Le 03/03/2021 à 15:17, Philipp Zabel a écrit :
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.
They are all part of the control block and of the reset process for this
hardware that why I put them here. I guess it is border line :-)
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.
I will give a try in this direction.
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.
If I want to use a syscon (or a reset) the driver must not ioremap the "ctrl"
registers. It means that "ctrl" has to be removed from the driver requested
reg-names (imx8mq_reg_names[]). Doing that break the kernel/DT compatibility.
Somehow syscon and "ctrl" are exclusive.
Benjamin
regards
Philipp
