Backlighting for JJ40 and underglow initialisation code (#2260)

* Cleanup Mechmini keymap. Once the custom RGB function is defined, there is no need to manually handle RGB code.

* Change default to KEYMAP_MIT, not KEYMAP_OFFSET

* Add custom RGB code for JJ40

* Reset Mechmini advertised power draw to 500. Will have to test actual maximum power draw later.

* RGB working on JJ40.

* Fix: saturation increase/decrease flipped

* Add new directory for my custom keymap with RGB keycodes

* Swap LAlt and LGUI

* Update JJ40 max power draw with measured value

* Update: fun40 rules.mk to enable underglow; earlier failed Travis CI

* Fix: init RGB LEDs on boot. Also added HHKB-like keymap for XD60.

* Super rudimentary backlight test, init RGB LEDs on boot

* Backlighting works - stays on for now

* Toggling working

* Now can override backlight.c functions. Problem was functions in backlight.c weren't called before due to a lack of matrix_scan_quantum() in matrix.c

* Timers not working

* Delete global.h

* Cleanup

* Compiles

* Good sign: LEDs stop working again

* Handle timer1 overflow

* Progress: fix: forgot to init

* Backlighting fully working now except breathing.

* Revert keymap to original keycodes

* Update XD60 keymap README

* Update JJ40 keymap with backlight toggles

* Breathing working just fine.

* Update references

* Add backlight_set() call

* Cleanup code to disable backlight

* Fix: does not compile

* Fix: missing call to rgblight_task.

* Testing with BACKLIGHT_BREATHING

* Cleanup

* Cleanup comments

* More commenting cleanup.

