Hi Charles
On Fri, 14 May 2010, Charles D. Krebs wrote:
> Guennadi,
>
> > No, subdevice drivers, using the mediabus API, know nothing about fourcc
> > codes, that belongs to the user side of the pixel format handling API. The
> > path, e.g., for the VIDIOC_S_FMT ioctl() is
> >
> > soc_camera.c::soc_camera_s_fmt_vid_cap(V4L2_PIX_FMT_GREY)
> > sh_mobile_ceu_camera.c::sh_mobile_ceu_set_fmt(V4L2_PIX_FMT_GREY)
> >
> > the latter will try to call the .s_mbus_fmt() method from
> > soc_camera_platform.c and will fail, because that got lost during the
> > v4l2-subdev conversion, which is a bug and has to be fixed, patch welcome.
> >
>
> In trying to figure out how to best patch the lacking .s_mbus_fmt() option, I
> setup:
>
> static struct v4l2_subdev_video_ops platform_subdev_video_ops = {
> .s_stream = soc_camera_platform_s_stream,
> .try_mbus_fmt = soc_camera_platform_try_fmt,
> .enum_mbus_fmt = soc_camera_platform_enum_fmt,
> .g_mbus_fmt = soc_camera_platform_try_fmt,
> .s_mbus_fmt = soc_camera_platform_try_fmt,
>
> };
>
> Is there any reason I can't reuse a slightly modified "try_fmt" function to do
> the set?
>
> Here's what I currently have:
>
> static int soc_camera_platform_try_fmt(struct v4l2_subdev *sd,
> struct v4l2_mbus_framefmt *mf)
> {
> struct soc_camera_platform_info *p = v4l2_get_subdevdata(sd);
>
> mf->width = p->format.width;
> mf->height = p->format.height;
> mf->code = p->format.code;
> mf->colorspace = p->format.colorspace;
> mf->field = p->format.field;
>
> return 0;
> }
How is this different from this patch from Morimoto-san:
http://article.gmane.org/gmane.linux.drivers.video-input-infrastructure/19191
> > > But regardless of how I set this structure up, I don't see any direct
> > > support
> > > for a Grayscale mode data capture in the ceu driver. For example,
> > > "sh_mobile_ceu_set_bus_param" does not contain V4L2_PIX_FMT_GREY in its
> > > list
> > > of fourcc formats. Yet based on the 7724 hardware manual, and from the
> > > information I have received from Renesas, I'm not seeing any reason why
> > > this
> > > format should not be supported.
> > >
> > > Is grayscale somehow supported under the current CEU driver?
> >
> > Sure, that's what the pass-through mode with a standard soc-mbus format
> > conversion is for (see soc_mbus_get_fmtdesc()).
>
>
> After thoroughly reviewing the register documentation for the CEU, there are
> several changes I'm implementing. This camera doesn't put out any color
> sampling, so the registers in the CEU must be configured to use "image data
> fetch" mode.
>
> Where I'm currently struggling is in "sh_mobile_ceu_set_fmt" where the call is
> made to "soc_camera_xlate_by_fourcc(icd, pixfmt)".
>
> I'm still trying to figure out where the data needs to be defined that
> eventually becomes "pixfmt". Should this be setup as an additional parameter
> from inside "soc_camera_platform_try_fmt"?
>
> What's the relationship between "v4l2_format" and "v4l2_mbus_framefmt"?
Have you set up platform data similar to "struct soc_camera_link
camera_link" in arch/sh/boards/mach-ap325rxa/setup.c. The
soc_camera_platform.c driver should be getting pixel format information
from the static struct soc_camera_platform_info, doesn't this work for
you?
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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