src/main/drivers/temperature/lm75.c

   1 /*
   2  * This file is part of Cleanflight.
   3  *
   4  * Cleanflight is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Cleanflight is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <stdbool.h>
  19 #include <stdint.h>
  20
  21 #include <math.h>
  22
  23 #include "platform.h"
  24
  25 #include "build/debug.h"
  26
  27 #include "drivers/sensor.h"
  28 #include "drivers/temperature/lm75.h"
  29 #include "drivers/temperature/temperature.h"
  30 #include "drivers/time.h"
  31
  32 #define LM75_TEMPERATURE_REG_ADDR 0x0
  33
  34
  35 #ifdef USE_TEMPERATURE_LM75
  36
  37 static bool lm75Read(temperatureDev_t *tempDev, int16_t *temperature)
  38 {
  39     uint8_t buf[2];
  40
  41     bool ack = busReadBuf(tempDev->busDev, LM75_TEMPERATURE_REG_ADDR, buf, 2);
  42
  43     if (ack) {
  44         if (temperature) *temperature = (int8_t)buf[0] * 10 + (buf[1] >> 7) * 5;
  45         return true;
  46     }
  47
  48     return false;
  49 }
  50
  51 #define DETECTION_MAX_RETRY_COUNT 5
  52 static bool deviceDetect(temperatureDev_t *tempDev)
  53 {
  54     for (int retryCount = 0; retryCount < DETECTION_MAX_RETRY_COUNT; retryCount++) {
  55         delay(10);
  56         if (lm75Read(tempDev, NULL)) return true;
  57     }
  58
  59     return false;
  60 }
  61
  62 bool lm75Detect(temperatureDev_t *tempDev, uint8_t partialAddress)
  63 {
  64     if (partialAddress > 7)  return false; // invalid address
  65
  66     tempDev->busDev = busDeviceInit(BUSTYPE_I2C, DEVHW_LM75_0 + partialAddress, 0, OWNER_TEMPERATURE);
  67     if (tempDev->busDev == NULL) {
  68         return false;
  69     }
  70
  71     if (!deviceDetect(tempDev)) {
  72         busDeviceDeInit(tempDev->busDev);
  73         return false;
  74     }
  75
  76     tempDev->read = lm75Read;
  77
  78     return true;
  79 }
  80
  81 #endif /* USE_TEMPERATURE_LM75 */