f32xbase/f32x/boundary.c

/*
 * f32x/boundary.c - I/O pin access
 *
 * Written 2008 by Werner Almesberger
 * Copyright 2008 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 <stdlib.h>
#include <stdio.h>

#include "c2.h"
#include "boundary.h"


#define	P0	0x80
#define	P0MDOUT	0xa4
#define	P2	0xa0
#define	P2MDOUT	0xa6


static uint8_t reg_read(uint8_t addr)
{
	c2_addr_write(addr);
	return c2_data_read(1);
}


static void reg_write(uint8_t addr, uint8_t value)
{
	c2_addr_write(addr);
	c2_data_write(value, 1);
}


static const char *parse(const char *s, uint8_t *port, uint8_t *mode, int bits)
{
	int pos;

	*port = *mode = 0;
	pos = 0;
	while (pos != bits) {
		switch (*s++) {
		case '.':
	    		continue;
		case '1':
			*port |= 1 << pos;
			/* fall through */
		case '0':
			*mode |= 1 << pos;
			break;
		case 'r':
		case 'R':
			*port |= 1 << pos;
			break;
		case 0:
			fprintf(stderr, "not enough pin settings\n");
			exit(1);
		default:
			fprintf(stderr,
			    "unrecognized pin setting \"%c\"\n", s[-1]);
			exit(1);
		}
		pos++;
    	}
	return s;
}


static void setup(const char *init)
{
	uint8_t p0, p0mdout, p2, p2mdout;

	init = parse(init, &p0, &p0mdout, 8);
	init = parse(init, &p2, &p2mdout, 6);
	if (*init) {
		fprintf(stderr, "too many pin settings\n");
		exit(1);
	}
	reg_write(P0, p0);
	reg_write(P0MDOUT, p0mdout);
	reg_write(P2, p2);
	reg_write(P2MDOUT, p2mdout);
}


static void print(uint8_t v, int bits)
{
	int pos;

	for (pos = 0; pos != bits; pos++)
		putchar(v & (1 << pos) ? '1' : '0');
}


static void scan(void)
{
	uint8_t p0, p2;

	p0 = reg_read(P0);
	p2 = reg_read(P2);
	print(p0, 8);
	putchar('.');
	print(p2, 6);
	putchar('\n');
}


static void __attribute__((unused)) dump(void)
{
	fprintf(stderr, "GPIOCN %02x\n", reg_read(0xe2));
	fprintf(stderr, "  P0      %02x\n", reg_read(P0));
	fprintf(stderr, "  P0MDOUT %02x\n", reg_read(P0MDOUT));
	fprintf(stderr, "  P2      %02x\n", reg_read(P2));
	fprintf(stderr, "  P2MDOUT %02x\n", reg_read(P2MDOUT));
}


void boundary(const char *init)
{
//dump();
	setup(init);
	scan();
}