* Do not enable BACKLIGHT_BREATHING by default

12 files changed, 451 insertions, 60 deletions

diff --git a/keyboards/jj40/backlight.c b/keyboards/jj40/backlight.c
new file mode 100644
index 0000000000..079c410ff5
--- /dev/null
+++ b/keyboards/jj40/backlight.c
@@ -0,0 +1,212 @@
+/**
+ * Backlighting code for PS2AVRGB boards (ATMEGA32A)
+ * Kenneth A. (github.com/krusli | krusli.me)
+ */
+
+#include "backlight.h"
+#include "quantum.h"
+
+#include <avr/pgmspace.h>
+#include <avr/interrupt.h>
+
+#include "backlight_custom.h"
+#include "breathing_custom.h"
+
+// DEBUG
+#include <stdlib.h>
+#include <stdio.h>
+
+// Port D: digital pins of the AVR chipset
+#define NUMLOCK_PORT    (1 << 1)  // 1st pin of Port D (digital)
+#define CAPSLOCK_PORT   (1 << 2)  // 2nd pin
+#define BACKLIGHT_PORT  (1 << 4)  // 4th pin
+#define SCROLLLOCK_PORT (1 << 6)  // 6th pin
+
+#define TIMER_CLK_DIV64			  0x03	///< Timer clocked at F_CPU/64
+#define TIMER1PRESCALE	TIMER_CLK_DIV64 ///< timer 1 prescaler default
+
+#define TIMER_PRESCALE_MASK		0x07	///< Timer Prescaler Bit-Mask
+
+#define PWM_MAX 0xFF
+#define TIMER_TOP 255 // 8 bit PWM
+
+extern backlight_config_t backlight_config;
+
+/**
+ * References
+ * Port Registers: https://www.arduino.cc/en/Reference/PortManipulation
+ * TCCR1A: https://electronics.stackexchange.com/questions/92350/what-is-the-difference-between-tccr1a-and-tccr1b
+ * Timers: http://www.avrbeginners.net/architecture/timers/timers.html
+ * 16-bit timer setup: http://sculland.com/ATmega168/Interrupts-And-Timers/16-Bit-Timer-Setup/
+ * PS2AVRGB firmware: https://github.com/showjean/ps2avrU/tree/master/firmware
+ */
+
+// @Override
+// turn LEDs on and off depending on USB caps/num/scroll lock states.
+void led_set_user(uint8_t usb_led) {
+    if (usb_led & (1 << USB_LED_NUM_LOCK)) {
+      // turn on
+      DDRD  |= NUMLOCK_PORT;
+      PORTD |= NUMLOCK_PORT;
+    } else {
+      // turn off
+      DDRD  &= ~NUMLOCK_PORT;
+      PORTD &= ~NUMLOCK_PORT;
+    }
+
+    if (usb_led & (1 << USB_LED_CAPS_LOCK)) {
+      DDRD  |= CAPSLOCK_PORT;
+      PORTD |= CAPSLOCK_PORT;
+    } else {
+      DDRD  &= ~CAPSLOCK_PORT;
+      PORTD &= ~CAPSLOCK_PORT;
+    }
+
+    if (usb_led & (1 << USB_LED_SCROLL_LOCK)) {
+      DDRD  |= SCROLLLOCK_PORT;
+      PORTD |= SCROLLLOCK_PORT;
+    } else {
+      DDRD  &= ~SCROLLLOCK_PORT;
+      PORTD &= ~SCROLLLOCK_PORT;
+    }
+}
+
+#ifdef BACKLIGHT_ENABLE
+
+// sets up Timer 1 for 8-bit PWM
+void timer1PWMSetup(void) { // NOTE ONLY CALL THIS ONCE
+  // default 8 bit mode
+  TCCR1A &= ~(1 << 1); // cbi(TCCR1A,PWM11); <- set PWM11 bit to HIGH
+  TCCR1A |= (1 << 0);  // sbi(TCCR1A,PWM10); <- set PWM10 bit to LOW
+
+  // clear output compare value A
+  // outb(OCR1AH, 0);
+  // outb(OCR1AL, 0);
+
+  // clear output comparator registers for B
+	OCR1BH = 0; // outb(OCR1BH, 0);
+	OCR1BL = 0; // outb(OCR1BL, 0);
+}
+
+bool is_init = false;
+void timer1Init(void) {
+  // timer1SetPrescaler(TIMER1PRESCALE)
+  // set to DIV/64
+  (TCCR1B) = ((TCCR1B) & ~TIMER_PRESCALE_MASK) | TIMER1PRESCALE;
+
+  // reset TCNT1
+  TCNT1H = 0;  // outb(TCNT1H, 0);
+	TCNT1L = 0;  // outb(TCNT1L, 0);
+
+  // TOIE1: Timer Overflow Interrupt Enable (Timer 1);
+	TIMSK |= _BV(TOIE1); // sbi(TIMSK, TOIE1);
+
+  is_init = true;
+}
+
+void timer1UnInit(void) {
+  // set prescaler back to NONE
+  (TCCR1B) = ((TCCR1B) & ~TIMER_PRESCALE_MASK) | 0x00;  // TIMERRTC_CLK_STOP
+
+  // disable timer overflow interrupt
+  TIMSK &= ~_BV(TOIE1); // overflow bit?
+
+  setPWM(0);
+
+  is_init = false;
+}
+
+
+// handle TCNT1 overflow
+//! Interrupt handler for tcnt1 overflow interrupt
+ISR(TIMER1_OVF_vect, ISR_NOBLOCK)
+{
+	// sei();
