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From: =?UTF-8?Q?Pawe=C5=82_Anikiel?= <panikiel@google.com>
Date: Wed, 28 Feb 2024 16:08:35 +0100
Message-ID: <CAM5zL5oAUKBf5aOJk=Ekko12pwhshv4of1=LsdsZN7G4VhY2+Q@mail.gmail.com>
Subject: Re: [PATCH v2 2/9] media: Add Chameleon v3 framebuffer driver
To: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: airlied@gmail.com, akpm@linux-foundation.org, conor+dt@kernel.org, 
	daniel@ffwll.ch, dinguyen@kernel.org, krzysztof.kozlowski+dt@linaro.org, 
	maarten.lankhorst@linux.intel.com, mchehab@kernel.org, mripard@kernel.org, 
	robh+dt@kernel.org, tzimmermann@suse.de, devicetree@vger.kernel.org, 
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, 
	linux-media@vger.kernel.org, chromeos-krk-upstreaming@google.com, 
	ribalda@chromium.org
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Hi Hans, thanks for the review!

On Wed, Feb 28, 2024 at 12:24=E2=80=AFPM Hans Verkuil <hverkuil-cisco@xs4al=
l.nl> wrote:
>
> Hi Pawe=C5=82,
>
> On 21/02/2024 17:02, Pawe=C5=82 Anikiel wrote:
> > Add v4l2 driver for the Google Chameleon v3 framebuffer device.
>
> This is just a video capture device, right? A framebuffer device is somet=
hing
> that lives in drivers/video/fbdev.

Yes, it is just a capture device.

>
> It is *very* confusing to see the term 'framebuffer' used in a video
> capture context.

I agree the name is confusing. I think it started out as something
else and unfortunately stuck around. I think it's possible to change
it, though.

>
> This commit log should also give a better description of the hardware.
> Just a single one-liner is a bit on the short side :-)

Would it be fine to just put the Kconfig help text there?

>
> >
> > Signed-off-by: Pawe=C5=82 Anikiel <panikiel@google.com>
> > ---
> >  drivers/media/platform/Kconfig                |   1 +
> >  drivers/media/platform/Makefile               |   1 +
> >  drivers/media/platform/google/Kconfig         |   3 +
> >  drivers/media/platform/google/Makefile        |   2 +
> >  .../media/platform/google/chameleonv3/Kconfig |  13 +
> >  .../platform/google/chameleonv3/Makefile      |   3 +
> >  .../platform/google/chameleonv3/chv3-fb.c     | 895 ++++++++++++++++++
>
> chv3-video.c would be a much better name for chv3-fb.c.
>
> That's a commonly used filename for video capture drivers.

I'm guessing all the instances of fb or framebuffer in the driver
itself should be changed as well in that case?

