upiwin/src/gpio.c

#include <stddef.h>
#include <stdint.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <bcm2835.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 PWM_BACKLIGHT   0

int Gpio_setup(void)
{
  if (!bcm2835_init())
  {
    Log(LFATAL, "Error initializing BCM2835 library");
    return -1;
  }

  /* configure the buttons */
  bcm2835_gpio_set_pud(GLINE_BUTTON1, BCM2835_GPIO_PUD_UP);
  bcm2835_gpio_fsel(GLINE_BUTTON1, BCM2835_GPIO_FSEL_INPT);
  bcm2835_gpio_set_pud(GLINE_BUTTON2, BCM2835_GPIO_PUD_UP);
  bcm2835_gpio_fsel(GLINE_BUTTON2, BCM2835_GPIO_FSEL_INPT);
  bcm2835_gpio_set_pud(GLINE_BUTTON3, BCM2835_GPIO_PUD_UP);
  bcm2835_gpio_fsel(GLINE_BUTTON3, BCM2835_GPIO_FSEL_INPT);
  bcm2835_gpio_set_pud(GLINE_BUTTON4, BCM2835_GPIO_PUD_UP);
  bcm2835_gpio_fsel(GLINE_BUTTON4, BCM2835_GPIO_FSEL_INPT);

  /* 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)
{
  /* 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);
  bcm2835_gpio_fsel(GLINE_BUTTON1, BCM2835_GPIO_FSEL_INPT);
  bcm2835_gpio_set_pud(GLINE_BUTTON2, BCM2835_GPIO_PUD_OFF);
  bcm2835_gpio_fsel(GLINE_BUTTON2, BCM2835_GPIO_FSEL_INPT);
  bcm2835_gpio_set_pud(GLINE_BUTTON3, BCM2835_GPIO_PUD_OFF);
  bcm2835_gpio_fsel(GLINE_BUTTON3, BCM2835_GPIO_FSEL_INPT);
  bcm2835_gpio_set_pud(GLINE_BUTTON4, BCM2835_GPIO_PUD_OFF);
  bcm2835_gpio_fsel(GLINE_BUTTON4, BCM2835_GPIO_FSEL_INPT);

  if (!bcm2835_close())
    Log(LWARN, "Closing BCM2835 library failed");
}

int Gpio_read_buttons(void)
{
  int rc = 0;

  if (bcm2835_gpio_lev(GLINE_BUTTON1) == LOW)
    rc |= STATE_BUTTON1;
  if (bcm2835_gpio_lev(GLINE_BUTTON2) == LOW)
    rc |= STATE_BUTTON2;
  if (bcm2835_gpio_lev(GLINE_BUTTON3) == LOW)
    rc |= STATE_BUTTON3;
  if (bcm2835_gpio_lev(GLINE_BUTTON4) == LOW)
    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);
}