gpio.c

/*
 * See https://pastebin.com/i3z2Ts50
 *
 * Copyright 2018 strict-flower
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "hidapi.h"
#include "libmcp2221.h"
#include "avr_writer.h"

const pin_config_t g_config[4] = {
  {AVR_SCK, MCP2221_GPIO0, MCP2221_GPIO_DIR_OUTPUT},
  {AVR_MISO, MCP2221_GPIO1, MCP2221_GPIO_DIR_INPUT},
  {AVR_MOSI, MCP2221_GPIO2, MCP2221_GPIO_DIR_OUTPUT},
  {AVR_RESET, MCP2221_GPIO3, MCP2221_GPIO_DIR_OUTPUT},
};

void gpio_init(void) {
  if (g_is_gpio_init) {
    mcp2221_exit();
    fputs("[-] GPIO was already initialized\n", stderr);
    exit(1);
  }

  g_gpio_conf = mcp2221_GPIOConfInit();
  for (int i = 0; i < (int)(sizeof(g_config) / sizeof(pin_config_t)); i++) {
    g_gpio_conf.conf[i].gpios = g_config[i].pin;
    g_gpio_conf.conf[i].mode = MCP2221_GPIO_MODE_GPIO;
    g_gpio_conf.conf[i].direction = g_config[i].direction;
    if (g_config[i].direction == MCP2221_GPIO_DIR_OUTPUT) {
      g_gpio_conf.conf[i].value = MCP2221_GPIO_VALUE_LOW;
    }
  }
  mcp2221_setGPIOConf(g_dev, &g_gpio_conf);
  g_is_gpio_init = 1;
}

void gpio_set_value(int idx, int value) {
  g_gpio_conf.conf[idx].value = (value != 0) ? MCP2221_GPIO_VALUE_HIGH : MCP2221_GPIO_VALUE_LOW;
  mcp2221_setGPIOConf(g_dev, &g_gpio_conf);
}

int gpio_get_value(int idx) {
  mcp2221_gpio_value_t values[MCP2221_GPIO_COUNT];
  if (!(0 <= idx < 4)) {
    mcp2221_exit();
    fputs("[-] specified invalid index range (valid range is 0 - 3)\n", stderr);
    exit(1);
  }
  if (mcp2221_readGPIO(g_dev, values) != MCP2221_SUCCESS) {
    mcp2221_exit();
    fputs("[-] Failed read from GPIO\n", stderr);
    exit(1);
  }
  return values[idx];
}