esp-idf/components/driver/i2c/i2c.c

/*
 * SPDX-FileCopyrightText: 2015-2024 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#include <string.h>
#include <stdio.h>
#include "sdkconfig.h"
#include "esp_types.h"
#include "esp_attr.h"
#include "esp_intr_alloc.h"
#include "esp_log.h"
#include "esp_check.h"
#include "malloc.h"
#include "freertos/FreeRTOS.h"
#include "freertos/semphr.h"
#include "freertos/task.h"
#include "freertos/ringbuf.h"
#include "freertos/idf_additions.h"
#include "esp_pm.h"
#include "soc/soc_memory_layout.h"
#include "hal/i2c_hal.h"
#include "hal/gpio_hal.h"
#include "soc/i2c_periph.h"
#include "driver/i2c.h"
#include "esp_private/periph_ctrl.h"
#include "esp_rom_gpio.h"
#include "esp_rom_sys.h"
#include <sys/param.h>
#include "soc/clk_tree_defs.h"

#if SOC_I2C_SUPPORT_APB || SOC_I2C_SUPPORT_XTAL
#include "esp_private/esp_clk.h"
#endif
#if SOC_I2C_SUPPORT_RTC
#include "clk_ctrl_os.h"
#endif

static const char *I2C_TAG = "i2c";

/* DRAM_ATTR is required to avoid I2C array placed in flash, due to accessed from ISR */

#define I2C_ENTER_CRITICAL_ISR(mux)    portENTER_CRITICAL_ISR(mux)
#define I2C_EXIT_CRITICAL_ISR(mux)     portEXIT_CRITICAL_ISR(mux)
#define I2C_ENTER_CRITICAL(mux)        portENTER_CRITICAL(mux)
#define I2C_EXIT_CRITICAL(mux)         portEXIT_CRITICAL(mux)

#define I2C_DRIVER_ERR_STR             "i2c driver install error"
#define I2C_DRIVER_MALLOC_ERR_STR      "i2c driver malloc error"
#define I2C_INTR_ALLOC_ERR_STR         "i2c interrupt allocation error"
#define I2C_NUM_ERROR_STR              "i2c number error"
#define I2C_TIMING_VAL_ERR_STR         "i2c timing value error"
#define I2C_ADDR_ERROR_STR             "i2c null address error"
#define I2C_DRIVER_NOT_INSTALL_ERR_STR "i2c driver not installed"
#if SOC_I2C_SUPPORT_SLAVE
    #define I2C_SLAVE_BUFFER_LEN_ERR_STR   "i2c buffer size too small for slave mode"
    #define I2C_MODE_SLAVE_ERR_STR         "Only allowed in slave mode"
#endif
#define I2C_EVT_QUEUE_ERR_STR          "i2c evt queue error"
#define I2C_SEM_ERR_STR                "i2c semaphore error"
#define I2C_BUF_ERR_STR                "i2c ringbuffer error"
#define I2C_MASTER_MODE_ERR_STR        "Only allowed in master mode"
#define I2C_CMD_MALLOC_ERR_STR         "i2c command link malloc error"
#define I2C_CMD_USER_ALLOC_ERR_STR     "i2c command link allocation error: the buffer provided is too small."
#define I2C_TRANS_MODE_ERR_STR         "i2c trans mode error"
#define I2C_MODE_ERR_STR               "i2c mode error"
#define I2C_SDA_IO_ERR_STR             "sda gpio number error"
#define I2C_SCL_IO_ERR_STR             "scl gpio number error"
#define I2C_SCL_SDA_EQUAL_ERR_STR      "scl and sda gpio numbers are the same"
#define I2C_CMD_LINK_INIT_ERR_STR      "i2c command link error"
#define I2C_GPIO_PULLUP_ERR_STR        "this i2c pin does not support internal pull-up"
#define I2C_ACK_TYPE_ERR_STR           "i2c ack type error"
#define I2C_DATA_LEN_ERR_STR           "i2c data read length error"
#define I2C_PSRAM_BUFFER_WARN_STR      "Using buffer allocated from psram"
#define I2C_LOCK_ERR_STR               "Power lock creation error"
#define I2C_CLK_FLAG_ERR_STR           "i2c clock choice is invalid, please check flag and frequency"
#define I2C_FIFO_FULL_THRESH_VAL       (28)
#define I2C_FIFO_EMPTY_THRESH_VAL      (5)
#define I2C_IO_INIT_LEVEL              (1)
#define I2C_CMD_ALIVE_INTERVAL_TICK    (1000 / portTICK_PERIOD_MS)
#define I2C_CMD_EVT_ALIVE              (0)
#define I2C_CMD_EVT_DONE               (1)
#define I2C_EVT_QUEUE_LEN              (1)
#if SOC_I2C_SUPPORT_SLAVE
    #define I2C_SLAVE_TIMEOUT_DEFAULT      (32000)     /* I2C slave timeout value, APB clock cycle number */
    #define I2C_SLAVE_SDA_SAMPLE_DEFAULT   (10)        /* I2C slave sample time after scl positive edge default value */
    #define I2C_SLAVE_SDA_HOLD_DEFAULT     (10)        /* I2C slave hold time after scl negative edge default value */
#endif
#define I2C_MASTER_TOUT_CNUM_DEFAULT   (8)         /* I2C master timeout cycle number of I2C clock, after which the timeout interrupt will be triggered */
#define I2C_ACKERR_CNT_MAX             (10)
#define I2C_FILTER_CYC_NUM_DEF         (7)         /* The number of apb cycles filtered by default*/
#define I2C_CLR_BUS_SCL_NUM            (9)
#define I2C_CLR_BUS_HALF_PERIOD_US     (5)
#define I2C_TRANS_BUF_MINIMUM_SIZE     (sizeof(i2c_cmd_desc_t) + \
                                        sizeof(i2c_cmd_link_t) * 8) /* It is required to have allocate one i2c_cmd_desc_t per command:
                                                                     * start + write (device address) + write buffer +
                                                                     * start + write (device address) + read buffer + read buffer for NACK +
                                                                     * stop */

#define I2C_CONTEX_INIT_DEF(uart_num) {\
    .hal.dev = I2C_LL_GET_HW(uart_num),\
    .spinlock = portMUX_INITIALIZER_UNLOCKED,\
    .hw_enabled = false,\
}

#define I2C_CLOCK_INVALID                 (-1)

#if CONFIG_SPIRAM_USE_MALLOC
#define I2C_MEM_ALLOC_CAPS_INTERNAL     (MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT)
#endif
#define I2C_MEM_ALLOC_CAPS_DEFAULT      MALLOC_CAP_DEFAULT

#if SOC_PERIPH_CLK_CTRL_SHARED
#define I2C_CLOCK_SRC_ATOMIC() PERIPH_RCC_ATOMIC()
#else
#define I2C_CLOCK_SRC_ATOMIC()
#endif

#if !SOC_RCC_IS_INDEPENDENT
#define I2C_RCC_ATOMIC() PERIPH_RCC_ATOMIC()
#else
#define I2C_RCC_ATOMIC()
#endif

/**
 * I2C bus are defined in the header files, let's check that the values are correct
 */
#if SOC_I2C_NUM >= 2
_Static_assert(I2C_NUM_1 == 1, "I2C_NUM_1 must be equal to 1");
#endif // SOC_I2C_NUM >= 2
#if SOC_LP_I2C_SUPPORTED
_Static_assert(I2C_NUM_MAX == (SOC_I2C_NUM + SOC_LP_I2C_NUM), "I2C_NUM_MAX must be equal to SOC_I2C_NUM + SOC_LP_I2C_NUM");
#else
_Static_assert(I2C_NUM_MAX == SOC_I2C_NUM, "I2C_NUM_MAX must be equal to SOC_I2C_NUM");
#endif /* SOC_LP_I2C_SUPPORTED */

typedef struct {
    i2c_ll_hw_cmd_t hw_cmd;
    union {
        uint8_t* data;      // When total_bytes > 1
        uint8_t data_byte;  //when total_byte == 1
    };
    size_t bytes_used;
    size_t total_bytes;
} i2c_cmd_t;

typedef struct i2c_cmd_link {
    i2c_cmd_t cmd;              /*!< command in current cmd link */
    struct i2c_cmd_link *next;  /*!< next cmd link */
} i2c_cmd_link_t;

typedef struct {
    i2c_cmd_link_t *head;     /*!< head of the command link */
    i2c_cmd_link_t *cur;      /*!< last node of the command link */
    i2c_cmd_link_t *free;     /*!< the first node to free of the command link */

    void     *free_buffer;    /*!< pointer to the next free data in user's buffer */
    uint32_t  free_size;      /*!< remaining size of the user's buffer */
} i2c_cmd_desc_t;

