rt-thread/components/drivers/adc/adc_v2.c

/*
 * Copyright (c) 2006-2026, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2026-04-21     wdfk-prog    add standalone adc v2 framework implementation
 */

/**
 * @file adc_v2.c
 * @brief Standalone ADC V2 framework implementation.
 */

#include <rtconfig.h>

#if defined(RT_USING_ADC_V2)

#include <rtdevice.h>
#include <rtthread.h>

#define DBG_TAG "adc.v2"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>

#include <drivers/adc_v2.h>
#include "adc_v2_internal.h"

/**
 * @brief Get the current ADC framework state atomically.
 * @param device Pointer to the ADC device object.
 * @return Current ADC runtime state.
 */
enum rt_adc_state adc_get_state(rt_adc_device_t device)
{
    return (enum rt_adc_state)rt_atomic_load(&device->state);
}

#if DBG_LVL >= DBG_LOG
/**
 * @brief Convert one ADC framework state to a debug log string.
 * @param state ADC runtime state.
 * @return Constant state name string.
 */
static const char *adc_state_name(enum rt_adc_state state)
{
    switch (state)
    {
    case RT_ADC_STATE_IDLE:
        return "IDLE";

    case RT_ADC_STATE_LOCKED:
        return "BUSY";

#ifdef RT_ADC_USING_STREAM
    case RT_ADC_STATE_STREAM:
        return "STREAM";
#endif /* RT_ADC_USING_STREAM */

    default:
        return "UNKNOWN";
    }
}

/** @brief ADC control command string table offset base. */
#define RT_ADC_CMD_NAME_BASE RT_ADC_CMD_GET_RESOLUTION

/** @brief ADC control command string table entry count. */
#define RT_ADC_CMD_NAME_COUNT (RT_ADC_CMD_CLEAR_CHANNEL_CONFIG - RT_ADC_CMD_GET_RESOLUTION + 1)

/**
 * @brief ADC control command name table.
 */
static const char * const rt_adc_control_cmd_names[RT_ADC_CMD_NAME_COUNT] =
{
    [RT_ADC_CMD_GET_RESOLUTION        - RT_ADC_CMD_NAME_BASE] = "GET_RESOLUTION",
    [RT_ADC_CMD_CALIBRATE             - RT_ADC_CMD_NAME_BASE] = "CALIBRATE",
    [RT_ADC_CMD_SET_VREF              - RT_ADC_CMD_NAME_BASE] = "SET_VREF",
    [RT_ADC_CMD_CALC_VREF             - RT_ADC_CMD_NAME_BASE] = "CALC_VREF",
    [RT_ADC_CMD_GET_VREF_CHANNEL      - RT_ADC_CMD_NAME_BASE] = "GET_VREF_CHANNEL",
    [RT_ADC_CMD_SET_SESSION           - RT_ADC_CMD_NAME_BASE] = "SET_SESSION",
    [RT_ADC_CMD_SET_CONFIG            - RT_ADC_CMD_NAME_BASE] = "SET_CONFIG",
    [RT_ADC_CMD_GET_CONFIG            - RT_ADC_CMD_NAME_BASE] = "GET_CONFIG",
    [RT_ADC_CMD_CLEAR_CHANNEL_CONFIG  - RT_ADC_CMD_NAME_BASE] = "CLEAR_CHANNEL_CONFIG",
};

/**
 * @brief Get ADC control command name.
 * @param cmd ADC control command identifier.
 * @return ADC control command name string.
 */
static const char *rt_adc_control_cmd_name(int cmd)
{
    int index;

    index = cmd - RT_ADC_CMD_NAME_BASE;
    if ((index < 0) || (index >= RT_ADC_CMD_NAME_COUNT) || (rt_adc_control_cmd_names[index] == RT_NULL))
    {
        return "UNKNOWN";
    }

    return rt_adc_control_cmd_names[index];
}

#ifdef RT_ADC_USING_STREAM
/**
 * @brief Convert one ADC stream policy to a debug log string.
 * @param policy ADC stream buffering policy.
 * @return Constant stream policy name string.
 */
static const char *adc_stream_policy_name(enum rt_adc_stream_policy policy)
{
    switch (policy)
    {
#ifdef RT_ADC_STREAM_USING_LATEST
    case RT_ADC_STREAM_POLICY_LATEST:
        return "LATEST";
#endif /* RT_ADC_STREAM_USING_LATEST */

#ifdef RT_ADC_STREAM_USING_FIFO
    case RT_ADC_STREAM_POLICY_FIFO:
        return "FIFO";
#endif /* RT_ADC_STREAM_USING_FIFO */

    default:
        return "UNKNOWN";
    }
}
#endif /* RT_ADC_USING_STREAM */

#endif /* DBG_LVL >= DBG_LOG */

/**
 * @brief Store one ADC framework state atomically.
 * @param device Pointer to the ADC device object.
 * @param state New ADC runtime state.
 */
static void adc_set_state(rt_adc_device_t device, enum rt_adc_state state)
{
    LOG_D("state set: device=%s state=%s", device->parent.parent.name, adc_state_name(state));
    rt_atomic_store(&device->state, (rt_atomic_t)state);
}

/**
 * @brief Clear the cached active ADC session configuration.
 * @param device Pointer to the ADC device object.
 */
static void adc_clear_session_ctrl(rt_adc_device_t device)
{
    rt_memset(&device->session_ctrl, 0, sizeof(device->session_ctrl));
}

/**
 * @brief Cache one ADC session while the caller owns the device BUSY state.
 * @param device Pointer to the ADC device object.
 * @param channels ADC channel selection mask.
 * @return Operation status.
 */
static rt_err_t adc_cache_session_ctrl(rt_adc_device_t device, rt_uint32_t channels)
{
    rt_size_t channel_count;

    if ((device == RT_NULL) || (channels == 0U))
    {
        return -RT_EINVAL;
    }

    channel_count = rt_adc_channel_mask_count(channels);
    if (channel_count == 0U)
    {
        return -RT_EINVAL;
    }

    device->session_ctrl.channels = channels;
    device->session_ctrl.channel_count = channel_count;
    device->session_ctrl.configured = RT_TRUE;

    return RT_EOK;
}

/**
 * @brief Try to change the ADC framework state atomically.
 * @param device Pointer to the ADC device object.
 * @param expected Expected current ADC runtime state.
 * @param target Target ADC runtime state.
 * @return RT_TRUE if the state transition succeeded.
 */
static rt_bool_t adc_try_set_state(rt_adc_device_t device, enum rt_adc_state expected, enum rt_adc_state target)
{
    rt_atomic_t old_state;
    rt_bool_t matched;

    old_state = (rt_atomic_t)expected;
    matched = (rt_atomic_compare_exchange_strong(&device->state, &old_state, (rt_atomic_t)target) != 0) ? RT_TRUE : RT_FALSE;
    if (matched == RT_TRUE)
    {
        LOG_D("state transition: device=%s %s -> %s", device->parent.parent.name, adc_state_name(expected), adc_state_name(target));
    }
    else
    {
        LOG_W("state transition rejected: device=%s expected=%d actual=%d target=%d", device->parent.parent.name, (int)expected, (int)old_state, (int)target);
    }

    return matched;
}

/**
 * @brief Apply one ADC conversion session to the backend driver.
 * @param device Pointer to the ADC device object.
 * @param channels ADC channel selection mask.
 * @return Operation status.
 */
static rt_err_t adc_session_config(rt_adc_device_t device, rt_uint32_t channels)
{
    rt_size_t channel_count;
    rt_err_t result;

    if ((device == RT_NULL) || (channels == 0U) ||
        (device->ops == RT_NULL) || (device->ops->core == RT_NULL) ||
        (device->ops->core->session_config == RT_NULL))
    {
        return -RT_EINVAL;
    }

    channel_count = rt_adc_channel_mask_count(channels);
    LOG_D("session config: device=%s channels=0x%08x count=%d",
          device->parent.parent.name, channels, channel_count);

    result = device->ops->core->session_config(device, channels);
    if (result != RT_EOK)
    {
        goto fail;
    }

    result = adc_cache_session_ctrl(device, channels);
    if (result != RT_EOK)
    {
        goto fail;
    }

