mirror of
git://projects.qi-hardware.com/ben-blinkenlights.git
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130 lines
2.8 KiB
C
130 lines
2.8 KiB
C
/*
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* bbl.c - Produce a "Knight Rider" effect on the LED board
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*
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* Written 2010-2011 by Werner Almesberger <werner@openmoko.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <unistd.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <signal.h>
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#include <fcntl.h>
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#include <sys/mman.h>
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#define GPIO_BASE 0x10010000
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#define REG(n) (*(volatile uint32_t *) (mem+(n)-GPIO_BASE))
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/*
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* The XBurst CPUs use an interesting concept for setting GPIOs: instead of
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* writing the value of a pin (0 or 1) directly to an output latch, the latch
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* is set by writing a 1 to a "set" register and cleared by writing a 1 to a
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* "clear" register. This way, only an atomic store but no atomic
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* read-modify-write operations are necessary for changing only part of the
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* bits on a port.
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*
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* The same set/clear mechanism is also used for the other writable registers
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* affecting GPIOs, e.g., the direction (input/output) and function (GPIO or
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* MMC) registers.
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*/
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#define PDDATS REG(0x10010314) /* port D data set */
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#define PDDATC REG(0x10010318) /* port D data clear */
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#define PDFUNC REG(0x10010348) /* port D function clear */
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#define PDDIRS REG(0x10010364) /* port D direction set */
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#define PDDIRC REG(0x10010368) /* port D direction clear */
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#define LEDS 10 /* number of LEDs */
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#define GROUP_SEL 11 /* PD11, DAT1 - LED group selection */
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#define LED_MASK 0x3f00 /* all the LED groups and GROUP_SEL */
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#define DELAY_US 50000
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#define PAGE_SIZE 4096
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static volatile void *mem;
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static int map(int group)
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{
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switch (group) {
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case 0:
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return 12; /* PD12, DAT2 */
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case 1:
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return 13; /* PD13, DAT3/CD */
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case 2:
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return 8; /* PD08, CMD */
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case 3:
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return 9; /* PD09, CLK */
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case 4:
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return 10; /* PD10, DAT0 */
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default:
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abort();
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}
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}
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static void set(int n)
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{
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if (n & 1) {
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PDDATC = LED_MASK;
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PDDATS = 1 << map(n >> 1);
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} else {
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PDDATS = LED_MASK;
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PDDATC = 1 << map(n >> 1);
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}
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}
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static void die(int sig)
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{
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PDDIRC = LED_MASK; /* make all MMC pins inputs again */
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_exit(0);
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}
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int main(int argc, char **argv)
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{
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int fd, i;
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fd = open("/dev/mem", O_RDWR | O_SYNC);
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if (fd < 0) {
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perror("/dev/mem");
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exit(1);
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}
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mem = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
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GPIO_BASE);
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if (mem == MAP_FAILED) {
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perror("mmap");
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exit(1);
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}
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signal(SIGINT, die);
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PDFUNC = LED_MASK; /* make all MMC pins GPIOs */
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PDDIRS = LED_MASK; /* make all MMC pins outputs */
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while (1) {
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for (i = 0; i != LEDS-1; i++) {
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set(i);
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usleep(DELAY_US);
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}
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for (i = LEDS-1; i != 0; i--) {
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set(i);
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usleep(DELAY_US);
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}
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}
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return 0;
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}
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