/* INTERNAL_STRUCT_SIZE must be at least sizeof(i2c_cmd_link_t) */
_Static_assert(I2C_INTERNAL_STRUCT_SIZE >= sizeof(i2c_cmd_link_t),
                "I2C_INTERNAL_STRUCT_SIZE must be at least sizeof(i2c_cmd_link_t), please adjust this value.");

typedef enum {
    I2C_STATUS_READ,      /*!< read status for current master command */
    I2C_STATUS_WRITE,     /*!< write status for current master command */
    I2C_STATUS_IDLE,      /*!< idle status for current master command */
    I2C_STATUS_ACK_ERROR, /*!< ack error status for current master command */
    I2C_STATUS_DONE,      /*!< I2C command done */
    I2C_STATUS_TIMEOUT,   /*!< I2C bus status error, and operation timeout */
} i2c_status_t;

typedef struct {
    int type;
} i2c_cmd_evt_t;

typedef struct {
    int i2c_num;                     /*!< I2C port number */
    int mode;                        /*!< I2C mode, master or slave */
    intr_handle_t intr_handle;       /*!< I2C interrupt handle*/
    int cmd_idx;                     /*!< record current command index, for master mode */
    int status;                      /*!< record current command status, for master mode */
    int rx_cnt;                      /*!< record current read index, for master mode */
    uint8_t data_buf[SOC_I2C_FIFO_LEN ];  /*!< a buffer to store i2c fifo data */

    i2c_cmd_desc_t cmd_link;         /*!< I2C command link */
    QueueHandle_t cmd_evt_queue;     /*!< I2C command event queue */
#if CONFIG_SPIRAM_USE_MALLOC
    int intr_alloc_flags;            /*!< Used to allocate the interrupt */
#endif
    SemaphoreHandle_t cmd_mux;        /*!< semaphore to lock command process */
#ifdef CONFIG_PM_ENABLE
    esp_pm_lock_handle_t pm_lock;
#endif
#if SOC_I2C_SUPPORT_SLAVE
    SemaphoreHandle_t slv_rx_mux;     /*!< slave rx buffer mux */
    SemaphoreHandle_t slv_tx_mux;     /*!< slave tx buffer mux */
#endif // SOC_I2C_SUPPORT_SLAVE
    size_t rx_buf_length;            /*!< rx buffer length */
    RingbufHandle_t rx_ring_buf;     /*!< rx ringbuffer handler of slave mode */
    size_t tx_buf_length;            /*!< tx buffer length */
    RingbufHandle_t tx_ring_buf;     /*!< tx ringbuffer handler of slave mode */
} i2c_obj_t;

typedef struct {
    i2c_hal_context_t hal;      /*!< I2C hal context */
    portMUX_TYPE spinlock;
    bool hw_enabled;
#if !SOC_I2C_SUPPORT_HW_CLR_BUS
    int scl_io_num;
    int sda_io_num;
#endif
} i2c_context_t;

typedef struct
{
    uint8_t character;          /*!< I2C source clock characteristic */
} i2c_clk_alloc_t;

static i2c_context_t i2c_context[I2C_NUM_MAX] = {
    I2C_CONTEX_INIT_DEF(I2C_NUM_0),
/* Now that I2C_NUM_MAX is part of an enum (i2c_port_t), we cannot use
 * it anomore in the preprocessor! */
#if SOC_I2C_NUM > 1
    I2C_CONTEX_INIT_DEF(I2C_NUM_1),
#endif
};

// i2c clock characteristic, the entry order and numbers MUST be the same as SOC_I2C_CLKS
static i2c_clk_alloc_t i2c_clk_alloc[] = {
#if SOC_I2C_SUPPORT_APB
    {0},                                                                /*!< I2C APB clock characteristic*/
#endif
#if SOC_I2C_SUPPORT_XTAL
    {0},                                                               /*!< I2C XTAL characteristic*/
#endif
#if SOC_I2C_SUPPORT_RTC
    {I2C_SCLK_SRC_FLAG_LIGHT_SLEEP | I2C_SCLK_SRC_FLAG_AWARE_DFS},      /*!< I2C 20M RTC characteristic*/
#endif
#if SOC_I2C_SUPPORT_REF_TICK
    {I2C_SCLK_SRC_FLAG_AWARE_DFS},                                 /*!< I2C REF_TICK characteristic*/
#endif
};

static i2c_obj_t *p_i2c_obj[I2C_NUM_MAX] = {0};
static void i2c_isr_handler_default(void *arg);
static void i2c_master_cmd_begin_static(i2c_port_t i2c_num, BaseType_t* HPTaskAwoken);
static esp_err_t i2c_hw_fsm_reset(i2c_port_t i2c_num);

static void i2c_hw_disable(i2c_port_t i2c_num)
{
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    if (i2c_context[i2c_num].hw_enabled != false) {
        I2C_RCC_ATOMIC() {
            i2c_ll_enable_bus_clock(i2c_num, false);
        }
        i2c_context[i2c_num].hw_enabled = false;
    }
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
}

static void i2c_hw_enable(i2c_port_t i2c_num)
{
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    if (i2c_context[i2c_num].hw_enabled != true) {
        I2C_RCC_ATOMIC() {
            i2c_ll_enable_bus_clock(i2c_num, true);
            i2c_ll_reset_register(i2c_num);
        }
        i2c_context[i2c_num].hw_enabled = true;
    }
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
}

/*
    For i2c master mode, we don't need to use a buffer for the data, the APIs will execute the master commands
and return after all of the commands have been sent out or when error occurs. So when we send master commands,
we should free or modify the source data only after the i2c_master_cmd_begin function returns.
    For i2c slave mode, we need a data buffer to stash the sending and receiving data, because the hardware fifo
has only 32 bytes.
*/
esp_err_t i2c_driver_install(i2c_port_t i2c_num, i2c_mode_t mode, size_t slv_rx_buf_len, size_t slv_tx_buf_len,
                             int intr_alloc_flags)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
#if SOC_LP_I2C_SUPPORTED
    // TODO: IDF-5817
    ESP_RETURN_ON_FALSE(i2c_num != LP_I2C_NUM_0, ESP_ERR_INVALID_ARG, I2C_TAG, "LP_I2C is not supported via i2c_driver_intall()");
#endif // SOC_LP_I2C_SUPPORTED
#if SOC_I2C_SUPPORT_SLAVE
    ESP_RETURN_ON_FALSE(mode == I2C_MODE_MASTER || ( slv_rx_buf_len > 100 || slv_tx_buf_len > 100 ),
              ESP_ERR_INVALID_ARG, I2C_TAG, I2C_SLAVE_BUFFER_LEN_ERR_STR);
#endif // SOC_I2C_SUPPORT_SLAVE
    esp_err_t ret = ESP_OK;

    if (p_i2c_obj[i2c_num] == NULL) {
        uint32_t alloc_caps;
#if CONFIG_SPIRAM_USE_MALLOC
        alloc_caps = (intr_alloc_flags & ESP_INTR_FLAG_IRAM) ? I2C_MEM_ALLOC_CAPS_INTERNAL : I2C_MEM_ALLOC_CAPS_DEFAULT;
#else
        alloc_caps = I2C_MEM_ALLOC_CAPS_DEFAULT;
#endif
        p_i2c_obj[i2c_num] = (i2c_obj_t *) heap_caps_calloc(1, sizeof(i2c_obj_t), alloc_caps);
        if (p_i2c_obj[i2c_num] == NULL) {
            ESP_LOGE(I2C_TAG, I2C_DRIVER_MALLOC_ERR_STR);
            return ESP_FAIL;
        }
        i2c_obj_t *p_i2c = p_i2c_obj[i2c_num];
        p_i2c->i2c_num = i2c_num;
        p_i2c->mode = mode;
        p_i2c->cmd_idx = 0;
        p_i2c->rx_cnt = 0;
        p_i2c->status = I2C_STATUS_IDLE;

#if CONFIG_SPIRAM_USE_MALLOC
        p_i2c->intr_alloc_flags = intr_alloc_flags;
#endif
#if SOC_I2C_SUPPORT_SLAVE
        if (mode == I2C_MODE_SLAVE) {

#if CONFIG_RINGBUF_PLACE_ISR_FUNCTIONS_INTO_FLASH
            if (intr_alloc_flags & ESP_INTR_FLAG_IRAM ) {
                ESP_LOGE(I2C_TAG, "ringbuf ISR functions in flash, but used in IRAM interrupt");
                goto err;
            }
#endif

            //we only use ringbuffer for slave mode.
            if (slv_rx_buf_len > 0) {
                p_i2c->rx_ring_buf = xRingbufferCreate(slv_rx_buf_len, RINGBUF_TYPE_BYTEBUF);
                if (p_i2c->rx_ring_buf == NULL) {
                    ESP_LOGE(I2C_TAG, I2C_BUF_ERR_STR);
                    goto err;
                }
                p_i2c->rx_buf_length = slv_rx_buf_len;
            } else {
                p_i2c->rx_ring_buf = NULL;
                p_i2c->rx_buf_length = 0;
            }
            if (slv_tx_buf_len > 0) {
                p_i2c->tx_ring_buf = xRingbufferCreate(slv_tx_buf_len, RINGBUF_TYPE_BYTEBUF);
                if (p_i2c->tx_ring_buf == NULL) {
                    ESP_LOGE(I2C_TAG, I2C_BUF_ERR_STR);
                    goto err;
                }
                p_i2c->tx_buf_length = slv_tx_buf_len;
            } else {
                p_i2c->tx_ring_buf = NULL;
                p_i2c->tx_buf_length = 0;
            }
            p_i2c->slv_rx_mux = xSemaphoreCreateMutex();
            p_i2c->slv_tx_mux = xSemaphoreCreateMutex();
            if (p_i2c->slv_rx_mux == NULL || p_i2c->slv_tx_mux == NULL) {
                ESP_LOGE(I2C_TAG, I2C_SEM_ERR_STR);
                goto err;
            }
        } else
#endif // SOC_I2C_SUPPORT_SLAVE
        {
            //semaphore to sync sending process, because we only have 32 bytes for hardware fifo.
            p_i2c->cmd_mux = xSemaphoreCreateMutex();
#ifdef CONFIG_PM_ENABLE
            if (esp_pm_lock_create(ESP_PM_APB_FREQ_MAX, 0, "i2c_driver", &p_i2c->pm_lock) != ESP_OK) {
                ESP_LOGE(I2C_TAG, I2C_LOCK_ERR_STR);
                goto err;
            }
#endif
            uint32_t alloc_caps;
#if CONFIG_SPIRAM_USE_MALLOC
            alloc_caps = (intr_alloc_flags & ESP_INTR_FLAG_IRAM) ? I2C_MEM_ALLOC_CAPS_INTERNAL : I2C_MEM_ALLOC_CAPS_DEFAULT;
#else
            alloc_caps = I2C_MEM_ALLOC_CAPS_DEFAULT;
#endif
            p_i2c->cmd_evt_queue = xQueueCreateWithCaps(I2C_EVT_QUEUE_LEN, sizeof(i2c_cmd_evt_t), alloc_caps);
            if (p_i2c->cmd_mux == NULL || p_i2c->cmd_evt_queue == NULL) {
                ESP_LOGE(I2C_TAG, I2C_SEM_ERR_STR);
                goto err;
            }
            //command link
            p_i2c->cmd_link.cur = NULL;
            p_i2c->cmd_link.head = NULL;
            p_i2c->cmd_link.free = NULL;