>
> >  7 files changed, 918 insertions(+)
> >  create mode 100644 drivers/media/platform/google/Kconfig
> >  create mode 100644 drivers/media/platform/google/Makefile
> >  create mode 100644 drivers/media/platform/google/chameleonv3/Kconfig
> >  create mode 100644 drivers/media/platform/google/chameleonv3/Makefile
> >  create mode 100644 drivers/media/platform/google/chameleonv3/chv3-fb.c
> >
> > diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kc=
onfig
> > index 91e54215de3a..b82f7b142b85 100644
> > --- a/drivers/media/platform/Kconfig
> > +++ b/drivers/media/platform/Kconfig
> > @@ -69,6 +69,7 @@ source "drivers/media/platform/aspeed/Kconfig"
> >  source "drivers/media/platform/atmel/Kconfig"
> >  source "drivers/media/platform/cadence/Kconfig"
> >  source "drivers/media/platform/chips-media/Kconfig"
> > +source "drivers/media/platform/google/Kconfig"
> >  source "drivers/media/platform/intel/Kconfig"
> >  source "drivers/media/platform/marvell/Kconfig"
> >  source "drivers/media/platform/mediatek/Kconfig"
> > diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/M=
akefile
> > index 3296ec1ebe16..f7067eb05f76 100644
> > --- a/drivers/media/platform/Makefile
> > +++ b/drivers/media/platform/Makefile
> > @@ -12,6 +12,7 @@ obj-y +=3D aspeed/
> >  obj-y +=3D atmel/
> >  obj-y +=3D cadence/
> >  obj-y +=3D chips-media/
> > +obj-y +=3D google/
> >  obj-y +=3D intel/
> >  obj-y +=3D marvell/
> >  obj-y +=3D mediatek/
> > diff --git a/drivers/media/platform/google/Kconfig b/drivers/media/plat=
form/google/Kconfig
> > new file mode 100644
> > index 000000000000..2a5f01034c11
> > --- /dev/null
> > +++ b/drivers/media/platform/google/Kconfig
> > @@ -0,0 +1,3 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +
> > +source "drivers/media/platform/google/chameleonv3/Kconfig"
> > diff --git a/drivers/media/platform/google/Makefile b/drivers/media/pla=
tform/google/Makefile
> > new file mode 100644
> > index 000000000000..c971a09faeb4
> > --- /dev/null
> > +++ b/drivers/media/platform/google/Makefile
> > @@ -0,0 +1,2 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +obj-y +=3D chameleonv3/
> > diff --git a/drivers/media/platform/google/chameleonv3/Kconfig b/driver=
s/media/platform/google/chameleonv3/Kconfig
> > new file mode 100644
> > index 000000000000..76d0383a8589
> > --- /dev/null
> > +++ b/drivers/media/platform/google/chameleonv3/Kconfig
> > @@ -0,0 +1,13 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +
> > +config VIDEO_CHV3_FB
> > +     tristate "Google Chameleon v3 framebuffer video driver"
> > +     depends on V4L_PLATFORM_DRIVERS
> > +     depends on VIDEO_DEV
> > +     select VIDEOBUF2_DMA_CONTIG
> > +     select V4L2_FWNODE
> > +     help
> > +       v4l2 driver for the video interface present on the Google
> > +       Chameleon v3. The Chameleon v3 uses the framebuffer IP core
> > +       to take the video signal from different sources and directly
> > +       write frames into memory.
>
> So it is composing different video streams into buffers? Or does it
> capture from a single source at a time? The text is rather ambiguous.

You're right, I'll write a more precise description.

