rt_spi_configure配置相关问题

发布于 2025-03-14 17:53:24 浏览：97 订阅该版

在使用rt_spi_configure配置过程中，函数内必要要求`device->bus->owner == device`？
系统刚开始配置的时候，此处应该就是不相等的，为什么不能判断为不相等时，执行后续配置工作？
不然每次系统初始配置时，都执行不到后续配置，必须要到读写操作时，才能执行配置操作。

```c
rt_err_t rt_spi_bus_configure(struct rt_spi_device *device)
{
    rt_err_t result = -RT_ERROR;

if (device->bus != RT_NULL)
    {
        result = rt_mutex_take(&(device->bus->lock), RT_WAITING_FOREVER);
        if (result == RT_EOK)
        {
            if (device->bus->owner == device）    // 此处配置为什么要相等？每次初始配置时，都执行不到后续配置操作
            {
                /* current device is using, re-configure SPI bus */
                result = device->bus->ops->configure(device, &device->config);
                if (result != RT_EOK)
                {
                    /* configure SPI bus failed */
                    LOG_E("SPI device %s configuration failed", device->parent.parent.name);
                }
            }
            else
            {
                /* RT_EBUSY is not an error condition and
                 * the configuration will take effect once the device has the bus
                 */
                result = -RT_EBUSY;
            }

/* release lock */
            rt_mutex_release(&(device->bus->lock));
        }
    }
    else
    {
        result = RT_EOK;
    }

return result;
}
```

```c
rt_err_t rt_spi_configure(struct rt_spi_device        *device,
                          struct rt_spi_configuration *cfg)
{
    RT_ASSERT(device != RT_NULL);
    RT_ASSERT(cfg != RT_NULL);

/* reset the CS pin */
    if (device->cs_pin != PIN_NONE)
    {
        rt_err_t result = rt_mutex_take(&(device->bus->lock), RT_WAITING_FOREVER);
        if (result == RT_EOK)
        {
            if (cfg->mode & RT_SPI_CS_HIGH)
            {
                rt_pin_write(device->cs_pin, PIN_LOW);
            }
            else
            {
                rt_pin_write(device->cs_pin, PIN_HIGH);
            }
            rt_mutex_release(&(device->bus->lock));
        }
        else
        {
            return result;
        }
    }

/* If the configurations are the same, we don't need to set again. */
    if (device->config.data_width == cfg->data_width &&
        device->config.mode       == (cfg->mode & RT_SPI_MODE_MASK) &&
        device->config.max_hz     == cfg->max_hz)
    {
        return RT_EOK;
    }

/* set configuration */
    device->config.data_width = cfg->data_width;
    device->config.mode       = cfg->mode & RT_SPI_MODE_MASK;
    device->config.max_hz     = cfg->max_hz;

return rt_spi_bus_configure(device);
}
```

三世执戟 2025-03-14

这家伙很懒，什么也没写！

admin_wt 2025-03-14

这家伙很懒，什么也没写！

刚刚拉取了一下最新的源码，此处改动又改回去了。

```c
rt_err_t rt_spi_bus_configure(struct rt_spi_device *device)
{
    rt_err_t result = -RT_ERROR;

if (device->bus != RT_NULL)
    {
        result = rt_mutex_take(&(device->bus->lock), RT_WAITING_FOREVER);
        if (result == RT_EOK)
        {
            if (device->bus->owner == device)    // 当前最新版本源码
            {
                /* current device is using, re-configure SPI bus */
                result = device->bus->ops->configure(device, &device->config);
                if (result != RT_EOK)
                {
                    /* configure SPI bus failed */
                    LOG_E("SPI device %s configuration failed", device->parent.parent.name);
                }
            }
            else
            {
                /* RT_EBUSY is not an error condition and
                 * the configuration will take effect once the device has the bus
                 */
                result = -RT_EBUSY;
            }
            /* release lock */
            rt_mutex_release(&(device->bus->lock));
        }
    }
    else
    {
        result = RT_EOK;
    }

return result;
}
```
CS配置好了，等后面交互时再重新配置一边，使用上面没有什么问题，但是从使用逻辑上面来说，一步配置到位，后续也就不用再进行配置了。

所以就是有点不太明确此处判断相等的用意是什么？