Re: [PATCH v7 0/4] drm: add support for Cadence MHDP DPI/DP bridge.

From: Tomi Valkeinen <tomi.valkeinen@ti.com>
To: Damian Kos <dkos@cadence.com>
Cc: "David Airlie" <airlied@linux.ie>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Andrzej Hajda" <a.hajda@samsung.com>,
	"Laurent Pinchart" <Laurent.pinchart@ideasonboard.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <maxime.ripard@bootlin.com>,
	"Sean Paul" <sean@poorly.run>, "Sandy Huang" <hjc@rock-chips.com>,
	"Heiko Stübner" <heiko@sntech.de>,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, jbergsagel@ti.com,
	quentin.schulz@bootlin.com, piotrs@cadence.com,
	rafalc@cadence.com
Subject: Re: [PATCH v7 0/4] drm: add support for Cadence MHDP DPI/DP bridge.
Date: Wed, 20 Mar 2019 11:33:46 +0200	[thread overview]
Message-ID: <ce6ed2e6-90d5-fc7a-4d6d-ab27d62c5432@ti.com> (raw)
In-Reply-To: <0f11a4d8-d576-5af8-b7f4-afe3ff26678f@ti.com>

Damian, ping.

On 31/01/2019 14:08, Tomi Valkeinen wrote:
> Hi,
> 
> On 30/01/2019 13:03, Damian Kos wrote:
>> Hello!
>>
>> This is the series of patches that will add support for the Cadence's DPI/DP
>> bridge. Please note that this is a preliminary version of the driver and there
>> will be more patches in the future with updates, fixes and improvements.
>> Please keep that in mind when looking at FIXME/TODO/XXX comments.
>>
>> Initially, MHDP driver was developed as a DRM bridge driver and was planed to
>> be placed in drivers/gpu/drm/bridge/mhdp.c.  However, there was already
>> a driver for Cadence's DP controller developed by RockChip, but that driver
>> uses the different DRM framework and looks like a part of a bigger system.
>> Both controllers (including firmware) are quite different internally
>> (MST/FEC/DSC support, link training done by driver, additional commands, IRQ's
>> etc.) but they have similar register map, except for Framer/Streamer (which is
>> noticeably different), so they appear similar.
>>
>> The following patches contain:
>> - Moving common code to drivers/gpu/drm/bridge/cdns-mhdp-common.* and
>>   modifying it a bit (mostly new prefixes for functions and data types) so it
>>   can be used by two, higher level, drivers.
>> - Modifying existing RockChip's DP driver to use the common code after changes
>>   made to it (use the new cdns_mhdp_device structure and new function names).
>> - Modifying DRM helpers a bit. Some are required for new driver, some are
>>   updates from DP 1.2 to 1.3 or 1.4.
>> - Adding documentation for device tree bindings.
>> - Adding preliminary Cadence DPI/DP bridge driver.
>>
>> Some of the things that will be added later on include (but are not limited
>> to):
>> - DSC support
>> - FEC support
>> - HDCP support
> 
> A few random comments/questions after a quick look at the patches.
> 
> The names of the source files and the kernel Kconfig are only about
> "Cadence DP". But the DT bindings is for cdns,mhdp8546, and the
> resulting module file is mhdp8546.ko. I think more consistency here
> would be good.
> 
> I presume the part number (or family? are there other similar parts with
> similar part numbers?) is relevant, so it should be in the Kconfig
> option and help text, and probably in the file names too. The module
> name should have "cdns" prefix there, similar to the source files and
> the cdns-dsi.ko.
> 
> Or maybe the same driver will handle all Cadence DP parts, in which case
> generic filenames are fine, but then the resulting kernel module should
> also be just "cdns-mhdp.ko".
> 
> I see some audio functions in the code, but it's not mentioned in the DT
> bindings. I'm not an audio guy, but the display bridges with audio
> support I have seen have had DT bindings for the audio source too. Is
> audio supported in the current driver?
> 
>  Tomi
> 

-- 
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki