esp-idf/components/driver/include/driver/ledc.h

/*
 * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#pragma once

#include "esp_err.h"
#include "esp_intr_alloc.h"
#include "hal/ledc_types.h"
#include "driver/gpio.h"

#ifdef __cplusplus
extern "C" {
#endif

#define LEDC_APB_CLK_HZ         (APB_CLK_FREQ)
#define LEDC_REF_CLK_HZ         (REF_CLK_FREQ)
#define LEDC_ERR_DUTY           (0xFFFFFFFF)
#define LEDC_ERR_VAL            (-1)

/**
 * @brief Configuration parameters of LEDC channel for ledc_channel_config function
 */
typedef struct {
    int gpio_num;                   /*!< the LEDC output gpio_num, if you want to use gpio16, gpio_num = 16 */
    ledc_mode_t speed_mode;         /*!< LEDC speed speed_mode, high-speed mode or low-speed mode */
    ledc_channel_t channel;         /*!< LEDC channel (0 - 7) */
    ledc_intr_type_t intr_type;     /*!< configure interrupt, Fade interrupt enable  or Fade interrupt disable */
    ledc_timer_t timer_sel;         /*!< Select the timer source of channel (0 - 3) */
    uint32_t duty;                  /*!< LEDC channel duty, the range of duty setting is [0, (2**duty_resolution)] */
    int hpoint;                     /*!< LEDC channel hpoint value, the max value is 0xfffff */
    struct {
        unsigned int output_invert: 1;/*!< Enable (1) or disable (0) gpio output invert */
    } flags;                        /*!< LEDC flags */

} ledc_channel_config_t;

/**
 * @brief Configuration parameters of LEDC Timer timer for ledc_timer_config function
 */
typedef struct {
    ledc_mode_t speed_mode;                /*!< LEDC speed speed_mode, high-speed mode or low-speed mode */
    union {
        ledc_timer_bit_t duty_resolution;  /*!< LEDC channel duty resolution */
        ledc_timer_bit_t bit_num __attribute__((deprecated)); /*!< Deprecated in ESP-IDF 3.0. This is an alias to 'duty_resolution' for backward compatibility with ESP-IDF 2.1 */
    };
    ledc_timer_t  timer_num;               /*!< The timer source of channel (0 - 3) */
    uint32_t freq_hz;                      /*!< LEDC timer frequency (Hz) */
    ledc_clk_cfg_t clk_cfg;                /*!< Configure LEDC source clock.
                                                For low speed channels and high speed channels, you can specify the source clock using LEDC_USE_REF_TICK, LEDC_USE_APB_CLK or LEDC_AUTO_CLK.
                                                For low speed channels, you can also specify the source clock using LEDC_USE_RTC8M_CLK, in this case, all low speed channel's source clock must be RTC8M_CLK*/
} ledc_timer_config_t;

typedef intr_handle_t ledc_isr_handle_t;

/**
 * @brief LEDC callback event type
 */
typedef enum {
    LEDC_FADE_END_EVT                   /**< LEDC fade end event */
} ledc_cb_event_t;

/**
 * @brief LEDC callback parameter
 */
typedef struct {
    ledc_cb_event_t event;              /**< Event name */
    uint32_t speed_mode;                /**< Speed mode of the LEDC channel group */
    uint32_t channel;                   /**< LEDC channel (0 - LEDC_CHANNEL_MAX-1) */
    uint32_t duty;                      /**< LEDC current duty of the channel, the range of duty is [0, (2**duty_resolution) - 1] */
} ledc_cb_param_t;

/**
 * @brief Type of LEDC event callback
 * @param param LEDC callback parameter
 * @param user_arg User registered data
 */
typedef bool (* ledc_cb_t)(const ledc_cb_param_t *param, void *user_arg);

/**
 * @brief Group of supported LEDC callbacks
 * @note The callbacks are all running under ISR environment
 */
typedef struct {
    ledc_cb_t fade_cb;                  /**< LEDC fade_end callback function */
} ledc_cbs_t;

/**
 * @brief LEDC channel configuration
 *        Configure LEDC channel with the given channel/output gpio_num/interrupt/source timer/frequency(Hz)/LEDC duty resolution
 *
 * @param ledc_conf Pointer of LEDC channel configure struct
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t ledc_channel_config(const ledc_channel_config_t* ledc_conf);

/**
 * @brief LEDC timer configuration
 *        Configure LEDC timer with the given source timer/frequency(Hz)/duty_resolution
 *
 * @param  timer_conf Pointer of LEDC timer configure struct
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_FAIL Can not find a proper pre-divider number base on the given frequency and the current duty_resolution.
 */
esp_err_t ledc_timer_config(const ledc_timer_config_t* timer_conf);

