From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: "Paweł Anikiel" <panikiel@google.com>, "Rob Herring" <robh@kernel.org>
Cc: airlied@gmail.com, akpm@linux-foundation.org,
conor+dt@kernel.org, daniel@ffwll.ch, dinguyen@kernel.org,
hverkuil-cisco@xs4all.nl, krzysztof.kozlowski+dt@linaro.org,
maarten.lankhorst@linux.intel.com, mchehab@kernel.org,
mripard@kernel.org, tzimmermann@suse.de,
devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
chromeos-krk-upstreaming@google.com, ribalda@chromium.org
Subject: Re: [PATCH v2 8/9] media: dt-bindings: Add Intel Displayport RX IP
Date: Wed, 28 Feb 2024 13:18:26 +0100 [thread overview]
Message-ID: <324f7b6e-c72c-40aa-afe6-779345c2eade@linaro.org> (raw)
In-Reply-To: <CAM5zL5pXu5sbzCHY_BrCJ7eZj-p9n0tCo6CmuTqUpvniTrqWJg@mail.gmail.com>
On 28/02/2024 12:05, Paweł Anikiel wrote:
> On Tue, Feb 27, 2024 at 3:29 PM Rob Herring <robh@kernel.org> wrote:
>>
>> On Mon, Feb 26, 2024 at 11:59:42AM +0100, Paweł Anikiel wrote:
>>> On Mon, Feb 26, 2024 at 10:13 AM Krzysztof Kozlowski
>>> <krzysztof.kozlowski@linaro.org> wrote:
>>>>
>>>> On 21/02/2024 17:02, Paweł Anikiel wrote:
>>>>> The Intel Displayport RX IP is a part of the DisplayPort Intel FPGA IP
>>>>> Core. It implements a DisplayPort 1.4 receiver capable of HBR3 video
>>>>> capture and Multi-Stream Transport. The user guide can be found here:
>>>>>
>>>>> https://www.intel.com/programmable/technical-pdfs/683273.pdf
>>>>>
>>>>> Signed-off-by: Paweł Anikiel <panikiel@google.com>
>>>>> ---
>>>>> .../devicetree/bindings/media/intel,dprx.yaml | 160 ++++++++++++++++++
>>>>> 1 file changed, 160 insertions(+)
>>>>> create mode 100644 Documentation/devicetree/bindings/media/intel,dprx.yaml
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/media/intel,dprx.yaml b/Documentation/devicetree/bindings/media/intel,dprx.yaml
>>>>> new file mode 100644
>>>>> index 000000000000..31025f2d5dcd
>>>>> --- /dev/null
>>>>> +++ b/Documentation/devicetree/bindings/media/intel,dprx.yaml
>>>>> @@ -0,0 +1,160 @@
>>>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>>>> +%YAML 1.2
>>>>> +---
>>>>> +$id: http://devicetree.org/schemas/media/intel,dprx.yaml#
>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>>> +
>>>>> +title: Intel DisplayPort RX IP
>>>>> +
>>>>> +maintainers:
>>>>> + - Paweł Anikiel <panikiel@google.com>
>>>>> +
>>>>> +description: |
>>>>> + The Intel Displayport RX IP is a part of the DisplayPort Intel FPGA IP
>>>>> + Core. It implements a DisplayPort 1.4 receiver capable of HBR3 video
>>>>> + capture and Multi-Stream Transport.
>>>>> +
>>>>> + The IP features a large number of configuration parameters, found at:
>>>>> + https://www.intel.com/content/www/us/en/docs/programmable/683273/23-3-20-0-1/sink-parameters.html
>>>>> +
>>>>> + The following parameters have to be enabled:
>>>>> + - Support DisplayPort sink
>>>>> + - Enable GPU control
>>>>> + The following parameters' values have to be set in the devicetree:
>>>>> + - RX maximum link rate
>>>>> + - Maximum lane count
>>>>> + - Support MST
>>>>> + - Max stream count (only if Support MST is enabled)
>>>>> +
>>>>> +properties:
>>>>> + compatible:
>>>>> + const: intel,dprx-20.0.1
>>>>> +
>>>>> + reg:
>>>>> + maxItems: 1
>>>>> +
>>>>> + interrupts:
>>>>> + maxItems: 1
>>>>> +
>>>>> + intel,max-link-rate:
>>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>>> + description: Max link rate configuration parameter
>>>>
>>>> Please do not duplicate property name in description. It's useless.
>>>> Instead explain what is this responsible for.
>>>>
>>>> Why max-link-rate would differ for the same dprx-20.0.1? And why
>>>> standard properties cannot be used?
>>>>
>>>> Same for all questions below.