>
> > diff --git a/drivers/media/platform/google/chameleonv3/Makefile b/drive=
rs/media/platform/google/chameleonv3/Makefile
> > new file mode 100644
> > index 000000000000..d63727148688
> > --- /dev/null
> > +++ b/drivers/media/platform/google/chameleonv3/Makefile
> > @@ -0,0 +1,3 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +
> > +obj-$(CONFIG_VIDEO_CHV3_FB) +=3D chv3-fb.o
> > diff --git a/drivers/media/platform/google/chameleonv3/chv3-fb.c b/driv=
ers/media/platform/google/chameleonv3/chv3-fb.c
> > new file mode 100644
> > index 000000000000..35a44365eba0
> > --- /dev/null
> > +++ b/drivers/media/platform/google/chameleonv3/chv3-fb.c
> > @@ -0,0 +1,895 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright 2023-2024 Google LLC.
> > + * Author: Pawe=C5=82 Anikiel <panikiel@google.com>
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/videodev2.h>
> > +#include <media/v4l2-ctrls.h>
> > +#include <media/v4l2-device.h>
> > +#include <media/v4l2-dv-timings.h>
> > +#include <media/v4l2-event.h>
> > +#include <media/v4l2-fwnode.h>
> > +#include <media/v4l2-ioctl.h>
> > +#include <media/videobuf2-dma-contig.h>
> > +
> > +#define DEVICE_NAME  "chv3-fb"
> > +
> > +/*
> > + * The device is expected to report some format even if there's curren=
tly no
> > + * active video stream. In such case we default to 1080p.
> > + */
> > +#define DEFAULT_WIDTH        1920
> > +#define DEFAULT_HEIGHT       1080
> > +
> > +#define FB_EN                                0x00
> > +#define FB_EN_BIT                    BIT(0)
> > +#define FB_HEIGHT                    0x04
> > +#define FB_WIDTH                     0x08
> > +#define FB_BUFFERA                   0x0c
> > +#define FB_BUFFERB                   0x10
> > +#define FB_BUFFERSIZE                        0x14
> > +#define FB_RESET                     0x18
> > +#define FB_RESET_BIT                 BIT(0)
> > +#define FB_ERRORSTATUS                       0x1c
> > +#define FB_IOCOLOR                   0x20
> > +#define FB_DATARATE                  0x24
> > +#define FB_DATARATE_SINGLE           0x0
> > +#define FB_DATARATE_DOUBLE           0x1
> > +#define FB_PIXELMODE                 0x28
> > +#define FB_PIXELMODE_SINGLE          0x0
> > +#define FB_PIXELMODE_DOUBLE          0x1
> > +#define FB_SYNCPOLARITY                      0x2c
> > +#define FB_DMAFORMAT                 0x30
> > +#define FB_DMAFORMAT_8BPC            0x0
> > +#define FB_DMAFORMAT_10BPC_UPPER     0x1
> > +#define FB_DMAFORMAT_10BPC_LOWER     0x2
> > +#define FB_DMAFORMAT_12BPC_UPPER     0x3
> > +#define FB_DMAFORMAT_12BPC_LOWER     0x4
> > +#define FB_DMAFORMAT_16BPC           0x5
> > +#define FB_DMAFORMAT_RAW             0x6
> > +#define FB_DMAFORMAT_8BPC_LEGACY     0x7
> > +#define FB_VERSION                   0x34
> > +#define FB_VERSION_CURRENT           0xc0fb0001
> > +
> > +#define FB_IRQ_MASK          0x8
> > +#define FB_IRQ_CLR           0xc
> > +#define FB_IRQ_ALL           0xf
> > +#define FB_IRQ_BUFF0         BIT(0)
> > +#define FB_IRQ_BUFF1         BIT(1)
> > +#define FB_IRQ_RESOLUTION    BIT(2)
> > +#define FB_IRQ_ERROR         BIT(3)
> > +
> > +struct chv3_fb {
> > +     struct device *dev;
> > +     void __iomem *iobase;
> > +     void __iomem *iobase_irq;
> > +
> > +     struct v4l2_device v4l2_dev;
> > +     struct vb2_queue queue;
> > +     struct video_device vdev;
> > +     struct v4l2_pix_format pix_fmt;
> > +     struct v4l2_dv_timings timings;
> > +
> > +     struct v4l2_async_notifier notifier;
> > +     struct v4l2_subdev *subdev;
> > +     int subdev_source_pad;
> > +
> > +     u32 sequence;
> > +     bool writing_to_a;
> > +
> > +     struct list_head bufs;
> > +     spinlock_t bufs_lock;
> > +
> > +     struct mutex fb_lock;
> > +};
> > +
> > +struct chv3_fb_buffer {
> > +     struct vb2_v4l2_buffer vb;
> > +     struct list_head link;
> > +};
> > +
> > +static void chv3_fb_set_format_resolution(struct chv3_fb *fb, u32 widt=
h, u32 height)
> > +{
> > +     u32 bytes_per_pixel;
> > +
> > +     if (fb->pix_fmt.pixelformat =3D=3D V4L2_PIX_FMT_RGB24)
> > +             bytes_per_pixel =3D 3;
> > +     else
> > +             bytes_per_pixel =3D 4;
> > +
> > +     fb->pix_fmt.width =3D width;
> > +     fb->pix_fmt.height =3D height;
> > +     fb->pix_fmt.bytesperline =3D width * bytes_per_pixel;
> > +     fb->pix_fmt.sizeimage =3D fb->pix_fmt.bytesperline * height;
> > +}
> > +
> > +/*
> > + * The video interface has hardware counters which expose the width an=
d
> > + * height of the current video stream. It can't reliably detect if the=
 stream
> > + * is present or not, so this is only used as a fallback in the case w=
here
> > + * we don't have access to the receiver hardware.
> > + */
> > +static int chv3_fb_query_dv_timings_fallback(struct chv3_fb *fb,
> > +                                          struct v4l2_dv_timings *timi=
ngs)
> > +{
> > +     u32 width, height;
> > +
> > +     width  =3D readl(fb->iobase + FB_WIDTH);
> > +     height =3D readl(fb->iobase + FB_HEIGHT);
> > +     if (width =3D=3D 0 || height =3D=3D 0)
> > +             return -ENOLINK;
> > +
> > +     memset(timings, 0, sizeof(*timings));
> > +     timings->type =3D V4L2_DV_BT_656_1120;
> > +     timings->bt.width  =3D width;
> > +     timings->bt.height =3D height;
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_query_dv_timings(struct chv3_fb *fb, struct v4l2_dv=
_timings *timings)
> > +{
> > +     if (fb->subdev) {
> > +             return v4l2_subdev_call(fb->subdev, pad, query_dv_timings=
,
> > +                                     fb->subdev_source_pad, timings);
> > +     } else {
> > +             return chv3_fb_query_dv_timings_fallback(fb, timings);
> > +     }
> > +}
> > +
> > +static const struct v4l2_dv_timings_cap chv3_fb_fallback_dv_timings_ca=
p =3D {
> > +     .type =3D V4L2_DV_BT_656_1120,
> > +     .bt =3D {
> > +             .min_width =3D 0,
>
> This is an unlikely minimum width (ditto for height below).
>
> > +             .max_width =3D 65535,
>
> The max is suspect as well: I would expect it to be a multiple of 2/4/8/1=
6.
>
> > +             .min_height =3D 0,
> > +             .max_height =3D 65535,
> > +             .min_pixelclock =3D 0,
> > +             .max_pixelclock =3D 2147483647,
>
> Ditto for these.