            p_i2c->tx_ring_buf = NULL;
            p_i2c->rx_buf_length = 0;
            p_i2c->tx_ring_buf = NULL;
            p_i2c->tx_buf_length = 0;
        }
    } else {
        ESP_LOGE(I2C_TAG, I2C_DRIVER_ERR_STR);
        return ESP_FAIL;
    }
    i2c_hw_enable(i2c_num);
    I2C_CLOCK_SRC_ATOMIC() {
        i2c_hal_init(&i2c_context[i2c_num].hal, i2c_num);
    }
    //Disable I2C interrupt.
    i2c_ll_disable_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
    i2c_ll_clear_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
    //hook isr handler
    ret = esp_intr_alloc(i2c_periph_signal[i2c_num].irq, intr_alloc_flags,
                           i2c_isr_handler_default, p_i2c_obj[i2c_num],
                           &p_i2c_obj[i2c_num]->intr_handle);
    ESP_GOTO_ON_ERROR(ret, err, I2C_TAG, I2C_INTR_ALLOC_ERR_STR);
#if SOC_I2C_SUPPORT_SLAVE
    //Enable I2C slave rx interrupt
    if (mode == I2C_MODE_SLAVE) {
        i2c_ll_slave_enable_rx_it(i2c_context[i2c_num].hal.dev);
    }
#endif // SOC_I2C_SUPPORT_SLAVE
    return ESP_OK;

err:
    //Some error has happened. Free/destroy all allocated things and return ESP_FAIL.
    if (p_i2c_obj[i2c_num]) {
        if (p_i2c_obj[i2c_num]->rx_ring_buf) {
            vRingbufferDelete(p_i2c_obj[i2c_num]->rx_ring_buf);
            p_i2c_obj[i2c_num]->rx_ring_buf = NULL;
            p_i2c_obj[i2c_num]->rx_buf_length = 0;
        }
        if (p_i2c_obj[i2c_num]->tx_ring_buf) {
            vRingbufferDelete(p_i2c_obj[i2c_num]->tx_ring_buf);
            p_i2c_obj[i2c_num]->tx_ring_buf = NULL;
            p_i2c_obj[i2c_num]->tx_buf_length = 0;
        }
        if (p_i2c_obj[i2c_num]->cmd_evt_queue) {
            vQueueDeleteWithCaps(p_i2c_obj[i2c_num]->cmd_evt_queue);
            p_i2c_obj[i2c_num]->cmd_evt_queue = NULL;
        }
        if (p_i2c_obj[i2c_num]->cmd_mux) {
            vSemaphoreDelete(p_i2c_obj[i2c_num]->cmd_mux);
        }
#if SOC_I2C_SUPPORT_SLAVE
        if (p_i2c_obj[i2c_num]->slv_rx_mux) {
            vSemaphoreDelete(p_i2c_obj[i2c_num]->slv_rx_mux);
        }
        if (p_i2c_obj[i2c_num]->slv_tx_mux) {
            vSemaphoreDelete(p_i2c_obj[i2c_num]->slv_tx_mux);
        }
#endif
#ifdef CONFIG_PM_ENABLE
        if (p_i2c_obj[i2c_num]->pm_lock) {
            esp_pm_lock_delete(p_i2c_obj[i2c_num]->pm_lock);
            p_i2c_obj[i2c_num]->pm_lock = NULL;
        }
#endif
    }
    free(p_i2c_obj[i2c_num]);
    p_i2c_obj[i2c_num] = NULL;
    return ESP_FAIL;
}

esp_err_t i2c_driver_delete(i2c_port_t i2c_num)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE(p_i2c_obj[i2c_num] != NULL, ESP_FAIL, I2C_TAG, I2C_DRIVER_ERR_STR);

    i2c_obj_t *p_i2c = p_i2c_obj[i2c_num];
    i2c_ll_disable_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
    esp_intr_free(p_i2c->intr_handle);
    p_i2c->intr_handle = NULL;

    if (p_i2c->cmd_mux) {
        // Let any command in progress finish.
        xSemaphoreTake(p_i2c->cmd_mux, portMAX_DELAY);
        xSemaphoreGive(p_i2c->cmd_mux);
        vSemaphoreDelete(p_i2c->cmd_mux);
    }
    if (p_i2c_obj[i2c_num]->cmd_evt_queue) {
        vQueueDeleteWithCaps(p_i2c_obj[i2c_num]->cmd_evt_queue);
        p_i2c_obj[i2c_num]->cmd_evt_queue = NULL;
    }
#if SOC_I2C_SUPPORT_SLAVE
    if (p_i2c->slv_rx_mux) {
        vSemaphoreDelete(p_i2c->slv_rx_mux);
    }
    if (p_i2c->slv_tx_mux) {
        vSemaphoreDelete(p_i2c->slv_tx_mux);
    }
#endif

    if (p_i2c->rx_ring_buf) {
        vRingbufferDelete(p_i2c->rx_ring_buf);
        p_i2c->rx_ring_buf = NULL;
        p_i2c->rx_buf_length = 0;
    }
    if (p_i2c->tx_ring_buf) {
        vRingbufferDelete(p_i2c->tx_ring_buf);
        p_i2c->tx_ring_buf = NULL;
        p_i2c->tx_buf_length = 0;
    }
#ifdef CONFIG_PM_ENABLE
    if (p_i2c->pm_lock) {
        esp_pm_lock_delete(p_i2c->pm_lock);
        p_i2c->pm_lock = NULL;
    }
#endif

    I2C_CLOCK_SRC_ATOMIC() {
        i2c_hal_deinit(&i2c_context[i2c_num].hal);
    }
    free(p_i2c_obj[i2c_num]);
    p_i2c_obj[i2c_num] = NULL;

    i2c_hw_disable(i2c_num);
    return ESP_OK;
}

esp_err_t i2c_reset_tx_fifo(i2c_port_t i2c_num)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_txfifo_rst(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_reset_rx_fifo(i2c_port_t i2c_num)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_rxfifo_rst(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

static void IRAM_ATTR i2c_isr_handler_default(void *arg)
{
    i2c_obj_t *p_i2c = (i2c_obj_t *) arg;
    int i2c_num = p_i2c->i2c_num;
    // Interrupt protection.
    // On C3 and S3 targets, the I2C may trigger a spurious interrupt,
    // in order to detect these false positive, check the I2C's hardware interrupt mask
    uint32_t int_mask;
    i2c_ll_get_intr_mask(i2c_context[i2c_num].hal.dev, &int_mask);
    if (int_mask == 0) {
        return;
    }
    i2c_intr_event_t evt_type = I2C_INTR_EVENT_ERR;
    BaseType_t HPTaskAwoken = pdFALSE;
    BaseType_t HPTaskAwokenCallee = pdFALSE;
    if (p_i2c->mode == I2C_MODE_MASTER) {
        if (p_i2c->status == I2C_STATUS_WRITE) {
            i2c_hal_master_handle_tx_event(&(i2c_context[i2c_num].hal), &evt_type);
        } else if (p_i2c->status == I2C_STATUS_READ) {
            i2c_hal_master_handle_rx_event(&(i2c_context[i2c_num].hal), &evt_type);
        }
        if (evt_type == I2C_INTR_EVENT_NACK) {
            p_i2c_obj[i2c_num]->status = I2C_STATUS_ACK_ERROR;
            i2c_master_cmd_begin_static(i2c_num, &HPTaskAwokenCallee);
        } else if (evt_type == I2C_INTR_EVENT_TOUT) {
            p_i2c_obj[i2c_num]->status = I2C_STATUS_TIMEOUT;
            i2c_master_cmd_begin_static(i2c_num, &HPTaskAwokenCallee);
        } else if (evt_type == I2C_INTR_EVENT_ARBIT_LOST) {
            p_i2c_obj[i2c_num]->status = I2C_STATUS_TIMEOUT;
            i2c_master_cmd_begin_static(i2c_num, &HPTaskAwokenCallee);
        } else if (evt_type == I2C_INTR_EVENT_END_DET) {
            i2c_master_cmd_begin_static(i2c_num, &HPTaskAwokenCallee);
        } else if (evt_type == I2C_INTR_EVENT_TRANS_DONE) {
            if (p_i2c->status != I2C_STATUS_ACK_ERROR && p_i2c->status != I2C_STATUS_IDLE) {
                i2c_master_cmd_begin_static(i2c_num, &HPTaskAwokenCallee);
            }
        } else {
            // Do nothing if there is no proper event.
            return;
        }
        i2c_cmd_evt_t evt = {
            .type = I2C_CMD_EVT_ALIVE
        };
        xQueueSendFromISR(p_i2c->cmd_evt_queue, &evt, &HPTaskAwoken);
    }
#if SOC_I2C_SUPPORT_SLAVE
    else {
        i2c_ll_slave_get_event(i2c_context[i2c_num].hal.dev, &evt_type);
        if (evt_type == I2C_INTR_EVENT_TRANS_DONE || evt_type == I2C_INTR_EVENT_RXFIFO_FULL) {
            uint32_t rx_fifo_cnt;
            i2c_ll_get_rxfifo_cnt(i2c_context[i2c_num].hal.dev, &rx_fifo_cnt);
            i2c_ll_read_rxfifo(i2c_context[i2c_num].hal.dev, p_i2c->data_buf, rx_fifo_cnt);
            xRingbufferSendFromISR(p_i2c->rx_ring_buf, p_i2c->data_buf, rx_fifo_cnt, &HPTaskAwoken);
            i2c_ll_clear_intr_mask(i2c_context[i2c_num].hal.dev, int_mask);
        } else if (evt_type == I2C_INTR_EVENT_TXFIFO_EMPTY) {
            uint32_t tx_fifo_rem;
            i2c_ll_get_txfifo_len(i2c_context[i2c_num].hal.dev, &tx_fifo_rem);
            size_t size = 0;
            uint8_t *data = (uint8_t *) xRingbufferReceiveUpToFromISR(p_i2c->tx_ring_buf, &size, tx_fifo_rem);
            if (data) {
                i2c_ll_write_txfifo(i2c_context[i2c_num].hal.dev, data, size);
                vRingbufferReturnItemFromISR(p_i2c->tx_ring_buf, data, &HPTaskAwoken);
            } else {
                i2c_ll_slave_disable_tx_it(i2c_context[i2c_num].hal.dev);
            }
            i2c_ll_clear_intr_mask(i2c_context[i2c_num].hal.dev, int_mask);
        }
    }
#endif // SOC_I2C_SUPPORT_SLAVE
    //We only need to check here if there is a high-priority task needs to be switched.
    if (HPTaskAwoken == pdTRUE || HPTaskAwokenCallee == pdTRUE) {
        portYIELD_FROM_ISR();
    }
}

esp_err_t i2c_set_data_mode(i2c_port_t i2c_num, i2c_trans_mode_t tx_trans_mode, i2c_trans_mode_t rx_trans_mode)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE(tx_trans_mode < I2C_DATA_MODE_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TRANS_MODE_ERR_STR);
    ESP_RETURN_ON_FALSE(rx_trans_mode < I2C_DATA_MODE_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TRANS_MODE_ERR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_set_data_mode(i2c_context[i2c_num].hal.dev, tx_trans_mode, rx_trans_mode);
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_get_data_mode(i2c_port_t i2c_num, i2c_trans_mode_t *tx_trans_mode, i2c_trans_mode_t *rx_trans_mode)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    i2c_ll_get_data_mode(i2c_context[i2c_num].hal.dev, tx_trans_mode, rx_trans_mode);
    return ESP_OK;
}