    LOG_D("session configure done: device=%s", device->parent.parent.name);
    return RT_EOK;

fail:
    adc_clear_session_ctrl(device);
    LOG_E("session configure failed: device=%s result=%d", device->parent.parent.name, result);

    return result;
}

/**
 * @brief Get the raw sample index of one channel in a configured session.
 * @param session_channels Configured ADC session channel mask.
 * @param channel Single-channel mask to locate.
 * @param index Pointer to the output raw sample index.
 * @return Operation status.
 */
rt_err_t rt_adc_session_channel_index(rt_uint32_t session_channels, rt_uint32_t channel, rt_size_t *index)
{
    if ((index == RT_NULL) || (session_channels == 0U) || (rt_adc_channel_mask_count(channel) != 1U) || ((session_channels & channel) == 0U))
    {
        return -RT_EINVAL;
    }

    *index = rt_adc_channel_mask_count(session_channels & (channel - 1U));
    return RT_EOK;
}

/**
 * @brief Transfer ADC sequence samples after the session has been selected.
 * @param device Pointer to the ADC device object.
 * @param channels ADC channel selection mask.
 * @param cfg Pointer to the sequence request object.
 * @param sample_total Number of samples to read.
 * @param read_count Pointer to the stored sample count.
 * @return Operation status.
 */
static rt_err_t adc_sequence_transfer_locked(rt_adc_device_t device, rt_uint32_t channels,
                                             const struct rt_adc_sequence_cfg *cfg, rt_size_t sample_total, rt_size_t *read_count)
{
    rt_err_t result;
    rt_err_t stop_result;
    rt_size_t index;

    *read_count = 0U;
    result = device->ops->sequence->start(device, channels, cfg);
    if (result != RT_EOK)
    {
        LOG_E("sequence start failed: device=%s result=%d", device->parent.parent.name, result);
        return result;
    }

    for (index = 0U; index < sample_total; index++)
    {
        result = device->ops->sequence->read(device, &cfg->buffer[index], cfg->timeout_ms);
        if (result != RT_EOK)
        {
            LOG_E("sequence read failed: device=%s index=%u result=%d",
                  device->parent.parent.name, (unsigned int)index, result);
            break;
        }

        (*read_count)++;
    }

    stop_result = device->ops->sequence->stop(device);
    if (stop_result != RT_EOK)
    {
        LOG_E("sequence stop failed: device=%s result=%d", device->parent.parent.name, stop_result);
        return (result != RT_EOK) ? result : stop_result;
    }

    return result;
}

/**
 * @brief Open the ADC device.
 * @param dev Pointer to the RT-Thread device object.
 * @param oflag Open flags.
 * @return Operation status.
 */
static rt_err_t adc_open_device(rt_device_t dev, rt_uint16_t oflag)
{
    rt_adc_device_t device;
    rt_err_t result;

    RT_UNUSED(oflag);

    if (dev == RT_NULL)
    {
        return -RT_EINVAL;
    }

    device = (rt_adc_device_t)dev;
    if ((device->ops == RT_NULL) || (device->ops->core == RT_NULL) ||
        (device->ops->core->open == RT_NULL))
    {
        return -RT_ENOSYS;
    }

    if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
    {
        return -RT_EBUSY;
    }

    LOG_D("open start: device=%s", device->parent.parent.name);
    result = device->ops->core->open(device);
    adc_set_state(device, RT_ADC_STATE_IDLE);
    if (result == RT_EOK)
    {
        LOG_I("open done: device=%s", device->parent.parent.name);
    }
    else
    {
        LOG_E("open failed: device=%s result=%d", device->parent.parent.name, result);
    }
    return result;
}

/**
 * @brief Close the ADC device.
 * @param dev Pointer to the RT-Thread device object.
 * @return Operation status.
 */
static rt_err_t adc_close_device(rt_device_t dev)
{
    rt_adc_device_t device;
    rt_err_t result;

    if (dev == RT_NULL)
    {
        return -RT_EINVAL;
    }

    device = (rt_adc_device_t)dev;
    if ((device->ops == RT_NULL) || (device->ops->core == RT_NULL) || (device->ops->core->close == RT_NULL))
    {
        return -RT_ENOSYS;
    }

#ifdef RT_ADC_USING_STREAM
    enum rt_adc_state state = adc_get_state(device);
    if (state == RT_ADC_STATE_STREAM)
    {
        result = rt_adc_stream_stop(device);
        if (result != RT_EOK)
        {
            LOG_E("stop stream before close failed: device=%s result=%d", device->parent.parent.name, result);
            return result;
        }
    }
    else if (state != RT_ADC_STATE_IDLE)
    {
        return -RT_EBUSY;
    }
#endif /* RT_ADC_USING_STREAM */

    if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
    {
        return -RT_EBUSY;
    }

    LOG_D("close start: device=%s", device->parent.parent.name);
    result = device->ops->core->close(device);
    if (result == RT_EOK)
    {
        adc_clear_session_ctrl(device);
    }
    adc_set_state(device, RT_ADC_STATE_IDLE);
    if (result == RT_EOK)
    {
        LOG_I("close done: device=%s", device->parent.parent.name);
    }
    else
    {
        LOG_E("close failed: device=%s result=%d", device->parent.parent.name, result);
    }
    return result;
}

/**
 * @brief Read ADC raw samples from the configured session.
 * @param dev Pointer to the RT-Thread device object.
 * @param pos Unused read position.
 * @param buffer Pointer to the output sample buffer.
 * @param size Output sample buffer length in samples.
 * @return Number of samples read, or negative error code on failure.
 *
 * @note @p size must match the configured session channel count. The output
 *       order follows the ascending bit order of the configured channel mask.
 */
static rt_ssize_t adc_read_device(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
{
    rt_adc_device_t device;
    rt_uint32_t *values;
    rt_err_t result;

    RT_UNUSED(pos);

    if ((dev == RT_NULL) || (buffer == RT_NULL))
    {
        return -RT_EINVAL;
    }

    device = (rt_adc_device_t)dev;
    values = (rt_uint32_t *)buffer;

    if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
    {
        return -RT_EBUSY;
    }

    if ((device->session_ctrl.configured != RT_TRUE) || (device->session_ctrl.channel_count == 0U) ||
        (size != device->session_ctrl.channel_count))
    {
        result = -RT_EINVAL;
        goto out;
    }

    struct rt_adc_sequence_cfg sequence_cfg;
    rt_size_t read_count;

    rt_memset(&sequence_cfg, 0, sizeof(sequence_cfg));
    sequence_cfg.buffer = values;
    sequence_cfg.buffer_length = size;
    sequence_cfg.timeout_ms = -1;

    result = adc_sequence_transfer_locked(device, device->session_ctrl.channels,
                                          &sequence_cfg, size, &read_count);
    if ((result == RT_EOK) && (read_count != size))
    {
        result = -RT_ERROR;
    }

out:
    adc_set_state(device, RT_ADC_STATE_IDLE);

    return (result == RT_EOK) ? (rt_ssize_t)size : (rt_ssize_t)result;
}

/**
 * @brief Handle ADC control commands.
 * @param dev Pointer to the RT-Thread device object.
 * @param cmd Control command.
 * @param args Pointer to the control argument buffer.
 * @return Operation status.
 */
static rt_err_t adc_control_device(rt_device_t dev, int cmd, void *args)
{
    rt_adc_device_t device;
    rt_err_t result;

    if (dev == RT_NULL)
    {
        return -RT_EINVAL;
    }

    device = (rt_adc_device_t)dev;
    LOG_D("control request: device=%s cmd=%s(0x%x)", device->parent.parent.name, rt_adc_control_cmd_name(cmd), cmd);
    switch (cmd)
    {
    case RT_ADC_CMD_GET_RESOLUTION:
    case RT_ADC_CMD_GET_VREF_CHANNEL:
    case RT_ADC_CMD_CALC_VREF:
    case RT_ADC_CMD_CALIBRATE:
    case RT_ADC_CMD_SET_CONFIG:
    case RT_ADC_CMD_GET_CONFIG:
        if ((device->ops == RT_NULL) || (device->ops->core == RT_NULL) ||
            (device->ops->core->control == RT_NULL))
        {
            return -RT_ENOSYS;
        }
        if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
        {
            return -RT_EBUSY;
        }
        result = device->ops->core->control(device, cmd, args);
        adc_set_state(device, RT_ADC_STATE_IDLE);
        return result;