>>>
>>> These four properties are the IP configuration parameters mentioned in
>>> the device description. When generating the IP core you can set these
>>> parameters, which could make them differ for the same dprx-20.0.1.
>>> They are documented in the user guide, for which I also put a link in
>>> the description. Is that enough? Or should I also document these
>>> parameters here?
>>
>> Use the standard properties: link-frequencies and data-lanes. Those go
>> under the port(s) because they are inheritly per logical link.
>
> The DP receiver has one input interface (a deserialized DP stream),
> and up to four output interfaces (the decoded video streams). The "max
> link rate" and "max lane count" parameters only describe the input
> interface to the receiver. However, the port(s) I am using here are
> for the output streams. They are not affected by those parameters, so
> I don't think these properties should go under the output port(s).
>
> The receiver doesn't have an input port in the DT, because there isn't
> any controllable entity on the other side - the deserializer doesn't
> have any software interface. Since these standard properties
> (link-frequencies and data-lanes) are only defined in
> video-interfaces.yaml (which IIUC describes a graph endpoint), I can't
> use them directly in the device node.
DT describes the hardware, so where does the input come? From something,
right? Regardless if you have a driver or not. There is dp-connector
binding, if this is physical port.
>
> Do you see a way to use these standard properties here?
Best regards,
Krzysztof
next prev parent reply other threads:[~2024-02-28 12:18 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-21 16:02 [PATCH v2 0/9] Add Chameleon v3 video support Paweł Anikiel
2024-02-21 16:02 ` [PATCH v2 1/9] media: v4l2-subdev: Add a pad variant of .query_dv_timings() Paweł Anikiel
2024-02-28 11:25 ` Hans Verkuil
2024-02-28 15:34 ` Paweł Anikiel
2024-02-29 8:02 ` Hans Verkuil
2024-02-29 11:33 ` Paweł Anikiel
2024-02-29 12:05 ` Hans Verkuil
2024-02-21 16:02 ` [PATCH v2 2/9] media: Add Chameleon v3 framebuffer driver Paweł Anikiel
2024-02-28 11:24 ` Hans Verkuil
2024-02-28 15:08 ` Paweł Anikiel
2024-02-28 15:14 ` Hans Verkuil
2024-02-21 16:02 ` [PATCH v2 3/9] drm/dp_mst: Move DRM-independent structures to separate header Paweł Anikiel
2024-02-21 16:02 ` [PATCH v2 4/9] lib: Move DisplayPort CRC functions to common lib Paweł Anikiel
2024-02-21 16:02 ` [PATCH v2 5/9] drm/display: Add mask definitions for DP_PAYLOAD_ALLOCATE_* registers Paweł Anikiel
2024-02-21 16:02 ` [PATCH v2 6/9] media: intel: Add Displayport RX IP driver Paweł Anikiel
2024-02-28 12:11 ` Hans Verkuil
2024-02-21 16:02 ` [PATCH v2 7/9] media: dt-bindings: Add Chameleon v3 framebuffer Paweł Anikiel
2024-02-26 9:10 ` Krzysztof Kozlowski
2024-04-23 17:00 ` Paweł Anikiel
2024-02-21 16:02 ` [PATCH v2 8/9] media: dt-bindings: Add Intel Displayport RX IP Paweł Anikiel
2024-02-26 9:12 ` Krzysztof Kozlowski
2024-02-26 10:59 ` Paweł Anikiel
2024-02-26 12:06 ` Krzysztof Kozlowski
2024-02-26 12:43 ` Paweł Anikiel
2024-02-26 17:29 ` Krzysztof Kozlowski
2024-02-27 13:11 ` Paweł Anikiel
2024-02-27 14:24 ` Rob Herring
2024-02-27 14:29 ` Rob Herring
2024-02-28 11:05 ` Paweł Anikiel
2024-02-28 12:18 ` Krzysztof Kozlowski [this message]
2024-02-28 13:09 ` Paweł Anikiel
2024-02-28 18:09 ` Rob Herring
2024-02-29 10:25 ` Paweł Anikiel
2024-03-01 16:26 ` Rob Herring
2024-02-21 16:02 ` [PATCH v2 9/9] ARM: dts: chameleonv3: Add video device nodes Paweł Anikiel
2024-02-26 9:15 ` Krzysztof Kozlowski
2024-02-26 11:09 ` Paweł Anikiel
2024-02-26 12:07 ` Krzysztof Kozlowski
2024-02-26 12:27 ` Paweł Anikiel
2024-02-26 17:30 ` Krzysztof Kozlowski
2024-02-27 11:26 ` Paweł Anikiel
2024-02-23 19:04 ` [PATCH v2 0/9] Add Chameleon v3 video support Conor Dooley
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