Re: [PATCH v3 0/5] Reset driver for IMX8MQ VPU hardware block

Philipp Zabel
2021-03-03T18:23:16Z

Hi Benjamin,

On Mon, 2021-03-01 at 16:17 +0100, Benjamin Gaignard wrote:
> The two VPUs inside IMX8MQ share the same control block which can be see
> as a reset hardware block.

This isn't a reset controller though. The control block also contains
clock gates of some sort and a filter register for the featureset fuses.
Those shouldn't be manipulated via the reset API.

> In order to be able to add the second VPU (for HECV decoding) it will be
> more handy if the both VPU drivers instance don't have to share the
> control block registers. This lead to implement it as an independ reset
> driver and to change the VPU driver to use it.

Why not switch to a syscon regmap for the control block? That should
also allow to keep backwards compatibility with the old binding with
minimal effort.

> Please note that this series break the compatibility between the DTB and
> kernel. This break is limited to IMX8MQ SoC and is done when the driver
> is still in staging directory.

I know in this case we are pretty sure there are no users of this
binding except for a staging driver, but it would still be nice to keep
support for the deprecated binding, to avoid the requirement of updating
kernel and DT in lock-step.

regards
Philipp