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  * 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 #define DTT_READ_TEMP           0x0
  42 #define DTT_CONFIG              0x1
  43 #define DTT_TEMP_HIGH           0x2
  44 #define DTT_TEMP_LOW            0x3
  45 #define DTT_CONTROL             0x4
  46 #define DTT_ID                  0x7
  47
  48 int dtt_read(int const sensor, int const reg)
  49 {
  50         int dlen;
  51         uint8_t data[2];
  52
  53         /*
  54          * Validate 'reg' param and get register size.
  55          */
  56         switch (reg) {
  57         case DTT_CONFIG:
  58         case DTT_CONTROL:
  59                 dlen = 1;
  60                 break;
  61         case DTT_READ_TEMP:
  62         case DTT_TEMP_HIGH:
  63         case DTT_TEMP_LOW:
  64         case DTT_ID:
  65                 dlen = 2;
  66                 break;
  67         default:
  68                 return -1;
  69         }
  70         /*
  71          * Try to read the register at the calculated sensor address.
  72          */
  73         if (0 !=
  74             i2c_read(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data, dlen))
  75                 return -1;
  76         /*
  77          * Handle 2 byte result.
  78          */
  79         if (2 == dlen)
  80                 return (int)((unsigned)data[0] << 8 | (unsigned)data[1]);
  81
  82         return (int)data[0];
  83 } /* dtt_read() */
  84
  85 int dtt_write(int const sensor, int const reg, int const val)
  86 {
  87         int dlen;
  88         uint8_t data[2];
  89
  90         /*
  91          * Validate 'reg' param and handle register size
  92          */
  93         switch (reg) {
  94         case DTT_CONFIG:
  95         case DTT_CONTROL:
  96                 dlen = 1;
  97                 data[0] = (uint8_t) val;
  98                 break;
  99         case DTT_TEMP_HIGH:
 100         case DTT_TEMP_LOW:
 101                 dlen = 2;
 102                 data[0] = (uint8_t) (val >> 8); /* MSB first */
 103                 data[1] = (uint8_t) val;
 104                 break;
 105         default:
 106                 return -1;
 107         }
 108         /*
 109          * Write value to register at the calculated sensor address.
 110          */
 111         return 0 != i2c_write(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data,
 112                               dlen);
 113 } /* dtt_write() */
 114
 115 static int _dtt_init(int const 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 = CONFIG_SYS_DTT_MAX_TEMP << 7;
 128         if (dtt_write(sensor, DTT_TEMP_HIGH, val))
 129                 return -1;
 130
 131         val = CONFIG_SYS_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 (0 != _dtt_init(sensors[i]))
 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 const sensor)
 170 {
 171         int const ret = dtt_read(sensor, DTT_READ_TEMP);
 172
 173         if (ret < 0) {
 174                 printf("DTT temperature read failed.\n");
 175                 return 0;
 176         }
 177         return (int)((int16_t) ret + 0x0040) >> 7;
 178 } /* dtt_get_temp() */