+  // handle breathing here
+  #ifdef BACKLIGHT_BREATHING
+  if (is_breathing()) {
+    custom_breathing_handler();
+  }
+  #endif
+
+  // TODO call user defined function
+}
+
+// enable timer 1 PWM
+// timer1PWMBOn()
+void timer1PWMBEnable(void) {
+  // turn on channel B (OC1B) PWM output
+  // set OC1B as non-inverted PWM
+  TCCR1A |= _BV(COM1B1);
+  TCCR1A &= ~_BV(COM1B0);
+}
+
+// disable timer 1 PWM
+// timer1PWMBOff()
+void timer1PWMBDisable(void) {
+  TCCR1A &= ~_BV(COM1B1);
+  TCCR1A &= ~_BV(COM1B0);
+}
+
+void enableBacklight(void) {
+  DDRD  |= BACKLIGHT_PORT;  // set digital pin 4 as output
+  PORTD |= BACKLIGHT_PORT;  // set digital pin 4 to high
+}
+
+void disableBacklight(void) {
+  // DDRD  &= ~BACKLIGHT_PORT;  // set digital pin 4 as input
+  PORTD &= ~BACKLIGHT_PORT;  // set digital pin 4 to low
+}
+
+void startPWM(void) {
+  timer1Init();
+  timer1PWMBEnable();
+  enableBacklight();
+}
+
+void stopPWM(void) {
+  timer1UnInit();
+  disableBacklight();
+  timer1PWMBDisable();
+}
+
+void b_led_init_ports(void) {
+  /* turn backlight on/off depending on user preference */
+  #if BACKLIGHT_ON_STATE == 0
+    // DDRx register: sets the direction of Port D
+    // DDRD  &= ~BACKLIGHT_PORT;  // set digital pin 4 as input
+    PORTD &= ~BACKLIGHT_PORT;  // set digital pin 4 to low
+  #else
+    DDRD  |= BACKLIGHT_PORT;  // set digital pin 4 as output
+    PORTD |= BACKLIGHT_PORT;  // set digital pin 4 to high
+  #endif
+
+  timer1PWMSetup();
+  startPWM();
+
+  #ifdef BACKLIGHT_BREATHING
+  breathing_enable();
+  #endif
+}
+
+void b_led_set(uint8_t level) {
+  if (level > BACKLIGHT_LEVELS) {
+    level = BACKLIGHT_LEVELS;
+  }
+
+  setPWM((int)(TIMER_TOP * (float) level / BACKLIGHT_LEVELS));
+}
+
+// called every matrix scan
+void b_led_task(void) {
+  // do nothing for now
+}
+
+void setPWM(uint16_t xValue) {
+  if (xValue > TIMER_TOP) {
+    xValue = TIMER_TOP;
+  }
+  OCR1B = xValue; // timer1PWMBSet(xValue);
+}
+
+#endif  // BACKLIGHT_ENABLE
diff --git a/keyboards/jj40/backlight_custom.h b/keyboards/jj40/backlight_custom.h
new file mode 100644
index 0000000000..7210be840e
--- /dev/null
+++ b/keyboards/jj40/backlight_custom.h
@@ -0,0 +1,15 @@
+/**
+ * Backlighting code for PS2AVRGB boards (ATMEGA32A)
+ * Kenneth A. (github.com/krusli | krusli.me)
+ */
+
+#ifndef BACKLIGHT_CUSTOM_H
+#define BACKLIGHT_CUSTOM_H
+
+#include <avr/pgmspace.h>
+void b_led_init_ports(void);
+void b_led_set(uint8_t level);
+void b_led_task(void);
+void setPWM(uint16_t xValue);
+
+#endif  // BACKLIGHT_CUSTOM_H
diff --git a/keyboards/jj40/breathing_custom.h b/keyboards/jj40/breathing_custom.h
new file mode 100644
index 0000000000..71416b1b45
--- /dev/null
+++ b/keyboards/jj40/breathing_custom.h
@@ -0,0 +1,140 @@
+/**
+ * Breathing effect code for PS2AVRGB boards (ATMEGA32A)
+ * Works in conjunction with `backlight.c`.
+ *
+ * Code adapted from `quantum.c` to register with the existing TIMER1 overflow
+ * handler in `backlight.c` instead of setting up its own timer.
+ * Kenneth A. (github.com/krusli | krusli.me)
+ */
+
+#ifdef BACKLIGHT_ENABLE
+#ifdef BACKLIGHT_BREATHING
+
+#include "backlight_custom.h"
+
+#ifndef BREATHING_PERIOD
+#define BREATHING_PERIOD 6
+#endif
+
+#define breathing_min() do {breathing_counter = 0;} while (0)
+#define breathing_max() do {breathing_counter = breathing_period * 244 / 2;} while (0)
+
+// TODO make this share code with quantum.c
+
+#define BREATHING_NO_HALT  0
+#define BREATHING_HALT_OFF 1
+#define BREATHING_HALT_ON  2
+#define BREATHING_STEPS 128
+
+static uint8_t breathing_period = BREATHING_PERIOD;
+static uint8_t breathing_halt = BREATHING_NO_HALT;
+static uint16_t breathing_counter = 0;
+
+static bool breathing = false;
