// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <esp_types.h>
#include "esp_intr.h"
#include "esp_intr_alloc.h"
#include "freertos/FreeRTOS.h"
#include "freertos/semphr.h"
#include "freertos/xtensa_api.h"
#include "soc/gpio_sig_map.h"
#include "driver/ledc.h"
#include "soc/ledc_reg.h"
#include "soc/ledc_struct.h"
#include "esp_log.h"

static const char* LEDC_TAG = "ledc";
static portMUX_TYPE ledc_spinlock = portMUX_INITIALIZER_UNLOCKED;
#define LEDC_CHECK(a, str, ret_val) \
    if (!(a)) { \
        ESP_LOGE(LEDC_TAG,"%s(%d): %s", __FUNCTION__, __LINE__, str); \
        return (ret_val); \
    }

typedef struct {
    uint16_t speed_mode;
    uint16_t direction;
    int target_duty;
    int cycle_num;
    int scale;
    ledc_fade_mode_t mode;
    xSemaphoreHandle ledc_fade_sem;
    xSemaphoreHandle ledc_fade_mux;
} ledc_fade_t;

static ledc_fade_t *s_ledc_fade_rec[LEDC_SPEED_MODE_MAX][LEDC_CHANNEL_MAX];
static ledc_isr_handle_t s_ledc_fade_isr_handle = NULL;

#define LEDC_VAL_NO_CHANGE   (-1)
#define LEDC_STEP_NUM_MAX    (1023)
#define LEDC_DUTY_DECIMAL_BIT_NUM  (4)

#define LEDC_MODE_ERR_STR  "LEDC mode error"
#define LEDC_TIMER_ERR_STR "LEDC timer error"
#define LEDC_CHANNEL_ERR_STR  "LEDC channel error"
#define LEDC_GPIO_OUT_ERR_STR  "LEDC GPIO output number error"
#define LEDC_FADE_DIR_ERR_STR   "LEDC fade direction error"
#define LEDC_FADE_SERVICE_ERR_STR   "LEDC fade service not installed"
#define LEDC_FADE_TARGET_ERR_STR    "LEDC fade target duty error"
#define LEDC_FADE_INSTALLED_ERR_STR  "LEDC fade service already installed"
#define LEDC_FADE_MODE_ERR_STR       "LEDC fade mode error"
#define LEDC_FADE_INIT_ERROR_STR     "LEDC fade channel init error"

static void ledc_ls_timer_update(ledc_mode_t speed_mode, ledc_timer_t timer_sel)
{
    if (speed_mode == LEDC_LOW_SPEED_MODE) {
        LEDC.timer_group[speed_mode].timer[timer_sel].conf.low_speed_update = 1;
    }
}

static IRAM_ATTR void ledc_ls_channel_update(ledc_mode_t speed_mode, ledc_channel_t channel_num)
{
    if (speed_mode == LEDC_LOW_SPEED_MODE) {
        LEDC.channel_group[speed_mode].channel[channel_num].conf0.low_speed_update = 1;
    }
}

esp_err_t ledc_timer_set(ledc_mode_t speed_mode, ledc_timer_t timer_sel, uint32_t div_num, uint32_t bit_num,
        ledc_clk_src_t clk_src)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(timer_sel <= LEDC_TIMER_3, LEDC_TIMER_ERR_STR, ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    LEDC.timer_group[speed_mode].timer[timer_sel].conf.div_num = div_num;
    LEDC.timer_group[speed_mode].timer[timer_sel].conf.tick_sel = clk_src;
    LEDC.timer_group[speed_mode].timer[timer_sel].conf.bit_num = bit_num;
    ledc_ls_timer_update(speed_mode, timer_sel);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

