linux-kernel - Re: [PATCH v3 RESEND] media: i2c: Add OV05C10 camera sensor driver

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Message-ID: <20250623220612.GB15951@pendragon.ideasonboard.com>
Date: Tue, 24 Jun 2025 01:06:12 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: "Nirujogi, Pratap" <pnirujog@....com>
Cc: Sakari Ailus <sakari.ailus@...ux.intel.com>,
	Hao Yao <hao.yao@...el.com>,
	Pratap Nirujogi <pratap.nirujogi@....com>, mchehab@...nel.org,
	hverkuil@...all.nl, bryan.odonoghue@...aro.org, krzk@...nel.org,
	dave.stevenson@...pberrypi.com, hdegoede@...hat.com,
	jai.luthra@...asonboard.com, tomi.valkeinen@...asonboard.com,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
	benjamin.chan@....com, bin.du@....com, grosikop@....com,
	king.li@....com, dantony@....com, vengutta@....com,
	dongcheng.yan@...el.com, jason.z.chen@...el.com, jimmy.su@...el.com,
	Svetoslav.Stoilov@....com, Yana.Zheleva@....com
Subject: Re: [PATCH v3 RESEND] media: i2c: Add OV05C10 camera sensor driver

On Mon, Jun 23, 2025 at 05:55:14PM -0400, Nirujogi, Pratap wrote:
> On 6/23/2025 9:42 AM, Laurent Pinchart wrote:
> > On Mon, Jun 23, 2025 at 01:22:00PM +0000, Sakari Ailus wrote:
> >> On Mon, Jun 23, 2025 at 03:09:29PM +0300, Laurent Pinchart wrote:
> >>> On Mon, Jun 16, 2025 at 07:12:28PM -0400, Nirujogi, Pratap wrote:
> >>>> On 6/13/2025 6:02 PM, Sakari Ailus wrote:
> >>>>> On Fri, Jun 13, 2025 at 12:55:46PM +0800, Hao Yao wrote:
> >>>>>> Hi Pratap,
> >>>>>>
> >>>>>> Thanks for your patch.
> >>>>>>
> >>>>>> This patch is written for your camera sensor module, which seems very
> >>>>>> different from those already applied on Dell laptops (some of "Dell Pro"
> >>>>>> series). Looking into the driver, I think this version will break the
> >>>>>> devices using ov05c10 sensor.
> >>>>>
> >>>>> There never was such a driver in upstream so nothing breaks. However, in
> >>>>> order to support these, could you check what would it take to support them
> >>>>> using this driver and post patches, please?
> >>>>>
> >>>>>> I think this patch is better to be validated on existing devices, but please
> >>>>>> do some fixes before we can do validation. Please check my comments inline.
> >>>>>>
> >>>>>> On 2025/6/10 03:42, Pratap Nirujogi wrote:
> >>>>>>> Add driver for OmniVision 5.2M OV05C10 sensor. This driver
> >>>>>>> supports only the full size normal 2888x1808@...ps 2-lane
> >>>>>>> sensor profile.
> >>>>>>>
> >>>>>>> Co-developed-by: Venkata Narendra Kumar Gutta <vengutta@....com>
> >>>>>>> Signed-off-by: Venkata Narendra Kumar Gutta <vengutta@....com>
> >>>>>>> Co-developed-by: Bin Du <bin.du@....com>
> >>>>>>> Signed-off-by: Bin Du <bin.du@....com>
> >>>>>>> Signed-off-by: Pratap Nirujogi <pratap.nirujogi@....com>
> >>>
> >>> [snip]
> >>>
> >>>>>> Hi Sakari,
> >>>>>>
> >>>>>> Seems there are already several camera sensors using page-based registers.
> >>>>>> Is it a good idea to add page support in CCI interface?
> >>>>>
> >>>>> Sounds like a good idea as such but I'm not sure how common this really is,
> >>>>> I think I've seen a few Omnivision sensors doing this. If implemented, I
> >>>>> think it would be nice if the page could be encoded in the register address
> >>>>> which V4L2 CCI would store and switch page if needed only. This would
> >>>>> require serialising accesses, too. There's some room in CCI register raw
> >>>>> value space so this could be done without even changing that, say, with
> >>>>> 8-bit page and 8-bit register address.
> >>>>
> >>>> Hi Sakari, thank you for sharing your insights and guiding us. Could you
> >>>> please suggest if we should take up this work implementing the helpers
> >>>> in CCI and submit the patch or is it okay to leave it as-is for now and
> >>>> take care of updating in future once the implementation is ready.
> >>>
> >>> I think it can live in the driver for now. Given that the device uses
> >>> only 8 bits of register address, I would store the page number in bits
> >>> 15:8 instead of bits 31:24, as the CCI helpers do not make bits 27:24
> >>> available for driver-specific purpose.
> >>
> >> I'd use the CCI private bits, the driver uses page numbers up to 4 so 4
> >> bits are plenty for that. If we add pages to CCI later, this may be
> >> refactored then.
> > 
> > That works too.
> 
> Thanks for your support. We will add the page number in the register 
> address 15:8 or 11:8 and will update the implementation accordingly in 
> the next version.

The CCI private bits are bits 31:28.

-- 
Regards,

Laurent Pinchart