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first gpio and low-level logging

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Amy G. Bowersox 2019-11-29 01:52:56 -07:00
parent 69341fb6cf
commit 2da798238b
4 changed files with 251 additions and 0 deletions
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1
.gitignore vendored Normal file
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*~

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src/gpio.c Normal file
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#include <stdint.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>
#include "log.h"
#define GLINE_BUTTON1 17
#define GLINE_BUTTON2 22
#define GLINE_BUTTON3 23
#define GLINE_BUTTON4 27
#define STATE_BUTTON1 (1 << 0)
#define STATE_BUTTON2 (1 << 1)
#define STATE_BUTTON3 (1 << 2)
#define STATE_BUTTON4 (1 << 3)
#define INPUT 1 /* is really 0 for control register! */
#define OUTPUT 0 /* is really 1 for control register! */
#define ALT0 4
#define PUD_OFF 0
#define PUD_DOWN 1
#define PUD_UP 2
#define FSEL_OFFSET 0
#define SET_OFFSET 7
#define CLR_OFFSET 10
#define PINLEVEL_OFFSET 13
#define EVENT_DETECT_OFFSET 16
#define RISING_ED_OFFSET 19
#define FALLING_ED_OFFSET 22
#define HIGH_DETECT_OFFSET 25
#define LOW_DETECT_OFFSET 28
#define PULLUPDN_OFFSET 37
#define PULLUPDNCLK_OFFSET 38
#define PULLUPDN_OFFSET_2711_0 57
#define PULLUPDN_OFFSET_2711_1 58
#define PULLUPDN_OFFSET_2711_2 59
#define PULLUPDN_OFFSET_2711_3 60
#define PULLUPDN_2711_MAGIC 0x6770696F
#define BLOCK_SIZE (4*1024)
static int mem_fd = -1;
static volatile uint32_t *gpio_map = NULL;
static int is_2711 = 0;
static int last_state = 0;
static void short_wait(void)
{
int i;
for (i=0; i<150; i++)
{ /* wait 150 cycles */
asm volatile("nop");
}
}
static int setup_the_memmap(void)
{
if ((mem_fd = open("/dev/gpiomem", O_RDWR|O_SYNC)) > 0)
{
if ((gpio_map = (unit32_t *)mmap(NULL, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, mem_fd, 0)) == MAP_FAILED)
{
gpio_map = NULL;
close(mem_fd);
log(LFATAL, "Unable to map /dev/gpiomem (%d)", errno);
return -1;
}
}
/* ignore the rest of the possibilities for now */
return 0;
}
static void set_pullupdn(int gpio, int pud)
{
if (is_2711)
{ /* method for RPi 4 */
int pullreg = PULLUPDN_OFFSET_2711_0 + (gpio >> 4);
int pullshift = (gpio & 0xF) << 1;
uint32_t pullbits;
unsigned pull = 0;
switch (pud)
{
case PUD_OFF: pull = 0; break;
case PUD_UP: pull = 1; break;
case PUD_DOWN: pull = 2; break;
default: pull = 0; /* keep as "off" */
}
pullbits = *(gpio_map + pullreg);
pullbits &= ~(3 << pullshift);
pullbits |= (pull << pullshift);
*(gpio_map + pullreg) = pullbits;
}
else
{ /* method for older models */
int clk_offset = PULLUPDNCLK_OFFSET + (gpio / 32);
int shift = gpio % 32;
if (pud == PUD_DOWN)
{
*(gpio_map + PULLUPDN_OFFSET) = (*(gpio_map + PULLUPDN_OFFSET) & ~3) | PUD_DOWN;
}
else if (pud == PUD_UP)
{
*(gpio_map + PULLUPDN_OFFSET) = (*(gpio_map + PULLUPDN_OFFSET) & ~3) | PUD_UP;
}
else
{ /* pud == PUD_OFF */
*(gpio_map + PULLUPDN_OFFSET) &= ~3;
