spi: rspi: Fix DMA mode when the DMA controller is built as a module

On the Renesas RZ/G2L platform, the RSPI driver falls back to PIO mode
instead of using DMA when the DMA controller driver is built as a module
(CONFIG_RZ_DMAC=m):

    renesas_spi 1004b000.spi: dma_request_slave_channel_compat failed
    renesas_spi 1004b000.spi: DMA not available, using PIO

The driver requests DMA channels through dma_request_slave_channel_compat()
which returns either a valid pointer or NULL and cannot handle
-EPROBE_DEFER. If the DMA controller has not probed yet, the driver falls
back to PIO directly.

Fix this by replacing the dma_request_slave_channel_compat() call with a
regular dma_request_chan() call. dma_request_slave_channel_compat() is
always passed a NULL fn_param in all code paths, so it actually behaves
like a plain dma_request_chan() call.

Fixes: e825b8dd2b36 ("spi: rspi: Add DT support to DMA setup")
Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
Link: https://patch.msgid.link/20260921195943.107247-1-ovidiu.panait.rb@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

0 files changed, 0 insertions, 0 deletions