static IRAM_ATTR esp_err_t ledc_duty_config(ledc_mode_t speed_mode, ledc_channel_t channel_num, int hpoint_val, uint32_t duty_val,
    uint32_t duty_direction, uint32_t duty_num, uint32_t duty_cycle, uint32_t duty_scale)
{
    portENTER_CRITICAL(&ledc_spinlock);
    if (hpoint_val >= 0) {
        LEDC.channel_group[speed_mode].channel[channel_num].hpoint.hpoint = hpoint_val;
    }
    LEDC.channel_group[speed_mode].channel[channel_num].duty.duty = duty_val;
    LEDC.channel_group[speed_mode].channel[channel_num].conf1.val = ((duty_direction & LEDC_DUTY_INC_HSCH0_V) << LEDC_DUTY_INC_HSCH0_S) |
                                                                    ((duty_num & LEDC_DUTY_NUM_HSCH0_V) << LEDC_DUTY_NUM_HSCH0_S) |
                                                                    ((duty_cycle & LEDC_DUTY_CYCLE_HSCH0_V) << LEDC_DUTY_CYCLE_HSCH0_S) |
                                                                    ((duty_scale & LEDC_DUTY_SCALE_HSCH0_V) << LEDC_DUTY_SCALE_HSCH0_S);
    ledc_ls_channel_update(speed_mode, channel_num);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

esp_err_t ledc_bind_channel_timer(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t timer_idx)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(timer_idx <= LEDC_TIMER_3, LEDC_TIMER_ERR_STR, ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    LEDC.channel_group[speed_mode].channel[channel].conf0.timer_sel = timer_idx;
    ledc_ls_channel_update(speed_mode, channel);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

esp_err_t ledc_timer_rst(ledc_mode_t speed_mode, uint32_t timer_sel)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(timer_sel <= LEDC_TIMER_3, LEDC_TIMER_ERR_STR, ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    LEDC.timer_group[speed_mode].timer[timer_sel].conf.rst = 1;
    LEDC.timer_group[speed_mode].timer[timer_sel].conf.rst = 0;
    ledc_ls_timer_update(speed_mode, timer_sel);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

esp_err_t ledc_timer_pause(ledc_mode_t speed_mode, uint32_t timer_sel)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(timer_sel <= LEDC_TIMER_3, LEDC_TIMER_ERR_STR, ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    LEDC.timer_group[speed_mode].timer[timer_sel].conf.pause = 1;
    ledc_ls_timer_update(speed_mode, timer_sel);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

esp_err_t ledc_timer_resume(ledc_mode_t speed_mode, uint32_t timer_sel)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(timer_sel <= LEDC_TIMER_3, LEDC_TIMER_ERR_STR, ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    LEDC.timer_group[speed_mode].timer[timer_sel].conf.pause = 0;
    ledc_ls_timer_update(speed_mode, timer_sel);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

static esp_err_t ledc_enable_intr_type(ledc_mode_t speed_mode, uint32_t channel, ledc_intr_type_t type)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    uint32_t value;
    uint32_t intr_type = type;
    portENTER_CRITICAL(&ledc_spinlock);
    value = LEDC.int_ena.val;
    uint8_t int_en_base = LEDC_DUTY_CHNG_END_HSCH0_INT_ENA_S;
    if (speed_mode == LEDC_LOW_SPEED_MODE) {
        int_en_base = LEDC_DUTY_CHNG_END_LSCH0_INT_ENA_S;
    }
    if (intr_type == LEDC_INTR_FADE_END) {
        LEDC.int_ena.val = value | BIT(int_en_base + channel);
    } else {
        LEDC.int_ena.val = (value & (~(BIT(int_en_base + channel))));
    }
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

esp_err_t ledc_isr_register(void (*fn)(void*), void * arg, int intr_alloc_flags, ledc_isr_handle_t *handle)
{
    esp_err_t ret;
    LEDC_CHECK(fn, "ledc isr null", ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    ret = esp_intr_alloc(ETS_LEDC_INTR_SOURCE, intr_alloc_flags, fn, arg, handle);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ret;
}