/* Some slave device will die by accident and keep the SDA in low level,
 * in this case, master should send several clock to make the slave release the bus.
 * Slave mode of ESP32 might also get in wrong state that held the SDA low,
 * in this case, master device could send a stop signal to make esp32 slave release the bus.
 **/
static esp_err_t i2c_master_clear_bus(i2c_port_t i2c_num)
{
#if !SOC_I2C_SUPPORT_HW_CLR_BUS
    const int scl_half_period = I2C_CLR_BUS_HALF_PERIOD_US; // use standard 100kHz data rate
    int i = 0;
    int scl_io = i2c_context[i2c_num].scl_io_num;
    int sda_io = i2c_context[i2c_num].sda_io_num;
    gpio_set_direction(scl_io, GPIO_MODE_OUTPUT_OD);
    gpio_set_direction(sda_io, GPIO_MODE_INPUT_OUTPUT_OD);
    // If a SLAVE device was in a read operation when the bus was interrupted, the SLAVE device is controlling SDA.
    // The only bit during the 9 clock cycles of a READ byte the MASTER(ESP32) is guaranteed control over is during the ACK bit
    // period. If the slave is sending a stream of ZERO bytes, it will only release SDA during the ACK bit period.
    // So, this reset code needs to synchronize the bit stream with, Either, the ACK bit, Or a 1 bit to correctly generate
    // a STOP condition.
    gpio_set_level(scl_io, 0);
    gpio_set_level(sda_io, 1);
    esp_rom_delay_us(scl_half_period);
    while (!gpio_get_level(sda_io) && (i++ < I2C_CLR_BUS_SCL_NUM)) {
        gpio_set_level(scl_io, 1);
        esp_rom_delay_us(scl_half_period);
        gpio_set_level(scl_io, 0);
        esp_rom_delay_us(scl_half_period);
    }
    gpio_set_level(sda_io, 0); // setup for STOP
    gpio_set_level(scl_io, 1);
    esp_rom_delay_us(scl_half_period);
    gpio_set_level(sda_io, 1); // STOP, SDA low -> high while SCL is HIGH
    i2c_set_pin(i2c_num, sda_io, scl_io, 1, 1, I2C_MODE_MASTER);
#else
    i2c_ll_master_clr_bus(i2c_context[i2c_num].hal.dev, I2C_CLR_BUS_SCL_NUM, true);
    while (i2c_ll_master_is_bus_clear_done(i2c_context[i2c_num].hal.dev)) {
    }
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
#endif
    return ESP_OK;
}

/**if the power and SDA/SCL wires are in proper condition, everything works find with reading the slave.
 * If we remove the power supply for the slave during I2C is reading, or directly connect SDA or SCL to ground,
 * this would cause the I2C FSM get stuck in wrong state, all we can do is to reset the I2C hardware in this case.
 **/
static esp_err_t i2c_hw_fsm_reset(i2c_port_t i2c_num)
{
// A workaround for avoiding cause timeout issue when using
// hardware reset.
#if !SOC_I2C_SUPPORT_HW_FSM_RST
    i2c_hal_timing_config_t timing_config;
    uint8_t filter_cfg;

    i2c_hal_get_timing_config(&i2c_context[i2c_num].hal, &timing_config);
    i2c_ll_master_get_filter(i2c_context[i2c_num].hal.dev, &filter_cfg);

    //to reset the I2C hw module, we need re-enable the hw
    i2c_hw_disable(i2c_num);
    i2c_master_clear_bus(i2c_num);
    i2c_hw_enable(i2c_num);

    i2c_hal_master_init(&(i2c_context[i2c_num].hal));
    i2c_ll_disable_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
    i2c_ll_clear_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
    i2c_hal_set_timing_config(&i2c_context[i2c_num].hal, &timing_config);
    i2c_ll_master_set_filter(i2c_context[i2c_num].hal.dev, filter_cfg);
#else
    i2c_ll_master_fsm_rst(i2c_context[i2c_num].hal.dev);
    i2c_master_clear_bus(i2c_num);
#endif
    return ESP_OK;
}

static uint32_t s_get_src_clk_freq(i2c_clock_source_t clk_src)
{
    // TODO: replace the following switch table by clk_tree API
    uint32_t periph_src_clk_hz = 0;
    switch (clk_src) {
#if SOC_I2C_SUPPORT_APB
    case I2C_CLK_SRC_APB:
        periph_src_clk_hz = esp_clk_apb_freq();
        break;
#endif
#if SOC_I2C_SUPPORT_XTAL
    case I2C_CLK_SRC_XTAL:
        periph_src_clk_hz = esp_clk_xtal_freq();
        break;
#endif
#if SOC_I2C_SUPPORT_RTC
    case I2C_CLK_SRC_RC_FAST:
        periph_rtc_dig_clk8m_enable();
        periph_src_clk_hz = periph_rtc_dig_clk8m_get_freq();
        break;
#endif
#if SOC_I2C_SUPPORT_REF_TICK
    case RMT_CLK_SRC_REF_TICK:
        periph_src_clk_hz = REF_CLK_FREQ;
        break;
#endif
    default:
        ESP_RETURN_ON_FALSE(false, ESP_ERR_NOT_SUPPORTED, I2C_TAG, "clock source %d is not supported", clk_src);
        break;
    }

    return periph_src_clk_hz;
}

static i2c_clock_source_t s_get_clk_src(const uint32_t clk_flags, const uint32_t clk_speed)
{
    i2c_clock_source_t clk_srcs[] = SOC_I2C_CLKS;
    for (size_t i = 0; i < sizeof(clk_srcs)/ sizeof(clk_srcs[0]); i++) {
        if ( ((clk_flags & i2c_clk_alloc[i].character) == clk_flags) &&
             (clk_speed <= (s_get_src_clk_freq(clk_srcs[i]) / 20))) { // I2C SCL clock frequency should not larger than clock source frequency/20
            return clk_srcs[i];
        }
    }
    return I2C_CLOCK_INVALID;     // flag invalid;
}

esp_err_t i2c_param_config(i2c_port_t i2c_num, const i2c_config_t *i2c_conf)
{
    i2c_clock_source_t src_clk = I2C_CLK_SRC_DEFAULT;
    esp_err_t ret = ESP_OK;

    ESP_RETURN_ON_FALSE(i2c_conf != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_ADDR_ERROR_STR);
    ESP_RETURN_ON_FALSE(i2c_conf->mode < I2C_MODE_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_MODE_ERR_STR);

    if (i2c_conf->mode == I2C_MODE_MASTER) {
        src_clk = s_get_clk_src(i2c_conf->clk_flags, i2c_conf->master.clk_speed);
    }
#if SOC_I2C_SUPPORT_SLAVE
    else {
    #if SOC_I2C_SUPPORT_REF_TICK
        /* On ESP32-S2, APB clock shall always be used in slave mode as the
         * other one, I2C_CLK_SRC_REF_TICK, is too slow, even for sampling a
         * 100KHz SCL. */
        src_clk = I2C_CLK_SRC_APB;
    #else
        src_clk = s_get_clk_src(i2c_conf->clk_flags, i2c_conf->slave.maximum_speed);
    #endif // CONFIG_IDF_TARGET_ESP32S2
    }
#endif // SOC_I2C_SUPPORT_SLAVE
    ESP_RETURN_ON_FALSE(src_clk != I2C_CLOCK_INVALID, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_CLK_FLAG_ERR_STR);

    ret = i2c_set_pin(i2c_num, i2c_conf->sda_io_num, i2c_conf->scl_io_num,
                      i2c_conf->sda_pullup_en, i2c_conf->scl_pullup_en, i2c_conf->mode);
    if (ret != ESP_OK) {
        return ret;
    }
    i2c_hw_enable(i2c_num);
    I2C_CLOCK_SRC_ATOMIC() {
        i2c_hal_init(&i2c_context[i2c_num].hal, i2c_num);
    }
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_disable_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
    i2c_ll_clear_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
#if SOC_I2C_SUPPORT_SLAVE
    if (i2c_conf->mode == I2C_MODE_SLAVE) {  //slave mode
        i2c_hal_slave_init(&(i2c_context[i2c_num].hal));
        i2c_ll_slave_tx_auto_start_en(i2c_context[i2c_num].hal.dev, true);
        I2C_CLOCK_SRC_ATOMIC() {
            i2c_ll_set_source_clk(i2c_context[i2c_num].hal.dev, src_clk);
        }
        i2c_ll_set_slave_addr(i2c_context[i2c_num].hal.dev, i2c_conf->slave.slave_addr, i2c_conf->slave.addr_10bit_en);
        i2c_ll_set_rxfifo_full_thr(i2c_context[i2c_num].hal.dev, I2C_FIFO_FULL_THRESH_VAL);
        i2c_ll_set_txfifo_empty_thr(i2c_context[i2c_num].hal.dev, I2C_FIFO_EMPTY_THRESH_VAL);
        //set timing for data
        i2c_ll_set_sda_timing(i2c_context[i2c_num].hal.dev, I2C_SLAVE_SDA_SAMPLE_DEFAULT, I2C_SLAVE_SDA_HOLD_DEFAULT);
        i2c_ll_set_tout(i2c_context[i2c_num].hal.dev, I2C_SLAVE_TIMEOUT_DEFAULT);
        i2c_ll_slave_enable_rx_it(i2c_context[i2c_num].hal.dev);
    } else
#endif // SOC_I2C_SUPPORT_SLAVE
    {
        i2c_hal_master_init(&(i2c_context[i2c_num].hal));
        //Default, we enable hardware filter
        i2c_ll_master_set_filter(i2c_context[i2c_num].hal.dev, I2C_FILTER_CYC_NUM_DEF);
        I2C_CLOCK_SRC_ATOMIC() {
            i2c_hal_set_bus_timing(&(i2c_context[i2c_num].hal), i2c_conf->master.clk_speed, src_clk, s_get_src_clk_freq(src_clk));
        }
    }
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_set_period(i2c_port_t i2c_num, int high_period, int low_period)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE((high_period <= I2C_SCL_HIGH_PERIOD_V) && (high_period > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);
    ESP_RETURN_ON_FALSE((low_period <= I2C_SCL_LOW_PERIOD_V) && (low_period > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);

