[PATCH 3/4] spi: stm32: properly fail on dma_request_chan error

[Alain Volmat]

Hi Mark,

On Thu, Dec 18, 2025 at 08:00:57AM +0000, Mark Brown wrote:
> On Wed, Dec 17, 2025 at 10:51:33PM +0100, Alain Volmat wrote:
> > Correct handling of the dma_request_chan call in order to avoid
> > misleading warn message if no DMA is provided within the device-tree
> > and moreover fail if dma_request_chan has returned a valid error.
> 
> Bug fixes should go at the start of serieses to avoid spurious
> dependencies on new or cleanup changes.

Actually I wasn't thinking about requiring this commit to go into
stable branches. Without commit, the driver will still work even if
there is an issue to request a dma channel since it will fallback to
interrupt based transfers.
This commit makes the error visible now, ensuring that if the
device-tree indicates that a DMA should be used, it will either be used
or probe will fail.

Alain