esp_err_t ledc_timer_config(const ledc_timer_config_t* timer_conf)
{
    int freq_hz = timer_conf->freq_hz;
    int bit_num = timer_conf->bit_num;
    int timer_num = timer_conf->timer_num;
    int speed_mode = timer_conf->speed_mode;
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    periph_module_enable(PERIPH_LEDC_MODULE);
    if (freq_hz == 0 || bit_num == 0 || bit_num > LEDC_TIMER_15_BIT) {
        ESP_LOGE(LEDC_TAG, "freq_hz=%u bit_num=%u", freq_hz, bit_num);
        return ESP_ERR_INVALID_ARG;
    }
    if (timer_num > LEDC_TIMER_3) {
        ESP_LOGE(LEDC_TAG, "invalid timer #%u", timer_num);
        return ESP_ERR_INVALID_ARG;
    }
    esp_err_t ret = ESP_OK;
    uint32_t precision = ( 0x1 << bit_num );  // 2**depth
    // Try calculating divisor based on LEDC_APB_CLK
    ledc_clk_src_t timer_clk_src = LEDC_APB_CLK;
    // div_param is a Q10.8 fixed point value
    uint64_t div_param = ( (uint64_t) LEDC_APB_CLK_HZ << 8 ) / freq_hz / precision;
    if (div_param < 256) {
        // divisor is too low
        ESP_LOGE(LEDC_TAG, "requested frequency and bit depth can not be achieved, try reducing freq_hz or bit_num. div_param=%d",
            (uint32_t ) div_param);
        ret = ESP_FAIL;
    }
    if (div_param > LEDC_DIV_NUM_HSTIMER0_V) {
        // APB_CLK results in divisor which too high. Try using REF_TICK as clock source.
        timer_clk_src = LEDC_REF_TICK;
        div_param = ((uint64_t) LEDC_REF_CLK_HZ << 8) / freq_hz / precision;
        if (div_param < 256 || div_param > LEDC_DIV_NUM_HSTIMER0_V) {
            ESP_LOGE(LEDC_TAG, "requested frequency and bit depth can not be achieved, try increasing freq_hz or bit_num. div_param=%d",
                (uint32_t ) div_param);
            ret = ESP_FAIL;
        }
    } else {
        if (speed_mode == LEDC_LOW_SPEED_MODE) {
            //for now, we only select 80mhz for slow clk of LEDC low speed channels.
            LEDC.conf.slow_clk_sel = 1;
        }
    }
    // set timer parameters
    ledc_timer_set(speed_mode, timer_num, div_param, bit_num, timer_clk_src);
    // reset timer
    ledc_timer_rst(speed_mode, timer_num);
    return ret;
}

esp_err_t ledc_set_pin(int gpio_num, ledc_mode_t speed_mode, ledc_channel_t ledc_channel)
{
    LEDC_CHECK(ledc_channel <= LEDC_CHANNEL_7, LEDC_CHANNEL_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(GPIO_IS_VALID_OUTPUT_GPIO(gpio_num), LEDC_GPIO_OUT_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[gpio_num], PIN_FUNC_GPIO);
    gpio_set_direction(gpio_num, GPIO_MODE_OUTPUT);
    if (speed_mode == LEDC_HIGH_SPEED_MODE) {
        gpio_matrix_out(gpio_num, LEDC_HS_SIG_OUT0_IDX + ledc_channel, 0, 0);
    } else {
        gpio_matrix_out(gpio_num, LEDC_LS_SIG_OUT0_IDX + ledc_channel, 0, 0);
    }
    return ESP_OK;
}