/**
 * @brief LEDC update channel parameters
 * @note  Call this function to activate the LEDC updated parameters.
 *        After ledc_set_duty, we need to call this function to update the settings.
 *        And the new LEDC parameters don't take effect until the next PWM cycle.
 * @note  ledc_set_duty, ledc_set_duty_with_hpoint and ledc_update_duty are not thread-safe, do not call these functions to
 *        control one LEDC channel in different tasks at the same time.
 *        A thread-safe version of API is ledc_set_duty_and_update
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 *
 */
esp_err_t ledc_update_duty(ledc_mode_t speed_mode, ledc_channel_t channel);

/**
 * @brief Set LEDC output gpio.
 *
 * @note This function only routes the LEDC signal to GPIO through matrix, other LEDC resources initialization are not involved.
 *       Please use `ledc_channel_config()` instead to fully configure a LEDC channel.
 *
 * @param  gpio_num The LEDC output gpio
 * @param  speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param  ledc_channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t ledc_set_pin(int gpio_num, ledc_mode_t speed_mode, ledc_channel_t ledc_channel);

/**
 * @brief LEDC stop.
 *        Disable LEDC output, and set idle level
 *
 * @param  speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param  channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param  idle_level Set output idle level after LEDC stops.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t ledc_stop(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t idle_level);

/**
 * @brief LEDC set channel frequency (Hz)
 *
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param  timer_num LEDC timer index (0-3), select from ledc_timer_t
 * @param  freq_hz Set the LEDC frequency
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_FAIL Can not find a proper pre-divider number base on the given frequency and the current duty_resolution.
 */
esp_err_t ledc_set_freq(ledc_mode_t speed_mode, ledc_timer_t timer_num, uint32_t freq_hz);

/**
 * @brief      LEDC get channel frequency (Hz)
 *
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param timer_num LEDC timer index (0-3), select from ledc_timer_t
 *
 * @return
 *     - 0  error
 *     - Others Current LEDC frequency
 */
uint32_t ledc_get_freq(ledc_mode_t speed_mode, ledc_timer_t timer_num);

/**
 * @brief LEDC set duty and hpoint value
 *        Only after calling ledc_update_duty will the duty update.
 * @note  ledc_set_duty, ledc_set_duty_with_hpoint and ledc_update_duty are not thread-safe, do not call these functions to
 *        control one LEDC channel in different tasks at the same time.
 *        A thread-safe version of API is ledc_set_duty_and_update
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param duty Set the LEDC duty, the range of duty setting is [0, (2**duty_resolution) - 1]
 * @param hpoint Set the LEDC hpoint value(max: 0xfffff)
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t ledc_set_duty_with_hpoint(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t duty, uint32_t hpoint);

/**
 * @brief LEDC get hpoint value, the counter value when the output is set high level.
 *
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @return
 *     - LEDC_ERR_VAL if parameter error
 *     - Others Current hpoint value of LEDC channel
 */
int ledc_get_hpoint(ledc_mode_t speed_mode, ledc_channel_t channel);

/**
 * @brief LEDC set duty
 *        This function do not change the hpoint value of this channel. if needed, please call ledc_set_duty_with_hpoint.
 *        only after calling ledc_update_duty will the duty update.
 * @note  ledc_set_duty, ledc_set_duty_with_hpoint and ledc_update_duty are not thread-safe, do not call these functions to
 *        control one LEDC channel in different tasks at the same time.
 *        A thread-safe version of API is ledc_set_duty_and_update.
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param duty Set the LEDC duty, the range of duty setting is [0, (2**duty_resolution) - 1]
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
esp_err_t ledc_set_duty(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t duty);

/**
 * @brief LEDC get duty
 *        This function returns the duty at the present PWM cycle.
 *        You shouldn't expect the function to return the new duty in the same cycle of calling ledc_update_duty,
 *        because duty update doesn't take effect until the next cycle.
 *
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 *
 * @return
 *     - LEDC_ERR_DUTY if parameter error
 *     - Others Current LEDC duty
 */
uint32_t ledc_get_duty(ledc_mode_t speed_mode, ledc_channel_t channel);

/**
 * @brief LEDC set gradient
 *        Set LEDC gradient, After the function calls the ledc_update_duty function, the function can take effect.
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param duty Set the start of the gradient duty, the range of duty setting is [0, (2**duty_resolution) - 1]
 * @param fade_direction Set the direction of the gradient
 * @param step_num Set the number of the gradient
 * @param duty_cycle_num Set how many LEDC tick each time the gradient lasts
 * @param duty_scale Set gradient change amplitude
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Parameter error
 */
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_cycle_num, uint32_t duty_scale);

