text: /*
   * Marlin 3D Printer Firmware
   * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
   *
   * Based on Sprinter and grbl.
   * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
   *
   * This program is free software: you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   */
  
  /**
   * PCA9533 LED controller driver (MightyBoard, FlashForge Creator Pro, etc.)
   *  by @grauerfuchs - 1 Apr 2020
   */
  #include "../../inc/MarlinConfig.h"
  
  #if ENABLED(PCA9533)
  
  #include "pca9533.h"
  #include <Wire.h>
  
  void PCA9533_init() {
    Wire.begin();
    PCA9533_reset();
  }
  
  static void PCA9533_writeAllRegisters(uint8_t psc0, uint8_t pwm0, uint8_t psc1, uint8_t pwm1, uint8_t ls0){
    uint8_t data[6] = { PCA9533_REG_PSC0 | PCA9533_REGM_AI, psc0, pwm0, psc1, pwm1, ls0 };
    Wire.beginTransmission(PCA9533_Addr >> 1);
    Wire.write(data, 6);
    Wire.endTransmission();
    delayMicroseconds(1);
  }
  
  static void PCA9533_writeRegister(uint8_t reg, uint8_t val){
    uint8_t data[2] = { reg, val };
    Wire.beginTransmission(PCA9533_Addr >> 1);
    Wire.write(data, 2);
    Wire.endTransmission();
    delayMicroseconds(1);
  }
  
  // Reset (clear) all registers
  void PCA9533_reset() {
    PCA9533_writeAllRegisters(0, 0, 0, 0, 0);
  }
  
  // Turn all LEDs off
  void PCA9533_setOff() {
    PCA9533_writeRegister(PCA9533_REG_SEL, 0);
  }
  
  void PCA9533_setColor(uint8_t red, uint8_t green, uint8_t blue) {
    uint8_t r_pwm0 = 0; // Register data - PWM value
    uint8_t r_pwm1 = 0; // Register data - PWM value
  
    uint8_t op_g = 0, op_r = 0, op_b = 0; // Opcodes - Green, Red, Blue
  
    // Light theory! GREEN takes priority because
    // it's the most visible to the human eye.
         if (green ==   0)  op_g = PCA9533_LED_OP_OFF;
    else if (green == 255)  op_g = PCA9533_LED_OP_ON;
    else { r_pwm0 = green;  op_g = PCA9533_LED_OP_PWM0; }
  
    // RED
         if (red ==   0)    op_r = PCA9533_LED_OP_OFF;
    else if (red == 255)    op_r = PCA9533_LED_OP_ON;
    else if (r_pwm0 == 0 || r_pwm0 == red) {
           r_pwm0 = red;    op_r = PCA9533_LED_OP_PWM0;
    }
    else {
           r_pwm1 = red;    op_r = PCA9533_LED_OP_PWM1;
    }
  
    // BLUE
         if (blue ==   0)   op_b = PCA9533_LED_OP_OFF;
    else if (blue == 255)   op_b = PCA9533_LED_OP_ON;
    else if (r_pwm0 == 0 || r_pwm0 == blue) {
           r_pwm0 = blue;   op_b = PCA9533_LED_OP_PWM0;
    }
    else if (r_pwm1 == 0 || r_pwm1 == blue) {
           r_pwm1 = blue;   op_b = PCA9533_LED_OP_PWM1;
    }
    else {
      /**
       * Conflict. 3 values are requested but only 2 channels exist.
       * G is on channel 0 and R is on channel 1, so work from there.
       * Find the closest match, average the values, then use the free channel.
       */
      uint8_t dgb = ABS(green - blue),
              dgr = ABS(green - red),
              dbr = ABS(blue - red);
      if (dgb < dgr && dgb < dbr) {         // Mix with G on channel 0.
        op_b = PCA9533_LED_OP_PWM0;
        r_pwm0 = uint8_t(((uint16_t)green + (uint16_t)blue) / 2);
      }
      else if (dbr <= dgr && dbr <= dgb) {  // Mix with R on channel 1.
        op_b = PCA9533_LED_OP_PWM1;
        r_pwm1 = uint8_t(((uint16_t)red + (uint16_t)blue) / 2);
      }
      else {                                // Mix R+G on 0 and put B on 1.
        op_r = PCA9533_LED_OP_PWM0;
        r_pwm0 = uint8_t(((uint16_t)green + (uint16_t)red) / 2);
        op_b = PCA9533_LED_OP_PWM1;
        r_pwm1 = blue;
      }
    }
  
    // Write the changes to the hardware
    PCA9533_writeAllRegisters(0, r_pwm0, 0, r_pwm1,
      (op_g << PCA9533_LED_OFS_GRN) | (op_r << PCA9533_LED_OFS_RED) | (op_b << PCA9533_LED_OFS_BLU)
    );
  }
  
  #endif // PCA9533
  