esp_err_t ledc_channel_config(const ledc_channel_config_t* ledc_conf)
{
    uint32_t speed_mode = ledc_conf->speed_mode;
    uint32_t gpio_num = ledc_conf->gpio_num;
    uint32_t ledc_channel = ledc_conf->channel;
    uint32_t timer_select = ledc_conf->timer_sel;
    uint32_t intr_type = ledc_conf->intr_type;
    uint32_t duty = ledc_conf->duty;
    LEDC_CHECK(ledc_channel <= LEDC_CHANNEL_7, LEDC_CHANNEL_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(GPIO_IS_VALID_OUTPUT_GPIO(gpio_num), LEDC_GPIO_OUT_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(timer_select <= LEDC_TIMER_3, LEDC_TIMER_ERR_STR, ESP_ERR_INVALID_ARG);
    periph_module_enable(PERIPH_LEDC_MODULE);
    esp_err_t ret = ESP_OK;
    /*set channel parameters*/
    /*   channel parameters decide how the waveform looks like in one period*/
    /*   set channel duty, duty range is (0 ~ ((2 ** bit_num) - 1))*/
    ledc_set_duty(speed_mode, ledc_channel, duty);
    /*update duty settings*/
    ledc_update_duty(speed_mode, ledc_channel);
    /*bind the channel with the timer*/
    ledc_bind_channel_timer(speed_mode, ledc_channel, timer_select);
    /*set interrupt type*/
    ledc_enable_intr_type(speed_mode, ledc_channel, intr_type);
    ESP_LOGD(LEDC_TAG, "LEDC_PWM CHANNEL %1u|GPIO %02u|Duty %04u|Time %01u",
        ledc_channel, gpio_num, duty, timer_select
    );
    /*set LEDC signal in gpio matrix*/
    PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[gpio_num], PIN_FUNC_GPIO);
    gpio_set_direction(gpio_num, GPIO_MODE_OUTPUT);
    if (speed_mode == LEDC_HIGH_SPEED_MODE) {
        gpio_matrix_out(gpio_num, LEDC_HS_SIG_OUT0_IDX + ledc_channel, 0, 0);
    } else {
        gpio_matrix_out(gpio_num, LEDC_LS_SIG_OUT0_IDX + ledc_channel, 0, 0);
    }
    return ret;
}

esp_err_t ledc_update_duty(ledc_mode_t speed_mode, ledc_channel_t channel)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(channel <= LEDC_CHANNEL_7, LEDC_CHANNEL_ERR_STR, ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    LEDC.channel_group[speed_mode].channel[channel].conf0.sig_out_en = 1;
    LEDC.channel_group[speed_mode].channel[channel].conf1.duty_start = 1;
    ledc_ls_channel_update(speed_mode, channel);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

esp_err_t ledc_stop(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t idle_level)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(channel <= LEDC_CHANNEL_7, LEDC_CHANNEL_ERR_STR, ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    LEDC.channel_group[speed_mode].channel[channel].conf0.idle_lv = idle_level & 0x1;
    LEDC.channel_group[speed_mode].channel[channel].conf0.sig_out_en = 0;
    LEDC.channel_group[speed_mode].channel[channel].conf1.duty_start = 0;
    ledc_ls_channel_update(speed_mode, channel);
    portEXIT_CRITICAL(&ledc_spinlock);
    return ESP_OK;
}

esp_err_t ledc_set_fade(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t duty, ledc_duty_direction_t fade_direction,
    uint32_t step_num, uint32_t duty_cyle_num, uint32_t duty_scale)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(channel <= LEDC_CHANNEL_7, LEDC_CHANNEL_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(fade_direction <= LEDC_DUTY_DIR_INCREASE, LEDC_FADE_DIR_ERR_STR, ESP_ERR_INVALID_ARG);
    if (step_num > LEDC_DUTY_NUM_HSCH0_V || duty_cyle_num > LEDC_DUTY_CYCLE_HSCH0_V || duty_scale > LEDC_DUTY_SCALE_HSCH0_V) {
        ESP_LOGE(LEDC_TAG, "step_num=%u duty_cyle_num=%u duty_scale=%u", step_num, duty_cyle_num, duty_scale);
        return ESP_ERR_INVALID_ARG;
    }
    if (s_ledc_fade_rec[speed_mode][channel]) {
        ledc_enable_intr_type(speed_mode, channel, LEDC_INTR_DISABLE);
    }
    ledc_duty_config(speed_mode,
                     channel,        //uint32_t chan_num,
                     0,              //uint32_t hpoint_val,
                     duty << 4,      //uint32_t duty_val,the least 4 bits are decimal part
                     fade_direction, //uint32_t increase,
                     step_num,       //uint32_t duty_num,
                     duty_cyle_num,  //uint32_t duty_cycle,
                     duty_scale      //uint32_t duty_scale
                     );
    return ESP_OK;
}