Note: these are used only when there is no controllable endpoint
attached to the video interface, and we don't know what the timing
caps are.

Should I then just pick something like 640x480p24 as min and 8Kp120 as max?

>
> > +             .standards =3D V4L2_DV_BT_STD_CEA861 | V4L2_DV_BT_STD_DMT=
 |
> > +                     V4L2_DV_BT_STD_CVT | V4L2_DV_BT_STD_GTF,
> > +             .capabilities =3D V4L2_DV_BT_CAP_PROGRESSIVE |
> > +                     V4L2_DV_BT_CAP_REDUCED_BLANKING |
> > +                     V4L2_DV_BT_CAP_CUSTOM,
> > +     },
> > +};
> > +
> > +static int chv3_fb_enum_dv_timings_fallback(struct chv3_fb *fb,
> > +                                         struct v4l2_enum_dv_timings *=
timings)
> > +{
> > +     return v4l2_enum_dv_timings_cap(timings, &chv3_fb_fallback_dv_tim=
ings_cap,
> > +                                     NULL, NULL);
> > +}
> > +
> > +static int chv3_fb_dv_timings_cap_fallback(struct chv3_fb *fb,
> > +                                        struct v4l2_dv_timings_cap *ca=
p)
> > +{
> > +     *cap =3D chv3_fb_fallback_dv_timings_cap;
> > +
> > +     return 0;
> > +}
> > +
> > +static void chv3_fb_apply_dv_timings(struct chv3_fb *fb)
> > +{
> > +     struct v4l2_dv_timings timings;
> > +     int res;
> > +
> > +     res =3D chv3_fb_query_dv_timings(fb, &timings);
> > +     if (res)
> > +             return;
> > +
> > +     fb->timings =3D timings;
> > +     chv3_fb_set_format_resolution(fb, timings.bt.width, timings.bt.he=
ight);
> > +}
> > +
> > +static int chv3_fb_querycap(struct file *file, void *fh,
> > +                         struct v4l2_capability *cap)
> > +{
> > +     strscpy(cap->driver, DEVICE_NAME, sizeof(cap->driver));
> > +     strscpy(cap->card, "Chameleon v3 video", sizeof(cap->card));
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_g_fmt_vid_cap(struct file *file, void *fh,
> > +                              struct v4l2_format *fmt)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +
> > +     fmt->fmt.pix =3D fb->pix_fmt;
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_enum_fmt_vid_cap(struct file *file, void *fh,
> > +                                 struct v4l2_fmtdesc *fmt)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +
> > +     if (fmt->index !=3D 0)
> > +             return -EINVAL;
> > +
> > +     fmt->flags =3D 0;
> > +     fmt->pixelformat =3D fb->pix_fmt.pixelformat;
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_enum_framesizes(struct file *file, void *fh,
> > +                                struct v4l2_frmsizeenum *frm)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +
> > +     if (frm->index !=3D 0)
> > +             return -EINVAL;
> > +
> > +     if (frm->pixel_format !=3D fb->pix_fmt.pixelformat)
> > +             return -EINVAL;
> > +
> > +     frm->type =3D V4L2_FRMSIZE_TYPE_DISCRETE;
> > +     frm->discrete.width  =3D fb->pix_fmt.width;
> > +     frm->discrete.height =3D fb->pix_fmt.height;
>
> This is not something you would expect to see supported for a
> video receiver input. This is something you use for camera sensors.
>
> This should almost certainly be dropped.

