SPI驱动框架一

spi总线

设备链表 spi_device

控制器spi_master

 

读写硬件：

spidev_sync_read(struct spidev_data *spidev, size_t len)
{
    struct spi_transfer t = {
            .rx_buf = spidev->rx_buffer,
            .len = len,
            .speed_hz = spidev->speed_hz,
    };
    struct spi_message m;
    
    spi_message_init(&m);
    spi_message_add_tail(&t, &m);
    return spidev_sync(spidev, &m);
}

spidev_sync_write(struct spidev_data *spidev, size_t len)
{
    struct spi_transfer t = {
            .rx_buf = spidev->tx_buffer,
            .len = len,
            .speed_hz = spidev->speed_hz,
    };
    struct spi_message m;
    
    spi_message_init(&m);
    spi_message_add_tail(&t, &m);
    return spidev_sync(spidev, &m);
}

 

spi_sync是同步函数，这个函数返回的时候，要么传输成功了，要么传输失败了

 

spi_transfer描述一次传输，里面有tx_buf和rx_buf

可以构造多个spi_transfer，然后初始化一个spi_message来进行管理