text: /*
   * This file is part of the Micro Python project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2013, 2014 Damien P. George
   *
   * 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 <stdint.h>
  #include <string.h>
  
  #include "py/nlr.h"
  #include "py/runtime.h"
  #include "py/mphal.h"
  
  #include "shared-bindings/digitalio/DigitalInOut.h"
  
  digitalinout_result_t common_hal_digitalio_digitalinout_construct(
          digitalio_digitalinout_obj_t* self, const mcu_pin_obj_t* pin) {
      self->pin = pin;
      PIN_FUNC_SELECT(self->pin->peripheral, self->pin->gpio_function);
      return DIGITALINOUT_OK;
  }
  
  void common_hal_digitalio_digitalinout_deinit(digitalio_digitalinout_obj_t* self) {
      if (self->pin->gpio_number < 16) {
          uint32_t pin_mask = 1 << self->pin->gpio_number;
          gpio_output_set(0x0, 0x0, 0x0, pin_mask);
          PIN_FUNC_SELECT(self->pin->peripheral, 0);
          PIN_PULLUP_DIS(self->pin->peripheral);
      }
  }
  
  void common_hal_digitalio_digitalinout_switch_to_input(
          digitalio_digitalinout_obj_t* self, enum digitalinout_pull_t pull) {
      self->output = false;
  
      if (self->pin->gpio_number == 16) {
          WRITE_PERI_REG(PAD_XPD_DCDC_CONF, (READ_PERI_REG(PAD_XPD_DCDC_CONF) & 0xffffffbc) | 1);
          WRITE_PERI_REG(RTC_GPIO_CONF, READ_PERI_REG(RTC_GPIO_CONF) & ~1);
          WRITE_PERI_REG(RTC_GPIO_ENABLE, (READ_PERI_REG(RTC_GPIO_ENABLE) & ~1)); // input
      } else {
          PIN_PULLUP_DIS(self->pin->peripheral);
          gpio_output_set(0, 0, 0, 1 << self->pin->gpio_number);
      }
      common_hal_digitalio_digitalinout_set_pull(self, pull);
  }
  
  void common_hal_digitalio_digitalinout_switch_to_output(
          digitalio_digitalinout_obj_t* self, bool value,
          enum digitalinout_drive_mode_t drive_mode) {
      self->output = true;
      self->open_drain = drive_mode == DRIVE_MODE_OPEN_DRAIN;
      if (self->pin->gpio_number == 16) {
          WRITE_PERI_REG(PAD_XPD_DCDC_CONF, (READ_PERI_REG(PAD_XPD_DCDC_CONF) & 0xffffffbc) | 1);
          WRITE_PERI_REG(RTC_GPIO_CONF, READ_PERI_REG(RTC_GPIO_CONF) & ~1);
          WRITE_PERI_REG(RTC_GPIO_ENABLE, (READ_PERI_REG(RTC_GPIO_ENABLE) & ~1) | 1); // output
      } else if (!self->open_drain) {
          gpio_output_set(0, 0, 1 << self->pin->gpio_number, 0);
          PIN_PULLUP_DIS(self->pin->peripheral);
      }
      common_hal_digitalio_digitalinout_set_value(self, value);
  }
  
  enum digitalinout_direction_t common_hal_digitalio_digitalinout_get_direction(
          digitalio_digitalinout_obj_t* self) {
      return self->output? DIRECTION_OUT : DIRECTION_IN;
  }
  
  void common_hal_digitalio_digitalinout_set_value(
          digitalio_digitalinout_obj_t* self, bool value) {
      if (value) {
          if (self->open_drain) {
              // Disable output.
              gpio_output_set(0, 0, 0, 1 << self->pin->gpio_number);
          } else {
              // Set high
              gpio_output_set(1 << self->pin->gpio_number, 0, 0, 0);
          }
      } else {
          if (self->open_drain) {
              // Enable the output
              gpio_output_set(0, 0, 1 << self->pin->gpio_number, 0);
          }
          // Set low
          gpio_output_set(0, 1 << self->pin->gpio_number, 0, 0);
      }
  }
  
  // Register addresses taken from: https://github.com/esp8266/esp8266-wiki/wiki/gpio-registers
  volatile uint32_t* PIN_DIR = (uint32_t *) 0x6000030C;
  volatile uint32_t* PIN_OUT = (uint32_t *) 0x60000300;
  bool common_hal_digitalio_digitalinout_get_value(
          digitalio_digitalinout_obj_t* self) {
      if (!self->output) {
          if (self->pin->gpio_number == 16) {
              return READ_PERI_REG(RTC_GPIO_IN_DATA) & 1;
          }
          return GPIO_INPUT_GET(self->pin->gpio_number);
      } else {
          uint32_t pin_mask = 1 << self->pin->gpio_number;
          if (self->open_drain && ((*PIN_DIR) & pin_mask) == 0) {
              return true;
          } else {
              return ((*PIN_OUT) & pin_mask) != 0;
          }
      }
  }
  
  void common_hal_digitalio_digitalinout_set_drive_mode(
          digitalio_digitalinout_obj_t* self,
          enum digitalinout_drive_mode_t drive_mode) {
      bool value = common_hal_digitalio_digitalinout_get_value(self);
      self->open_drain = drive_mode == DRIVE_MODE_OPEN_DRAIN;
      // True is implemented differently between modes so reset the value to make
      // sure its correct for the new mode.
      if (value) {
          common_hal_digitalio_digitalinout_set_value(self, value);
      }
  }
  
  enum digitalinout_drive_mode_t common_hal_digitalio_digitalinout_get_drive_mode(
          digitalio_digitalinout_obj_t* self) {
      if (self->open_drain) {
          return DRIVE_MODE_OPEN_DRAIN;
      } else {
          return DRIVE_MODE_PUSH_PULL;
      }
  }
  
  void common_hal_digitalio_digitalinout_set_pull(
          digitalio_digitalinout_obj_t* self, enum digitalinout_pull_t pull) {
      if (pull == PULL_DOWN) {
          nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError,
              "ESP8266 does not support pull down."));
          return;
      }
      if (self->pin->gpio_number == 16) {
          nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError,
              "Pin does not support pull."));
          return;
      }
      if (pull == PULL_NONE) {
          PIN_PULLUP_DIS(self->pin->peripheral);
      } else {
          PIN_PULLUP_EN(self->pin->peripheral);
      }
  }
  
  enum digitalinout_pull_t common_hal_digitalio_digitalinout_get_pull(
          digitalio_digitalinout_obj_t* self) {
      if (self->pin->gpio_number < 16 &&
          (READ_PERI_REG(self->pin->peripheral) & PERIPHS_IO_MUX_PULLUP) != 0) {
          return PULL_UP;
      }
      return PULL_NONE;
  }
  