    case RT_ADC_CMD_CLEAR_CHANNEL_CONFIG:
        if (args != RT_NULL)
        {
            return -RT_EINVAL;
        }

        if ((dev->open_flag & RT_DEVICE_OFLAG_OPEN) == 0U)
        {
            return -RT_EIO;
        }

        if ((device->ops == RT_NULL) || (device->ops->core == RT_NULL) ||
            (device->ops->core->control == RT_NULL))
        {
            return -RT_ENOSYS;
        }

        if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
        {
            return -RT_EBUSY;
        }

        result = device->ops->core->control(device, cmd, RT_NULL);
        if (result == RT_EOK)
        {
            adc_clear_session_ctrl(device);
        }

        adc_set_state(device, RT_ADC_STATE_IDLE);
        return result;

    case RT_ADC_CMD_SET_VREF:
        if (args == RT_NULL)
        {
            return -RT_EINVAL;
        }

        rt_uint32_t vref_mv = *((rt_uint32_t *)args);
        if (vref_mv == 0U)
        {
            return -RT_EINVAL;
        }

        if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
        {
            return -RT_EBUSY;
        }
        device->default_vref_mv = vref_mv;
        LOG_I("fallback vref updated: %lu mV", (unsigned long)device->default_vref_mv);
        adc_set_state(device, RT_ADC_STATE_IDLE);
        return RT_EOK;

    case RT_ADC_CMD_SET_SESSION:
        if (args == RT_NULL)
        {
            return -RT_EINVAL;
        }

        if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
        {
            return -RT_EBUSY;
        }
        result = adc_session_config(device, *((const rt_uint32_t *)args));
        adc_set_state(device, RT_ADC_STATE_IDLE);
        return result;

    default:
        if ((device->ops == RT_NULL) || (device->ops->core == RT_NULL) ||
            (device->ops->core->control == RT_NULL))
        {
            return -RT_ENOSYS;
        }
        if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
        {
            return -RT_EBUSY;
        }
        result = device->ops->core->control(device, cmd, args);
        adc_set_state(device, RT_ADC_STATE_IDLE);
        return result;
    }
}

#ifdef RT_USING_DEVICE_OPS
/**
 * @brief ADC device-framework operation table.
 */
static const struct rt_device_ops adc_device_ops = {
    RT_NULL,
    adc_open_device,
    adc_close_device,
    adc_read_device,
    RT_NULL,
    adc_control_device,
};
#endif /* RT_USING_DEVICE_OPS */

/**
 * @brief Register an ADC device.
 * @param device Pointer to the ADC device object.
 * @param name Pointer to the device name string.
 * @param ops Pointer to the ADC driver operation table.
 * @param user_data Pointer to the driver private data.
 * @return Operation status.
 */
rt_err_t rt_hw_adc_register(rt_adc_device_t device, const char *name, const struct rt_adc_ops *ops, const void *user_data)
{
    rt_err_t result;

    if ((device == RT_NULL) || (name == RT_NULL) || (ops == RT_NULL) ||
        (ops->core == RT_NULL) || (ops->core->session_config == RT_NULL) ||
        (ops->sequence == RT_NULL) || (ops->sequence->start == RT_NULL) ||
        (ops->sequence->read == RT_NULL) || (ops->sequence->stop == RT_NULL))
    {
        return -RT_EINVAL;
    }

    device->parent.type = RT_Device_Class_ADC;
    device->parent.rx_indicate = RT_NULL;
    device->parent.tx_complete = RT_NULL;
#ifdef RT_USING_DEVICE_OPS
    device->parent.ops = &adc_device_ops;
#else
    device->parent.init = RT_NULL;
    device->parent.open = adc_open_device;
    device->parent.close = adc_close_device;
    device->parent.read = adc_read_device;
    device->parent.write = RT_NULL;
    device->parent.control = adc_control_device;
#endif /* RT_USING_DEVICE_OPS */
    device->ops = ops;
    rt_spin_lock_init(&device->spinlock);
    rt_atomic_store(&device->state, (rt_atomic_t)RT_ADC_STATE_IDLE);
    device->default_vref_mv = 0;
    adc_clear_session_ctrl(device);
#if defined(RT_ADC_USING_TRIGGER)
    adc_trigger_init(device);
#endif /* defined(RT_ADC_USING_TRIGGER) */
#ifdef RT_ADC_USING_STREAM
    rt_memset(&device->stream_ctrl, 0, sizeof(device->stream_ctrl));
#endif /* RT_ADC_USING_STREAM */
    device->parent.user_data = (void *)user_data;

    result = rt_device_register(&device->parent, name, RT_DEVICE_FLAG_RDWR);
    if (result == RT_EOK)
    {
        LOG_I("device registered: %s", name);
    }
    else
    {
        LOG_E("device register failed: %s result=%d", name, result);
    }

    return result;
}

/**
 * @brief Read one validated ADC sequence while the caller owns the device state.
 * @param device Pointer to the ADC device object.
 * @param channels ADC channel selection mask.
 * @param cfg Pointer to the validated sequence request object.
 * @param keep_state_on_success Whether to keep BUSY state after a successful read.
 * @param read_count Pointer to the stored sample count.
 * @return Operation status.
 *
 * @note A synchronous sequence request reads one scan frame only. Partial
 *       samples are reported through @p read_count when a read error or timeout
 *       happens after at least one sample is stored.
 */
static rt_err_t adc_read_sequence_locked(rt_adc_device_t device, rt_uint32_t channels,
                                         const struct rt_adc_sequence_cfg *cfg, rt_bool_t keep_state_on_success, rt_size_t *read_count)
{
    rt_err_t result;
    rt_size_t channel_count;

    *read_count = 0U;
    channel_count = rt_adc_channel_mask_count(channels);

    result = adc_session_config(device, channels);
    if (result != RT_EOK)
    {
        LOG_E("sequence config failed: device=%s result=%d", device->parent.parent.name, result);
        adc_set_state(device, RT_ADC_STATE_IDLE);
        return result;
    }

    result = adc_sequence_transfer_locked(device, channels, cfg, channel_count, read_count);

    if ((result != RT_EOK) || (keep_state_on_success != RT_TRUE))
    {
        adc_set_state(device, RT_ADC_STATE_IDLE);
    }

    return result;
}

/**
 * @brief Read one ADC sequence frame.
 * @param device Pointer to the ADC device object.
 * @param channels ADC channel selection mask.
 * @param cfg Pointer to the sequence request object.
 * @param read_count Pointer to the stored sample count.
 * @return Operation status.
 */
rt_err_t rt_adc_read_sequence(rt_adc_device_t device, rt_uint32_t channels,
                              const struct rt_adc_sequence_cfg *cfg, rt_size_t *read_count)
{
    rt_size_t channel_count;

    if ((device == RT_NULL) || (cfg == RT_NULL) || (cfg->buffer == RT_NULL) ||
        (read_count == RT_NULL) || (channels == 0U) ||
        (device->ops == RT_NULL) || (device->ops->sequence == RT_NULL) || (device->ops->sequence->start == RT_NULL) ||
        (device->ops->sequence->read == RT_NULL) || (device->ops->sequence->stop == RT_NULL))
    {
        return -RT_EINVAL;
    }