Thanks for explaining, I'll remove it in v3.

>
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_g_input(struct file *file, void *fh, unsigned int *=
index)
> > +{
> > +     *index =3D 0;
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_s_input(struct file *file, void *fh, unsigned int i=
ndex)
> > +{
> > +     if (index !=3D 0)
> > +             return -EINVAL;
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_enum_input(struct file *file, void *fh,
> > +                           struct v4l2_input *input)
> > +{
> > +     if (input->index !=3D 0)
> > +             return -EINVAL;
> > +
> > +     strscpy(input->name, "input0", sizeof(input->name));
> > +     input->type =3D V4L2_INPUT_TYPE_CAMERA;
> > +     input->capabilities =3D V4L2_IN_CAP_DV_TIMINGS;
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_g_edid(struct file *file, void *fh,
> > +                       struct v4l2_edid *edid)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +     int res;
> > +
> > +     if (!fb->subdev)
> > +             return -ENOTTY;
> > +
> > +     if (edid->pad !=3D 0)
> > +             return -EINVAL;
> > +
> > +     edid->pad =3D fb->subdev_source_pad;
> > +     res =3D v4l2_subdev_call(fb->subdev, pad, get_edid, edid);
> > +     edid->pad =3D 0;
> > +
> > +     return res;
> > +}
> > +
> > +static int chv3_fb_s_edid(struct file *file, void *fh,
> > +                       struct v4l2_edid *edid)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +     int res;
> > +
> > +     if (!fb->subdev)
> > +             return -ENOTTY;
> > +
> > +     if (edid->pad !=3D 0)
> > +             return -EINVAL;
> > +
> > +     edid->pad =3D fb->subdev_source_pad;
> > +     res =3D v4l2_subdev_call(fb->subdev, pad, set_edid, edid);
> > +     edid->pad =3D 0;
> > +
> > +     return res;
> > +}
> > +
> > +static int chv3_fb_s_dv_timings(struct file *file, void *fh,
> > +                             struct v4l2_dv_timings *timings)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +
> > +     if (timings->bt.width =3D=3D fb->timings.bt.width &&
> > +         timings->bt.height =3D=3D fb->timings.bt.height)
>
> You would typically use v4l2_match_dv_timings() for this. The check above
> is insufficient since it does not even check for different framerates or
> interlaced vs progressive.

Okay, I changed it to use v4l2_match_dv_timings().