+
+bool is_breathing(void) {
+  return breathing;
+}
+
+// See http://jared.geek.nz/2013/feb/linear-led-pwm
+static uint16_t cie_lightness(uint16_t v) {
+  if (v <= 5243) // if below 8% of max
+    return v / 9; // same as dividing by 900%
+  else {
+    uint32_t y = (((uint32_t) v + 10486) << 8) / (10486 + 0xFFFFUL); // add 16% of max and compare
+    // to get a useful result with integer division, we shift left in the expression above
+    // and revert what we've done again after squaring.
+    y = y * y * y >> 8;
+    if (y > 0xFFFFUL) // prevent overflow
+      return 0xFFFFU;
+    else
+      return (uint16_t) y;
+  }
+}
+
+void breathing_enable(void) {
+  breathing = true;
+  breathing_counter = 0;
+  breathing_halt = BREATHING_NO_HALT;
+  // interrupt already registered
+}
+
+void breathing_pulse(void) {
+  if (get_backlight_level() == 0)
+    breathing_min();
+  else
+    breathing_max();
+  breathing_halt = BREATHING_HALT_ON;
+  // breathing_interrupt_enable();
+  breathing = true;
+}
+
+void breathing_disable(void) {
+  breathing = false;
+  // backlight_set(get_backlight_level());
+  b_led_set(get_backlight_level()); // custom implementation of backlight_set()
+}
+
+void breathing_self_disable(void)
+{
+  if (get_backlight_level() == 0)
+    breathing_halt = BREATHING_HALT_OFF;
+  else
+    breathing_halt = BREATHING_HALT_ON;
+}
+
+void breathing_toggle(void) {
+  if (is_breathing())
+    breathing_disable();
+  else
+    breathing_enable();
+}
+
+void breathing_period_set(uint8_t value)
+{
+  if (!value)
+    value = 1;
+  breathing_period = value;
+}
+
+void breathing_period_default(void) {
+  breathing_period_set(BREATHING_PERIOD);
+}
+
+void breathing_period_inc(void)
+{
+  breathing_period_set(breathing_period+1);
+}
+
+void breathing_period_dec(void)
+{
+  breathing_period_set(breathing_period-1);
+}
+
+/* To generate breathing curve in python:
+ * from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
+ */
+static const uint8_t breathing_table[BREATHING_STEPS] PROGMEM = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 17, 20, 24, 28, 32, 36, 41, 46, 51, 57, 63, 70, 76, 83, 91, 98, 106, 113, 121, 129, 138, 146, 154, 162, 170, 178, 185, 193, 200, 207, 213, 220, 225, 231, 235, 240, 244, 247, 250, 252, 253, 254, 255, 254, 253, 252, 250, 247, 244, 240, 235, 231, 225, 220, 213, 207, 200, 193, 185, 178, 170, 162, 154, 146, 138, 129, 121, 113, 106, 98, 91, 83, 76, 70, 63, 57, 51, 46, 41, 36, 32, 28, 24, 20, 17, 15, 12, 10, 8, 6, 5, 4, 3, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+// Use this before the cie_lightness function.
+static inline uint16_t scale_backlight(uint16_t v) {
+  return v / BACKLIGHT_LEVELS * get_backlight_level();
+}
+
+void custom_breathing_handler(void) {
+  uint16_t interval = (uint16_t) breathing_period * 244 / BREATHING_STEPS;
+  // resetting after one period to prevent ugly reset at overflow.
+  breathing_counter = (breathing_counter + 1) % (breathing_period * 244);
+  uint8_t index = breathing_counter / interval % BREATHING_STEPS;
+
+  if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) ||
+      ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1)))
+  {
+      // breathing_interrupt_disable();
+  }
+
+  setPWM(cie_lightness(scale_backlight((uint16_t) pgm_read_byte(&breathing_table[index]) * 0x0101U)));
+}
+
+#endif // BACKLIGHT_BREATHING
+#endif  // BACKLIGHT_ENABLE
diff --git a/keyboards/jj40/config.h b/keyboards/jj40/config.h
index 3152f22beb..7fac1ed5b9 100644
--- a/keyboards/jj40/config.h
+++ b/keyboards/jj40/config.h
@@ -34,8 +34,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* COL2ROW or ROW2COL */
 #define DIODE_DIRECTION COL2ROW
 