esp_err_t ledc_set_duty(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t duty)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(channel <= LEDC_CHANNEL_7, LEDC_CHANNEL_ERR_STR, ESP_ERR_INVALID_ARG);
    if (s_ledc_fade_rec[speed_mode][channel]) {
        ledc_enable_intr_type(speed_mode, channel, LEDC_INTR_DISABLE);
    }
    ledc_duty_config(speed_mode,
                     channel,         //uint32_t chan_num,
                     0,               //uint32_t hpoint_val,
                     duty << 4,       //uint32_t duty_val,the least 4 bits are decimal part
                     1,               //uint32_t increase,
                     1,               //uint32_t duty_num,
                     1,               //uint32_t duty_cycle,
                     0                //uint32_t duty_scale
                     );
    return ESP_OK;
}

int ledc_get_duty(ledc_mode_t speed_mode, ledc_channel_t channel)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, (-1));
    uint32_t duty = (LEDC.channel_group[speed_mode].channel[channel].duty_rd.duty_read >> 4);
    return duty;
}

esp_err_t ledc_set_freq(ledc_mode_t speed_mode, ledc_timer_t timer_num, uint32_t freq_hz)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    portENTER_CRITICAL(&ledc_spinlock);
    esp_err_t ret = ESP_OK;
    uint32_t div_num = 0;
    uint32_t bit_num = LEDC.timer_group[speed_mode].timer[timer_num].conf.bit_num;
    uint32_t timer_source_clk = LEDC.timer_group[speed_mode].timer[timer_num].conf.tick_sel;
    uint32_t precision = (0x1 << bit_num);
    if (timer_source_clk == LEDC_APB_CLK) {
        div_num = ((uint64_t) LEDC_APB_CLK_HZ << 8) / freq_hz / precision;
    } else {
        div_num = ((uint64_t) LEDC_REF_CLK_HZ << 8) / freq_hz / precision;
    }
    if (div_num <= 256 || div_num > LEDC_DIV_NUM_HSTIMER0) {
        ESP_LOGE(LEDC_TAG, "div param err,div_param=%u", div_num);
        ret = ESP_FAIL;
    }
    LEDC.timer_group[speed_mode].timer[timer_num].conf.div_num = div_num;
    portEXIT_CRITICAL(&ledc_spinlock);
    return ret;
}

uint32_t ledc_get_freq(ledc_mode_t speed_mode, ledc_timer_t timer_num)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, (0));
    portENTER_CRITICAL(&ledc_spinlock);
    uint32_t freq = 0;
    uint32_t timer_source_clk = LEDC.timer_group[speed_mode].timer[timer_num].conf.tick_sel;
    uint32_t bit_num = LEDC.timer_group[speed_mode].timer[timer_num].conf.bit_num;
    uint32_t div_num = LEDC.timer_group[speed_mode].timer[timer_num].conf.div_num;
    uint32_t precision = (0x1 << bit_num);
    if (timer_source_clk == LEDC_APB_CLK) {
        freq = ((uint64_t) LEDC_APB_CLK_HZ << 8) / precision / div_num;
    } else {
        freq = ((uint64_t) LEDC_REF_CLK_HZ << 8) / precision / div_num;
    }
    portEXIT_CRITICAL(&ledc_spinlock);
    return freq;
}

