Subject: Re: [PATCH 00/49] DRM driver for Hikey 970

From: Sam Ravnborg <[email-masked]>
Date: Tue, 25 Aug 2020 22:21:53 +0200

Hi Mauro.

Laurent and I discussed this driver a little on irc.
Some highlights:

This parts could use register names:
+       writel(0x2, noc_dss_base + 0xc);
+       writel(0x2, noc_dss_base + 0x8c);
+       writel(0x2, noc_dss_base + 0x10c);
+       writel(0x2, noc_dss_base + 0x18c);

The two nodes in the DT for DPE and DSI uses overlapping range for reg
entries. It looks like a syscon node or some iommu thing is needed to do
this properly.

The chain will lok like this:

DPE -> DSI -> video mux -> {adv7533, panel}

But drm_bridge has not yet support for such non-linear setup.
The recommendation is to focus on the HDMI prat. Then we can later
come up with support for a video mux.

The video mux should have a dedicated node with one input node and two
output nodes. Which is also where the gpio should be.

The DSI node references two DPHY instances - should it be PHY driver(s)?

Does the DSI part contain one or two instances. Clocks looks duplicated.

Does the DPE and DSI share a lot of register blocks - or does it just
look like this from a first point of view?

You can read though the logs here:
https://people.freedesktop.org/~cbrill/dri-log/index.php

Could you please try to get back on some of the points above so we can
help you move forward in the right direction.

Thanks,
	Sam