Re: [PATCH 0/3] media: imx258: Remove rotation=<80 requirement

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Hi Jacopo and Sakari

On Thu, 26 Jan 2023 at 14:52, Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> wrote:
>
> Hi Jacopo,
>
> On Tue, Jan 17, 2023 at 11:06:00AM +0100, Jacopo Mondi wrote:
> > Currently the imx258 driver requires to have the 'rotation' device node
> > property specified in DTS with a fixed value of 180 degrees.
> >
> > The "rotation" fwnode device property is intended to allow specify the
> > sensor's physical mounting rotation, so that it can be exposed through
> > the read-only V4L2_CID_CAMERA_SENSOR_ROTATION control and applications
> > can decide how to compensate for that.
> >
> > The imx258 driver has read-only VFLIP and HFLIP enabled, resulting in
> > a 180 degrees image rotation being produced by the sensor. But this
> > doesn't imply that the physical mounting rotation should match the
> > driver's implementation.
> >
> > I took into the series Robert's patch that register device node properties and
> > on top of that register flips controls, in order to remove the hard requirement
> > of the 180 degrees rotation property presence.
>
> Reconsidering these patches after the flipping vs. rotation discussion,
> they seem fine. The only thing I'd like to see, after removing the rotation
> property check, would be to add support for the actual flipping controls.
> I'm pretty sure they can be found in the same registers as on CCS --- the
> rest of the registers look very much like that. Would you like to send a
> patch? :-)

Yes it is register 0x0101, bits 0 (H) & 1 (V).

Do watch out as there are register errors in the driver. Currently
Y_ADD_STA is set to 0, and Y_ADD_END to 3118, giving 3119 lines total.
That means that when you initially implement flips the Bayer order
won't change, but you change the field of view by one line.
The start and end values also break the requirements listed in the
datasheets for STA/END values being multiples of X (table 4-2 of the
datasheet). Correcting that will change the Bayer order when inverted.
Does that count as a regression to userspace? I hope not. Memory says
that if you don't correct Y_ADD_END then some of the binned modes
misbehave.

I have been through this loop before as Soho Enterprise [1] make an
IMX258 board for the Pi. I haven't upstreamed the patches [2] though
(sorry).

  Dave

[1] https://soho-enterprise.com/
[2] https://github.com/raspberrypi/linux/commits/rpi-5.15.y/drivers/media/i2c/imx258.c

> --
> Regards,
>
> Sakari Ailus



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