ben-blinkenlights/libubb/ubb.c

/*
 * libubb/ubb.c - Open/close UBB
 *
 * Written 2012 by Werner Almesberger
 * Copyright 2012 Werner Almesberger
 *
 * This program 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.
 */


#include <stdint.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>

#include <ubb/ubb.h>


volatile void *ubb_mem;

static int ubb_fd;
static uint32_t data, dir, pull, func, sel;


static void *map(off_t addr, size_t size, int *fd)
{
	void *mem;

	*fd = open("/dev/mem", O_RDWR | O_SYNC);
	if (*fd < 0)
		return NULL;
	mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, *fd, addr);
	if (mem == MAP_FAILED) {
		(void) close(*fd);
		return NULL;
	}
	return mem;
}


int ubb_open(uint32_t keep)
{
	ubb_mem = map(UBB_SOC_BASE, UBB_REG_WINDOW, &ubb_fd);
	if (!ubb_mem)
		return -1;

	data = PDDAT & UBB_ALL;
	dir = PDDIR & UBB_ALL;
	pull = PDPULL & UBB_ALL;
	func = PDFUN & UBB_ALL;
	sel = PDSEL & UBB_ALL;

	/* enable pull-ups to let card ramp up power */

	PDPULLC = UBB_ALL_IO & ~keep;
	PDDIRC = UBB_ALL_IO & ~keep;

	PDFUNC = UBB_ALL & ~keep;
	PDSELC = UBB_ALL & ~keep;

	PDDATS = UBB_nPWR & ~keep;
	PDDIRS = UBB_nPWR & ~keep;

	return 0;
}


void ubb_power(int on)
{
	if (on) {
		usleep(10*1000);
		PDDATC = UBB_nPWR;
	} else {
		PDDATS = UBB_nPWR;
	}
}


void ubb_close(uint32_t keep)
{
	PDSELS = sel & ~keep;
	PDFUNS = func & ~keep;

	PDDATS = (data | UBB_nPWR) & ~keep;
	PDDIRS = (dir | UBB_nPWR) & ~keep;

	PDPULLS = pull & ~keep;

	close(ubb_fd);
}