void IRAM_ATTR ledc_fade_isr(void* arg)
{
    int channel;
    portBASE_TYPE HPTaskAwoken = pdFALSE;
    uint32_t intr_status = LEDC.int_st.val;  //read LEDC interrupt status.
    LEDC.int_clr.val = intr_status;  //clear LEDC interrupt status.
    int speed_mode = LEDC_HIGH_SPEED_MODE;
    for (channel = 0; channel < LEDC_CHANNEL_MAX; channel++) {
        if (intr_status & (BIT(LEDC_DUTY_CHNG_END_HSCH0_INT_ST_S + channel) | BIT(LEDC_DUTY_CHNG_END_LSCH0_INT_ST_S + channel))) {
            if (intr_status & BIT(LEDC_DUTY_CHNG_END_HSCH0_INT_ST_S + channel)) {
                speed_mode = LEDC_HIGH_SPEED_MODE;
            } else {
                speed_mode = LEDC_LOW_SPEED_MODE;
            }
            if (s_ledc_fade_rec[speed_mode][channel] == NULL) {
                //fade object not initialized yet.
                continue;
            }
            int duty_cur = LEDC.channel_group[speed_mode].channel[channel].duty_rd.duty_read >> LEDC_DUTY_DECIMAL_BIT_NUM;
            if (duty_cur == s_ledc_fade_rec[speed_mode][channel]->target_duty) {
                if (s_ledc_fade_rec[speed_mode][channel]->mode == LEDC_FADE_WAIT_DONE) {
                    xSemaphoreGiveFromISR(s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem, &HPTaskAwoken);
                    if (HPTaskAwoken == pdTRUE) {
                        portYIELD_FROM_ISR();
                    }
                }
                continue;
            }
            int duty_tar = s_ledc_fade_rec[speed_mode][channel]->target_duty;
            int scale = s_ledc_fade_rec[speed_mode][channel]->scale;
            if (scale == 0) {
                continue;
            }
            int cycle = s_ledc_fade_rec[speed_mode][channel]->cycle_num;
            int delta = s_ledc_fade_rec[speed_mode][channel]->direction == LEDC_DUTY_DIR_DECREASE ? duty_cur - duty_tar : duty_tar - duty_cur;
            int step = delta / scale > LEDC_STEP_NUM_MAX ? LEDC_STEP_NUM_MAX : delta / scale;
            if (delta > scale) {
                ledc_duty_config(
                    speed_mode,
                    channel,
                    LEDC_VAL_NO_CHANGE,
                    duty_cur << LEDC_DUTY_DECIMAL_BIT_NUM,
                    s_ledc_fade_rec[speed_mode][channel]->direction,
                    step,
                    cycle,
                    scale);
            } else {
                ledc_duty_config(
                    speed_mode,
                    channel,
                    LEDC_VAL_NO_CHANGE,
                    duty_tar << LEDC_DUTY_DECIMAL_BIT_NUM,
                    s_ledc_fade_rec[speed_mode][channel]->direction,
                    1,
                    1,
                    0);
            }
            LEDC.channel_group[speed_mode].channel[channel].conf1.duty_start = 1;
        }
    }
    LEDC.int_clr.val = intr_status;  //clear LEDC interrupt status.
}

static esp_err_t ledc_fade_channel_deinit(ledc_mode_t speed_mode, ledc_channel_t channel)
{
    if (s_ledc_fade_rec[speed_mode][channel]) {
        if (s_ledc_fade_rec[speed_mode][channel]->ledc_fade_mux) {
            vSemaphoreDelete(s_ledc_fade_rec[speed_mode][channel]->ledc_fade_mux);
            s_ledc_fade_rec[speed_mode][channel]->ledc_fade_mux = NULL;
        }
        if (s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem) {
            vSemaphoreDelete(s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem);
            s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem = NULL;
        }
        free(s_ledc_fade_rec[speed_mode][channel]);
        s_ledc_fade_rec[speed_mode][channel] = NULL;
    }
    return ESP_OK;
}

static esp_err_t ledc_fade_channel_init_check(ledc_mode_t speed_mode, ledc_channel_t channel)
{
    if (s_ledc_fade_rec[speed_mode][channel] == NULL) {
        s_ledc_fade_rec[speed_mode][channel] = (ledc_fade_t *) calloc(1, sizeof(ledc_fade_t));
        s_ledc_fade_rec[speed_mode][channel]->ledc_fade_mux = xSemaphoreCreateMutex();
        s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem = xSemaphoreCreateBinary();
    }
    if (s_ledc_fade_rec[speed_mode][channel]
        && s_ledc_fade_rec[speed_mode][channel]->ledc_fade_mux
        && s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem) {
        return ESP_OK;
    } else {
        ledc_fade_channel_deinit(speed_mode, channel);
        return ESP_FAIL;
    }
}

