From: Marek Vasut <marex@denx.de>
To: Ian Arkver <ian.arkver.dev@gmail.com>, Jacopo Mondi <jacopo@jmondi.org>
Cc: linux-media@vger.kernel.org,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
devicetree@vger.kernel.org
Subject: Re: [PATCH 1/2] media: dt-bindings: Add Intersil ISL7998x DT bindings
Date: Wed, 29 May 2019 13:09:47 +0200 [thread overview]
Message-ID: <acb6c57e-49da-614b-d9fd-833b5eca131c@denx.de> (raw)
In-Reply-To: <59881e2a-56c2-3801-2058-d939b25d6259@gmail.com>
On 5/29/19 1:04 PM, Ian Arkver wrote:
> Hi,
>
> On 29/05/2019 11:41, Marek Vasut wrote:
>> On 5/29/19 8:28 AM, Jacopo Mondi wrote:
>>
>> [...]
>>
>>>>>>> [1]
>>>>>>> https://www.renesas.com/eu/en/products/audio-video/video-decoders-encoders/video-decoders/device/ISL79987.html
>>>>>>>
>>>>>>>
>>>>>>>> +Required Properties:
>>>>>>>> +- compatible: value should be "isil,isl79987"
>>>>>
>>>>> And here you might want to have 2 different compatibles for 79987 and
>>>>> 79988.
>>>>
>>>> The 79988 is not supported yet, do we want to have it in the binding
>>>> doc?
>>>>
>>>
>>> I got mislead by the isl7998x naming scheme you used...
>>>
>>> I would say that's up to you, the two chips seems very similar,
>>> and it might make sense to provide bindings that support both. At the
>>> same time, as long as the here defined bindings does not prevent
>>> future expansions to include the ISL79988, its support could be safely
>>> post-poned. In that case please s/isl7998x/isl79987/ in this document
>>> and do not mention BT565 in the description.
>>
>> Right
>>
>>>> [...]
>>>>
>>>>>>> I see from the example you only support one output port? How do you
>>>>>>> model the input ones.
>>>>>>
>>>>>> I don't . Do we model analog inputs now somehow ?
>>>>>
>>>>> I really think so, please see:
>>>>> Documentation/devicetree/bindings/display/connector/analog-tv-connector.txt
>>>>>
>>>>>
>>>>> And as an example of a board device tree using connectors to model
>>>>> analog input see how the cvbs input on Salvator-X is described:
>>>>>
>>>>> cvbs-in {
>>>>> compatible = "composite-video-connector";
>>>>> label = "CVBS IN";
>>>>>
>>>>> port {
>>>>> cvbs_con: endpoint {
>>>>> remote-endpoint = <&adv7482_ain7>;
>>>>> };
>>>>> };
>>>>> };
>>>>>
>>>>> I think you should provide 4 input ports, where to connect input from
>>>>> the analog connectors, and derive the number of enabled inputs from
>>>>> the number of endpoints connected to an active remote.
>>>>
>>>> Deriving the number of active physical inputs from some existing
>>>> binding
>>>> makes sense.
>>>>
>>>> However unlike the adv7482, the isl79987 does not support remapping the
>>>> physical inputs to ADCs in the chip. It does support some remapping of
>>>> physical inputs to MIPI CSI2 channels, but that's probably not very
>>>> useful.
>>>>
>>>
>>> I understand, but I will now use against you the argument you have
>>> correctly pointed out here below that DT should describe hardware, and
>>> the hardware has indeed 4 input ports..
>>
>> My question here is whether it makes sense to describe the ports even if
>> they cannot be muxed to different ADC. Does it ?
>
> Each input port can be either differential CVBS or single ended with a
> 2:1 input select mux. It would be nice to be able to describe this.
Where do you see that ?
> You cannot remap the inputs to different ADCs, but you can remap the
> ADCs to different VC IDs using the
> ISL7998x_REG_P5_LI_ENGINE_VC_ASSIGNMENT register. Describing each input
> would proivde somewhere to specify the vc-id.
I think Jacopo mentioned above the input muxing and the MIPI CSI2 VC
muxing are two separate things. But I have to wonder, do we have a way
of muxing the VCs in the DT or via the media controller yet ?
--
Best regards,
Marek Vasut
next prev parent reply other threads:[~2019-05-29 11:09 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-20 20:18 [PATCH 1/2] media: dt-bindings: Add Intersil ISL7998x DT bindings Marek Vasut
2019-05-20 20:18 ` [PATCH 2/2] media: i2c: isl7998x: Add driver for Intersil ISL7998x Marek Vasut
2019-07-01 7:58 ` Jacopo Mondi
2019-08-06 14:03 ` Marek Vasut
2019-08-12 15:39 ` Jacopo Mondi
2019-07-01 8:43 ` Sakari Ailus
2019-08-06 14:25 ` Marek Vasut
2019-07-01 8:46 ` Sakari Ailus
2019-05-28 11:47 ` [PATCH 1/2] media: dt-bindings: Add Intersil ISL7998x DT bindings Jacopo Mondi
2019-05-28 14:36 ` Marek Vasut
2019-05-28 15:10 ` Jacopo Mondi
2019-05-28 17:49 ` Marek Vasut
2019-05-29 6:28 ` Jacopo Mondi
2019-05-29 10:41 ` Marek Vasut
2019-05-29 11:04 ` Ian Arkver
2019-05-29 11:09 ` Marek Vasut [this message]
2019-05-29 11:15 ` Ian Arkver
2019-08-06 13:35 ` Marek Vasut
2019-05-29 13:43 ` Jacopo Mondi
2019-08-06 13:35 ` Marek Vasut
2019-07-01 8:04 ` Sakari Ailus
2019-08-06 13:35 ` Marek Vasut
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