Linux-Media Archive on lore.kernel.org
 help / color / Atom feed
From: Helen Koike <helen.koike@collabora.com>
To: Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
	Maxime Ripard <maxime@cerno.tech>
Cc: linux-media@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org,
	linux-sunxi@googlegroups.com,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Rob Herring <robh+dt@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	Yong Deng <yong.deng@magewell.com>,
	Kishon Vijay Abraham I <kishon@ti.com>,
	Vinod Koul <vkoul@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Hans Verkuil <hans.verkuil@cisco.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Hans Verkuil <hverkuil@xs4all.nl>,
	kevin.lhopital@hotmail.com
Subject: Re: [PATCH 08/14] media: sunxi: Add support for the A31 MIPI CSI-2 controller
Date: Wed, 4 Nov 2020 13:38:08 -0300
Message-ID: <f74e4d59-a391-36ab-74aa-8e02aca1b0bc@collabora.com> (raw)
In-Reply-To: <20201104111710.GB287014@aptenodytes>



On 11/4/20 8:17 AM, Paul Kocialkowski wrote:
> Hi,
> 
> On Mon 02 Nov 20, 10:21, Maxime Ripard wrote:
>> On Fri, Oct 30, 2020 at 07:45:18PM -0300, Helen Koike wrote:
>>> On 10/23/20 2:45 PM, Paul Kocialkowski wrote:
>>>> The A31 MIPI CSI-2 controller is a dedicated MIPI CSI-2 controller
>>>> found on Allwinner SoCs such as the A31 and V3/V3s.
>>>>
>>>> It is a standalone block, connected to the CSI controller on one side
>>>> and to the MIPI D-PHY block on the other. It has a dedicated address
>>>> space, interrupt line and clock.
>>>>
>>>> Currently, the MIPI CSI-2 controller is hard-tied to a specific CSI
>>>> controller (CSI0) but newer SoCs (such as the V5) may allow switching
>>>> MIPI CSI-2 controllers between CSI controllers.
>>>>
>>>> It is represented as a V4L2 subdev to the CSI controller and takes a
>>>> MIPI CSI-2 sensor as its own subdev, all using the fwnode graph and
>>>> media controller API.
>>>
>>> Maybe this is a bad idea, but I was thinking:
>>> This driver basically just turn on/off and catch some interrupts for errors,
>>> and all the rest of v4l2 config you just forward to the next subdevice
>>> on the pipeline.
>>>
>>> So instead of exposing it as a subdevice, I was wondering if modeling
>>> this driver also through the phy subsystem wouldn't be cleaner, so
>>> you won't need all the v4l2 subdevice/topology boilerplate code that
>>> it seems you are not using (unless you have plans to add controls or
>>> some specific configuration on this node later).
>>>
>>> But this would require changes on the sun6i-csi driver.
>>>
>>> What do you think?
>>
>> Eventually we'll need to filter the virtual channels / datatypes I
>> guess, so it's definitely valuable to have it in v4l2

Which kind of datatypes? I ask to know if this shouldn't be configured
through the video node instead of subdevice.

Regarding channels, we had a discussion to implement it through the video
node (and not subdevice) [1]. But we discussed about blitters and multi-scalers,
so now I'm wondering if we could use the same API for mipi-csi virtual channels
in the video entity device, or if it doesn't apply and we need another API
for that in a subdevice instead.

[1] https://patchwork.linuxtv.org/project/linux-media/cover/20200717115435.2632623-1-helen.koike@collabora.com/

> 
> Agreed and like I mentionned in the discussion on 00/14 I don't think it
> would be a cleaner way to expose things.
> 
> There's also the fact that newer SoCs like the V5 seem to allow connecting
> any MIPI CSI-2 controller to any CSI controller, so the graph representation
> is definitely welcome here.

I'm not sure this is an advantage in userspace pov, because it means we'll
have different topologies for basically the same end result to userspace.