-#define BACKLIGHT_PIN B6
-#define BACKLIGHT_LEVELS 3
+#define BACKLIGHT_LEVELS 12
+// #define BACKLIGHT_BREATHING  // works, but BL_TOGG might not work
 
 #define TAPPING_TOGGLE 3
 
@@ -45,7 +45,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // The RGB_DI_PIN value seems to be shared between all PS2AVRGB boards.
 // The same pin is used on the JJ40, at least.
 #define RGBLED_NUM 5
-#define RGB_DI_PIN E2
+#define RGB_DI_PIN E2 // NOTE: for PS2AVRGB boards, underglow commands are sent via I2C to 0xB0.
 #define RGBLIGHT_ANIMATIONS
 
 /* key combination for command */
diff --git a/keyboards/jj40/jj40.c b/keyboards/jj40/jj40.c
index 6044e83fdf..9c1775d6a1 100644
--- a/keyboards/jj40/jj40.c
+++ b/keyboards/jj40/jj40.c
@@ -1,5 +1,6 @@
 /*
 Copyright 2017 Luiz Ribeiro <luizribeiro@gmail.com>
+Modified 2018 Kenneth A. <github.com/krusli>
 
 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
@@ -24,8 +25,34 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include "i2c.h"
 
-// custom RGB driver
+#include "backlight.h"
+#include "backlight_custom.h"
+
 extern rgblight_config_t rgblight_config;
+
+// for keyboard subdirectory level init functions
+// @Override
+void matrix_init_kb(void) {
+  // call user level keymaps, if any
+  // matrix_init_user();
+}
+
+#ifdef BACKLIGHT_ENABLE
+/// Overrides functions in `quantum.c`
+void backlight_init_ports(void) {
+  b_led_init_ports();
+}
+
+void backlight_task(void) {
+  b_led_task();
+}
+
+void backlight_set(uint8_t level) {
+  b_led_set(level);
+}
+#endif
+
+// custom RGB driver
 void rgblight_set(void) {
   if (!rgblight_config.enable) {
     for (uint8_t i=0; i<RGBLED_NUM; i++) {
@@ -39,8 +66,15 @@ void rgblight_set(void) {
   i2c_send(0xb0, (uint8_t*)led, 3 * RGBLED_NUM);
 }
 
-__attribute__ ((weak))
+bool rgb_init = false;
 void matrix_scan_user(void) {
-    rgblight_task();
-    /* Nothing else for now. */
+  // if LEDs were previously on before poweroff, turn them back on
+  if (rgb_init == false && rgblight_config.enable) {
+    i2c_init();
+    i2c_send(0xb0, (uint8_t*)led, 3 * RGBLED_NUM);
+    rgb_init = true;
+  }
+
+  rgblight_task();
+  /* Nothing else for now. */
 }
diff --git a/keyboards/jj40/jj40.h b/keyboards/jj40/jj40.h
index 6837423f8a..44d8b0f375 100644
--- a/keyboards/jj40/jj40.h
+++ b/keyboards/jj40/jj40.h
@@ -23,6 +23,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "keycode.h"
 #include "action.h"
 
+void matrix_init_user(void);  // TODO port this to other PS2AVRGB boards
+
 #define KEYMAP_GRID( \
     K01, K02, K03, K04, K05, K06, K07, K08, K09, K010, K011, K012, \
     K11, K12, K13, K14, K15, K16, K17, K18, K19, K110, K111, K112, \
diff --git a/keyboards/jj40/keymaps/default/keymap.c b/keyboards/jj40/keymaps/default/keymap.c
index 480486a18c..e02dd902a7 100644
--- a/keyboards/jj40/keymaps/default/keymap.c
+++ b/keyboards/jj40/keymaps/default/keymap.c
@@ -1,20 +1,3 @@
-/*
-Copyright 2017 Luiz Ribeiro <luizribeiro@gmail.com>
-
-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 2 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/>.
-*/
-
 #include "jj40.h"
 #include "action_layer.h"
 
