src/main/drivers/io_pcf8574.c

   1 /*
   2  * This file is part of INAV.
   3  *
   4  * This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   6  * You can obtain one at http://mozilla.org/MPL/2.0/.
   7  *
   8  * Alternatively, the contents of this file may be used under the terms
   9  * of the GNU General Public License Version 3, as described below:
  10  *
  11  * This file is free software: you may copy, redistribute and/or modify
  12  * it under the terms of the GNU General Public License as published by the
  13  * Free Software Foundation, either version 3 of the License, or (at your
  14  * option) any later version.
  15  *
  16  * This file is distributed in the hope that it will be useful, but
  17  * WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
  19  * Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program. If not, see http://www.gnu.org/licenses/.
  23  */
  24
  25 #include <stdbool.h>
  26 #include <stdint.h>
  27 #include "drivers/bus.h"
  28 #include "drivers/io_pcf8574.h"
  29 #include "drivers/time.h"
  30 #include "build/debug.h"
  31
  32 #define PCF8574_WRITE_ADDRESS 0x40
  33 #define PCF8574_READ_ADDRESS 0x41
  34
  35 static busDevice_t *busDev;
  36
  37 static bool deviceDetect(busDevice_t *busDev)
  38 {
  39     for (int retry = 0; retry < 5; retry++)
  40     {
  41         uint8_t sig;
  42
  43         delay(150);
  44
  45         bool ack = busRead(busDev, 0x00, &sig);
  46         if (ack)
  47         {
  48             return true;
  49         }
  50     };
  51
  52     return false;
  53 }
  54
  55 bool pcf8574Init(void)
  56 {
  57     busDev = busDeviceInit(BUSTYPE_I2C, DEVHW_PCF8574, 0, 0);
  58     if (busDev == NULL)
  59     {
  60         DEBUG_SET(DEBUG_PCF8574, 0, 1);
  61         return false;
  62     }
  63
  64     if (!deviceDetect(busDev))
  65     {
  66         DEBUG_SET(DEBUG_PCF8574, 0, 2);
  67         busDeviceDeInit(busDev);
  68         return false;
  69     }
  70
  71     return true;
  72 }
  73
  74 void pcf8574Write(uint8_t data)
  75 {
  76     busWrite(busDev, PCF8574_WRITE_ADDRESS, data);
  77 }
  78
  79 uint8_t pcf8574Read(void)
  80 {
  81     uint8_t data;
  82     busRead(busDev, PCF8574_READ_ADDRESS, &data);
  83     return data;
  84 }