File content as of revision 162:16168a1438f3:

/* mbed Microcontroller Library
 * Copyright (c) 2006-2015 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 "mbed_assert.h"
#include "pinmap.h"
#include "mbed_error.h"

void pin_function(PinName pin, int function) {
    MBED_ASSERT(pin != (PinName)NC);
    
    uint32_t pin_number = (uint32_t)pin - (uint32_t)P0_0;
    int index = pin_number >> 4;
    int offset = (pin_number & 0xF) << 1;
    
    PINCONARRAY->PINSEL[index] &= ~(0x3 << offset);
    PINCONARRAY->PINSEL[index] |= function << offset;
}

void pin_mode(PinName pin, PinMode mode) {
    MBED_ASSERT((pin != (PinName)NC) && (mode != OpenDrain));

    uint32_t pin_number = (uint32_t)pin - (uint32_t)P0_0;
    int index = pin_number >> 5;
    int offset = pin_number & 0x1F;
    uint32_t drain = ((uint32_t) mode & (uint32_t) OpenDrain) >> 2;

    if (!drain) {
        index = pin_number >> 4;
        offset = (pin_number & 0xF) << 1;
        
        PINCONARRAY->PINMODE[index] &= ~(0x3 << offset);
        PINCONARRAY->PINMODE[index] |= (uint32_t)mode << offset;
    }
}