esp_err_t ledc_set_fade_with_time(ledc_mode_t speed_mode, ledc_channel_t channel, int target_duty, int max_fade_time_ms)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(channel < LEDC_CHANNEL_MAX, LEDC_CHANNEL_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(ledc_fade_channel_init_check(speed_mode, channel) == ESP_OK , LEDC_FADE_INIT_ERROR_STR, ESP_FAIL);

    int timer_sel = LEDC.channel_group[speed_mode].channel[channel].conf0.timer_sel;
    int max_duty = (1 << (LEDC.timer_group[speed_mode].timer[timer_sel].conf.bit_num)) - 1;
    LEDC_CHECK(target_duty <= max_duty, LEDC_FADE_TARGET_ERR_STR, ESP_ERR_INVALID_ARG);
    uint32_t freq = ledc_get_freq(speed_mode, timer_sel);
    int duty_cur = LEDC.channel_group[speed_mode].channel[channel].duty_rd.duty_read >> LEDC_DUTY_DECIMAL_BIT_NUM;
    int duty_delta = target_duty > duty_cur ? target_duty - duty_cur : duty_cur - target_duty;

    if (duty_delta == 0) {
        return ESP_OK;
    }
    int total_cycles = max_fade_time_ms * freq / 1000;
    int scale, cycle_num;
    if (total_cycles > duty_delta) {
        scale = 1;
        cycle_num = total_cycles / duty_delta;
    } else {
        cycle_num = 1;
        scale = (duty_delta + total_cycles - 1) / total_cycles;
    }
    return ledc_set_fade_with_step(speed_mode, channel, target_duty, scale, cycle_num);
}

esp_err_t ledc_set_fade_with_step(ledc_mode_t speed_mode, ledc_channel_t channel, int target_duty, int scale, int cycle_num)
{
    LEDC_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, LEDC_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(channel < LEDC_CHANNEL_MAX, LEDC_CHANNEL_ERR_STR, ESP_ERR_INVALID_ARG);
    LEDC_CHECK(ledc_fade_channel_init_check(speed_mode, channel) == ESP_OK , LEDC_FADE_INIT_ERROR_STR, ESP_FAIL);

    int timer_sel = LEDC.channel_group[speed_mode].channel[channel].conf0.timer_sel;
    int max_duty = (1 << (LEDC.timer_group[speed_mode].timer[timer_sel].conf.bit_num)) - 1;
    LEDC_CHECK(target_duty <= max_duty, LEDC_FADE_TARGET_ERR_STR, ESP_ERR_INVALID_ARG);
    //disable the interrupt, so the operation will not mess up
    ledc_enable_intr_type(speed_mode, channel, LEDC_INTR_DISABLE);

    portENTER_CRITICAL(&ledc_spinlock);
    int duty_cur = LEDC.channel_group[speed_mode].channel[channel].duty_rd.duty_read >> LEDC_DUTY_DECIMAL_BIT_NUM;
    int duty_delta = target_duty > duty_cur ? target_duty - duty_cur : duty_cur - target_duty;
    if (duty_delta == 0) {
        portEXIT_CRITICAL(&ledc_spinlock);
        return ESP_OK;
    }
    s_ledc_fade_rec[speed_mode][channel]->speed_mode = speed_mode;
    s_ledc_fade_rec[speed_mode][channel]->target_duty = target_duty;
    s_ledc_fade_rec[speed_mode][channel]->cycle_num = cycle_num;
    s_ledc_fade_rec[speed_mode][channel]->scale = scale;
    int step_num;
    if (duty_cur > target_duty) {
        s_ledc_fade_rec[speed_mode][channel]->direction = LEDC_DUTY_DIR_DECREASE;
        step_num = (duty_cur - target_duty) / scale;
        step_num = step_num > LEDC_STEP_NUM_MAX ? LEDC_STEP_NUM_MAX : step_num;
    } else {
        s_ledc_fade_rec[speed_mode][channel]->direction = LEDC_DUTY_DIR_INCREASE;
        step_num = (target_duty - duty_cur) / scale;
        step_num = step_num > LEDC_STEP_NUM_MAX ? LEDC_STEP_NUM_MAX : step_num;
    }
    portEXIT_CRITICAL(&ledc_spinlock);