    *read_count = 0U;
    channel_count = rt_adc_channel_mask_count(channels);
    if ((channel_count == 0U) || (cfg->buffer_length < channel_count))
    {
        return -RT_EINVAL;
    }

    if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
    {
        return -RT_EBUSY;
    }

    return adc_read_sequence_locked(device, channels, cfg, RT_FALSE, read_count);
}


#ifdef RT_ADC_USING_STREAM
/**
 * @brief Check whether an ADC stream policy is enabled by configuration.
 * @param policy ADC stream buffering policy.
 * @return RT_TRUE if the policy is supported, otherwise RT_FALSE.
 */
static rt_bool_t adc_stream_policy_is_supported(enum rt_adc_stream_policy policy)
{
    switch (policy)
    {
#ifdef RT_ADC_STREAM_USING_LATEST
    case RT_ADC_STREAM_POLICY_LATEST:
        return RT_TRUE;
#endif /* RT_ADC_STREAM_USING_LATEST */
#ifdef RT_ADC_STREAM_USING_FIFO
    case RT_ADC_STREAM_POLICY_FIFO:
        return RT_TRUE;
#endif /* RT_ADC_STREAM_USING_FIFO */
    default:
        return RT_FALSE;
    }
}

/**
 * @brief Resolve the effective DMA data event mode for one stream request.
 * @param policy Active stream buffering policy.
 * @param request Requested DMA event mode.
 * @param effective Pointer to the output effective event mode.
 * @return Operation status.
 */
static rt_err_t adc_stream_resolve_dma_event_mode(enum rt_adc_stream_policy policy,
                                                  enum rt_adc_stream_dma_event_mode request,
                                                  enum rt_adc_stream_dma_event_mode *effective)
{
    if (request == RT_ADC_STREAM_DMA_EVENT_AUTO)
    {
#ifdef RT_ADC_STREAM_USING_LATEST
        if (policy == RT_ADC_STREAM_POLICY_LATEST)
        {
            *effective = RT_ADC_STREAM_DMA_EVENT_NONE;
            return RT_EOK;
        }
#endif /* RT_ADC_STREAM_USING_LATEST */
#ifdef RT_ADC_STREAM_USING_FIFO
        if (policy == RT_ADC_STREAM_POLICY_FIFO)
        {
            *effective = RT_ADC_STREAM_DMA_EVENT_HALF_FULL;
            return RT_EOK;
        }
#endif /* RT_ADC_STREAM_USING_FIFO */
        return -RT_ENOSYS;
    }

#ifdef RT_ADC_STREAM_USING_FIFO
    if ((policy == RT_ADC_STREAM_POLICY_FIFO) && (request == RT_ADC_STREAM_DMA_EVENT_NONE))
    {
        return -RT_EINVAL;
    }
#endif /* RT_ADC_STREAM_USING_FIFO */

    if ((request != RT_ADC_STREAM_DMA_EVENT_NONE) &&
        (request != RT_ADC_STREAM_DMA_EVENT_FULL_ONLY) &&
        (request != RT_ADC_STREAM_DMA_EVENT_HALF_FULL))
    {
        return -RT_EINVAL;
    }

    *effective = request;
    return RT_EOK;
}

/**
 * @brief Reset one ADC stream runtime control block.
 * @param ctrl Pointer to the stream control block.
 */
static void adc_stream_ctrl_reset(struct rt_adc_stream_ctrl *ctrl)
{
    rt_memset(ctrl, 0, sizeof(*ctrl));
}

#ifdef RT_ADC_STREAM_USING_FIFO
/**
 * @brief Wake FIFO stream readers when the active stream owns a FIFO.
 * @param ctrl Pointer to the stream control block.
 */
static void adc_stream_fifo_wakeup(struct rt_adc_stream_ctrl *ctrl)
{
    if ((ctrl->policy == RT_ADC_STREAM_POLICY_FIFO) && (ctrl->fifo_enabled == RT_TRUE))
    {
        rt_completion_done(&ctrl->rx_cpt);
    }
}
#endif /* RT_ADC_STREAM_USING_FIFO */

/**
 * @brief Validate a stream request and initialize the stream control block.
 * @param device Pointer to the ADC device object.
 * @param cfg Pointer to the stream configuration object.
 * @param frame_length Samples in one ADC scan frame.
 * @return Operation status.
 */
static rt_err_t adc_stream_ctrl_configure(rt_adc_device_t device, const struct rt_adc_stream_cfg *cfg, rt_size_t frame_length)
{
    struct rt_adc_stream_ctrl *ctrl;
    enum rt_adc_stream_dma_event_mode dma_event_mode;
    rt_err_t result;

    if ((cfg->dma_buffer == RT_NULL) || (cfg->dma_buffer_length == 0U) || (frame_length == 0U) ||
        (adc_stream_policy_is_supported(cfg->policy) != RT_TRUE))
    {
        LOG_E("stream ctrl config invalid args: device=%s buffer=%p len=%u frame=%u",
              device->parent.parent.name, cfg->dma_buffer, (unsigned int)cfg->dma_buffer_length, (unsigned int)frame_length);
        return -RT_EINVAL;
    }

    result = adc_stream_resolve_dma_event_mode(cfg->policy, cfg->dma_event_mode, &dma_event_mode);
    if (result != RT_EOK)
    {
        LOG_E("stream ctrl config invalid event mode: device=%s policy=%d mode=%d",
              device->parent.parent.name, (int)cfg->policy, (int)cfg->dma_event_mode);
        return result;
    }

    LOG_D("stream ctrl config start: device=%s policy=%s frame=%u dma=%u event_mode=%d",
          device->parent.parent.name, adc_stream_policy_name(cfg->policy),
          (unsigned int)frame_length, (unsigned int)cfg->dma_buffer_length, (int)dma_event_mode);
    ctrl = &device->stream_ctrl;
    adc_stream_ctrl_reset(ctrl);

#ifdef RT_ADC_STREAM_USING_LATEST
    if (cfg->policy == RT_ADC_STREAM_POLICY_LATEST)
    {
        if (cfg->dma_buffer_length != frame_length)
        {
            LOG_E("latest stream invalid length: device=%s dma=%u frame=%u",
                  device->parent.parent.name, (unsigned int)cfg->dma_buffer_length, (unsigned int)frame_length);
            return -RT_EINVAL;
        }

        ctrl->active = RT_TRUE;
        ctrl->policy = cfg->policy;
        ctrl->dma_event_mode = dma_event_mode;
        ctrl->dma_buffer = cfg->dma_buffer;
        ctrl->dma_buffer_length = cfg->dma_buffer_length;
        ctrl->frame_length = frame_length;
        LOG_D("latest stream configured: device=%s frame=%u", device->parent.parent.name, (unsigned int)frame_length);
        return RT_EOK;
    }
#endif /* RT_ADC_STREAM_USING_LATEST */

#ifdef RT_ADC_STREAM_USING_FIFO
    if (cfg->policy == RT_ADC_STREAM_POLICY_FIFO)
    {
        if ((cfg->fifo_buffer == RT_NULL) || (cfg->fifo_buffer_length == 0U))
        {
            LOG_E("fifo stream invalid fifo buffer: device=%s len=%u",
                  device->parent.parent.name, (unsigned int)cfg->fifo_buffer_length);
            return -RT_EINVAL;
        }

        if ((cfg->watermark != 0U) && (cfg->watermark > cfg->fifo_buffer_length))
        {
            LOG_E("fifo stream invalid watermark: device=%s watermark=%u fifo=%u",
                  device->parent.parent.name, (unsigned int)cfg->watermark, (unsigned int)cfg->fifo_buffer_length);
            return -RT_EINVAL;
        }

        if (cfg->dma_buffer_length < frame_length)
        {
            LOG_E("fifo stream invalid dma length: device=%s dma=%u frame=%u",
                  device->parent.parent.name, (unsigned int)cfg->dma_buffer_length, (unsigned int)frame_length);
            return -RT_EINVAL;
        }

