Hello,

There's been this patch going on, which adds DMA mode into MXS i2c driver:
https://patchwork.kernel.org/patch/1174051/

Recent nitpick was about toggling the PIOQUEUE (almost like PIO, only
transfer mode in current implementation) vs. DMA mode (newly added) on a
per-bus basis.

Current implementation in the patch adds a DT property, "fsl,use-pio"
(shall be changed to "fsl,use-pioqueue", but that's irrelevant) to select
between the PIOQUEUE and DMA mode on per-bus basis.

There was now a suggestion to dump this property and use kernel module
parameter instead. This obviously disallows to configure this behavior on
per-bus basis. Consider a scenario where small transfers happens on one
bus (possibly from a sensor) and large transfers on the other bus (eg. i2c
EEPROM). In such scenario, it's beneficial to enable PIOQUEUE mode for the
sensor and DMA mode for the EEPROM to minimize the overall overhead.

The mixed mode (PIOQ for small data and DMA for large data transfers) isn't
supported yet.

Please advise.

Best regards,
Marek Vasut

BUMP?