    ledc_set_fade(
        speed_mode,
        channel,
        duty_cur,
        s_ledc_fade_rec[speed_mode][channel]->direction,
        step_num,
        s_ledc_fade_rec[speed_mode][channel]->cycle_num,
        s_ledc_fade_rec[speed_mode][channel]->scale
        );
    ESP_LOGD(LEDC_TAG, "cur duty: %d; target: %d, step: %d, cycle: %d; scale: %d\n",
        LEDC.channel_group[speed_mode].channel[channel].duty_rd.duty_read >> LEDC_DUTY_DECIMAL_BIT_NUM,
        target_duty,
        step_num,
        s_ledc_fade_rec[speed_mode][channel]->cycle_num,
        s_ledc_fade_rec[speed_mode][channel]->scale
        );
    int bit_num_ch0 = (speed_mode == LEDC_HIGH_SPEED_MODE) ? LEDC_DUTY_CHNG_END_HSCH0_INT_ENA_S : LEDC_DUTY_CHNG_END_LSCH0_INT_ENA_S;
    LEDC.int_clr.val |= BIT(bit_num_ch0 + channel);
    ledc_enable_intr_type(speed_mode, channel, LEDC_INTR_FADE_END);
    return ESP_OK;
}

esp_err_t ledc_fade_func_install(int intr_alloc_flags)
{
    //OR intr_alloc_flags with ESP_INTR_FLAG_IRAM because the fade isr is in IRAM
    return ledc_isr_register(ledc_fade_isr, NULL, intr_alloc_flags | ESP_INTR_FLAG_IRAM, &s_ledc_fade_isr_handle);
}

void ledc_fade_func_uninstall()
{
    if (s_ledc_fade_rec == NULL) {
        return;
    }
    if (s_ledc_fade_isr_handle) {
        esp_intr_free(s_ledc_fade_isr_handle);
        s_ledc_fade_isr_handle = NULL;
    }
    int channel, mode;
    for (mode = 0; mode < LEDC_SPEED_MODE_MAX; mode++) {
        for (channel = 0; channel < LEDC_CHANNEL_MAX; channel++) {
            ledc_fade_channel_deinit(mode, channel);
        }
    }
    return;
}

esp_err_t ledc_fade_start(ledc_mode_t speed_mode, ledc_channel_t channel, ledc_fade_mode_t wait_done)
{
    LEDC_CHECK(s_ledc_fade_rec != NULL, LEDC_FADE_SERVICE_ERR_STR, ESP_ERR_INVALID_STATE);
    LEDC_CHECK(wait_done < LEDC_FADE_MAX, LEDC_FADE_MODE_ERR_STR, ESP_ERR_INVALID_ARG);
    xSemaphoreTake(s_ledc_fade_rec[speed_mode][channel]->ledc_fade_mux, portMAX_DELAY);
    if (wait_done == LEDC_FADE_WAIT_DONE) {
        s_ledc_fade_rec[speed_mode][channel]->mode = LEDC_FADE_WAIT_DONE;
        ledc_update_duty(speed_mode, channel);
        xSemaphoreTake(s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem, portMAX_DELAY);
    } else {
        s_ledc_fade_rec[speed_mode][channel]->mode = LEDC_FADE_NO_WAIT;
        ledc_update_duty(speed_mode, channel);
    }
    xSemaphoreGive(s_ledc_fade_rec[speed_mode][channel]->ledc_fade_mux);
    return ESP_OK;
}