请教rt_spi_configure函数理解

发布于 2015-07-28 20:04:39 浏览：3440 订阅该版

```c
rt_err_t rt_spi_configure(struct rt_spi_device        *device,
                          struct rt_spi_configuration *cfg)
{
    rt_err_t result;

RT_ASSERT(device != RT_NULL);

/* 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 ;

if (device->bus != RT_NULL)
    {
        result = rt_mutex_take(&(device->bus->lock), RT_WAITING_FOREVER);
        if (result == RT_EOK)
        {
            if (device->bus->owner == device)
            {
                device->bus->ops->configure(device, &device->config);
            }

/* release lock */
            rt_mutex_release(&(device->bus->lock));
        }
    }

return RT_EOK;
}
```
以sst25vfxx为例使用到device->bus->owner主要是以下2个函数，并没有对owner进行赋值 ，导致今天调试时发现底层的configure没有执行，请大家指教是我理解出错，还是其他原因。
```c
rt_err_t sst25vfxx_init(const char * flash_device_name, const char * spi_device_name)
    /* config spi */
    {
        struct rt_spi_configuration cfg;
        cfg.data_width = 8;
        cfg.mode = RT_SPI_MODE_0 | RT_SPI_MSB; /* SPI Compatible: Mode 0 and Mode 3 */
        cfg.max_hz = 50000000; /* 50M */
        rt_spi_configure(spi_flash->rt_spi_device, &cfg);
    }

rt_err_t rt_spi_bus_register(struct rt_spi_bus       *bus,
                             const char              *name,
                             const struct rt_spi_ops *ops)
{
    rt_err_t result;

result = rt_spi_bus_device_init(bus, name);
    if (result != RT_EOK)
        return result;

/* initialize mutex lock */
    rt_mutex_init(&(bus->lock), name, RT_IPC_FLAG_FIFO);
    /* set ops */
    bus->ops = ops;
    /* initialize owner */
    bus->owner = RT_NULL;

return RT_EOK;
}
```