    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_set_scl_timing(i2c_context[i2c_num].hal.dev, high_period, low_period);
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_get_period(i2c_port_t i2c_num, int *high_period, int *low_period)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX && high_period != NULL && low_period != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_get_scl_timing(i2c_context[i2c_num].hal.dev, high_period, low_period);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_filter_enable(i2c_port_t i2c_num, uint8_t cyc_num)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE(p_i2c_obj[i2c_num] != NULL, ESP_FAIL, I2C_TAG, I2C_DRIVER_ERR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_master_set_filter(i2c_context[i2c_num].hal.dev, cyc_num);
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_filter_disable(i2c_port_t i2c_num)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_master_set_filter(i2c_context[i2c_num].hal.dev, 0);
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_set_start_timing(i2c_port_t i2c_num, int setup_time, int hold_time)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE((hold_time <= I2C_SCL_START_HOLD_TIME_V) && (hold_time > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);
    ESP_RETURN_ON_FALSE((setup_time <= I2C_SCL_RSTART_SETUP_TIME_V) && (setup_time > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);

    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_master_set_start_timing(i2c_context[i2c_num].hal.dev, setup_time, hold_time);
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_get_start_timing(i2c_port_t i2c_num, int *setup_time, int *hold_time)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX && setup_time != NULL && hold_time != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_get_start_timing(i2c_context[i2c_num].hal.dev, setup_time, hold_time);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_set_stop_timing(i2c_port_t i2c_num, int setup_time, int hold_time)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE((setup_time <= I2C_SCL_STOP_SETUP_TIME_V) && (setup_time > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);
    ESP_RETURN_ON_FALSE((hold_time <= I2C_SCL_STOP_HOLD_TIME_V) && (hold_time > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);

    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_master_set_stop_timing(i2c_context[i2c_num].hal.dev, setup_time, hold_time);
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_get_stop_timing(i2c_port_t i2c_num, int *setup_time, int *hold_time)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX && setup_time != NULL && hold_time != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_get_stop_timing(i2c_context[i2c_num].hal.dev, setup_time, hold_time);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_set_data_timing(i2c_port_t i2c_num, int sample_time, int hold_time)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE((sample_time <= I2C_SDA_SAMPLE_TIME_V) && (sample_time > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);
    ESP_RETURN_ON_FALSE((hold_time <= I2C_SDA_HOLD_TIME_V) && (hold_time > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);

    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_set_sda_timing(i2c_context[i2c_num].hal.dev, sample_time, hold_time);
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_get_data_timing(i2c_port_t i2c_num, int *sample_time, int *hold_time)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX && sample_time != NULL && hold_time != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_get_sda_timing(i2c_context[i2c_num].hal.dev, sample_time, hold_time);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_set_timeout(i2c_port_t i2c_num, int timeout)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE((timeout <= I2C_LL_MAX_TIMEOUT) && (timeout > 0), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_TIMING_VAL_ERR_STR);

    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_set_tout(i2c_context[i2c_num].hal.dev, timeout);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    return ESP_OK;
}

esp_err_t i2c_get_timeout(i2c_port_t i2c_num, int *timeout)
{
    ESP_RETURN_ON_FALSE(i2c_num < I2C_NUM_MAX && timeout != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    i2c_ll_get_tout(i2c_context[i2c_num].hal.dev, timeout);
    return ESP_OK;
}

esp_err_t i2c_set_pin(i2c_port_t i2c_num, int sda_io_num, int scl_io_num, bool sda_pullup_en, bool scl_pullup_en, i2c_mode_t mode)
{
    ESP_RETURN_ON_FALSE(( i2c_num < I2C_NUM_MAX ), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE(((sda_io_num < 0) || ((GPIO_IS_VALID_OUTPUT_GPIO(sda_io_num)))), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_SDA_IO_ERR_STR);
    ESP_RETURN_ON_FALSE(scl_io_num < 0 ||
#if SOC_I2C_SUPPORT_SLAVE
              (GPIO_IS_VALID_GPIO(scl_io_num) && mode == I2C_MODE_SLAVE) ||
#endif // SOC_I2C_SUPPORT_SLAVE
              (GPIO_IS_VALID_OUTPUT_GPIO(scl_io_num)),
              ESP_ERR_INVALID_ARG, I2C_TAG,
              I2C_SCL_IO_ERR_STR);
    ESP_RETURN_ON_FALSE(sda_io_num < 0 ||
              (sda_pullup_en == GPIO_PULLUP_ENABLE && GPIO_IS_VALID_OUTPUT_GPIO(sda_io_num)) ||
              sda_pullup_en == GPIO_PULLUP_DISABLE, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_GPIO_PULLUP_ERR_STR);
    ESP_RETURN_ON_FALSE(scl_io_num < 0 ||
              (scl_pullup_en == GPIO_PULLUP_ENABLE && GPIO_IS_VALID_OUTPUT_GPIO(scl_io_num)) ||
              scl_pullup_en == GPIO_PULLUP_DISABLE, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_GPIO_PULLUP_ERR_STR);
    ESP_RETURN_ON_FALSE((sda_io_num != scl_io_num), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_SCL_SDA_EQUAL_ERR_STR);

    int sda_in_sig, sda_out_sig, scl_in_sig, scl_out_sig;
    sda_out_sig = i2c_periph_signal[i2c_num].sda_out_sig;
    sda_in_sig = i2c_periph_signal[i2c_num].sda_in_sig;
    scl_out_sig = i2c_periph_signal[i2c_num].scl_out_sig;
    scl_in_sig = i2c_periph_signal[i2c_num].scl_in_sig;
    if (sda_io_num >= 0) {
        gpio_set_level(sda_io_num, I2C_IO_INIT_LEVEL);
        gpio_hal_iomux_func_sel(GPIO_PIN_MUX_REG[sda_io_num], PIN_FUNC_GPIO);
        gpio_set_direction(sda_io_num, GPIO_MODE_INPUT_OUTPUT_OD);

        if (sda_pullup_en == GPIO_PULLUP_ENABLE) {
            gpio_set_pull_mode(sda_io_num, GPIO_PULLUP_ONLY);
        } else {
            gpio_set_pull_mode(sda_io_num, GPIO_FLOATING);
        }
        esp_rom_gpio_connect_out_signal(sda_io_num, sda_out_sig, 0, 0);
        esp_rom_gpio_connect_in_signal(sda_io_num, sda_in_sig, 0);
    }
    if (scl_io_num >= 0) {
        if (mode == I2C_MODE_MASTER) {
            gpio_set_level(scl_io_num, I2C_IO_INIT_LEVEL);
            gpio_hal_iomux_func_sel(GPIO_PIN_MUX_REG[scl_io_num], PIN_FUNC_GPIO);
            gpio_set_direction(scl_io_num, GPIO_MODE_INPUT_OUTPUT_OD);
            esp_rom_gpio_connect_out_signal(scl_io_num, scl_out_sig, 0, 0);
        } else {
            gpio_hal_iomux_func_sel(GPIO_PIN_MUX_REG[scl_io_num], PIN_FUNC_GPIO);
            gpio_set_direction(scl_io_num, GPIO_MODE_INPUT);
        }
        esp_rom_gpio_connect_in_signal(scl_io_num, scl_in_sig, 0);
        if (scl_pullup_en == GPIO_PULLUP_ENABLE) {
            gpio_set_pull_mode(scl_io_num, GPIO_PULLUP_ONLY);
        } else {
            gpio_set_pull_mode(scl_io_num, GPIO_FLOATING);
        }
    }
#if !SOC_I2C_SUPPORT_HW_CLR_BUS
    i2c_context[i2c_num].scl_io_num = scl_io_num;
    i2c_context[i2c_num].sda_io_num = sda_io_num;
#endif
    return ESP_OK;
}

esp_err_t i2c_master_write_to_device(i2c_port_t i2c_num, uint8_t device_address,
                                     const uint8_t* write_buffer, size_t write_size,
                                     TickType_t ticks_to_wait)
{
    esp_err_t err = ESP_OK;
    uint8_t buffer[I2C_TRANS_BUF_MINIMUM_SIZE] = { 0 };

    i2c_cmd_handle_t handle = i2c_cmd_link_create_static(buffer, sizeof(buffer));
    assert (handle != NULL);

    err = i2c_master_start(handle);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_write_byte(handle, device_address << 1 | I2C_MASTER_WRITE, true);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_write(handle, write_buffer, write_size, true);
    if (err != ESP_OK) {
        goto end;
    }

    i2c_master_stop(handle);
    err = i2c_master_cmd_begin(i2c_num, handle, ticks_to_wait);

end:
    i2c_cmd_link_delete_static(handle);
    return err;
}


esp_err_t i2c_master_read_from_device(i2c_port_t i2c_num, uint8_t device_address,
                                      uint8_t* read_buffer, size_t read_size,
                                      TickType_t ticks_to_wait)
{
    esp_err_t err = ESP_OK;
    uint8_t buffer[I2C_TRANS_BUF_MINIMUM_SIZE] = { 0 };

    i2c_cmd_handle_t handle = i2c_cmd_link_create_static(buffer, sizeof(buffer));
    assert (handle != NULL);