        /* The default FIFO start path accepts generic DMA staging buffers and
         * reports runtime overflow through last_error. Use
         * rt_adc_stream_start_frame_aligned_fifo() when the caller requires a DMA
         * data-event block layout that never splits ADC scan frames.
         */
        ctrl->active = RT_TRUE;
        ctrl->policy = cfg->policy;
        ctrl->dma_event_mode = dma_event_mode;
        ctrl->dma_buffer = cfg->dma_buffer;
        ctrl->dma_buffer_length = cfg->dma_buffer_length;
        ctrl->frame_length = frame_length;
        ctrl->watermark = cfg->watermark;
        ctrl->callback = cfg->callback;
        ctrl->user_data = cfg->user_data;
        ctrl->overflow_count = 0U;
        rt_atomic_store(&ctrl->last_error, (rt_atomic_t)RT_EOK);
        rt_ringbuffer_init(&ctrl->fifo, (rt_uint8_t *)cfg->fifo_buffer, (rt_int32_t)(cfg->fifo_buffer_length * sizeof(rt_uint32_t)));
        rt_completion_init(&ctrl->rx_cpt);
        ctrl->fifo_enabled = RT_TRUE;
        LOG_D("fifo stream configured: device=%s frame=%u dma=%u fifo=%u watermark=%u event_mode=%d",
              device->parent.parent.name, (unsigned int)frame_length, (unsigned int)cfg->dma_buffer_length,
              (unsigned int)cfg->fifo_buffer_length, (unsigned int)cfg->watermark, (int)dma_event_mode);
        return RT_EOK;
    }
#endif /* RT_ADC_STREAM_USING_FIFO */

    LOG_E("stream policy unsupported: device=%s policy=%d", device->parent.parent.name, (int)cfg->policy);
    return -RT_ENOSYS;
}

#ifdef RT_ADC_STREAM_USING_LATEST
/**
 * @brief Read the latest ADC rank values from the DMA buffer.
 * @param device Pointer to the ADC device object.
 * @param buffer Pointer to the destination sample buffer.
 * @param sample_count Destination buffer length in samples.
 * @param timeout_ms Unused timeout parameter.
 * @return Number of samples read, or a negative RT-Thread error code.
 *
 * @note Latest mode is a lockless DMA-buffer view. CPU-side atomic operations,
 *       spin locks, mutexes, or read-write locks cannot prevent the DMA engine
 *       from updating memory concurrently, because DMA does not participate in
 *       CPU locking protocols. This mode only guarantees that each buffer index
 *       maps to the corresponding ADC rank latest value; it does not guarantee
 *       that the copied frame is a single hardware scan-cycle snapshot. Use FIFO
 *       mode when ordered and frame-accurate samples are required.
 */
static rt_ssize_t rt_adc_stream_read_latest(rt_adc_device_t device, rt_uint32_t *buffer,
                                             rt_size_t sample_count, rt_int32_t timeout_ms)
{
    struct rt_adc_stream_ctrl *ctrl;
    rt_err_t result;

    RT_UNUSED(timeout_ms);

    ctrl = &device->stream_ctrl;
    if (sample_count < ctrl->frame_length)
    {
        LOG_E("latest read buffer too small: device=%s samples=%u frame=%u",
              device->parent.parent.name, (unsigned int)sample_count, (unsigned int)ctrl->frame_length);
        return -RT_EINVAL;
    }

    result = (rt_err_t)rt_atomic_load(&ctrl->last_error);
    if (result != RT_EOK)
    {
        return result;
    }

    if ((device->ops != RT_NULL) && (device->ops->stream != RT_NULL) && (device->ops->stream->sync != RT_NULL))
    {
        result = device->ops->stream->sync(device, ctrl->dma_buffer, ctrl->frame_length);
        if (result != RT_EOK)
        {
            return result;
        }
    }

    result = (rt_err_t)rt_atomic_load(&ctrl->last_error);
    if (result != RT_EOK)
    {
        return result;
    }

    rt_memcpy(buffer, ctrl->dma_buffer, ctrl->frame_length * sizeof(rt_uint32_t));
    return (rt_ssize_t)ctrl->frame_length;
}
#endif /* RT_ADC_STREAM_USING_LATEST */

#ifdef RT_ADC_STREAM_USING_FIFO
/**
 * @brief Read ordered ADC samples from the framework FIFO.
 * @param device Pointer to the ADC device object.
 * @param buffer Pointer to the destination sample buffer.
 * @param sample_count Number of samples to read before returning unless timeout or error occurs.
 * @param timeout_ms Total read timeout in milliseconds; negative means wait forever.
 * @return Number of samples read, or a negative RT-Thread error code.
 * @note In blocking mode, this function waits until the requested sample count is read or timeout occurs.
 *       On timeout, the partial sample count is returned if any samples were read.
 */
static rt_ssize_t rt_adc_stream_read_fifo(rt_adc_device_t device, rt_uint32_t *buffer, rt_size_t sample_count, rt_int32_t timeout_ms)
{
    struct rt_adc_stream_ctrl *ctrl;
    rt_size_t read_count;
    rt_tick_t timeout_tick;
    rt_tick_t begin_tick;

    ctrl = &device->stream_ctrl;
    read_count = 0U;
    timeout_tick = (timeout_ms < 0) ? RT_WAITING_FOREVER : rt_tick_from_millisecond(timeout_ms);
    begin_tick = rt_tick_get();

    while (read_count < sample_count)
    {
        enum rt_adc_state state;
        rt_base_t level;
        rt_size_t got;
        rt_err_t result;
        rt_tick_t wait_tick;

        state = adc_get_state(device);
        if (state != RT_ADC_STATE_STREAM)
        {
            return (read_count > 0U) ? (rt_ssize_t)read_count : ((state == RT_ADC_STATE_IDLE) ? -RT_EINVAL : -RT_EBUSY);
        }

        level = rt_spin_lock_irqsave(&device->spinlock);
        got = rt_ringbuffer_get(&ctrl->fifo, (rt_uint8_t *)&buffer[read_count],
                                 (rt_uint32_t)((sample_count - read_count) * sizeof(rt_uint32_t)));
        rt_spin_unlock_irqrestore(&device->spinlock, level);

        read_count += got / sizeof(rt_uint32_t);
        if (read_count >= sample_count)
        {
            return (rt_ssize_t)read_count;
        }

        result = (rt_err_t)rt_atomic_load(&ctrl->last_error);
        if (result != RT_EOK)
        {
            return result;
        }

        if (timeout_ms == RT_WAITING_NO)
        {
            return (read_count > 0U) ? (rt_ssize_t)read_count : -RT_ETIMEOUT;
        }

        if (timeout_ms < 0)
        {
            wait_tick = RT_WAITING_FOREVER;
        }
        else
        {
            rt_tick_t delta_tick;

            delta_tick = rt_tick_get_delta(begin_tick);
            if (delta_tick >= timeout_tick)
            {
                return (read_count > 0U) ? (rt_ssize_t)read_count : -RT_ETIMEOUT;
            }

            wait_tick = timeout_tick - delta_tick;
        }

        if (rt_completion_wait(&ctrl->rx_cpt, wait_tick) != RT_EOK)
        {
            return (read_count > 0U) ? (rt_ssize_t)read_count : -RT_ETIMEOUT;
        }
    }

    return (rt_ssize_t)read_count;
}
#endif /* RT_ADC_STREAM_USING_FIFO */

/**
 * @brief Start one ADC stream session.
 * @param device Pointer to the ADC device object.
 * @param channels ADC channel selection mask.
 * @param cfg Pointer to the stream configuration object.
 * @return Operation status.
 */
rt_err_t rt_adc_stream_start(rt_adc_device_t device, rt_uint32_t channels, const struct rt_adc_stream_cfg *cfg)
{
    rt_size_t frame_length;
    rt_err_t result;
    rt_bool_t start_called;

    if ((device == RT_NULL) || (cfg == RT_NULL) || (channels == 0U))
    {
        return -RT_EINVAL;
    }

    if ((device->ops == RT_NULL) || (device->ops->stream == RT_NULL) ||
        (device->ops->stream->start == RT_NULL) || (device->ops->stream->stop == RT_NULL))
    {
        return -RT_ENOSYS;
    }

    if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
    {
        return -RT_EBUSY;
    }
    start_called = RT_FALSE;
#if defined(RT_ADC_USING_TRIGGER)
    rt_bool_t trigger_started = RT_FALSE;
#endif /* defined(RT_ADC_USING_TRIGGER) */

    frame_length = rt_adc_channel_mask_count(channels);
    result = adc_cache_session_ctrl(device, channels);
    if (result != RT_EOK)
    {
        goto fail_after_lock;
    }

    result = adc_stream_ctrl_configure(device, cfg, frame_length);
    if (result != RT_EOK)
    {
        goto fail_after_lock;
    }

