text: /* mbed Microcontroller Library
   * Copyright (c) 2006-2013 ARM Limited
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  #include "gpio_api.h"
  #include "pinmap.h"
  
  uint32_t gpio_set(PinName pin) {
      pin_function(pin, 0);
      return (1 << ((int)pin & 0x1F));
  }
  
  void gpio_init(gpio_t *obj, PinName pin, PinDirection direction) {
      if(pin == NC) return;
      
      obj->pin = pin;
      obj->mask = gpio_set(pin);
      
      LPC_GPIO_TypeDef *port_reg = (LPC_GPIO_TypeDef *) ((int)pin & ~0x1F);
      obj->reg_set = &port_reg->FIOSET;
      obj->reg_clr = &port_reg->FIOCLR;
      obj->reg_in  = &port_reg->FIOPIN;
      obj->reg_dir = &port_reg->FIODIR;
      
      gpio_dir(obj, direction);
      switch (direction) {
          case PIN_OUTPUT: pin_mode(pin, PullNone); break;
          case PIN_INPUT : pin_mode(pin, PullDown); break;
      }
  }
  
  void gpio_mode(gpio_t *obj, PinMode mode) {
      pin_mode(obj->pin, mode);
  }
  
  void gpio_dir(gpio_t *obj, PinDirection direction) {
      switch (direction) {
          case PIN_INPUT : *obj->reg_dir &= ~obj->mask; break;
          case PIN_OUTPUT: *obj->reg_dir |=  obj->mask; break;
      }
  }
  