/**
 * @brief Register LEDC interrupt handler, the handler is an ISR.
 *        The handler will be attached to the same CPU core that this function is running on.
 *
 * @param fn Interrupt handler function.
 * @param arg User-supplied argument passed to the handler function.
 * @param intr_alloc_flags Flags used to allocate the interrupt. One or multiple (ORred)
 *        ESP_INTR_FLAG_* values. See esp_intr_alloc.h for more info.
 * @param handle Pointer to return handle. If non-NULL, a handle for the interrupt will
 *        be returned here.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Function pointer error.
 */
esp_err_t ledc_isr_register(void (*fn)(void*), void * arg, int intr_alloc_flags, ledc_isr_handle_t *handle);

/**
 * @brief Configure LEDC settings
 *
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param timer_sel  Timer index (0-3), there are 4 timers in LEDC module
 * @param clock_divider Timer clock divide value, the timer clock is divided from the selected clock source
 * @param duty_resolution Resolution of duty setting in number of bits. The range of duty values is [0, (2**duty_resolution)]
 * @param clk_src Select LEDC source clock.
 *
 * @return
 *     - (-1) Parameter error
 *     - Other Current LEDC duty
 */
esp_err_t ledc_timer_set(ledc_mode_t speed_mode, ledc_timer_t timer_sel, uint32_t clock_divider, uint32_t duty_resolution, ledc_clk_src_t clk_src);

/**
 * @brief Reset LEDC timer
 *
 * @param  speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param  timer_sel LEDC timer index (0-3), select from ledc_timer_t
 *
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 */
esp_err_t ledc_timer_rst(ledc_mode_t speed_mode, ledc_timer_t timer_sel);

/**
 * @brief Pause LEDC timer counter
 *
 * @param  speed_mode  Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param  timer_sel LEDC timer index (0-3), select from ledc_timer_t
 *
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 *
 */
esp_err_t ledc_timer_pause(ledc_mode_t speed_mode, ledc_timer_t timer_sel);

/**
 * @brief Resume LEDC timer
 *
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param timer_sel LEDC timer index (0-3), select from ledc_timer_t
 *
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 */
esp_err_t ledc_timer_resume(ledc_mode_t speed_mode, ledc_timer_t timer_sel);

/**
 * @brief Bind LEDC channel with the selected timer
 *
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel index (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param timer_sel LEDC timer index (0-3), select from ledc_timer_t
 *
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 */
esp_err_t ledc_bind_channel_timer(ledc_mode_t speed_mode, ledc_channel_t channel, ledc_timer_t timer_sel);

/**
 * @brief Set LEDC fade function.
 * @note  Call ledc_fade_func_install() once before calling this function.
 *        Call ledc_fade_start() after this to start fading.
 * @note  ledc_set_fade_with_step, ledc_set_fade_with_time and ledc_fade_start are not thread-safe, do not call these functions to
 *        control one LEDC channel in different tasks at the same time.
 *        A thread-safe version of API is ledc_set_fade_step_and_start
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode. ,
 * @param channel LEDC channel index (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param target_duty Target duty of fading [0, (2**duty_resolution) - 1]
 * @param scale Controls the increase or decrease step scale.
 * @param cycle_num increase or decrease the duty every cycle_num cycles
 *
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_STATE Fade function not installed.
 *     - ESP_FAIL Fade function init error
 */
esp_err_t ledc_set_fade_with_step(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t target_duty, uint32_t scale, uint32_t cycle_num);

/**
 * @brief Set LEDC fade function, with a limited time.
 * @note  Call ledc_fade_func_install() once before calling this function.
 *        Call ledc_fade_start() after this to start fading.
 * @note  ledc_set_fade_with_step, ledc_set_fade_with_time and ledc_fade_start are not thread-safe, do not call these functions to
 *        control one LEDC channel in different tasks at the same time.
 *        A thread-safe version of API is ledc_set_fade_step_and_start
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode. ,
 * @param channel LEDC channel index (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param target_duty Target duty of fading [0, (2**duty_resolution) - 1]
 * @param max_fade_time_ms The maximum time of the fading ( ms ).
 *
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_STATE Fade function not installed.
 *     - ESP_FAIL Fade function init error
 */
esp_err_t ledc_set_fade_with_time(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t target_duty, int max_fade_time_ms);