>
> > +             return 0;
> > +
> > +     if (vb2_is_busy(&fb->queue))
> > +             return -EBUSY;
> > +
> > +     if (!v4l2_valid_dv_timings(timings, &chv3_fb_fallback_dv_timings_=
cap, NULL, NULL))
> > +             return -ERANGE;
> > +
> > +     fb->timings =3D *timings;
> > +     chv3_fb_set_format_resolution(fb, timings->bt.width, timings->bt.=
height);
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_g_dv_timings(struct file *file, void *fh,
> > +                             struct v4l2_dv_timings *timings)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +
> > +     *timings =3D fb->timings;
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_vidioc_query_dv_timings(struct file *file, void *fh=
,
> > +                                        struct v4l2_dv_timings *timing=
s)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +
> > +     return chv3_fb_query_dv_timings(fb, timings);
> > +}
> > +
> > +static int chv3_fb_enum_dv_timings(struct file *file, void *fh,
> > +                                struct v4l2_enum_dv_timings *timings)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +     int res;
> > +
> > +     if (timings->pad !=3D 0)
> > +             return -EINVAL;
> > +
> > +     if (fb->subdev) {
> > +             timings->pad =3D fb->subdev_source_pad;
> > +             res =3D v4l2_subdev_call(fb->subdev, pad, enum_dv_timings=
, timings);
> > +             timings->pad =3D 0;
> > +             return res;
> > +     } else {
> > +             return chv3_fb_enum_dv_timings_fallback(fb, timings);
> > +     }
> > +}
> > +
> > +static int chv3_fb_dv_timings_cap(struct file *file, void *fh,
> > +                               struct v4l2_dv_timings_cap *cap)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +     int res;
> > +
> > +     if (cap->pad !=3D 0)
> > +             return -EINVAL;
> > +
> > +     if (fb->subdev) {
> > +             cap->pad =3D fb->subdev_source_pad;
> > +             res =3D v4l2_subdev_call(fb->subdev, pad, dv_timings_cap,=
 cap);
> > +             cap->pad =3D 0;
> > +             return res;
> > +     } else {
> > +             return chv3_fb_dv_timings_cap_fallback(fb, cap);
> > +     }
> > +}
> > +
> > +static int chv3_fb_subscribe_event(struct v4l2_fh *fh,
> > +                                const struct v4l2_event_subscription *=
sub)
> > +{
> > +     switch (sub->type) {
> > +     case V4L2_EVENT_SOURCE_CHANGE:
> > +             return v4l2_src_change_event_subscribe(fh, sub);
> > +     }
> > +
> > +     return v4l2_ctrl_subscribe_event(fh, sub);
> > +}
>
> I am missing support for the V4L2_CID_DV_RX_POWER_PRESENT control:
>
> https://hverkuil.home.xs4all.nl/spec/userspace-api/v4l/ext-ctrls-dv.html

I'll try to implement it.

