On 17/12/21 05:16PM, Miquel Raynal wrote: > It seems that the number of command bytes must be "2" only when the > command itself is sent in DTR mode. The current logic checks if the > number of command bytes is "2" when any of the cycles is a DTR cycle. It > is likely that so far no device was actually mixing DTR/non-DTR cycles > in the same operation, explaining why this was left undetected until > now. This was intentional. spi_mem_dtr_supports_op() must only be called when the operation is DTR in all phases so I did not add any sanity checks if someone was using it for non-DTR ops. In fact, I added on to this function in [0] to check nbytes for other phases as well. The patch fell off my radar unfortunately, and it didn't get merged. I would like to keep this as it is since we have no user of mixed DTR/non-DTR modes yet. But if you really want to support it, please apply my patch first to make sure we check for every phase, not just command. [0] https://lore.kernel.org/all/20210531181757.19458-5-p.yadav@xxxxxx/ -- Regards, Pratyush Yadav Texas Instruments Inc.