gpio_lib.c

/*
 * 
 * This file is part of pyA20.
 * gpio_lib.c is python GPIO extension.
 * 
 * Copyright (c) 2014 Stefan Mavrodiev @ OLIMEX LTD, <support@olimex.com> 
 * 
 * pyA20 is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 */


#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/select.h>
#include <pthread.h>
#include <unistd.h>
#include <sched.h>

#include "gpio_lib.h"

unsigned int SUNXI_PIO_BASE = 0;

int sunxi_gpio_init(void) {
    int fd;
    unsigned int addr_start, addr_offset;
    unsigned int PageSize, PageMask;
    void *pc;

    fd = open("/dev/mem", O_RDWR);
    if (fd < 0) {
        return (-1);
    }


    PageSize = sysconf(_SC_PAGESIZE);
    PageMask = (~(PageSize - 1));

    addr_start = SW_PORTC_IO_BASE & PageMask;
    addr_offset = SW_PORTC_IO_BASE & ~PageMask;

    pc = (void *) mmap(0, PageSize * 2, PROT_READ | PROT_WRITE, MAP_SHARED, fd, addr_start);
    if (pc == MAP_FAILED) {
        return (-1);
    }

    SUNXI_PIO_BASE = (unsigned int) pc;
    SUNXI_PIO_BASE += addr_offset;

    close(fd);
    return 0;
}

int sunxi_gpio_set_cfgpin(unsigned int pin, unsigned int val) {

    unsigned int cfg;
    unsigned int bank = GPIO_BANK(pin);
    unsigned int index = GPIO_CFG_INDEX(pin);
    unsigned int offset = GPIO_CFG_OFFSET(pin);

    if (SUNXI_PIO_BASE == 0) {
        return -1;
    }

    struct sunxi_gpio *pio =
            &((struct sunxi_gpio_reg *) SUNXI_PIO_BASE)->gpio_bank[bank];


    cfg = *(&pio->cfg[0] + index);
    cfg &= ~(0xf << offset);
    cfg |= val << offset;

    *(&pio->cfg[0] + index) = cfg;

    return 0;
}

int sunxi_gpio_get_cfgpin(unsigned int pin) {

    unsigned int cfg;
    unsigned int bank = GPIO_BANK(pin);
    unsigned int index = GPIO_CFG_INDEX(pin);
    unsigned int offset = GPIO_CFG_OFFSET(pin);
    if (SUNXI_PIO_BASE == 0) {
        return -1;
    }
    struct sunxi_gpio *pio = &((struct sunxi_gpio_reg *) SUNXI_PIO_BASE)->gpio_bank[bank];
    cfg = *(&pio->cfg[0] + index);
    cfg >>= offset;
    return (cfg & 0xf);
}

int sunxi_gpio_output(unsigned int pin, unsigned int val) {

    unsigned int bank = GPIO_BANK(pin);
    unsigned int num = GPIO_NUM(pin);

    if (SUNXI_PIO_BASE == 0) {
        return -1;
    }
    struct sunxi_gpio *pio = &((struct sunxi_gpio_reg *) SUNXI_PIO_BASE)->gpio_bank[bank];

    if (val)
        *(&pio->dat) |= 1 << num;
    else
        *(&pio->dat) &= ~(1 << num);

    return 0;
}

int sunxi_gpio_pullup(unsigned int pin, unsigned int pull) {

    unsigned int cfg;
    unsigned int bank = GPIO_BANK(pin);
    unsigned int index = GPIO_PUL_INDEX(pin);
    unsigned int offset = GPIO_PUL_OFFSET(pin);

    if (SUNXI_PIO_BASE == 0) {
        return -1;
    }

    struct sunxi_gpio *pio =
            &((struct sunxi_gpio_reg *) SUNXI_PIO_BASE)->gpio_bank[bank];

    cfg = *(&pio->pull[0] + index);
    cfg &= ~(0x3 << offset);
    cfg |= pull << offset;

    *(&pio->pull[0] + index) = cfg;

    return 0;
}

int sunxi_gpio_input(unsigned int pin) {

    unsigned int dat;
    unsigned int bank = GPIO_BANK(pin);
    unsigned int num = GPIO_NUM(pin);

    if (SUNXI_PIO_BASE == 0) {
        return -1;
    }

    struct sunxi_gpio *pio = &((struct sunxi_gpio_reg *) SUNXI_PIO_BASE)->gpio_bank[bank];

    dat = *(&pio->dat);
    dat >>= num;

    return (dat & 0x1);
}