On Sat, Nov 07, 2020 at 05:13:53PM +0900, Damien Le Moal wrote:
> On slow systems, i.e. systems with a slow CPU resulting in slow context
> switches, calling spi_delay_exec() when executing polled transfers
> using dw_spi_poll_transfer() can lead to RX FIFO overflows. Allow
> platforms to opt out of delayed polling by introducing the
> DW_SPI_CAP_POLL_NODELAY DW SPI capability flag to disable
> the execution of spi_delay_exec() in dw_spi_poll_transfer().

This feels like it should be done based on something like a cutoff for
sufficiently small delays rather than with a capability - it's tuning,
not a property of the system.