#if defined(RT_ADC_USING_TRIGGER)
    result = adc_trigger_preconfig(device);
    if (result != RT_EOK)
    {
        goto fail_after_lock;
    }
#endif /* defined(RT_ADC_USING_TRIGGER) */

    start_called = RT_TRUE;
    result = device->ops->stream->start(device, channels, cfg);
    if (result != RT_EOK)
    {
        goto fail_after_lock;
    }

    result = (rt_err_t)rt_atomic_load(&device->stream_ctrl.last_error);
    if (result != RT_EOK)
    {
        goto fail_after_lock;
    }

#if defined(RT_ADC_USING_TRIGGER)
    result = adc_trigger_source_control(device, ADC_TRIGGER_SOURCE_START, &trigger_started, RT_EOK);
    if (result != RT_EOK)
    {
        goto fail_after_lock;
    }
#endif /* defined(RT_ADC_USING_TRIGGER) */

    adc_set_state(device, RT_ADC_STATE_STREAM);
    return RT_EOK;

fail_after_lock:
    if(result != RT_EOK)
    {
        LOG_E("stream start failed: device=%s result=%d", device->parent.parent.name, result);
    }
#if defined(RT_ADC_USING_TRIGGER)
    result = adc_trigger_source_control(device, ADC_TRIGGER_SOURCE_STOP, &trigger_started, result);
#endif /* defined(RT_ADC_USING_TRIGGER) */

    if (start_called == RT_TRUE)
    {
        rt_err_t stop_result;
        rt_bool_t hardware_stopped;

        hardware_stopped = RT_FALSE;
        stop_result = device->ops->stream->stop(device, &hardware_stopped);
        if ((stop_result != RT_EOK) && (hardware_stopped != RT_TRUE))
        {
            adc_set_state(device, RT_ADC_STATE_STREAM);
            return stop_result;
        }
    }

    adc_stream_ctrl_reset(&device->stream_ctrl);
    adc_clear_session_ctrl(device);
    adc_set_state(device, RT_ADC_STATE_IDLE);
    return result;
}

#ifdef RT_ADC_STREAM_USING_FIFO
/**
 * @brief Start a FIFO ADC stream with strict frame-aligned buffer layout.
 * @param device Pointer to the ADC device object.
 * @param channels ADC channel selection mask.
 * @param cfg Pointer to the stream configuration object.
 * @return Operation status.
 *
 * @note This helper is intended for continuous FIFO sampling where DMA
 *       data-event blocks must not split ADC scan frames. It validates that
 *       each DMA event block contains complete frames and that the FIFO can
 *       accept at least one complete event block.
 * @note Passing this validation does not prove that samples can never be lost.
 *       The reader must still drain the FIFO fast enough for the selected
 *       sample rate and scheduler latency. Runtime overflow is still reported
 *       through the stream error state.
 */
rt_err_t rt_adc_stream_start_frame_aligned_fifo(rt_adc_device_t device, rt_uint32_t channels, const struct rt_adc_stream_cfg *cfg)
{
    rt_size_t frame_length;
    rt_size_t block_length;
    enum rt_adc_stream_dma_event_mode dma_event_mode;
    rt_err_t result;

    if ((device == RT_NULL) || (cfg == RT_NULL) || (channels == 0U) ||
        (cfg->policy != RT_ADC_STREAM_POLICY_FIFO) ||
        (cfg->dma_buffer == RT_NULL) || (cfg->dma_buffer_length == 0U) ||
        (cfg->fifo_buffer == RT_NULL) || (cfg->fifo_buffer_length == 0U))
    {
        return -RT_EINVAL;
    }

    frame_length = rt_adc_channel_mask_count(channels);
    if (frame_length == 0U)
    {
        return -RT_EINVAL;
    }

    result = adc_stream_resolve_dma_event_mode(cfg->policy, cfg->dma_event_mode, &dma_event_mode);
    if (result != RT_EOK)
    {
        return result;
    }

    block_length = (dma_event_mode == RT_ADC_STREAM_DMA_EVENT_FULL_ONLY) ? cfg->dma_buffer_length : (cfg->dma_buffer_length / 2U);
    if ((cfg->dma_buffer_length < frame_length) ||          /* DMA buffer must contain at least one complete scan frame. */
        ((cfg->dma_buffer_length % frame_length) != 0U) ||  /* DMA buffer length must be aligned to complete scan frames. */
        (block_length == 0U) ||                             /* The selected DMA event mode must produce a non-empty staging block. */
        ((block_length % frame_length) != 0U) ||            /* Each staging block copied to FIFO must contain complete scan frames only. */
        (cfg->fifo_buffer_length < block_length) ||         /* FIFO must be able to store at least one completed DMA staging block. */
        ((cfg->fifo_buffer_length % frame_length) != 0U))   /* FIFO capacity must also be aligned to complete scan frames. */
    {
        LOG_E("frame-aligned fifo stream invalid layout: device=%s dma=%u block=%u frame=%u fifo=%u",
              device->parent.parent.name, (unsigned int)cfg->dma_buffer_length,
              (unsigned int)block_length, (unsigned int)frame_length,
              (unsigned int)cfg->fifo_buffer_length);
        return -RT_EINVAL;
    }

    if ((dma_event_mode == RT_ADC_STREAM_DMA_EVENT_HALF_FULL) && ((cfg->dma_buffer_length % 2U) != 0U))
    {
        return -RT_EINVAL;
    }

    return rt_adc_stream_start(device, channels, cfg);
}
#endif /* RT_ADC_STREAM_USING_FIFO */

/**
 * @brief Read converted samples from an active ADC stream session.
 * @param device Pointer to the ADC device object.
 * @param buffer Pointer to the destination sample buffer.
 * @param sample_count Number of samples to read.
 * @param timeout_ms Read timeout in milliseconds; negative means wait forever.
 * @return Number of samples read, or a negative RT-Thread error code.
 */
rt_ssize_t rt_adc_stream_read(rt_adc_device_t device, rt_uint32_t *buffer, rt_size_t sample_count, rt_int32_t timeout_ms)
{
    struct rt_adc_stream_ctrl *ctrl;
    rt_ssize_t read_count;

    if ((device == RT_NULL) || (buffer == RT_NULL) || (sample_count == 0U))
    {
        return -RT_EINVAL;
    }

    if (adc_get_state(device) != RT_ADC_STATE_STREAM)
    {
        return -RT_EINVAL;
    }

    ctrl = &device->stream_ctrl;
    switch (ctrl->policy)
    {
#ifdef RT_ADC_STREAM_USING_LATEST
    case RT_ADC_STREAM_POLICY_LATEST:
        read_count = rt_adc_stream_read_latest(device, buffer, sample_count, timeout_ms);
        break;
#endif /* RT_ADC_STREAM_USING_LATEST */
#ifdef RT_ADC_STREAM_USING_FIFO
    case RT_ADC_STREAM_POLICY_FIFO:
        read_count = rt_adc_stream_read_fifo(device, buffer, sample_count, timeout_ms);
        break;
#endif /* RT_ADC_STREAM_USING_FIFO */
    default:
        read_count = -RT_EINVAL;
        break;
    }

    return read_count;
}

/**
 * @brief Cancel a blocked ADC stream reader before stream shutdown.
 * @param device Pointer to the ADC device object.
 * @return Operation status.
 */
rt_err_t rt_adc_stream_cancel(rt_adc_device_t device)
{
    struct rt_adc_stream_ctrl *ctrl;
    rt_atomic_t old_error;
    enum rt_adc_state state;

    if (device == RT_NULL)
    {
        return -RT_EINVAL;
    }

    state = adc_get_state(device);
    if (state != RT_ADC_STATE_STREAM)
    {
        return (state == RT_ADC_STATE_IDLE) ? -RT_EINVAL : -RT_EBUSY;
    }

    ctrl = &device->stream_ctrl;
    old_error = (rt_atomic_t)RT_EOK;
    (void)rt_atomic_compare_exchange_strong(&ctrl->last_error, &old_error, (rt_atomic_t)-RT_EINTR);

