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

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Hi Jacopo

On Thu, 26 Jan 2023 at 17:31, Jacopo Mondi
<jacopo.mondi@xxxxxxxxxxxxxxxx> wrote:
>
> Hello
>
> On Thu, Jan 26, 2023 at 06:02:07PM +0200, Sakari Ailus wrote:
> > Hi Dave,
> >
> > On Thu, Jan 26, 2023 at 03:48:04PM +0000, Dave Stevenson wrote:
> > > 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.
> >
> > Yes, this is the problem with register list based drivers. Well spotted.
> >
> > I remember one driver for a Toshiba sensor using value of 5 for a register
> > the range of which was 2--10, but only even values were allowed. It worked
> > nonetheless... oh well.
> >
> > I wonder if this sensor would work better with the CCS driver
> >
> > > 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.
> >
> > Most sensors also require even values for the ?_ADDR_START registers (and
> > odd for the _ADDR_END registers). Using an invalid value sometimes might
> > work, too, but only testing will tell.
> >
> > >
> > > 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).
> >
> > It'd be nice if both worked with the same driver.
> >
>
> There are a lot of interesting changes in here that would be worth
> upstreaming
> https://github.com/raspberrypi/linux/commits/rpi-5.15.y/drivers/media/i2c/imx258.c

I do feel a little guilty for not upstreaming these patches myself,
but I'm currently not being given any time to do so. Perhaps I'll take
an afternoon off and blitz a load of patches (imx258, imx290, and
ov7251 for a start).

Obviously that branch is based on 5.15. I was going to say that the
rpi-6.2.y branch may be a better source, however it looks like all the
commits got squashed :-(

> I would prefer if we can get these three easy patches of minr in and
> then start shoveling the good stuff from the rpi repo ?
>
> Otherwise I can plumb flip support in with the current wrong totals
> which, if I understand you right, doesn't require changing the bayer
> patter order ?

Memory says VFLIP won't currently change Bayer order, but I think HFLIP will.
If it is permitted to merge the current read-only FLIP patches, then
I'd suggest doing that initially.

Out of interest, do you have a user of imx258, or is this just as clean ups?
It may be possible to get a sample from Soho Enterprises if you
explain your involvement in libcamera. They're generally very
approachable.

  Dave

>
> > --
> > Kind regards,
> >
> > Sakari Ailus



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