/**********************************************************************
 *   Copyright: (C)2024 LingYun IoT System Studio
 *      Author: GuoWenxue<guowenxue@gmail.com>
 *
 * Description: WS2812B strip lights driver on ISKBoard
 *
 * Reference  : https://blog.csdn.net/Lennon8_8/article/details/108980808
 *
 * COMPILER OPTIMIZATION WARNING:
 *   This driver uses NOP-based delays for precise WS2812B pulse timing. Keil5
 *   Arm Compiler(AC6) default '-O3' optimization breaks this by altering loop
 *   assembly and branch structures, causing timing collapse.
 *   Fix: Options for Target -> C/C++ (AC6)  Set Optimization to -O1.
 *  Note: GCC compiler (STM32CubeIDE/VSCode) is NOT affected.
 *
 *   ChangeLog:
 *        Version    Date       Author            Description
 *        V1.0.0  2024.08.29    GuoWenxue      Release initial version
 *
 ***********************************************************************/
#include <string.h>
#include <stdint.h>
#include "ws2812b.h"
#include "miscdev.h"

#define mdelay(ms) HAL_Delay(ms)

static color_t g_ColorPanel[WS2812_NUM];

typedef struct ws_gpio_s
{
    GPIO_TypeDef        *group;
    uint16_t             pin;
} ws_gpio_t;

/* 使用 ws_gpio 结构体进行 GPIO 操作，便于移植 */
static ws_gpio_t   ws_gpio =
{
    .group = GPIOC,
    .pin   = GPIO_PIN_2,
};
#define ws_set_high()   (ws_gpio.group->BSRR = ws_gpio.pin)
#define ws_set_low()    (ws_gpio.group->BRR = ws_gpio.pin)


/* 配置 WS2812B 灯带的 GPIO 口 */
void ws2812b_init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0};

    GPIO_InitStruct.Pin = ws_gpio.pin;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;

    HAL_GPIO_Init(ws_gpio.group, &GPIO_InitStruct);

    ws2812b_reset();

    return ;
}

/*
 * 使用内联汇编 NOP 实现纳秒级精确延时 @ 80MHz: 1 NOP = 12.5ns
 *
 * 根据数据手册时序：
 * T0H: 220~380ns  (recommend 300ns = 24 cycles)
 * T0L: 580~1000ns (recommend 800ns = 64 cycles)
 * T1H: 580~1600ns (recommend 1100ns = 88 cycles)
 * T1L: 220~420ns  (recommend 320ns = 26 cycles)
 * RES: > 280us
 *
 * 实际测试建议：
 * - 考虑 GPIO 操作本身耗时约 2-3 个时钟周期
 * - 考虑函数调用、判断等开销
 * - 以下数值已预留开销，可根据实测微调 ±2~4 个 NOP
 */

/* T0H: 300ns ≈ 24 cycles
 * 减去 GPIO 和判断开销约 6 cycles，使用 18 NOPs
 */
#define delay_T0H() __ASM volatile( \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t" \
)

/* T0L: 800ns ≈ 64 cycles
 * 减去开销约 6 cycles，使用 58 NOPs
 */
#define delay_T0L() __ASM volatile( \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
)

/* T1H: 1100ns ≈ 88 cycles
 * 减去开销约 6 cycles，使用 82 NOPs
 */
#define delay_T1H() __ASM volatile( \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t" \
)

/* T1L: 320ns ≈ 26 cycles
 * 减去开销约 6 cycles，使用 20 NOPs
 */
#define delay_T1L() __ASM volatile( \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
    "NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
)

static inline void ws2812b_WriteByte(uint8_t byte)
{
    int i;

    for(i=0; i<8; i++)
    {
        if(byte & 0x80)
        {
            /* Sequence Send 1:
             *
             * +--------------+         +
             * |<-   T1H    ->|<- T1L ->|
             * |              +---------+
             */
            ws_set_high();
            delay_T1H();

            ws_set_low();
            delay_T1L();
        }
        else
        {
            /* Sequence Send 0:
             *
             * +---------+              +
             * |<- T0H ->|<-    T0L   ->|
             * |         +--------------+
             */
            ws_set_high();
            delay_T0H();

            ws_set_low();
            delay_T0L();
        }

        byte <<= 1;
    }

    return ;
}

void ws2812b_reset(void)
{
    /* RES: low voltage time > 280us */
    ws_set_low();
    udelay(300);

    memset(g_ColorPanel, 0, sizeof(g_ColorPanel));

    return ;
}

static inline void ws2812b_SendColor(color_t color)
{
    ws2812b_WriteByte(color.pixel.green);
    ws2812b_WriteByte(color.pixel.red);
    ws2812b_WriteByte(color.pixel.blue);

    return ;
}

static inline void ws2812b_Refresh(void)
{
    int i;
    uint32_t primask;

    /* 关闭中断保证时序准确 */
    primask = __get_PRIMASK();
    __disable_irq();

    for(i=0; i<WS2812_NUM; i++)
    {
        ws2812b_SendColor(g_ColorPanel[i]);
    }

    /* 恢复中断状态 */
    __set_PRIMASK(primask);

    return ;
}

static inline int ws2812b_SetPixel(int which, color_t color)
{
    if( which<0 || which>=WS2812_NUM )
        return -1;

    g_ColorPanel[which].pixel.red   = color.pixel.red;
    g_ColorPanel[which].pixel.green = color.pixel.green;
    g_ColorPanel[which].pixel.blue  = color.pixel.blue;

    return 0;
}

int ws2812b_turn(int which, color_t color)
{
    if( which<0 || which>=WS2812_NUM )
        return -1;

    ws2812b_SetPixel(which, color);
    ws2812b_Refresh();

    return 0;
}

void ws2812b_blink(void)
{
    int      c, i;
    color_t  colors[4] = {[0].data=PIXEL_B, [1].data=PIXEL_R, [2].data=PIXEL_G, [3].data=PIXEL_W};
    color_t  color_off = {.data = PIXEL_OFF};

    for(c=0; c<4; c++) /* color */
    {
        for(i=0; i<WS2812_NUM; i++)
        {
            ws2812b_turn(i, colors[c]);
            mdelay(300);
            ws2812b_turn(i, color_off);
            mdelay(300);
        }
    }
}