/**
 * @brief Install LEDC fade function. This function will occupy interrupt of LEDC module.
 * @param intr_alloc_flags Flags used to allocate the interrupt. One or multiple (ORred)
 *        ESP_INTR_FLAG_* values. See esp_intr_alloc.h for more info.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_STATE Fade function already installed.
 */
esp_err_t ledc_fade_func_install(int intr_alloc_flags);

/**
 * @brief Uninstall LEDC fade function.
 *
 */
void ledc_fade_func_uninstall(void);

/**
 * @brief Start LEDC fading.
 * @note  Call ledc_fade_func_install() once before calling this function.
 *        Call this API right after ledc_set_fade_with_time or ledc_set_fade_with_step before to start fading.
 * @note  Starting fade operation with this API is not thread-safe, use with care.
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel number
 * @param fade_mode Whether to block until fading done. See ledc_types.h ledc_fade_mode_t for more info.
 *        Note that this function will not return until fading to the target duty if LEDC_FADE_WAIT_DONE mode is selected.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_STATE Fade function not installed.
 *     - ESP_ERR_INVALID_ARG Parameter error.
 */
esp_err_t ledc_fade_start(ledc_mode_t speed_mode, ledc_channel_t channel, ledc_fade_mode_t fade_mode);

#if SOC_LEDC_SUPPORT_FADE_STOP
/**
 * @brief Stop LEDC fading. Duty of the channel will stay at its present vlaue.
 * @note  This API can be called if a new fixed duty or a new fade want to be set while the last fade operation is still running in progress.
 * @note  Call this API will abort the fading operation only if it was started by calling ledc_fade_start with LEDC_FADE_NO_WAIT mode.
 * @note  If a fade was started with LEDC_FADE_WAIT_DONE mode, calling this API afterwards is no use in stopping the fade. Fade will continue until it reachs the target duty.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel number
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_STATE Fade function not installed.
 *     - ESP_ERR_INVALID_ARG Parameter error.
 */
esp_err_t ledc_fade_stop(ledc_mode_t speed_mode, ledc_channel_t channel);
#endif

/**
 * @brief A thread-safe API to set duty for LEDC channel and return when duty updated.
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 *
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param duty Set the LEDC duty, the range of duty setting is [0, (2**duty_resolution) - 1]
 * @param hpoint Set the LEDC hpoint value(max: 0xfffff)
 *
 */
esp_err_t ledc_set_duty_and_update(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t duty, uint32_t hpoint);

/**
 * @brief A thread-safe API to set and start LEDC fade function, with a limited time.
 * @note  Call ledc_fade_func_install() once, before calling this function.
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel index (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param target_duty Target duty of fading [0, (2**duty_resolution) - 1]
 * @param max_fade_time_ms The maximum time of the fading ( ms ).
 * @param fade_mode choose blocking or non-blocking mode
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_STATE Fade function not installed.
 *     - ESP_FAIL Fade function init error
 */
esp_err_t ledc_set_fade_time_and_start(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t target_duty, uint32_t max_fade_time_ms, ledc_fade_mode_t fade_mode);

/**
 * @brief A thread-safe API to set and start LEDC fade function.
 * @note  Call ledc_fade_func_install() once before calling this function.
 * @note  For ESP32, hardware does not support any duty change while a fade operation is running in progress on that channel.
 *        Other duty operations will have to wait until the fade operation has finished.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel index (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param target_duty Target duty of fading [0, (2**duty_resolution) - 1]
 * @param scale Controls the increase or decrease step scale.
 * @param cycle_num increase or decrease the duty every cycle_num cycles
 * @param fade_mode choose blocking or non-blocking mode
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_STATE Fade function not installed.
 *     - ESP_FAIL Fade function init error
 */
esp_err_t ledc_set_fade_step_and_start(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t target_duty, uint32_t scale, uint32_t cycle_num, ledc_fade_mode_t fade_mode);

/**
 * @brief LEDC callback registration function
 * @note  The callback is called from an ISR, it must never attempt to block, and any FreeRTOS API called must be ISR capable.
 * @param speed_mode Select the LEDC channel group with specified speed mode. Note that not all targets support high speed mode.
 * @param channel LEDC channel index (0 - LEDC_CHANNEL_MAX-1), select from ledc_channel_t
 * @param cbs Group of LEDC callback functions
 * @param user_arg user registered data for the callback function
 * @return
 *     - ESP_ERR_INVALID_ARG Parameter error
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_STATE Fade function not installed.
 *     - ESP_FAIL Fade function init error
 */
esp_err_t ledc_cb_register(ledc_mode_t speed_mode, ledc_channel_t channel, ledc_cbs_t *cbs, void *user_arg);
#ifdef __cplusplus
}
#endif