keyboards/nek_type_a/mcp23017.c

   1 /* Copyright 2018 Mike Roberts
   2  *
   3  * This program is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16 #include <stdbool.h>
  17 #include "action.h"
  18 #include "lib/lufa/LUFA/Drivers/Peripheral/TWI.h"
  19 #include "lib/lufa/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c"
  20 #include "mcp23017.h"
  21 #include "debug.h"
  22 #include "wait.h"
  23
  24 uint8_t bit_for_pin(uint8_t pin);
  25
  26 uint8_t expander_write(uint8_t reg, uint8_t data);
  27
  28 uint8_t expander_read(uint8_t reg, uint8_t *data);
  29
  30 void expander_config(void);
  31
  32 static const char *twi_err_str(uint8_t res) {
  33     switch (res) {
  34         case TWI_ERROR_NoError:
  35             return "OK";
  36         case TWI_ERROR_BusFault:
  37             return "BUSFAULT";
  38         case TWI_ERROR_BusCaptureTimeout:
  39             return "BUSTIMEOUT";
  40         case TWI_ERROR_SlaveResponseTimeout:
  41             return "SLAVETIMEOUT";
  42         case TWI_ERROR_SlaveNotReady:
  43             return "SLAVENOTREADY";
  44         case TWI_ERROR_SlaveNAK:
  45             return "SLAVENAK";
  46         default:
  47             return "UNKNOWN";
  48     }
  49 }
  50
  51 void expander_init(void) {
  52     TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 400000));
  53 }
  54
  55 // set IN and HI
  56 void expander_unselect_all() {
  57     expander_write(EXPANDER_REG_IODIRA, 0xff);
  58     expander_write(EXPANDER_REG_IODIRB, 0xff);
  59     expander_write(EXPANDER_REG_OLATA, 0xff);
  60     expander_write(EXPANDER_REG_OLATB, 0xff);
  61     wait_us(EXPANDER_PAUSE);
  62 }
  63
  64 // set OUT and LOW
  65 void expander_select(uint8_t pin) {
  66     const uint8_t mask = 0xff & ~(1 << bit_for_pin(pin));
  67     if (pin < 8) {
  68         expander_write(EXPANDER_REG_IODIRA, mask);
  69         expander_write(EXPANDER_REG_OLATA, mask);
  70     } else {
  71         expander_write(EXPANDER_REG_IODIRB, mask);
  72         expander_write(EXPANDER_REG_OLATB, mask);
  73     }
  74     wait_us(EXPANDER_PAUSE);
  75 }
  76
  77 void expander_config() {
  78     // set everything to input
  79     expander_write(EXPANDER_REG_IODIRA, 0xff);
  80     expander_write(EXPANDER_REG_IODIRB, 0xff);
  81
  82     // turn on pull-ups
  83     expander_write(EXPANDER_REG_GPPUA, 0xff);
  84     expander_write(EXPANDER_REG_GPPUB, 0xff);
  85
  86     // disable interrupts
  87     expander_write(EXPANDER_REG_GPINTENA, 0x0);
  88     expander_write(EXPANDER_REG_GPINTENB, 0x0);
  89
  90     // polarity
  91     expander_write(EXPANDER_REG_IPOLA, 0x0);
  92     expander_write(EXPANDER_REG_IPOLB, 0x0);
  93 }
  94
  95 uint8_t bit_for_pin(uint8_t pin) {
  96     return pin % 8;
  97 }
  98
  99 uint8_t expander_write(uint8_t reg, unsigned char val) {
 100     uint8_t addr = reg;
 101     uint8_t result = TWI_WritePacket(EXPANDER_ADDR << 1, I2C_TIMEOUT, &addr, sizeof(addr), &val, sizeof(val));
 102     if (result) {
 103         xprintf("mcp: set_register %d = %d failed: %s\n", reg, val, twi_err_str(result));
 104     }
 105     return result == 0;
 106 }
 107