1 // Copyright (c) 2014 Adafruit Industries

     2 // Author: Tony DiCola

     3 // Based on code from Gert van Loo & Dom: http://elinux.org/RPi_Low-level_peripherals#GPIO_Code_examples

     4 

     5 // Permission is hereby granted, free of charge, to any person obtaining a copy

     6 // of this software and associated documentation files (the "Software"), to deal

     7 // in the Software without restriction, including without limitation the rights

     8 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

     9 // copies of the Software, and to permit persons to whom the Software is

    10 // furnished to do so, subject to the following conditions:

    11 

    12 // The above copyright notice and this permission notice shall be included in all

    13 // copies or substantial portions of the Software.

    14 

    15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

    16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

    17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

    18 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

    19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

    20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

    21 // SOFTWARE.

    22 

    23 // Simple fast memory-mapped GPIO library for the Raspberry Pi.

    24 #ifndef PI_2_MMIO_H

    25 #define PI_2_MMIO_H

    26 

    27 #include <stdint.h>

    28 

    29 #define MMIO_SUCCESS 0

    30 #define MMIO_ERROR_DEVMEM -1

    31 #define MMIO_ERROR_MMAP -2

    32 #define MMIO_ERROR_OFFSET -3

    33 

    34 volatile uint32_t* pi_2_mmio_gpio;

    35 

    36 int pi_2_mmio_init(void);

    37 

    38 static inline void pi_2_mmio_set_input(const int gpio_number) {

    39   // Set GPIO register to 000 for specified GPIO number.

    40   *(pi_2_mmio_gpio+((gpio_number)/10)) &= ~(7<<(((gpio_number)%10)*3));

    41 }

    42 

    43 static inline void pi_2_mmio_set_output(const int gpio_number) {

    44   // First set to 000 using input function.

    45   pi_2_mmio_set_input(gpio_number);

    46   // Next set bit 0 to 1 to set output.

    47   *(pi_2_mmio_gpio+((gpio_number)/10)) |=  (1<<(((gpio_number)%10)*3));

    48 }

    49 

    50 static inline void pi_2_mmio_set_high(const int gpio_number) {

    51   *(pi_2_mmio_gpio+7) = 1 << gpio_number;

    52 }

    53 

    54 static inline void pi_2_mmio_set_low(const int gpio_number) {

    55   *(pi_2_mmio_gpio+10) = 1 << gpio_number;

    56 }

    57 

    58 static inline uint32_t pi_2_mmio_input(const int gpio_number) {

    59   return *(pi_2_mmio_gpio+13) & (1 << gpio_number);

    60 }

    61 

    62 #endif