    err = i2c_master_start(handle);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_write_byte(handle, device_address << 1 | I2C_MASTER_READ, true);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_read(handle, read_buffer, read_size, I2C_MASTER_LAST_NACK);
    if (err != ESP_OK) {
        goto end;
    }

    i2c_master_stop(handle);
    err = i2c_master_cmd_begin(i2c_num, handle, ticks_to_wait);

end:
    i2c_cmd_link_delete_static(handle);
    return err;
}


esp_err_t i2c_master_write_read_device(i2c_port_t i2c_num, uint8_t device_address,
                                       const uint8_t* write_buffer, size_t write_size,
                                       uint8_t* read_buffer, size_t read_size,
                                       TickType_t ticks_to_wait)
{
    esp_err_t err = ESP_OK;
    uint8_t buffer[I2C_TRANS_BUF_MINIMUM_SIZE] = { 0 };

    i2c_cmd_handle_t handle = i2c_cmd_link_create_static(buffer, sizeof(buffer));
    assert (handle != NULL);

    err = i2c_master_start(handle);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_write_byte(handle, device_address << 1 | I2C_MASTER_WRITE, true);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_write(handle, write_buffer, write_size, true);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_start(handle);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_write_byte(handle, device_address << 1 | I2C_MASTER_READ, true);
    if (err != ESP_OK) {
        goto end;
    }

    err = i2c_master_read(handle, read_buffer, read_size, I2C_MASTER_LAST_NACK);
    if (err != ESP_OK) {
        goto end;
    }

    i2c_master_stop(handle);
    err = i2c_master_cmd_begin(i2c_num, handle, ticks_to_wait);

end:
    i2c_cmd_link_delete_static(handle);
    return err;
}

static inline bool i2c_cmd_link_is_static(i2c_cmd_desc_t *cmd_desc)
{
    return (cmd_desc->free_buffer != NULL);
}

i2c_cmd_handle_t i2c_cmd_link_create_static(uint8_t* buffer, uint32_t size)
{
    if (buffer == NULL || size <= sizeof(i2c_cmd_desc_t)) {
        return NULL;
    }

    i2c_cmd_desc_t *cmd_desc = (i2c_cmd_desc_t *) buffer;
    cmd_desc->head = NULL;
    cmd_desc->cur = NULL;
    cmd_desc->free = NULL;
    cmd_desc->free_buffer = cmd_desc + 1;
    cmd_desc->free_size = size - sizeof(i2c_cmd_desc_t);

    return (i2c_cmd_handle_t) cmd_desc;
}

i2c_cmd_handle_t i2c_cmd_link_create(void)
{
    uint32_t alloc_caps;
#if CONFIG_SPIRAM_USE_MALLOC
    alloc_caps = I2C_MEM_ALLOC_CAPS_INTERNAL;
#else
    alloc_caps = I2C_MEM_ALLOC_CAPS_DEFAULT;
#endif
    i2c_cmd_desc_t *cmd_desc = (i2c_cmd_desc_t *) heap_caps_calloc(1, sizeof(i2c_cmd_desc_t), alloc_caps);
    return (i2c_cmd_handle_t) cmd_desc;
}

void i2c_cmd_link_delete_static(i2c_cmd_handle_t cmd_handle)
{
    i2c_cmd_desc_t *cmd = (i2c_cmd_desc_t *) cmd_handle;
    if (cmd == NULL || !i2c_cmd_link_is_static(cmd)) {
        return;
    }
    /* Currently, this function does nothing, but it is not impossible
     * that it will change in a near future. */
}

void i2c_cmd_link_delete(i2c_cmd_handle_t cmd_handle)
{
    i2c_cmd_desc_t *cmd = (i2c_cmd_desc_t *) cmd_handle;

    /* Memory should be freed only if allocated dynamically.
     * If the user gave the buffer for a static allocation, do
     * nothing. */
    if (cmd == NULL || i2c_cmd_link_is_static(cmd)) {
        return;
    }

    while (cmd->free) {
        i2c_cmd_link_t *ptmp = cmd->free;
        cmd->free = cmd->free->next;
        free(ptmp);
    }
    cmd->cur = NULL;
    cmd->free = NULL;
    cmd->head = NULL;
    free(cmd_handle);
    return;
}

static esp_err_t i2c_cmd_allocate(i2c_cmd_desc_t *cmd_desc, size_t n, size_t size, void** outptr)
{
    esp_err_t err = ESP_OK;

    if (i2c_cmd_link_is_static(cmd_desc)) {
        const size_t required = n * size;
        /* User defined buffer.
         * Check whether there is enough space in the buffer. */
        if (cmd_desc->free_size < required) {
            err = ESP_ERR_NO_MEM;
        } else {
            /* Allocate the pointer. */
            *outptr = cmd_desc->free_buffer;

            /* Decrement the free size from the user's bufffer. */
            cmd_desc->free_buffer += required;
            cmd_desc->free_size -= required;
        }
    } else {
        uint32_t alloc_caps;
#if CONFIG_SPIRAM_USE_MALLOC
        alloc_caps = I2C_MEM_ALLOC_CAPS_INTERNAL;
#else
        alloc_caps = I2C_MEM_ALLOC_CAPS_DEFAULT;
#endif
        *outptr = heap_caps_calloc(n, size, alloc_caps);
        if (*outptr == NULL) {
            err = ESP_FAIL;
        }
    }

    return err;
}

static inline void i2c_cmd_log_alloc_error(i2c_cmd_desc_t *cmd_desc)
{
    if (i2c_cmd_link_is_static(cmd_desc)) {
        ESP_LOGE(I2C_TAG, I2C_CMD_USER_ALLOC_ERR_STR);
    } else {
        ESP_LOGE(I2C_TAG, I2C_CMD_MALLOC_ERR_STR);
    }
}

static esp_err_t i2c_cmd_link_append(i2c_cmd_handle_t cmd_handle, i2c_cmd_t *cmd)
{
    esp_err_t err = ESP_OK;
    i2c_cmd_desc_t *cmd_desc = (i2c_cmd_desc_t *) cmd_handle;

    assert(cmd_desc != NULL);

    if (cmd_desc->head == NULL) {
        err = i2c_cmd_allocate(cmd_desc, 1, sizeof(i2c_cmd_link_t), (void**) &cmd_desc->head);
        if (err != ESP_OK) {
            i2c_cmd_log_alloc_error(cmd_desc);
            return err;
        }
        cmd_desc->cur = cmd_desc->head;
        cmd_desc->free = cmd_desc->head;
    } else {
        assert(cmd_desc->cur != NULL);
        err = i2c_cmd_allocate(cmd_desc, 1, sizeof(i2c_cmd_link_t), (void**) &cmd_desc->cur->next);
        if (err != ESP_OK) {
            i2c_cmd_log_alloc_error(cmd_desc);
            return err;
        }
        cmd_desc->cur = cmd_desc->cur->next;
    }
    memcpy((uint8_t *) &cmd_desc->cur->cmd, (uint8_t *) cmd, sizeof(i2c_cmd_t));
    cmd_desc->cur->next = NULL;
    return err;
}

esp_err_t i2c_master_start(i2c_cmd_handle_t cmd_handle)
{
    ESP_RETURN_ON_FALSE(cmd_handle != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_CMD_LINK_INIT_ERR_STR);
    i2c_cmd_t cmd = { 0 };
    cmd.hw_cmd.op_code = I2C_LL_CMD_RESTART;
    return i2c_cmd_link_append(cmd_handle, &cmd);
}

esp_err_t i2c_master_stop(i2c_cmd_handle_t cmd_handle)
{
    ESP_RETURN_ON_FALSE(cmd_handle != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_CMD_LINK_INIT_ERR_STR);
    i2c_cmd_t cmd = { 0 };
    cmd.hw_cmd.op_code = I2C_LL_CMD_STOP;
    return i2c_cmd_link_append(cmd_handle, &cmd);
}

esp_err_t i2c_master_write(i2c_cmd_handle_t cmd_handle, const uint8_t *data, size_t data_len, bool ack_en)
{
    ESP_RETURN_ON_FALSE((data != NULL), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_ADDR_ERROR_STR);
    ESP_RETURN_ON_FALSE(cmd_handle != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_CMD_LINK_INIT_ERR_STR);

    if (data_len == 1) {
        /* If data_len if 1, i2c_master_write_byte should have been called,
         * correct this here. */
        return i2c_master_write_byte(cmd_handle, *data, ack_en);
    }

    i2c_cmd_t cmd = {
        .hw_cmd = {
            .ack_en = ack_en,
            .op_code = I2C_LL_CMD_WRITE,
        },
        .data = (uint8_t*) data,
        .total_bytes = data_len,
    };

    return i2c_cmd_link_append(cmd_handle, &cmd);
}

esp_err_t i2c_master_write_byte(i2c_cmd_handle_t cmd_handle, uint8_t data, bool ack_en)
{
    ESP_RETURN_ON_FALSE(cmd_handle != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_CMD_LINK_INIT_ERR_STR);

    i2c_cmd_t cmd = {
        .hw_cmd = {
            .ack_en = ack_en,
            .op_code = I2C_LL_CMD_WRITE,
        },
        .data_byte = data,
        .total_bytes = 1,
    };

    return i2c_cmd_link_append(cmd_handle, &cmd);
}

static esp_err_t i2c_master_read_static(i2c_cmd_handle_t cmd_handle, uint8_t *data, size_t data_len, i2c_ack_type_t ack)
{
    i2c_cmd_t cmd = {
        .hw_cmd = {
            .ack_val = ack & 0x1,
            .op_code = I2C_LL_CMD_READ,
        },
        .data = data,
        .total_bytes = data_len,
    };

    return i2c_cmd_link_append(cmd_handle, &cmd);
}

esp_err_t i2c_master_read_byte(i2c_cmd_handle_t cmd_handle, uint8_t *data, i2c_ack_type_t ack)
{
    ESP_RETURN_ON_FALSE((data != NULL), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_ADDR_ERROR_STR);
    ESP_RETURN_ON_FALSE(cmd_handle != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_CMD_LINK_INIT_ERR_STR);
    ESP_RETURN_ON_FALSE(ack < I2C_MASTER_ACK_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_ACK_TYPE_ERR_STR);

    i2c_cmd_t cmd = {
        .hw_cmd = {
            .ack_val = ((ack == I2C_MASTER_LAST_NACK) ? I2C_MASTER_NACK : (ack & 0x1)),
            .op_code = I2C_LL_CMD_READ,
        },
        .data = data,
        .total_bytes = 1,
    };

    return i2c_cmd_link_append(cmd_handle, &cmd);
}

esp_err_t i2c_master_read(i2c_cmd_handle_t cmd_handle, uint8_t *data, size_t data_len, i2c_ack_type_t ack)
{
    ESP_RETURN_ON_FALSE((data != NULL), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_ADDR_ERROR_STR);
    ESP_RETURN_ON_FALSE(cmd_handle != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_CMD_LINK_INIT_ERR_STR);
    ESP_RETURN_ON_FALSE(ack < I2C_MASTER_ACK_MAX, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_ACK_TYPE_ERR_STR);
    ESP_RETURN_ON_FALSE(data_len > 0, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_DATA_LEN_ERR_STR);

    esp_err_t ret = ESP_OK;