>
> > +
> > +static const struct v4l2_ioctl_ops chv3_fb_v4l2_ioctl_ops =3D {
> > +     .vidioc_querycap =3D chv3_fb_querycap,
> > +
> > +     .vidioc_enum_fmt_vid_cap =3D chv3_fb_enum_fmt_vid_cap,
> > +     .vidioc_g_fmt_vid_cap =3D chv3_fb_g_fmt_vid_cap,
> > +     .vidioc_s_fmt_vid_cap =3D chv3_fb_g_fmt_vid_cap,
> > +     .vidioc_try_fmt_vid_cap =3D chv3_fb_g_fmt_vid_cap,
> > +
> > +     .vidioc_enum_framesizes =3D chv3_fb_enum_framesizes,
> > +
> > +     .vidioc_enum_input =3D chv3_fb_enum_input,
> > +     .vidioc_g_input =3D chv3_fb_g_input,
> > +     .vidioc_s_input =3D chv3_fb_s_input,
> > +     .vidioc_g_edid =3D chv3_fb_g_edid,
> > +     .vidioc_s_edid =3D chv3_fb_s_edid,
> > +
> > +     .vidioc_reqbufs =3D vb2_ioctl_reqbufs,
> > +     .vidioc_create_bufs =3D vb2_ioctl_create_bufs,
> > +     .vidioc_querybuf =3D vb2_ioctl_querybuf,
> > +     .vidioc_prepare_buf =3D vb2_ioctl_prepare_buf,
> > +     .vidioc_expbuf =3D vb2_ioctl_expbuf,
> > +     .vidioc_qbuf =3D vb2_ioctl_qbuf,
> > +     .vidioc_dqbuf =3D vb2_ioctl_dqbuf,
> > +     .vidioc_streamon =3D vb2_ioctl_streamon,
> > +     .vidioc_streamoff =3D vb2_ioctl_streamoff,
> > +
> > +     .vidioc_s_dv_timings =3D chv3_fb_s_dv_timings,
> > +     .vidioc_g_dv_timings =3D chv3_fb_g_dv_timings,
> > +     .vidioc_query_dv_timings =3D chv3_fb_vidioc_query_dv_timings,
> > +     .vidioc_enum_dv_timings =3D chv3_fb_enum_dv_timings,
> > +     .vidioc_dv_timings_cap =3D chv3_fb_dv_timings_cap,
> > +
> > +     .vidioc_subscribe_event =3D chv3_fb_subscribe_event,
> > +     .vidioc_unsubscribe_event =3D v4l2_event_unsubscribe,
> > +};
> > +
> > +static int chv3_fb_queue_setup(struct vb2_queue *q,
> > +                            unsigned int *nbuffers, unsigned int *npla=
nes,
> > +                            unsigned int sizes[], struct device *alloc=
_devs[])
> > +{
> > +     struct chv3_fb *fb =3D vb2_get_drv_priv(q);
> > +
> > +     if (*nplanes) {
> > +             if (sizes[0] < fb->pix_fmt.sizeimage)
> > +                     return -EINVAL;
> > +             return 0;
> > +     }
> > +     *nplanes =3D 1;
> > +     sizes[0] =3D fb->pix_fmt.sizeimage;
> > +
> > +     return 0;
> > +}
> > +
> > +/*
> > + * There are two address registers: BUFFERA and BUFFERB. The framebuff=
er
> > + * alternates writing between them (i.e. even frames go to BUFFERA, od=
d
> > + * ones to BUFFERB).
> > + *
> > + *  (buffer queue) >     QUEUED ---> QUEUED ---> QUEUED ---> ...
> > + *                       BUFFERA     BUFFERB
> > + *  (hw writing to this) ^
> > + *                (and then to this) ^
> > + *
> > + * The buffer swapping happens at irq time. When an irq comes, the nex=
t
> > + * frame is already assigned an address in the buffer queue. This give=
s
> > + * the irq handler a whole frame's worth of time to update the buffer
> > + * address register.
> > + */
> > +
> > +static dma_addr_t chv3_fb_buffer_dma_addr(struct chv3_fb_buffer *buf)
> > +{
> > +     return vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0);
> > +}
> > +
> > +static void chv3_fb_start_frame(struct chv3_fb *fb, struct chv3_fb_buf=
fer *buf)
> > +{
> > +     fb->writing_to_a =3D 1;
> > +     writel(chv3_fb_buffer_dma_addr(buf), fb->iobase + FB_BUFFERA);
> > +     writel(FB_EN_BIT, fb->iobase + FB_EN);
> > +}
> > +
> > +static void chv3_fb_next_frame(struct chv3_fb *fb, struct chv3_fb_buff=
er *buf)
> > +{
> > +     u32 reg =3D fb->writing_to_a ? FB_BUFFERB : FB_BUFFERA;
> > +
> > +     writel(chv3_fb_buffer_dma_addr(buf), fb->iobase + reg);
> > +}
> > +
> > +static int chv3_fb_start_streaming(struct vb2_queue *q, unsigned int c=
ount)
> > +{
> > +     struct chv3_fb *fb =3D vb2_get_drv_priv(q);
> > +     struct chv3_fb_buffer *buf;
> > +     unsigned long flags;
> > +
> > +     fb->sequence =3D 0;
