In cases where requesting for DMA channels fails for some reason, or channel
numbers are not provided in DT or platform data, we switch to PIO-only mode
also checking if platform provides IRQ numbers and interrupt register offsets
in DT and platform data. All dma-only paths are avoided in this mode.
Signed-off-by: NJoel Fernandes <joelf@ti.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>