    /* Check if we can perform a single transfer.
     * This is the case if a NACK is NOT required at the end of the last transferred byte
     * (i.e. ACK is required at the end), or if a single byte has to be read.
     */
    if (ack != I2C_MASTER_LAST_NACK) {
        ret = i2c_master_read_static(cmd_handle, data, data_len, ack);
    } else if (data_len == 1) {
        ret = i2c_master_read_byte(cmd_handle, data, I2C_MASTER_NACK);
    } else {
        /* In this case, we have to read data_len-1 bytes sending an ACK at the end
         * of each one.
         */
        ret = i2c_master_read_static(cmd_handle, data, data_len - 1, I2C_MASTER_ACK);

        /* Last byte has to be NACKed. */
        if (ret == ESP_OK) {
            ret = i2c_master_read_byte(cmd_handle, data + data_len - 1, I2C_MASTER_NACK);
        }
    }

    return ret;
}

__attribute__((always_inline))
static inline bool i2c_cmd_is_single_byte(const i2c_cmd_t *cmd) {
    return cmd->total_bytes == 1;
}

static void IRAM_ATTR i2c_master_cmd_begin_static(i2c_port_t i2c_num, BaseType_t* HPTaskAwoken)
{
    i2c_obj_t *p_i2c = p_i2c_obj[i2c_num];
    i2c_cmd_evt_t evt = { 0 };
    if (p_i2c->cmd_link.head != NULL && p_i2c->status == I2C_STATUS_READ) {
        i2c_cmd_t *cmd = &p_i2c->cmd_link.head->cmd;
        i2c_ll_read_rxfifo(i2c_context[i2c_num].hal.dev, cmd->data + cmd->bytes_used, p_i2c->rx_cnt);
        /* rx_cnt bytes have just been read, increment the number of bytes used from the buffer */
        cmd->bytes_used += p_i2c->rx_cnt;

        /* Test if there are still some remaining bytes to send. */
        if (cmd->bytes_used != cmd->total_bytes) {
            p_i2c->cmd_idx = 0;
        } else {
            p_i2c->cmd_link.head = p_i2c->cmd_link.head->next;
            if (p_i2c->cmd_link.head != NULL) {
                p_i2c->cmd_link.head->cmd.bytes_used = 0;
            }
        }
    } else if ((p_i2c->status == I2C_STATUS_ACK_ERROR)
               || (p_i2c->status == I2C_STATUS_TIMEOUT)) {
        assert(HPTaskAwoken != NULL);
        evt.type = I2C_CMD_EVT_DONE;
        xQueueOverwriteFromISR(p_i2c->cmd_evt_queue, &evt, HPTaskAwoken);
        return;
    } else if (p_i2c->status == I2C_STATUS_DONE) {
        return;
    }

    if (p_i2c->cmd_link.head == NULL) {
        assert(HPTaskAwoken != NULL);
        p_i2c->cmd_link.cur = NULL;
        evt.type = I2C_CMD_EVT_DONE;
        xQueueOverwriteFromISR(p_i2c->cmd_evt_queue, &evt, HPTaskAwoken);
        // Return to the IDLE status after cmd_eve_done signal were send out.
        p_i2c->status = I2C_STATUS_IDLE;
        return;
    }
    const i2c_ll_hw_cmd_t hw_end_cmd = {
        .op_code = I2C_LL_CMD_END
    };
    while (p_i2c->cmd_link.head) {
        i2c_cmd_t *cmd = &p_i2c->cmd_link.head->cmd;
        const size_t remaining_bytes = cmd->total_bytes - cmd->bytes_used;

        i2c_ll_hw_cmd_t hw_cmd = cmd->hw_cmd;
        uint8_t fifo_fill = 0;

        if (cmd->hw_cmd.op_code == I2C_LL_CMD_WRITE) {
            uint8_t *write_pr = NULL;

            //TODO: to reduce interrupt number
            if (!i2c_cmd_is_single_byte(cmd)) {
                fifo_fill = MIN(remaining_bytes, SOC_I2C_FIFO_LEN);
                /* cmd->data shall not be altered!
                 * Else it would not be possible to reuse the commands list. */
                write_pr = cmd->data + cmd->bytes_used;
                cmd->bytes_used += fifo_fill;
            } else {
                fifo_fill = 1;
                /* `data_byte` field contains the data itself.
                 * NOTE: It is possible to get the correct data (and not 0s)
                 * because both Xtensa and RISC-V architectures used on ESP
                 * boards are little-endian.
                 */
                write_pr = (uint8_t*) &cmd->data_byte;
            }
            hw_cmd.byte_num = fifo_fill;
            i2c_ll_write_txfifo(i2c_context[i2c_num].hal.dev, write_pr, fifo_fill);
            i2c_ll_master_write_cmd_reg(i2c_context[i2c_num].hal.dev, hw_cmd, p_i2c->cmd_idx);
            i2c_ll_master_write_cmd_reg(i2c_context[i2c_num].hal.dev, hw_end_cmd, p_i2c->cmd_idx + 1);
            i2c_ll_master_enable_tx_it(i2c_context[i2c_num].hal.dev);
            p_i2c->cmd_idx = 0;
            if (i2c_cmd_is_single_byte(cmd) || cmd->total_bytes == cmd->bytes_used) {
                p_i2c->cmd_link.head = p_i2c->cmd_link.head->next;
                if(p_i2c->cmd_link.head) {
                    p_i2c->cmd_link.head->cmd.bytes_used = 0;
                }
            }
            p_i2c->status = I2C_STATUS_WRITE;
            break;
        } else if (cmd->hw_cmd.op_code == I2C_LL_CMD_READ) {
            //TODO: to reduce interrupt number
            fifo_fill = MIN(remaining_bytes, SOC_I2C_FIFO_LEN);
            p_i2c->rx_cnt = fifo_fill;
            hw_cmd.byte_num = fifo_fill;
            i2c_ll_master_write_cmd_reg(i2c_context[i2c_num].hal.dev, hw_cmd, p_i2c->cmd_idx);
            i2c_ll_master_write_cmd_reg(i2c_context[i2c_num].hal.dev, hw_end_cmd, p_i2c->cmd_idx + 1);
            i2c_ll_master_enable_rx_it(i2c_context[i2c_num].hal.dev);
            p_i2c->status = I2C_STATUS_READ;
            break;
        } else {
            i2c_ll_master_write_cmd_reg(i2c_context[i2c_num].hal.dev, hw_cmd, p_i2c->cmd_idx);
        }
        p_i2c->cmd_idx++;
        p_i2c->cmd_link.head = p_i2c->cmd_link.head->next;
        if (p_i2c->cmd_link.head == NULL || p_i2c->cmd_idx >= (SOC_I2C_CMD_REG_NUM-1)) {
            p_i2c->cmd_idx = 0;
            break;
        }
    }
    i2c_ll_update(i2c_context[i2c_num].hal.dev);
    i2c_ll_master_trans_start(i2c_context[i2c_num].hal.dev);
    return;
}

#if CONFIG_SPIRAM_USE_MALLOC
//Check whether read or write buffer in cmd_link is internal.
static bool is_cmd_link_buffer_internal(const i2c_cmd_link_t *link)
{
    bool is_internal = true;
    for (const i2c_cmd_link_t *cmd_link = link;
         cmd_link != NULL && is_internal;
         cmd_link = cmd_link->next)
    {
        /* A command node has a valid pointer if it is a read command or a write command with more than one byte. */
        const bool data_pointer = (cmd_link->cmd.hw_cmd.op_code == I2C_LL_CMD_WRITE && !i2c_cmd_is_single_byte(&cmd_link->cmd))
                                || cmd_link->cmd.hw_cmd.op_code == I2C_LL_CMD_READ;
        /* Check if the (non-NULL) pointer points to internal memory. */
        is_internal &= !data_pointer || cmd_link->cmd.data == NULL || esp_ptr_internal(cmd_link->cmd.data);
    }
    return is_internal;
}
#endif

static uint8_t clear_bus_cnt[I2C_NUM_MAX] = { 0 };

esp_err_t i2c_master_cmd_begin(i2c_port_t i2c_num, i2c_cmd_handle_t cmd_handle, TickType_t ticks_to_wait)
{
    ESP_RETURN_ON_FALSE(( i2c_num < I2C_NUM_MAX ), ESP_ERR_INVALID_ARG, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE(p_i2c_obj[i2c_num] != NULL, ESP_ERR_INVALID_STATE, I2C_TAG, I2C_DRIVER_NOT_INSTALL_ERR_STR);
    ESP_RETURN_ON_FALSE(p_i2c_obj[i2c_num]->mode == I2C_MODE_MASTER, ESP_ERR_INVALID_STATE, I2C_TAG, I2C_MASTER_MODE_ERR_STR);
    ESP_RETURN_ON_FALSE(cmd_handle != NULL, ESP_ERR_INVALID_ARG, I2C_TAG, I2C_CMD_LINK_INIT_ERR_STR);