But as I mentioned, I don't mind keeping it in the media topology.
Helen

> 
> Paul
> 

  reply index

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-23 17:45 [PATCH 00/14] Allwinner MIPI CSI-2 support for A31/V3s/A83T Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 01/14] phy: Distinguish between Rx and Tx for MIPI D-PHY with submodes Paul Kocialkowski
2020-10-23 18:18   ` [linux-sunxi] " Jernej Škrabec
2020-10-24  8:31     ` Paul Kocialkowski
2020-10-30 22:44   ` Helen Koike
2020-10-23 17:45 ` [PATCH 02/14] phy: allwinner: phy-sun6i-mipi-dphy: Support D-PHY Rx mode for MIPI CSI-2 Paul Kocialkowski
2020-10-26 15:38   ` Maxime Ripard
2020-10-27  9:23     ` Paul Kocialkowski
2020-10-27 18:28       ` Maxime Ripard
2020-11-04 10:53         ` Paul Kocialkowski
2020-10-30 22:44   ` Helen Koike
2020-11-04 10:54     ` Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 03/14] media: sun6i-csi: Support an optional dedicated memory pool Paul Kocialkowski
2020-10-26 15:41   ` Maxime Ripard
2020-10-27  9:26     ` Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 04/14] media: sun6i-csi: Fix the image storage bpp for 10/12-bit Bayer formats Paul Kocialkowski
2020-10-30 22:45   ` Helen Koike
2020-11-04 10:56     ` Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 05/14] media: sun6i-csi: Only configure the interface data width for parallel Paul Kocialkowski
2020-10-26 16:00   ` Maxime Ripard
2020-10-27  9:31     ` Paul Kocialkowski
2020-10-27 18:31       ` Maxime Ripard
2020-10-23 17:45 ` [PATCH 06/14] media: sun6i-csi: Support feeding from the MIPI CSI-2 controller Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 07/14] dt-bindings: media: i2c: Add A31 MIPI CSI-2 bindings documentation Paul Kocialkowski
2020-10-26 16:14   ` Maxime Ripard
2020-10-27  9:52     ` Paul Kocialkowski
2020-10-27 18:44       ` Maxime Ripard
2020-11-04 10:48         ` Paul Kocialkowski
2020-11-04 16:53           ` Maxime Ripard
2020-10-30 16:33   ` Rob Herring
2020-10-30 16:56   ` Sakari Ailus
2020-10-23 17:45 ` [PATCH 08/14] media: sunxi: Add support for the A31 MIPI CSI-2 controller Paul Kocialkowski
2020-10-26  8:39   ` Dan Carpenter
2020-10-26 16:54   ` Maxime Ripard
2020-11-04 11:34     ` Paul Kocialkowski
2020-11-04 18:56       ` Maxime Ripard
2020-11-05 14:52         ` Paul Kocialkowski
2020-10-30 22:45   ` Helen Koike
2020-11-02  9:21     ` Maxime Ripard
2020-11-04 11:17       ` Paul Kocialkowski
2020-11-04 16:38         ` Helen Koike [this message]
2020-11-04 18:45           ` Maxime Ripard
2020-11-05 14:14             ` Helen Koike
2020-11-05  8:45   ` Sakari Ailus
2020-11-05 14:55     ` Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 09/14] ARM: dts: sun8i: v3s: Add CSI0 camera interface node Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 10/14] ARM: dts: sun8i: v3s: Add MIPI D-PHY and MIPI CSI-2 interface nodes Paul Kocialkowski
2020-10-26 16:55   ` Maxime Ripard
2020-10-23 17:45 ` [PATCH 11/14] dt-bindings: media: i2c: Add A83T MIPI CSI-2 bindings documentation Paul Kocialkowski
2020-10-26 16:56   ` Maxime Ripard
2020-11-04 10:33     ` Paul Kocialkowski
2020-11-05  8:48   ` Sakari Ailus
2020-10-23 17:45 ` [PATCH 12/14] media: sunxi: Add support for the A83T MIPI CSI-2 controller Paul Kocialkowski
2020-10-26  8:53   ` Dan Carpenter
2020-10-26 17:00   ` Maxime Ripard
2020-11-04 10:37     ` Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 13/14] ARM: dts: sun8i: a83t: Add MIPI CSI-2 controller node Paul Kocialkowski
2020-10-23 17:45 ` [PATCH 14/14] media: sunxi: sun8i-a83t-mipi-csi2: Avoid using the (unsolicited) interrupt Paul Kocialkowski
2020-10-26 16:57   ` Maxime Ripard
2020-10-26 17:20 ` [PATCH 00/14] Allwinner MIPI CSI-2 support for A31/V3s/A83T Maxime Ripard
2020-10-30 22:44 ` Helen Koike
2020-11-02  9:17   ` Maxime Ripard
2020-11-04 11:11   ` Paul Kocialkowski
2020-11-04 11:14     ` Paul Kocialkowski
2020-11-04 16:36     ` Helen Koike
2020-11-05 14:58       ` Paul Kocialkowski

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=f74e4d59-a391-36ab-74aa-8e02aca1b0bc@collabora.com \
    --to=helen.koike@collabora.com \
    --cc=devel@driverdev.osuosl.org \
    --cc=devicetree@vger.kernel.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=hans.verkuil@cisco.com \
    --cc=hverkuil@xs4all.nl \
    --cc=kevin.lhopital@hotmail.com \
    --cc=kishon@ti.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-sunxi@googlegroups.com \
    --cc=maxime@cerno.tech \
    --cc=mchehab@kernel.org \
    --cc=p.zabel@pengutronix.de \
    --cc=paul.kocialkowski@bootlin.com \
    --cc=robh+dt@kernel.org \
    --cc=sakari.ailus@linux.intel.com \
    --cc=thomas.petazzoni@bootlin.com \
    --cc=vkoul@kernel.org \
    --cc=wens@csie.org \
    --cc=yong.deng@magewell.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Media Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-media/0 linux-media/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-media linux-media/ https://lore.kernel.org/linux-media \
		linux-media@vger.kernel.org
	public-inbox-index linux-media

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-media


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git