displaybrightness.c

// https://github.com/stevedekorte/io/blob/master/addons/AppleExtras/source/AppleSensors.c

enum {
  kGetSensorReadingID = 0, // getSensorReading(int *, int *)
  kGetLEDBrightnessID = 1, // getLEDBrightness(int, int *)
  kSetLEDBrightnessID = 2, // setLEDBrightness(int, int, int *)
  kSetLEDFadeID = 3, // setLEDFade(int, int, int, int *)
  // other firmware-related functions
  // verifyFirmwareID = 4,
  // verifyFirmware(int *)
  // getFirmwareVersionID = 5,
  // getFirmwareVersion(int *)
  // other flashing-related functions
  // ...
};

#include <unistd.h>
#include <mach/mach.h>
//#include <Carbon/Carbon.h>
#include <IOKit/IOKitLib.h>
#include <CoreFoundation/CoreFoundation.h>

static io_connect_t dataPort = 0; // shared?

io_connect_t getDataPort(void)
{
  kern_return_t     kr;
  io_service_t      serviceObject;

  if (dataPort) return dataPort;

  // Look up a registered IOService object whose class is AppleLMUController
  serviceObject = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("AppleLMUController"));

  if (!serviceObject)
  {
    printf("getLightSensors() error: failed to find ambient light sensor\n");
    return 0;
  }

  // Create a connection to the IOService object
  kr = IOServiceOpen(serviceObject, mach_task_self(), 0, &dataPort);
  IOObjectRelease(serviceObject);

  if (kr != KERN_SUCCESS)
  {
    printf("getLightSensors() error: failed to open IoService object\n");
    return 0;
  }

  return dataPort;
}

void getLightSensors(float *left, float *right)
{
    uint64_t inputValues[0];
  uint32_t inputCount = 0;

    uint64_t outputValues[2];
  uint32_t outputCount = 2;

  kern_return_t kr;

    kr = IOConnectCallScalarMethod(getDataPort(),
    kGetSensorReadingID,
    inputValues,
    inputCount,
    outputValues,
    &outputCount);

  if (kr != KERN_SUCCESS)
  {
    //printf("error getting light sensor values\n");
    return;
  }

  *left = outputValues[0];
  *right = outputValues[1];

  *left  /= 2000;
  *right /= 2000;
}

#include <stdio.h>
#include <IOKit/graphics/IOGraphicsLib.h>
#include <ApplicationServices/ApplicationServices.h>

float getDisplayBrightness(void)
{
  CGDisplayErr      dErr;
  io_service_t      service;
  CGDirectDisplayID targetDisplay;

  CFStringRef key = CFSTR(kIODisplayBrightnessKey);
  float brightness = HUGE_VALF;

  targetDisplay = CGMainDisplayID();
  service = CGDisplayIOServicePort(targetDisplay);

  dErr = IODisplayGetFloatParameter(service, kNilOptions, key, &brightness);

  return brightness;
}

void setDisplayBrightness(float brightness)
{
  CGDisplayErr      dErr;
  io_service_t      service;
  CGDirectDisplayID targetDisplay;
  CFStringRef key = CFSTR(kIODisplayBrightnessKey);

  targetDisplay = CGMainDisplayID();
  service = CGDisplayIOServicePort(targetDisplay);

  dErr = IODisplaySetFloatParameter(service, kNilOptions, key, brightness);

}

// Keyboard Brightness

float getKeyboardBrightness(void)
{
  float f;
  kern_return_t kr;

  uint64_t inputCount = 1;
    uint64_t inputValues[1] = {0};

    uint32_t outputCount = 1;
    uint64_t outputValues[1];

    uint32_t out_brightness;

  kr = IOConnectCallScalarMethod(getDataPort(),
      kGetLEDBrightnessID,
    inputValues,
    inputCount,
    outputValues,
    &outputCount);

    out_brightness = outputValues[0];

  if (kr != KERN_SUCCESS)
  {
    printf("getKeyboardBrightness() error\n");
    return 0;
  }

  f = out_brightness;
  f /= 0xfff;
  return (float)f;
}

void setKeyboardBrightness(float in)
{
  // static io_connect_t dp = 0; // shared?
  kern_return_t kr;

  uint64_t inputCount  = 2;
    uint64_t inputValues[2];
    uint64_t in_unknown = 0;
    uint64_t in_brightness = in * 0xfff;

    inputValues[0] = in_unknown;
    inputValues[1] = in_brightness;

    uint32_t outputCount = 1;
    uint64_t outputValues[1];

    uint32_t out_brightness;

  //kr = IOConnectMethodScalarIScalarO(dp, kSetLEDBrightnessID,
  kr = IOConnectCallScalarMethod(getDataPort(),
      kSetLEDBrightnessID,
    inputValues,
    inputCount,
    outputValues,
    &outputCount);

    out_brightness = outputValues[0];

  if (kr != KERN_SUCCESS)
  {
    printf("setKeyboardBrightness() error\n");
    return;
  }
}

int
main(int argc, char **argv)
{
    float x;
    float setb;
    /**
    if (argc > 1 && sscanf(argv[1], "%f", &setb) == 1) {
        setKeyboardBrightness(setb);
    }**/
    for (int i = 0; i < 10; i++) {
        x += 0.1;
        usleep(100000);
        printf("%s", "\tSleeping\n");
        setKeyboardBrightness(x);
        printf("%f", getKeyboardBrightness());
    }
  exit(0);
}