#ifdef RT_ADC_STREAM_USING_FIFO
    adc_stream_fifo_wakeup(ctrl);
#endif /* RT_ADC_STREAM_USING_FIFO */

    return RT_EOK;
}

/**
 * @brief Stop one ADC stream session.
 * @param device Pointer to the ADC device object.
 * @return Operation status.
 */
rt_err_t rt_adc_stream_stop(rt_adc_device_t device)
{
    rt_bool_t hardware_stopped;
    rt_err_t result;
    rt_err_t trigger_result;
    enum rt_adc_state state;

    if (device == RT_NULL)
    {
        return -RT_EINVAL;
    }

    if ((device->ops == RT_NULL) || (device->ops->stream == RT_NULL) || (device->ops->stream->stop == RT_NULL))
    {
        return -RT_ENOSYS;
    }

    state = adc_get_state(device);
    if (state == RT_ADC_STATE_IDLE)
    {
        return RT_EOK;
    }
    if (state != RT_ADC_STATE_STREAM)
    {
        return -RT_EBUSY;
    }

    if (adc_try_set_state(device, RT_ADC_STATE_STREAM, RT_ADC_STATE_LOCKED) != RT_TRUE)
    {
        return -RT_EBUSY;
    }

#if defined(RT_ADC_USING_TRIGGER)
    rt_bool_t trigger_started = RT_TRUE;
    trigger_result = adc_trigger_source_control(device, ADC_TRIGGER_SOURCE_STOP, &trigger_started, RT_EOK);
#else
    trigger_result = RT_EOK;
#endif /* defined(RT_ADC_USING_TRIGGER) */

    hardware_stopped = RT_FALSE;
    result = device->ops->stream->stop(device, &hardware_stopped);
    if ((result == RT_EOK) && (trigger_result != RT_EOK))
    {
        result = trigger_result;
    }

    if ((result == RT_EOK) || (hardware_stopped == RT_TRUE))
    {
#ifdef RT_ADC_STREAM_USING_FIFO
        rt_atomic_store(&device->stream_ctrl.last_error, (rt_atomic_t)((result == RT_EOK) ? -RT_EINVAL : result));
        adc_stream_fifo_wakeup(&device->stream_ctrl);
        device->stream_ctrl.fifo_enabled = RT_FALSE;
#endif /* RT_ADC_STREAM_USING_FIFO */
        adc_stream_ctrl_reset(&device->stream_ctrl);
        adc_clear_session_ctrl(device);
        adc_set_state(device, RT_ADC_STATE_IDLE);
    }
    else
    {
        adc_set_state(device, RT_ADC_STATE_STREAM);
    }

    return result;
}

/**
 * @brief ADC stream ISR event handler used by low-level drivers.
 * @param device Pointer to the ADC device object.
 * @param event Stream event.
 * @param sample_buffer Pointer to the completed DMA sample block.
 * @param sample_count Completed sample count.
 * @return Operation status.
 */
rt_err_t rt_hw_adc_stream_isr(rt_adc_device_t device, enum rt_adc_stream_event event,
                               const rt_uint32_t *sample_buffer, rt_size_t sample_count)
{
    struct rt_adc_stream_ctrl *ctrl;
    enum rt_adc_state state;
#ifdef RT_ADC_STREAM_USING_FIFO
    const rt_uint8_t *src;
    rt_size_t bytes;
    rt_size_t put_len;
    rt_size_t data_len;
    rt_base_t level;
#endif /* RT_ADC_STREAM_USING_FIFO */

    if (device == RT_NULL)
    {
        return -RT_EINVAL;
    }

    ctrl = &device->stream_ctrl;
    if (event == RT_ADC_STREAM_EVENT_ERROR)
    {
        rt_atomic_t old_error;

        old_error = (rt_atomic_t)RT_EOK;
        if (rt_atomic_compare_exchange_strong(&ctrl->last_error, &old_error, (rt_atomic_t)-RT_ERROR) == RT_TRUE)
        {
            LOG_W("stream error: device=%s event=%d", device->parent.parent.name, event);
        }
#ifdef RT_ADC_STREAM_USING_FIFO
        adc_stream_fifo_wakeup(ctrl);
#endif /* RT_ADC_STREAM_USING_FIFO */
        return RT_EOK;
    }

    state = adc_get_state(device);
#ifdef RT_ADC_STREAM_USING_FIFO
    if ((state != RT_ADC_STATE_STREAM) && !((state == RT_ADC_STATE_LOCKED) && (ctrl->fifo_enabled == RT_TRUE)))
    {
        return RT_EOK;
    }
#else
    if (state != RT_ADC_STATE_STREAM)
    {
        return RT_EOK;
    }
#endif /* RT_ADC_STREAM_USING_FIFO */

    if ((event != RT_ADC_STREAM_EVENT_DMA_HALF) && (event != RT_ADC_STREAM_EVENT_DMA_DONE))
    {
        return -RT_EINVAL;
    }

    if ((rt_err_t)rt_atomic_load(&ctrl->last_error) != RT_EOK)
    {
        return RT_EOK;
    }

#ifdef RT_ADC_STREAM_USING_FIFO
    if ((ctrl->policy != RT_ADC_STREAM_POLICY_FIFO) || (ctrl->fifo_enabled != RT_TRUE))
    {
        return RT_EOK;
    }

    if ((sample_buffer == RT_NULL) || (sample_count == 0U))
    {
        return -RT_EINVAL;
    }

    src = (const rt_uint8_t *)sample_buffer;
    bytes = sample_count * sizeof(rt_uint32_t);

    level = rt_spin_lock_irqsave(&device->spinlock);
    put_len = rt_ringbuffer_put(&ctrl->fifo, src, (rt_uint32_t)bytes);
    data_len = rt_ringbuffer_data_len(&ctrl->fifo);
    rt_spin_unlock_irqrestore(&device->spinlock, level);

    if (put_len < bytes)
    {
        rt_atomic_t old_error;
        ctrl->overflow_count++;
        old_error = (rt_atomic_t)RT_EOK;
        if (rt_atomic_compare_exchange_strong(&ctrl->last_error, &old_error, (rt_atomic_t)-RT_EFULL) == RT_TRUE)
        {
            LOG_W("stream fifo overflow: device=%s put=%u expected=%u data_len=%u",
                device->parent.parent.name, (unsigned int)put_len, (unsigned int)bytes, (unsigned int)data_len);
        }
        adc_stream_fifo_wakeup(ctrl);
    }

    if ((put_len > 0U) && ((ctrl->watermark == 0U) || (data_len >= (ctrl->watermark * sizeof(rt_uint32_t)))))
    {
        adc_stream_fifo_wakeup(ctrl);

        if (ctrl->callback != RT_NULL)
        {
            ctrl->callback(device, put_len / sizeof(rt_uint32_t), ctrl->user_data);
        }
    }

    return RT_EOK;
#else
    RT_UNUSED(sample_buffer);
    RT_UNUSED(sample_count);
    return RT_EOK;
#endif /* RT_ADC_STREAM_USING_FIFO */
}
#endif /* RT_ADC_USING_STREAM */

/**
 * @brief Convert one ADC raw sample to millivolts.
 * @param raw_value Raw ADC sample code.
 * @param vref_mv ADC reference voltage in millivolts.
 * @param resolution_bits ADC resolution in bits.
 * @param voltage_mv Pointer to the output voltage in millivolts.
 * @return Operation status.
 *
 * ADC codes are treated as an inclusive range from 0 to
 * ``(1 << resolution_bits) - 1``. The calculation uses a 64-bit
 * intermediate value and rounds to the nearest integer millivolt.
 */
rt_err_t rt_adc_raw_to_voltage_mv(rt_uint32_t raw_value, rt_uint32_t vref_mv,
                                  rt_uint8_t resolution_bits, rt_uint32_t *voltage_mv)
{
    rt_uint64_t full_scale_code;

    if ((voltage_mv == RT_NULL) || (vref_mv == 0U) || (resolution_bits == 0U) || (resolution_bits > 32U))
    {
        return -RT_EINVAL;
    }

    full_scale_code = ((rt_uint64_t)1 << resolution_bits) - 1ULL;
    if ((rt_uint64_t)raw_value > full_scale_code)
    {
        return -RT_EINVAL;
    }

