linux-kernel - Re: [PATCH 00/14] Add initial support for the Rockchip RK3588 HDMI TX Controller

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Date: Mon, 03 Jun 2024 15:03:12 +0200
From: Heiko Stuebner <heiko@...ech.de>
To: neil.armstrong@...aro.org,
 Cristian Ciocaltea <cristian.ciocaltea@...labora.com>,
 Andrzej Hajda <andrzej.hajda@...el.com>, Robert Foss <rfoss@...nel.org>,
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
 Sandy Huang <hjc@...k-chips.com>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
 Mark Yao <markyao0591@...il.com>, Andy Yan <andy.yan@...k-chips.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org,
 devicetree@...r.kernel.org, kernel@...labora.com,
 Alexandre ARNOUD <aarnoud@...com>, Luis de Arquer <ldearquer@...il.com>,
 Algea Cao <algea.cao@...k-chips.com>
Subject:
 Re: [PATCH 00/14] Add initial support for the Rockchip RK3588 HDMI TX
 Controller

Am Montag, 3. Juni 2024, 14:14:17 CEST schrieb Andy Yan:
> Hi Neil:
> 
> On 6/3/24 16:55, Neil Armstrong wrote:
> > Hi Christian,
> > 
> > On 01/06/2024 15:12, Cristian Ciocaltea wrote:
> >> The RK3588 SoC family integrates a Quad-Pixel (QP) variant of the
> >> Synopsys DesignWare HDMI TX controller used in the previous SoCs.
> >>
> >> It is HDMI 2.1 compliant and supports the following features, among
> >> others:
> >>
> > .
> > 
> > ..
> > 
> >> * SCDC I2C DDC access
> >> * TMDS Scrambler enabling 2160p@...z with RGB/YCbCr4:4:4
> >> * YCbCr4:2:0 enabling 2160p@...z at lower HDMI link speeds
> >> * Multi-stream audio
> >> * Enhanced Audio Return Channel (EARC)
> > -> Those features were already supported by the HDMI 2.0a compliant HW, just
> > list the _new_ features for HDMI 2.1
> > 
> > I did a quick review of your patchset and I don't understand why you need
> > to add a separate dw-hdmi-qp.c since you only need simple variants of the I2C
> > bus, infoframe and bridge setup.
> > 
> > Can you elaborate further ? isn't this Quad-Pixel (QP) TX controller version
> > detectable at runtime ?
> > 
> > I would prefer to keep a single dw-hdmi driver if possible.
> 
> 
> 
> The QP HDMI controller is a completely different variant with totally different
> registers layout, see PATCH 13/14.
> I think make it a separate driver will be easier for development and maintenance.

I'm with Andy here. Trying to navigate a driver for two IP blocks really
sounds taxing especially when both are so different.

Synopsis also created a new dsi controller for the DSI2 standard, with
a vastly different registers layout.

I guess at some point there is time to say this really is a new IP ;-) .


Though while on that thought, I don't fully understand why both a compiled
under the dw_hdmi kconfig symbol. People going for a minimal kernel might
want one or the other, but not both for their specific board.


Heiko