mirror of
https://github.com/Hopiu/rpi-rgb-led-matrix.git
synced 2026-05-23 14:15:49 +00:00
93 lines
3.1 KiB
C++
93 lines
3.1 KiB
C++
// -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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// Copyright (C) 2013 Henner Zeller <h.zeller@acm.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 version 2.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://gnu.org/licenses/gpl-2.0.txt>
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#include "gpio.h"
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#define BCM2708_PERI_BASE 0x20000000
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#define GPIO_BASE (BCM2708_PERI_BASE + 0x200000) /* GPIO controller */
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#define PAGE_SIZE (4*1024)
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#define BLOCK_SIZE (4*1024)
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// GPIO setup macros. Always use INP_GPIO(x) before using OUT_GPIO(x) or SET_GPIO_ALT(x,y)
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#define INP_GPIO(g) *(gpio_port_+((g)/10)) &= ~(7<<(((g)%10)*3))
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#define OUT_GPIO(g) *(gpio_port_+((g)/10)) |= (1<<(((g)%10)*3))
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#define SET_GPIO_ALT(g,a) *(gpio+(((g)/10))) |= (((a)<=3?(a)+4:(a)==4?3:2)<<(((g)%10)*3))
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#define GPIO_SET *(gpio+7) // sets bits which are 1 ignores bits which are 0
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#define GPIO_CLR *(gpio+10) // clears bits which are 1 ignores bits which are 0
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/*static*/ const uint32_t ::rgb_matrix::GPIO::kValidBits
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= ((1 << 0) | (1 << 1) | // Revision 1 accessible
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(1 << 2) | (1 << 3) | // Revision 2 accessible
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(1 << 4) | (1 << 7) | (1 << 8) | (1 << 9) |
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(1 << 10) | (1 << 11) | (1 << 14) | (1 << 15)| (1 <<17) | (1 << 18)|
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(1 << 22) | (1 << 23) | (1 << 24) | (1 << 25)| (1 << 27));
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namespace rgb_matrix {
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GPIO::GPIO() : output_bits_(0), gpio_port_(NULL) {
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}
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uint32_t GPIO::InitOutputs(uint32_t outputs) {
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if (gpio_port_ == NULL) {
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fprintf(stderr, "Attempt to init outputs but initialized.\n");
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return 0;
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}
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outputs &= kValidBits; // Sanitize input.
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output_bits_ = outputs;
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for (uint32_t b = 0; b < 27; ++b) {
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if (outputs & (1 << b)) {
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INP_GPIO(b); // for writing, we first need to set as input.
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OUT_GPIO(b);
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}
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}
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return output_bits_;
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}
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// Based on code example found in http://elinux.org/RPi_Low-level_peripherals
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bool GPIO::Init() {
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int mem_fd;
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if ((mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0) {
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perror("can't open /dev/mem: ");
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return false;
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}
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char *gpio_map =
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(char*) mmap(NULL, //Any adddress in our space will do
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BLOCK_SIZE, //Map length
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PROT_READ|PROT_WRITE,// Enable reading & writting to mapped memory
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MAP_SHARED, //Shared with other processes
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mem_fd, //File to map
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GPIO_BASE //Offset to GPIO peripheral
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);
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close(mem_fd); //No need to keep mem_fd open after mmap
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if (gpio_map == MAP_FAILED) {
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fprintf(stderr, "mmap error %ld\n", (long)gpio_map);
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return false;
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}
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gpio_port_ = (volatile uint32_t *)gpio_map;
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return true;
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}
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} // namespace rgb_matrix
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