    /*
     * Convert ADC code to millivolts:
     *
     *     voltage_mv = raw * vref_mv / full_scale_code
     *     full_scale_code = (1 << resolution_bits) - 1
     *
     * ADC codes are treated as an inclusive range from 0 to full scale.
     * The multiplication is promoted to 64-bit first, then half of the
     * denominator is added to round to the nearest integer millivolt instead
     * of truncating non-exact divisions toward zero.
     */
    *voltage_mv = (rt_uint32_t)(((rt_uint64_t)raw_value * (rt_uint64_t)vref_mv + (full_scale_code / 2ULL)) / full_scale_code);

    return RT_EOK;
}

/**
 * @brief Convert one ADC raw sample to a scaled voltage in millivolts.
 * @param raw_value Raw ADC sample code.
 * @param vref_mv ADC reference voltage in millivolts.
 * @param resolution_bits ADC resolution in bits.
 * @param scale_num Voltage scaling numerator.
 * @param scale_den Voltage scaling denominator.
 * @param voltage_mv Pointer to the output scaled voltage in millivolts.
 * @return Operation status.
 *
 * The scaled voltage is calculated as:
 *
 *     raw_to_voltage_mv(raw_value) * scale_num / scale_den
 *
 * @note @p scale_num and @p scale_den may describe any positive rational
 *       scaling ratio that does not overflow the internal calculation. The
 *       final scaled millivolt value must fit in rt_uint32_t.
 *
 * @retval RT_EOK The conversion completed successfully.
 * @retval -RT_EINVAL A pointer is null, a scale argument is zero, the ADC
 *         conversion arguments are invalid, or the scaled result overflows
 *         rt_uint32_t.
 */
rt_err_t rt_adc_raw_to_scaled_voltage_mv(rt_uint32_t raw_value, rt_uint32_t vref_mv,
                                         rt_uint8_t resolution_bits, rt_uint32_t scale_num,
                                         rt_uint32_t scale_den, rt_uint32_t *voltage_mv)
{
    rt_uint32_t input_mv;
    rt_uint64_t numerator;
    rt_uint64_t rounding;
    rt_uint64_t scaled_mv;
    rt_err_t result;

    if ((voltage_mv == RT_NULL) || (scale_num == 0U) || (scale_den == 0U))
    {
        return -RT_EINVAL;
    }

    result = rt_adc_raw_to_voltage_mv(raw_value, vref_mv, resolution_bits, &input_mv);
    if (result != RT_EOK)
    {
        return result;
    }

    numerator = (rt_uint64_t)input_mv * (rt_uint64_t)scale_num;
    rounding = (rt_uint64_t)scale_den / 2ULL;

    if (numerator > (((rt_uint64_t)~0ULL) - rounding))
    {
        return -RT_EINVAL;
    }

    scaled_mv = (numerator + rounding) / (rt_uint64_t)scale_den;
    if (scaled_mv > RT_UINT32_MAX)
    {
        return -RT_EINVAL;
    }

    *voltage_mv = (rt_uint32_t)scaled_mv;
    return RT_EOK;
}

/**
 * @brief Read voltage values from the configured ADC session.
 * @param device Pointer to the ADC device object.
 * @param voltages_mv Pointer to the output voltage buffer in millivolts.
 * @param size Output voltage buffer length in samples.
 * @param timeout_ms Read timeout in milliseconds; negative means wait forever.
 * @return Operation status.
 *
 * @note @p size must match the configured session channel count. The output
 *       order follows the ascending bit order of the configured channel mask.
 *       The configured default_vref_mv is preferred for voltage conversion. If
 *       default_vref_mv is not configured, the backend VREF channel is used for
 *       VDDA calculation only when it is present in the configured session.
 */
rt_err_t rt_adc_voltage(rt_adc_device_t device, rt_uint32_t *voltages_mv, rt_size_t size, rt_int32_t timeout_ms)
{
    rt_uint32_t vref_mv;
    rt_uint32_t vref_value;
    rt_uint8_t resolution_bits;
    rt_uint8_t vref_channel;
    rt_size_t vref_index;
    rt_size_t index;
    struct rt_adc_sequence_cfg sequence_cfg;
    rt_size_t read_count;
    rt_err_t result;

    if ((device == RT_NULL) || (voltages_mv == RT_NULL))
    {
        return -RT_EINVAL;
    }

    if ((device->ops == RT_NULL) || (device->ops->core == RT_NULL) || (device->ops->core->control == RT_NULL))
    {
        return -RT_ENOSYS;
    }

    if (adc_try_set_state(device, RT_ADC_STATE_IDLE, RT_ADC_STATE_LOCKED) != RT_TRUE)
    {
        return -RT_EBUSY;
    }

    LOG_D("voltage request: device=%s count=%u timeout=%ld", device->parent.parent.name, (unsigned int)size, (long)timeout_ms);

    if ((device->session_ctrl.configured != RT_TRUE) || (device->session_ctrl.channel_count == 0U) || (size != device->session_ctrl.channel_count))
    {
        result = -RT_EINVAL;
        goto out;
    }

    rt_memset(&sequence_cfg, 0, sizeof(sequence_cfg));
    sequence_cfg.buffer = voltages_mv;
    sequence_cfg.buffer_length = size;
    sequence_cfg.timeout_ms = timeout_ms;
    result = adc_sequence_transfer_locked(device, device->session_ctrl.channels,
                                        &sequence_cfg, size, &read_count);
    if ((result == RT_EOK) && (read_count != size))
    {
        result = -RT_ERROR;
    }
    if (result != RT_EOK)
    {
        LOG_E("voltage sample read failed: device=%s result=%d", device->parent.parent.name, result);
        goto out;
    }

    result = device->ops->core->control(device, RT_ADC_CMD_GET_RESOLUTION, &resolution_bits);
    if (result != RT_EOK)
    {
        goto out;
    }

    vref_mv = 0U;
    if (device->default_vref_mv != 0U)
    {
        vref_mv = device->default_vref_mv;
        result = RT_EOK;
    }
    else
    {
        vref_channel = 0U;
        result = device->ops->core->control(device, RT_ADC_CMD_GET_VREF_CHANNEL, &vref_channel);
        if ((result == RT_EOK) && (vref_channel < 32U) && ((device->session_ctrl.channels & RT_ADC_CHANNEL_MASK(vref_channel)) != 0U))
        {
            result = rt_adc_session_channel_index(device->session_ctrl.channels, RT_ADC_CHANNEL_MASK(vref_channel), &vref_index);
            if (result != RT_EOK)
            {
                goto out;
            }

            vref_value = voltages_mv[vref_index];
            result = device->ops->core->control(device, RT_ADC_CMD_CALC_VREF, &vref_value);
            if (result != RT_EOK)
            {
                LOG_E("vref calculate failed: device=%s raw=%lu result=%d",
                      device->parent.parent.name, (unsigned long)voltages_mv[vref_index], result);
                goto out;
            }

            if (vref_value == 0U)
            {
                result = -RT_EINVAL;
                goto out;
            }

            vref_mv = vref_value;
        }
        else
        {
            result = -RT_EINVAL;
            goto out;
        }
    }

    for (index = 0U; index < size; index++)
    {
        result = rt_adc_raw_to_voltage_mv(voltages_mv[index], vref_mv, resolution_bits, &voltages_mv[index]);
        if (result != RT_EOK)
        {
            goto out;
        }
    }

    LOG_D("voltage done: device=%s count=%u vref=%lu resolution=%u",
          device->parent.parent.name, (unsigned int)size,
          (unsigned long)vref_mv, (unsigned int)resolution_bits);
    result = RT_EOK;

out:
    adc_set_state(device, RT_ADC_STATE_IDLE);
    return result;
}

#endif /* defined(RT_USING_ADC_V2) */