1 files changed, 211 insertions, 0 deletions
diff --git a/keyboards/percent/skog/backlight.c b/keyboards/percent/skog/backlight.c
new file mode 100644
index 0000000000..94e8126d88
--- /dev/null
+++ b/keyboards/percent/skog/backlight.c
@@ -0,0 +1,211 @@
+/**
+ * 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 << 0)  // D0
+#define CAPSLOCK_PORT   (1 << 1)  // D1
+#define BACKLIGHT_PORT  (1 << 4)  // D4
+#define SCROLLLOCK_PORT (1 << 6)  // D6
+
+#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.
+__attribute__ ((weak))
+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
+}
+
+// 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