                 return 1;
 131         /*
 132          * Setup THIGH (upper-limit) and TLOW (lower-limit) registers
 133          */
 134         val = CFG_DTT_MAX_TEMP << 7;
 135         if (dtt_write(sensor, DTT_TEMP_HIGH, val))
 136                 return 1;
 137
 138         val = CFG_DTT_MIN_TEMP << 7;
 139         if (dtt_write(sensor, DTT_TEMP_LOW, val))
 140                 return 1;
 141         /*
 142          * Setup configuraton register
 143          */
 144         /* config = alert active low, disabled, and reset */
 145         val = 0x64;
 146         if (dtt_write(sensor, DTT_CONFIG, val))
 147                 return 1;
 148         /*
 149          * Setup control/status register
 150          */
 151         /* control = temp resolution 0.25C */
 152         val = 0x00;
 153         if (dtt_write(sensor, DTT_CONTROL, val))
 154                 return 1;
 155
 156         dtt_read(sensor, DTT_CONTROL);  /* clear temperature flags */
 157         return 0;
 158 } /* _dtt_init() */
 159
 160 int dtt_init(void)
 161 {
 162         int i;
 163         unsigned char sensors[] = CONFIG_DTT_SENSORS;
 164         const char *const header = "DTT:   ";
 165
 166         for (i = 0; i < sizeof(sensors); i++) {
 167                 if (_dtt_init(sensors[i]) != 0)
 168                         printf("%s%d FAILED INIT\n", header, i + 1);
 169                 else
 170                         printf("%s%d is %i C\n", header, i + 1,
 171                                dtt_get_temp(sensors[i]));
 172         }
 173         return 0;
 174 } /* dtt_init() */
 175
 176 int dtt_get_temp(int sensor)
 177 {
 178         return (dtt_read(sensor, DTT_READ_TEMP) + 0x0040) >> 7;
 179 } /* dtt_get_temp() */
 180
 181 #endif /* CONFIG_DTT_LM73 */