diff --git a/keyboards/jj40/keymaps/krusli/config.h b/keyboards/jj40/keymaps/krusli/config.h
new file mode 100644
index 0000000000..11cafbefcb
--- /dev/null
+++ b/keyboards/jj40/keymaps/krusli/config.h
@@ -0,0 +1,8 @@
+#ifndef CONFIG_USER_H
+#define CONFIG_USER_H
+
+#include "../../config.h"
+
+#define PREVENT_STUCK_MODIFIERS
+
+#endif
diff --git a/keyboards/jj40/keymaps/krusli/keymap.c b/keyboards/jj40/keymaps/krusli/keymap.c
index 59e3988e11..5a985199e4 100644
--- a/keyboards/jj40/keymaps/krusli/keymap.c
+++ b/keyboards/jj40/keymaps/krusli/keymap.c
@@ -1,20 +1,3 @@
-/*
-Copyright 2017 Luiz Ribeiro <luizribeiro@gmail.com>
-
-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 2 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/>.
-*/
-
 #include "jj40.h"
 #include "action_layer.h"
 
@@ -62,7 +45,7 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
   KC_TILD, KC_EXLM, KC_AT,   KC_HASH, KC_DLR,  KC_PERC, KC_CIRC, KC_AMPR, KC_ASTR, KC_LPRN, KC_RPRN, KC_BSPC, \
   KC_DEL,  KC_F1,   KC_F2,   KC_F3,   KC_F4,   KC_F5,   KC_F6,   KC_UNDS, KC_PLUS, KC_LCBR, KC_RCBR, KC_PIPE, \
   _______, KC_F7,   KC_F8,   KC_F9,   KC_F10,  KC_F11,  KC_F12,  _______, _______,_______, _______, _______, \
-  _______, _______, _______, _______, _______, _______, _______, KC_MNXT, KC_VOLD, KC_VOLU, KC_MPLY \
+  BL_TOGG, BL_STEP, BL_BRTG, _______, _______, _______, _______, KC_MNXT, KC_VOLD, KC_VOLU, KC_MPLY \
 ),
 
 /* Raise
@@ -73,13 +56,13 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
  * |------+------+------+------+------+------|------+------+------+------+------+------|
  * |      |  F7  |  F8  |  F9  |  F10 |  F11 |  F12 | RGB  | RGB  | RGB  | RGB  |Enter |
  * |------+------+------+------+------+------+------+------+------+------+------+------|
- * |      | RGB  | RGB  | RGB  | RGB  |             |      | Next | Vol- | Vol+ | Play |
+ * | RGB  | RGB  | RGB  | RGB  |      |             |      | Next | Vol- | Vol+ | Play |
  * `-----------------------------------------------------------------------------------'
  */
 [_RAISE] = KEYMAP( \
   KC_GRV,  KC_1,    KC_2,    KC_3,    KC_4,    KC_5,    KC_6,    KC_7,    KC_8,    KC_9,    KC_0,    KC_BSPC, \
   KC_DEL,  KC_F1,   KC_F2,   KC_F3,   KC_F4,   KC_F5,   KC_F6,   KC_MINS, KC_EQL,  KC_LBRC, KC_RBRC, KC_BSLS, \
   _______, KC_F7,   KC_F8,   KC_F9,   KC_F10,  KC_F11,  KC_F12,  RGB_TOG, RGB_MOD, RGB_VAD, RGB_VAI, _______, \
-  _______, RGB_HUD, RGB_HUI, RGB_SAD, RGB_SAI, _______, _______, KC_MNXT, KC_VOLD, KC_VOLU, KC_MPLY \
+  RGB_HUD, RGB_HUI, RGB_SAD, RGB_SAI, _______, _______, _______, KC_MNXT, KC_VOLD, KC_VOLU, KC_MPLY \
 )
 };
diff --git a/keyboards/jj40/matrix.c b/keyboards/jj40/matrix.c
index 140026013f..a9e9cb5397 100644
--- a/keyboards/jj40/matrix.c
+++ b/keyboards/jj40/matrix.c
@@ -29,6 +29,9 @@ static uint8_t debouncing = DEBOUNCE;
 static matrix_row_t matrix[MATRIX_ROWS];
 static matrix_row_t matrix_debouncing[MATRIX_ROWS];
 
