Hi Sakari,

-----Original Message-----
From: Sakari Ailus [mailto:sakari.ailus@linux.intel.com]
Sent: Thursday, June 06, 2019 5:43 PM
To: Vishal Sagar <redacted>
Cc: Vishal Sagar <redacted>; Hyun Kwon <redacted>;
laurent.pinchart@ideasonboard.com; mchehab@kernel.org;
robh+dt@kernel.org; mark.rutland@arm.com; Michal Simek
[off-list ref]; linux-media@vger.kernel.org;
devicetree@vger.kernel.org; hans.verkuil@cisco.com; linux-arm-
kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Dinesh Kumar
[off-list ref]; Sandip Kothari [off-list ref]; Luca Ceresoli
[off-list ref]; Jacopo Mondi [off-list ref]
Subject: Re: [PATCH v8 1/2] media: dt-bindings: media: xilinx: Add Xilinx MIPI
CSI-2 Rx Subsystem

Hi Vishal,

On Thu, Jun 06, 2019 at 11:54:19AM +0000, Vishal Sagar wrote:

quoted

Hi Sakari,

quoted

-----Original Message-----
From: Sakari Ailus [mailto:sakari.ailus@linux.intel.com]
Sent: Wednesday, June 05, 2019 12:54 AM
To: Vishal Sagar <redacted>
Cc: Hyun Kwon <redacted>; laurent.pinchart@ideasonboard.com;
mchehab@kernel.org; robh+dt@kernel.org; mark.rutland@arm.com;

Michal

quoted

quoted

Simek [off-list ref]; linux-media@vger.kernel.org;
devicetree@vger.kernel.org; hans.verkuil@cisco.com; linux-arm-
kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Dinesh Kumar
[off-list ref]; Sandip Kothari [off-list ref]; Luca Ceresoli
[off-list ref]; Jacopo Mondi [off-list ref]
Subject: Re: [PATCH v8 1/2] media: dt-bindings: media: xilinx: Add Xilinx

MIPI

quoted

quoted

CSI-2 Rx Subsystem

EXTERNAL EMAIL

Hi Vishal,

On Mon, Jun 03, 2019 at 03:29:30PM +0530, Vishal Sagar wrote:

quoted

+Optional properties:
+--------------------
+- .
+  Without this property the driver won't be loaded as IP won't be able to

generate

quoted

+  media bus format compliant stream output.

I think we previously concluded that the format will be just different in
this case. So the description appears incorrect.

Referring to your email https://lkml.org/lkml/2019/3/22/1823 in response to

v6 patches,

quoted

if the video format bridge is not enabled, then the way in which pixels are

transported on

quoted

the bus don't correspond to the existing media bus formats in Linux.

If not loading the driver is incorrect way, is it ok for the driver to allow same

media bus format

quoted

for packed and unpacked data type on the sink pad?

Or is it ok for the driver to not validate the media bus format set on the sink

pad?

Taking a fresh look at the issue --- usually such unpacking is done by the
DMA engine, or the same device contains both the CSI-2 RX and DMA. But here
it actually affects the input of that DMA engine. You're right in saying we
don't have format definitions from which you could tell which case it is,
and we also don't have other pre-existing means to tell them apart.

Feel free to keep the check in the driver, but we can't refer to the driver
loading in DT binding documentation: this is really not supposed to be
related to that driver, or even Linux at all.

Ok got it. The description here shouldn't be specific to driver.
I will keep the check in driver.

How about changing this to:

xlnx,vfb: Present when Video Format Bridge is enabled in IP configuration.

That'd be aligned with the other properties and would more accurately
convey what this means.

Agree this is a good way to define the property. I will update it the description as mentioned here.

--
Kind regards,

Sakari Ailus
sakari.ailus@linux.intel.com

Regards
Vishal Sagar

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