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add backlight control to the code

This commit is contained in:
Amy G. Bowersox 2019-12-01 14:34:57 -07:00
parent 3a5befa36f
commit 05e1028211
4 changed files with 37 additions and 214 deletions
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25
src/gpio.c
View File

@ -14,10 +14,7 @@
#define GLINE_BUTTON4 27
#define GLINE_BACKLIGHT 18
#define STATE_BUTTON1 (1 << 0)
#define STATE_BUTTON2 (1 << 1)
#define STATE_BUTTON3 (1 << 2)
#define STATE_BUTTON4 (1 << 3)
#define PWM_BACKLIGHT 0
int Gpio_setup(void)
{
@ -37,14 +34,23 @@ int Gpio_setup(void)
bcm2835_gpio_set_pud(GLINE_BUTTON4, BCM2835_GPIO_PUD_UP);
bcm2835_gpio_fsel(GLINE_BUTTON4, BCM2835_GPIO_FSEL_INPT);
/* TODO: other setup */
/* configure the PWM for the backlight */
bcm2835_gpio_set_pud(GLINE_BACKLIGHT, BCM2835_GPIO_PUD_OFF);
bcm2835_gpio_fsel(GLINE_BACKLIGHT, BCM2835_GPIO_FSEL_ALT5);
bcm2835_pwm_set_clock(BCM2835_PWM_CLOCK_DIVIDER_2);
bcm2835_pwm_set_mode(PWM_BACKLIGHT, 1, 1);
bcm2835_pwm_set_range(PWM_BACKLIGHT, BACKLIGHT_MAX + 1);
bcm2835_pwm_set_data(PWM_BACKLIGHT, BACKLIGHT_MAX);
return 0;
}
void Gpio_cleanup(void)
{
/* TODO: additional cleanup may be required */
/* close down the backlight lines */
bcm2835_pwm_set_mode(PWM_BACKLIGHT, 1, 0);
bcm2835_gpio_set_pud(GLINE_BACKLIGHT, BCM2835_GPIO_PUD_OFF);
bcm2835_gpio_fsel(GLINE_BACKLIGHT, BCM2835_GPIO_FSEL_INPT);
/* close down the button lines */
bcm2835_gpio_set_pud(GLINE_BUTTON1, BCM2835_GPIO_PUD_OFF);
@ -74,3 +80,10 @@ int Gpio_read_buttons(void)
rc |= STATE_BUTTON4;
return rc;
}
void Gpio_set_backlight(unsigned level)
{
if (level > BACKLIGHT_MAX)
level = BACKLIGHT_MAX;
bcm2835_pwm_set_data(PWM_BACKLIGHT, level);
}

8
src/gpio.h
View File

@ -1,8 +1,16 @@
#ifndef __GPIO_H_INCLUDED
#define __GPIO_H_INCLUDED
#define STATE_BUTTON1 (1 << 0)
#define STATE_BUTTON2 (1 << 1)
#define STATE_BUTTON3 (1 << 2)
#define STATE_BUTTON4 (1 << 3)
#define BACKLIGHT_MAX 1023
extern int Gpio_setup(void);
extern void Gpio_cleanup(void);
extern int Gpio_read_buttons(void);
extern void Gpio_set_backlight(unsigned level);
#endif /* __GPIO_H_INCLUDED */

208
src/gpio_old.c
View File

@ -1,208 +0,0 @@
#include <stddef.h>
#include <stdint.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include "log.h"
#include "gpio.h"
#define GLINE_BUTTON1 17
#define GLINE_BUTTON2 22
#define GLINE_BUTTON3 23
#define GLINE_BUTTON4 27
#define GLINE_BACKLIGHT 18
#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 = (uint32_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 void setup_gpio_alt5(int gpio)
{
int offset = FSEL_OFFSET + (gpio / 10);
int shift = (gpio % 10) * 3;
set_pullupdn(gpio, PUD_OFF);
*(gpio_map + offset) = (*(gpio_map + offset) & ~(7 << shift)) | (2 << 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((void *)gpio_map, BLOCK_SIZE);
gpio_map = NULL;
}
if (mem_fd >= 0)
{
close(mem_fd);
mem_fd = -1;
}
}
int Gpio_read_buttons(void)
{
int rc = 0;
if (gpio_input(GLINE_BUTTON1) == 0)
rc |= STATE_BUTTON1;
if (gpio_input(GLINE_BUTTON2) == 0)
rc |= STATE_BUTTON2;
if (gpio_input(GLINE_BUTTON3) == 0)
rc |= STATE_BUTTON3;
if (gpio_input(GLINE_BUTTON4) == 0)
rc |= STATE_BUTTON4;
return rc;
}

10
src/main.c
View File

@ -31,6 +31,16 @@ int main(int argc, char *argv[])
case WM_HWBUTTONUP:
Log(LINFO, "Button %d was released.", (int)(msg.attrs[0]));
if (msg.attrs[0] == 1)
{
Log(LINFO, "Backlight ON.");
Gpio_set_backlight(BACKLIGHT_MAX);
}
if (msg.attrs[0] == 2)
{
Log(LINFO, "Backlight OFF.");
Gpio_set_backlight(0);
}
if (msg.attrs[0] == 4)
{
Log(LINFO, "Quitting the message loop.");