+void matrix_set_row_status(uint8_t row);
+uint8_t bit_reverse(uint8_t x);
+
 void matrix_init(void) {
     // all outputs for rows high
     DDRB = 0xFF;
@@ -47,18 +50,8 @@ void matrix_init(void) {
         matrix[row] = 0x00;
         matrix_debouncing[row] = 0x00;
     }
-}
 
-void matrix_set_row_status(uint8_t row) {
-    DDRB = (1 << row);
-    PORTB = ~(1 << row);
-}
-
-uint8_t bit_reverse(uint8_t x) {
-    x = ((x >> 1) & 0x55) | ((x << 1) & 0xaa);
-    x = ((x >> 2) & 0x33) | ((x << 2) & 0xcc);
-    x = ((x >> 4) & 0x0f) | ((x << 4) & 0xf0);
-    return x;
+    matrix_init_quantum();  // missing from original port by Luiz
 }
 
 uint8_t matrix_scan(void) {
@@ -93,11 +86,30 @@ uint8_t matrix_scan(void) {
         }
     }
 
-    matrix_scan_user();
+    matrix_scan_quantum();  // also missing in original PS2AVRGB implementation
 
     return 1;
 }
 
+void matrix_scan_kb(void) {
+  // Looping keyboard code goes here
+  // This runs every cycle (a lot)
+  matrix_scan_user();
+};
+
+// declarations
+void matrix_set_row_status(uint8_t row) {
+    DDRB = (1 << row);
+    PORTB = ~(1 << row);
+}
+
+uint8_t bit_reverse(uint8_t x) {
+    x = ((x >> 1) & 0x55) | ((x << 1) & 0xaa);
+    x = ((x >> 2) & 0x33) | ((x << 2) & 0xcc);
+    x = ((x >> 4) & 0x0f) | ((x << 4) & 0xf0);
+    return x;
+}
+
 inline matrix_row_t matrix_get_row(uint8_t row) {
     return matrix[row];
 }
diff --git a/keyboards/jj40/rules.mk b/keyboards/jj40/rules.mk
index cdc898c0fa..670967fbd9 100644
--- a/keyboards/jj40/rules.mk
+++ b/keyboards/jj40/rules.mk
@@ -36,11 +36,13 @@ MOUSEKEY_ENABLE = no
 EXTRAKEY_ENABLE = yes
 CONSOLE_ENABLE = no
 COMMAND_ENABLE = yes
-BACKLIGHT_ENABLE = no
+
+BACKLIGHT_ENABLE = yes
+BACKLIGHT_CUSTOM_DRIVER = yes
 
 RGBLIGHT_ENABLE = yes
 RGBLIGHT_CUSTOM_DRIVER = yes
-DISABLE_WS2812 = yes  # TODO check if this is necessary
+# DISABLE_WS2812 = no
 
 KEY_LOCK_ENABLE = yes
 
@@ -51,7 +53,7 @@ OPT_DEFS = -DDEBUG_LEVEL=0
 
 # custom matrix setup
 CUSTOM_MATRIX = yes
-SRC = matrix.c i2c.c
+SRC = matrix.c i2c.c backlight.c
 
 # programming options
 PROGRAM_CMD = ./util/atmega32a_program.py $(TARGET).hex
diff --git a/keyboards/jj40/usbconfig.h b/keyboards/jj40/usbconfig.h
index 520d08f611..ad97e7f0a3 100644
--- a/keyboards/jj40/usbconfig.h
+++ b/keyboards/jj40/usbconfig.h
@@ -119,7 +119,7 @@ section at the end of this file).
  * device is powered from the USB bus.
  */
 // max power draw with maxed white underglow measured at 120 mA (peaks)
-#define USB_CFG_MAX_BUS_POWER           150
+#define USB_CFG_MAX_BUS_POWER           100
 /* Set this variable to the maximum USB bus power consumption of your device.
  * The value is in milliamperes. [It will be divided by two since USB
  * communicates power requirements in units of 2 mA.]