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qmk_firmware/quantum/backlight/backlight_soft.c
2019-12-14 17:25:32 +00:00

90 lines
2.5 KiB
C

#include "quantum.h"
#include "backlight.h"
#if !defined(BACKLIGHT_PIN) && !defined(BACKLIGHT_PINS)
# error "Backlight pin/pins not defined. Please configure."
#endif
#ifdef BACKLIGHT_BREATHING
# error "Backlight breathing is not available for software PWM. Please disable."
#endif
#ifndef BACKLIGHT_ON_STATE
# define BACKLIGHT_ON_STATE 1
#endif
#ifdef BACKLIGHT_PINS
# define BACKLIGHT_PIN_INIT BACKLIGHT_PINS
#else
# define BACKLIGHT_PIN_INIT \
{ BACKLIGHT_PIN }
#endif
static uint16_t s_duty_pattern = 0;
static const pin_t backlight_pins[] = BACKLIGHT_PIN_INIT;
#define BACKLIGHT_LED_COUNT (sizeof(backlight_pins) / sizeof(pin_t))
#define FOR_EACH_LED(x) \
for (uint8_t i = 0; i < BACKLIGHT_LED_COUNT; i++) { \
pin_t backlight_pin = backlight_pins[i]; \
{ x } \
}
void backlight_on(pin_t backlight_pin) {
#if BACKLIGHT_ON_STATE == 0
writePinLow(backlight_pin);
#else
writePinHigh(backlight_pin);
#endif
}
void backlight_off(pin_t backlight_pin) {
#if BACKLIGHT_ON_STATE == 0
writePinHigh(backlight_pin);
#else
writePinLow(backlight_pin);
#endif
}
void backlight_init_ports(void) {
// Setup backlight pin as output and output to off state.
FOR_EACH_LED(setPinOutput(backlight_pin); backlight_off(backlight_pin);)
}
// clang-format off
/** \brief PWM duty patterns
*
* We scale the current backlight level to an index within this array. This allows
* backlight_task to focus on just switching LEDs on/off, and we can predict the duty pattern
*/
static uint16_t backlight_duty_table[] = {
0b0000000000000000,
0b1000000000000000,
0b1000000010000000,
0b1000001000010000,
0b1000100010001000,
0b1001001001001000,
0b1010101010101010,
0b1110111011101110,
0b1111111111111111,
};
#define backlight_duty_table_size (sizeof(backlight_duty_table) / sizeof(backlight_duty_table[0]))
// clang-format on
static uint8_t scale_backlight(uint8_t v) { return v * (backlight_duty_table_size - 1) / BACKLIGHT_LEVELS; }
void backlight_task(void) {
static uint8_t backlight_tick = 0;
if (s_duty_pattern & ((uint16_t)1 << backlight_tick)) {
FOR_EACH_LED(backlight_on(backlight_pin);)
} else {
FOR_EACH_LED(backlight_off(backlight_pin);)
}
backlight_tick = (backlight_tick + 1) % 16;
}
void backlight_set(uint8_t level) { s_duty_pattern = backlight_duty_table[scale_backlight(level)]; }