drivers: spi: spi_mcux_dspi: bus busy status ignored in async

[aunsbjerg]

Describe the bug
When doing async SPI reads, the status code from DSPI_MasterTransferNonBlocking is ignored. This means that the context is not unlocked in spi_context_release even though an error condition is present.

I've seen a wide range of behaviour that I believe is caused by this bug. Sometimes, an imprecise bus error is produced, sometimes the board will just reset and sometimes, the board gets unresponsive and requires a hard reset to return to function.

To Reproduce
I've seen this issue on a custom board where we use SPI to read ADC samples from a streaming ADC chip. The driver reads samples from the ADC chip with a 2KHz frequency. Occasionally, the driver will attempt to read a sample before the previous read was finished, resulting in a busy bus and this will occasionally cause the aforementioned crashes, stalls etc.

Expected behavior
I would expect that the spi driver is able to gracefully handle a busy bus without crashing the kernel.

Impact
This is a showstopper as the board does not always restart when the error happens, forcing a manual reset of the board.

Environment:

• Ubuntu 18.04
• SDK 0.10.3
• Zephyr 1.14
• Custom K64f

[aunsbjerg]

A possible fix that works for me: #22582