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From: Benoit Parrot <bparrot@ti.com>
To: Jacopo Mondi <jacopo@jmondi.org>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>,
	Hans Verkuil <hverkuil@xs4all.nl>, <linux-media@vger.kernel.org>,
	<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<hugues.fruchet@st.com>
Subject: Re: [Patch 1/3] media: ov5640: add PIXEL_RATE control
Date: Wed, 2 Oct 2019 07:14:38 -0500	[thread overview]
Message-ID: <20191002121438.g3re6v54q4hit2wv@ti.com> (raw)
In-Reply-To: <20191002075951.afp2xligspqat4ew@uno.localdomain>

Hi Jacopo,

Maybe, I miss spoke when I mentioned a helper I did not intent a framework
level generic function. Just a function to help in this case :)

That being said, I re-read the thread you mentioned. And as Hughes pointed
out dynamically generating a "working" link frequency value which can be
used by a CSI2 receiver to properly configure its PHY is not trivial.

When I created this patch, I also had another to add V4L2_CID_LINK_FREQ
support. I am testing this against the TI CAL CSI2 receiver, which already
uses the V4L2_CID_PIXEL_RATE value for that purpose, so I also had a patch
to add support for V4L2_CID_LINK_FREQ to that driver as well.

Unfortunately, similar to Hughes' findings I was not able to make it "work"
with all supported resolution/framerate.

Unlike my V4L2_CID_PIXEL_RATE solution which now works in all mode with the
same receiver.

So long story short I dropped the V4L2_CID_LINK_FREQ patch and focused on
V4L2_CID_PIXEL_RATE instead.

Regard,
Benoit

Jacopo Mondi <jacopo@jmondi.org> wrote on Wed [2019-Oct-02 09:59:51 +0200]:
> Hi Benoit,
>   +Hugues
> 
> If you're considering an helper, this thread might be useful to you:
> https://patchwork.kernel.org/patch/11019673/
> 
> Thanks
>    j
> 



  reply	other threads:[~2019-10-02 12:12 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-25 15:22 [Patch 0/3] media: ov5640: updates Benoit Parrot
2019-09-25 15:22 ` [Patch 1/3] media: ov5640: add PIXEL_RATE control Benoit Parrot
2019-10-01  7:57   ` Sakari Ailus
2019-10-01 16:23     ` Benoit Parrot
2019-10-02  7:59       ` Jacopo Mondi
2019-10-02 12:14         ` Benoit Parrot [this message]
2019-10-02 12:35           ` Sakari Ailus
2019-10-02 12:40             ` Benoit Parrot
2019-10-02 14:32           ` Jacopo Mondi
2019-10-02 15:06             ` Benoit Parrot
2019-10-03  6:55               ` Jacopo Mondi
2019-09-25 15:23 ` [Patch 2/3] media: ov5640: Fix 1920x1080 mode to remove extra enable/disable Benoit Parrot
2019-09-25 15:23 ` [Patch 3/3] media: ov5640: Make 2592x1944 mode only available at 15 fps Benoit Parrot

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