Re: [PATCH v3 8/9] dt-bindings: media: nxp, imx8mq-vpu: Update bindings

On Tue, Feb 23, 2021 at 2:04 AM Benjamin Gaignard
[off-list ref] wrote:

Le 23/02/2021 à 01:34, Rob Herring a écrit :

quoted

On Mon, Feb 22, 2021 at 01:24:05PM +0100, Benjamin Gaignard wrote:

quoted

The current bindings seem to make the assumption that the
two VPUs hardware blocks (G1 and G2) are only one set of
registers.
After implementing the VPU reset driver and G2 decoder driver
it shows that all the VPUs are independent and don't need to
know about the registers of the other blocks.
Remove from the bindings the need to set all blocks register
but keep reg-names property because removing it from the driver
may affect other variants.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
version 2:
- be more verbose about why I change the bindings
Keep in mind that series comes after: https://www.spinics.net/lists/arm-kernel/msg875766.html
without that review and ack it won't work

Better, but you've still mentioned nothing about breaking compatibility.
Why is that okay?

Because this reg-names wasn't used before for this variant so remove it won't change anything.

It is the reset changes in the driver that break. The driver
previously got the 'ctrl' registers whether it went by name or index,
right? With an old DTB and a kernel with the changes (and vice-versa),
you'll have nothing to handle the VPU resets because the VPU reset
node doesn't exist. It could work if the default state is not held in
reset.

At least the removal of 'ctrl' registers belongs in the reset changes series.

Rob

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