}
short_wait();
*(gpio_map + clk_offset) = 1 << shift;
short_wait();
*(gpio_map + PULLUPDN_OFFSET) &= ~3;
*(gpio_map + clk_offset) = 0;
}
}
static void setup_gpio_line(int gpio, int direction, int pud)
{
int offset = FSEL_OFFSET + (gpio / 10);
int shift = (gpio % 10) * 3;
set_pullupdn(gpio, pud);
if (direction == OUTPUT)
*(gpio_map + offset) = (*(gpio_map + offset) & ~(7 << shift)) | (1 << shift);
else /* direction == INPUT */
*(gpio_map + offset) = (*(gpio_map + offset) & ~(7 << shift));
}
static int gpio_input(int gpio)
{
int offset, value, mask;
offset = PINLEVEL_OFFSET + (gpio / 32);
mask = (1 << gpio % 32);
value = *(gpio_map + offset) & mask;
return value;
}
int Gpio_setup(void)
{
if (setup_the_memmap() != 0)
return -1;
is_2711 = (*(gpio_map + PULLUPDN_OFFSET_2711_3) != PULLUPDN_2711_MAGIC);
setup_gpio_line(GLINE_BUTTON1, INPUT, PUD_UP);
setup_gpio_line(GLINE_BUTTON2, INPUT, PUD_UP);
setup_gpio_line(GLINE_BUTTON3, INPUT, PUD_UP);
setup_gpio_line(GLINE_BUTTON4, INPUT, PUD_UP);
/* TODO: other setup */
last_state = 0;
return 0;
}
void Gpio_cleanup(void)
{
/* TODO: additional cleanup may be required */
setup_gpio_line(GLINE_BUTTON1, INPUT, PUD_OFF);
setup_gpio_line(GLINE_BUTTON2, INPUT, PUD_OFF);
setup_gpio_line(GLINE_BUTTON3, INPUT, PUD_OFF);
setup_gpio_line(GLINE_BUTTON4, INPUT, PUD_OFF);
if (gpio_map)
{
munmap(gpio_map, BLOCK_SIZE);
gpio_map = NULL;
}
if (mem_fd >= 0)
{
close(mem_fd);
mem_fd = -1;
}
}
int Gpio_poll_buttons(void)
{
int new_state = 0;
int tmp, ndx, mask;
if (gpio_input(GLINE_BUTTON1) == 0)
new_state |= STATE_BUTTON1;
if (gpio_input(GLINE_BUTTON2) == 0)
new_state |= STATE_BUTTON2;
if (gpio_input(GLINE_BUTTON3) == 0)
new_state |= STATE_BUTTON3;
if (gpio_input(GLINE_BUTTON4) == 0)
new_state |= STATE_BUTTON4;
if (last_state != new_state)
{
tmp = last_state & ~new_state;
for (ndx = 1, mask = 1; ndx <= 4; ndx++, mask <<= 1)
{
if (tmp & mask)
log(LDEBUG, "Button %d was released", ndx);
}
tmp = new_state & ~last_state;
for (ndx = 1, mask = 1; ndx <= 4; ndx++, mask <<= 1)
{
if (tmp & mask)
log(LDEBUG, "Button %d was pressed", ndx);
}
last_state = new_state;
}
return new_state;
}

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#include <stdio.h>
#include <stdarg.h>
#include <time.h>
#include <sys/time.h>
#include "log.h"
static const char *severities[] = { "FATAL", "ERROR", "WARN ", "INFO ", "DEBUG" };
void log(int level, const char *format, ...)
{
va_list argp;
struct timeval tv;
struct tm tm;
char timestamp[32];
char buf[1024];
va_start(argp, format);
vsnprintf(buf, 1024, format, argp);
va_end(argp);
gettimeofday(&tv);
localtime_r(&(tv.tv_sec), &tm)
strftime(timestamp, 32, "%F %T", &tm);
printf("%s.%06u %s %s\n", timestamp, tv.tv_usec, severities[level], buf);
}

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#ifndef __LOG_H_INCLUDED
#define __LOG_H_INCLUDED
#define LFATAL 0
#define LERROR 1
#define LWARN 2
#define LINFO 3
#define LDEBUG 4
extern void log(int level, const char *format, ...);
#endif /* __LOG_H_INCLUDED */