qmk_firmware/keyboards/nuphy/air75_v2/ansi/side_driver.c

/*
Copyright 2023 @ Nuphy <https://nuphy.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 <ch.h>
#include <hal.h>

#include "quantum.h"
#include "ws2812.h"

/* Adapted from https://github.com/bigjosh/SimpleNeoPixelDemo/ */

#ifndef NOP_FUDGE
#if defined(STM32F0XX) || defined(STM32F1XX) || defined(GD32VF103) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32L0XX) || defined(WB32F3G71xx) || defined(WB32FQ95xx)
#define NOP_FUDGE 0.4
#else
#error("NOP_FUDGE configuration required")
#define NOP_FUDGE 1  // this just pleases the compile so the above error is easier to spot
#endif
#endif

// Push Pull or Open Drain Configuration
// Default Push Pull
#ifndef WS2812_EXTERNAL_PULLUP
#define WS2812_OUTPUT_MODE PAL_MODE_OUTPUT_PUSHPULL
#else
#define WS2812_OUTPUT_MODE PAL_MODE_OUTPUT_OPENDRAIN
#endif

// The reset gap can be 6000 ns, but depending on the LED strip it may have to be increased
// to values like 600000 ns. If it is too small, the pixels will show nothing most of the time.
#ifndef WS2812_RES
#define WS2812_RES (1000 * WS2812_TRST_US)  // Width of the low gap between bits to cause a frame to latch
#endif

#define NUMBER_NOPS     6
#define CYCLES_PER_SEC  (CPU_CLOCK / NUMBER_NOPS * NOP_FUDGE)
#define NS_PER_SEC      (1000000000L)  // Note that this has to be SIGNED since we want to be able to check for negative values of derivatives
#define NS_PER_CYCLE    (NS_PER_SEC / CYCLES_PER_SEC)
#define NS_TO_CYCLES(n) ((n) / NS_PER_CYCLE)

#define wait_ns(x)                                  \
    do {                                            \
        for (int i = 0; i < NS_TO_CYCLES(x); i++) { \
            __asm__ volatile(                       \
                "nop\n\t"                           \
                "nop\n\t"                           \
                "nop\n\t"                           \
                "nop\n\t"                           \
                "nop\n\t"                           \
                "nop\n\t");                         \
        }                                           \
    } while (0)

void side_sendByte(uint8_t byte)
{
    // WS2812 protocol wants most significant bits first
    for (unsigned char bit = 0; bit < 8; bit++) {
        bool is_one = byte & (1 << (7 - bit));
        // using something like wait_ns(is_one ? T1L : T0L) here throws off timings
        if (is_one) {
            // 1
            writePinHigh(DRIVER_SIDE_PIN);
            wait_ns(WS2812_T1H);
            writePinLow(DRIVER_SIDE_PIN);
            wait_ns(WS2812_T1L);
        } else {
            // 0
            writePinHigh(DRIVER_SIDE_PIN);
            wait_ns(WS2812_T0H);
            writePinLow(DRIVER_SIDE_PIN);
            wait_ns(WS2812_T0L);
        }
    }
}

// Setleds for standard RGB
void side_ws2812_setleds(rgb_led_t *ledarray, uint16_t leds)
{
    // this code is very time dependent, so we need to disable interrupts
    chSysLock();

    for (uint8_t i = 0; i < leds; i++) {
        // WS2812 protocol dictates grb order
        side_sendByte(ledarray[i].g);
        side_sendByte(ledarray[i].r);
        side_sendByte(ledarray[i].b);
    }

    wait_ns(WS2812_RES);

    chSysUnlock();
}