```
``number``: SPI muber (typically 0, on Compute Module 0-7).
-``channel``: SPI channel (typically 0 or 1, on Compute Module 0-3.).
+``channel``: SPI channel (typically 0 or 1, on Compute Module 0-3).
``speed``: SPI clock.
``mode``: SPI mode (https://www.kernel.org/doc/Documentation/spi/spidev).
``Return Value``: File handle to the SPI bus
```
``number``: SPI muber (typically 0, on Compute Module 0-7).
-``channel``: SPI channel (typically 0 or 1, on Compute Module 0-3.).
+``channel``: SPI channel (typically 0 or 1, on Compute Module 0-3).
``data``: Buffer
``len``: Size of ``data`` buffer or data size.
``Return Value``: Return Value of ``ioctl`` function (https://man7.org/linux/man-pages/man2/ioctl.2.html)
```
``number``: SPI muber (typically 0, on Compute Module 0-7).
-``channel``: SPI channel (typically 0 or 1, on Compute Module 0-3.).
+``channel``: SPI channel (typically 0 or 1, on Compute Module 0-3).
``Return Value``: File handle to the SPI bus
> -1 ... Invalid or not opened