#if CONFIG_SPIRAM_USE_MALLOC
    //If the i2c read or write buffer is not in internal RAM, we will return ESP_FAIL
    //to avoid the ISR handler function crashing when the cache is disabled.
    if ( (p_i2c_obj[i2c_num]->intr_alloc_flags & ESP_INTR_FLAG_IRAM) &&
         !is_cmd_link_buffer_internal(((const i2c_cmd_desc_t *)cmd_handle)->head) ) {
        ESP_LOGE(I2C_TAG, I2C_PSRAM_BUFFER_WARN_STR);
        return ESP_ERR_INVALID_ARG;
    }
#endif
    // Sometimes when the FSM get stuck, the ACK_ERR interrupt will occur endlessly until we reset the FSM and clear bus.
    esp_err_t ret = ESP_FAIL;
    i2c_obj_t *p_i2c = p_i2c_obj[i2c_num];
    const TickType_t ticks_start = xTaskGetTickCount();
    BaseType_t res = xSemaphoreTake(p_i2c->cmd_mux, ticks_to_wait);
    if (res == pdFALSE) {
        return ESP_ERR_TIMEOUT;
    }
#ifdef CONFIG_PM_ENABLE
    esp_pm_lock_acquire(p_i2c->pm_lock);
#endif
    xQueueReset(p_i2c->cmd_evt_queue);
    if (p_i2c->status == I2C_STATUS_TIMEOUT
            || i2c_ll_is_bus_busy(i2c_context[i2c_num].hal.dev)) {
        i2c_hw_fsm_reset(i2c_num);
        clear_bus_cnt[i2c_num] = 0;
    }
    i2c_reset_tx_fifo(i2c_num);
    i2c_reset_rx_fifo(i2c_num);
    const i2c_cmd_desc_t *cmd = (const i2c_cmd_desc_t *) cmd_handle;
    /* Before starting the transfer, resetset the number of bytes sent to 0.
     * `i2c_master_cmd_begin_static` will also reset this field for each node
     * while browsing the command list. */
    cmd->head->cmd.bytes_used = 0;
    p_i2c->cmd_link.free = cmd->free;
    p_i2c->cmd_link.cur = cmd->cur;
    p_i2c->cmd_link.head = cmd->head;
    p_i2c->status = I2C_STATUS_IDLE;
    p_i2c->cmd_idx = 0;
    p_i2c->rx_cnt = 0;
    i2c_reset_tx_fifo(i2c_num);
    i2c_reset_rx_fifo(i2c_num);
    // These two interrupts some times can not be cleared when the FSM gets stuck.
    // so we disable them when these two interrupt occurs and re-enable them here.
    i2c_ll_disable_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
    i2c_ll_clear_intr_mask(i2c_context[i2c_num].hal.dev, I2C_LL_INTR_MASK);
    //start send commands, at most 32 bytes one time, isr handler will process the remaining commands.
    i2c_master_cmd_begin_static(i2c_num, NULL);

    // Wait event bits
    i2c_cmd_evt_t evt;
    while (1) {
        TickType_t wait_time = xTaskGetTickCount();
        const TickType_t elapsed = wait_time - ticks_start;
        if (elapsed >= ticks_to_wait) { // out of time
            /* Before triggering a timeout, empty the queue by giving a wait_time of 0:
             * - if the queue is empty, `pdFALSE` will be returned and the loop will be exited
             * - if the queue is not empty, we will pop an element and come back here again
             */
            wait_time = 0;
        } else {
            wait_time = MIN(ticks_to_wait - elapsed, I2C_CMD_ALIVE_INTERVAL_TICK);
        }
        // In master mode, since we don't have an interrupt to detective bus error or FSM state, what we do here is to make
        // sure the interrupt mechanism for master mode is still working.
        // If the command sending is not finished and there is no interrupt any more, the bus is probably dead caused by external noise.
        BaseType_t evt_res = xQueueReceive(p_i2c->cmd_evt_queue, &evt, wait_time);
        if (evt_res == pdTRUE) {
            if (evt.type == I2C_CMD_EVT_DONE) {
                if (p_i2c->status == I2C_STATUS_TIMEOUT) {
                    // If the I2C slave are powered off or the SDA/SCL are connected to ground, for example,
                    // I2C hw FSM would get stuck in wrong state, we have to reset the I2C module in this case.
                    i2c_hw_fsm_reset(i2c_num);
                    clear_bus_cnt[i2c_num] = 0;
                    ret = ESP_ERR_TIMEOUT;
                } else if (p_i2c->status == I2C_STATUS_ACK_ERROR) {
                    clear_bus_cnt[i2c_num]++;
                    if (clear_bus_cnt[i2c_num] >= I2C_ACKERR_CNT_MAX) {
                        clear_bus_cnt[i2c_num] = 0;
                        i2c_hw_fsm_reset(i2c_num);
                    }
                    ret = ESP_FAIL;
                } else {
                    ret = ESP_OK;
                }
                break;
            }
            if (evt.type == I2C_CMD_EVT_ALIVE) {
            }
        } else {
            ret = ESP_ERR_TIMEOUT;
            // If the I2C slave are powered off or the SDA/SCL are connected to ground, for example,
            // I2C hw FSM would get stuck in wrong state, we have to reset the I2C module in this case.
            i2c_hw_fsm_reset(i2c_num);
            clear_bus_cnt[i2c_num] = 0;
            break;
        }
    }
    p_i2c->status = I2C_STATUS_DONE;
#ifdef CONFIG_PM_ENABLE
    esp_pm_lock_release(p_i2c->pm_lock);
#endif
    xSemaphoreGive(p_i2c->cmd_mux);
    return ret;
}
#if SOC_I2C_SUPPORT_SLAVE
int i2c_slave_write_buffer(i2c_port_t i2c_num, const uint8_t *data, int size, TickType_t ticks_to_wait)
{
    ESP_RETURN_ON_FALSE(( i2c_num < I2C_NUM_MAX ), ESP_FAIL, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE(p_i2c_obj[i2c_num] != NULL, ESP_FAIL, I2C_TAG, I2C_DRIVER_ERR_STR);
    ESP_RETURN_ON_FALSE((data != NULL), ESP_FAIL, I2C_TAG, I2C_ADDR_ERROR_STR);
    ESP_RETURN_ON_FALSE(p_i2c_obj[i2c_num]->mode == I2C_MODE_SLAVE, ESP_FAIL, I2C_TAG, I2C_MODE_SLAVE_ERR_STR);
    i2c_obj_t *p_i2c = p_i2c_obj[i2c_num];

    BaseType_t res;
    int cnt = 0;
    TickType_t ticks_end = xTaskGetTickCount() + ticks_to_wait;

    res = xSemaphoreTake(p_i2c->slv_tx_mux, ticks_to_wait);
    if (res == pdFALSE) {
        return 0;
    }
    ticks_to_wait = ticks_end - xTaskGetTickCount();
    res = xRingbufferSend(p_i2c->tx_ring_buf, data, size, ticks_to_wait);
    if (res == pdFALSE) {
        cnt = 0;
    } else {
        I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
        i2c_ll_slave_enable_tx_it(i2c_context[i2c_num].hal.dev);
        I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
        cnt = size;
    }
    xSemaphoreGive(p_i2c->slv_tx_mux);
    return cnt;
}

int i2c_slave_read_buffer(i2c_port_t i2c_num, uint8_t *data, size_t max_size, TickType_t ticks_to_wait)
{
    ESP_RETURN_ON_FALSE(( i2c_num < I2C_NUM_MAX ), ESP_FAIL, I2C_TAG, I2C_NUM_ERROR_STR);
    ESP_RETURN_ON_FALSE(p_i2c_obj[i2c_num] != NULL, ESP_FAIL, I2C_TAG, I2C_DRIVER_ERR_STR);
    ESP_RETURN_ON_FALSE((data != NULL), ESP_FAIL, I2C_TAG, I2C_ADDR_ERROR_STR);
    ESP_RETURN_ON_FALSE(p_i2c_obj[i2c_num]->mode == I2C_MODE_SLAVE, ESP_FAIL, I2C_TAG, I2C_MODE_SLAVE_ERR_STR);

    size_t size = 0;
    size_t size_rem = max_size;
    i2c_obj_t *p_i2c = p_i2c_obj[i2c_num];
    if (xSemaphoreTake(p_i2c->slv_rx_mux, ticks_to_wait) == pdFALSE) {
        return 0;
    }
    TickType_t ticks_rem = ticks_to_wait;
    TickType_t ticks_end = xTaskGetTickCount() + ticks_to_wait;
    I2C_ENTER_CRITICAL(&(i2c_context[i2c_num].spinlock));
    i2c_ll_slave_enable_rx_it(i2c_context[i2c_num].hal.dev);
    I2C_EXIT_CRITICAL(&(i2c_context[i2c_num].spinlock));
    while (size_rem && ticks_rem <= ticks_to_wait) {
        uint8_t *pdata = (uint8_t *) xRingbufferReceiveUpTo(p_i2c->rx_ring_buf, &size, ticks_to_wait, size_rem);
        if (pdata && size > 0) {
            memcpy(data, pdata, size);
            vRingbufferReturnItem(p_i2c->rx_ring_buf, pdata);
            data += size;
            size_rem -= size;
        }
        if (ticks_to_wait != portMAX_DELAY) {
            ticks_rem = ticks_end - xTaskGetTickCount();
        }
    }
    xSemaphoreGive(p_i2c->slv_rx_mux);
    return max_size - size_rem;
}
#endif

/**
 * @brief This function will be called during start up, to check that this legacy i2c driver is not running along with the new I2C driver
 */
__attribute__((constructor))
static void check_i2c_driver_conflict(void)
{
    // This function was declared as weak here. The new I2C driver has the implementation.
    // So if the new I2C driver is not linked in, then `i2c_acquire_bus_handle()` should be NULL at runtime.
    extern __attribute__((weak)) esp_err_t i2c_acquire_bus_handle(int port_num, void *i2c_new_bus, int mode);
    if ((void *)i2c_acquire_bus_handle != NULL) {
        ESP_EARLY_LOGE(I2C_TAG, "CONFLICT! driver_ng is not allowed to be used with this old driver");
        abort();
    }
    ESP_EARLY_LOGW(I2C_TAG, "This driver is an old driver, please migrate your application code to adapt `driver/i2c_master.h`");
}