> > +     writel(fb->pix_fmt.sizeimage, fb->iobase + FB_BUFFERSIZE);
> > +
> > +     spin_lock_irqsave(&fb->bufs_lock, flags);
> > +     buf =3D list_first_entry_or_null(&fb->bufs, struct chv3_fb_buffer=
, link);
> > +     if (buf) {
> > +             chv3_fb_start_frame(fb, buf);
> > +             if (!list_is_last(&buf->link, &fb->bufs))
> > +                     chv3_fb_next_frame(fb, list_next_entry(buf, link)=
);
> > +     }
> > +     spin_unlock_irqrestore(&fb->bufs_lock, flags);
> > +
> > +     return 0;
> > +}
> > +
> > +static void chv3_fb_stop_streaming(struct vb2_queue *q)
> > +{
> > +     struct chv3_fb *fb =3D vb2_get_drv_priv(q);
> > +     struct chv3_fb_buffer *buf;
> > +     unsigned long flags;
> > +
> > +     writel(0, fb->iobase + FB_EN);
> > +
> > +     spin_lock_irqsave(&fb->bufs_lock, flags);
> > +     list_for_each_entry(buf, &fb->bufs, link)
> > +             vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
> > +     INIT_LIST_HEAD(&fb->bufs);
> > +     spin_unlock_irqrestore(&fb->bufs_lock, flags);
> > +}
> > +
> > +static void chv3_fb_buf_queue(struct vb2_buffer *vb)
> > +{
> > +     struct chv3_fb *fb =3D vb2_get_drv_priv(vb->vb2_queue);
> > +     struct vb2_v4l2_buffer *v4l2_buf =3D to_vb2_v4l2_buffer(vb);
> > +     struct chv3_fb_buffer *buf =3D container_of(v4l2_buf, struct chv3=
_fb_buffer, vb);
> > +     bool first, second;
> > +     unsigned long flags;
> > +
> > +     spin_lock_irqsave(&fb->bufs_lock, flags);
> > +     first =3D list_empty(&fb->bufs);
> > +     second =3D list_is_singular(&fb->bufs);
> > +     list_add_tail(&buf->link, &fb->bufs);
> > +     if (vb2_is_streaming(vb->vb2_queue)) {
> > +             if (first)
> > +                     chv3_fb_start_frame(fb, buf);
> > +             else if (second)
> > +                     chv3_fb_next_frame(fb, buf);
> > +     }
> > +     spin_unlock_irqrestore(&fb->bufs_lock, flags);
> > +}
> > +
> > +static const struct vb2_ops chv3_fb_vb2_ops =3D {
> > +     .queue_setup =3D chv3_fb_queue_setup,
> > +     .wait_prepare =3D vb2_ops_wait_prepare,
> > +     .wait_finish =3D vb2_ops_wait_finish,
> > +     .start_streaming =3D chv3_fb_start_streaming,
> > +     .stop_streaming =3D chv3_fb_stop_streaming,
> > +     .buf_queue =3D chv3_fb_buf_queue,
> > +};
> > +
> > +static int chv3_fb_open(struct file *file)
> > +{
> > +     struct chv3_fb *fb =3D video_drvdata(file);
> > +     int res;
> > +
> > +     mutex_lock(&fb->fb_lock);
> > +     res =3D v4l2_fh_open(file);
> > +     if (!res) {
> > +             if (v4l2_fh_is_singular_file(file))
> > +                     chv3_fb_apply_dv_timings(fb);
> > +     }
> > +     mutex_unlock(&fb->fb_lock);
> > +
> > +     return res;
> > +}
> > +
> > +static const struct v4l2_file_operations chv3_fb_v4l2_fops =3D {
> > +     .owner =3D THIS_MODULE,
> > +     .open =3D chv3_fb_open,
> > +     .release =3D vb2_fop_release,
> > +     .unlocked_ioctl =3D video_ioctl2,
> > +     .mmap =3D vb2_fop_mmap,
> > +     .poll =3D vb2_fop_poll,
> > +};
> > +
> > +static void chv3_fb_frame_irq(struct chv3_fb *fb)
> > +{
> > +     struct chv3_fb_buffer *buf;
> > +
> > +     spin_lock(&fb->bufs_lock);
> > +
> > +     buf =3D list_first_entry_or_null(&fb->bufs, struct chv3_fb_buffer=
, link);
> > +     if (!buf)
> > +             goto empty;
> > +     list_del(&buf->link);
> > +
> > +     vb2_set_plane_payload(&buf->vb.vb2_buf, 0, fb->pix_fmt.sizeimage)=
;
> > +     buf->vb.vb2_buf.timestamp =3D ktime_get_ns();
> > +     buf->vb.sequence =3D fb->sequence++;
> > +     buf->vb.field =3D V4L2_FIELD_NONE;
> > +     vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
> > +
> > +     buf =3D list_first_entry_or_null(&fb->bufs, struct chv3_fb_buffer=
, link);
> > +     if (buf) {
> > +             fb->writing_to_a =3D !fb->writing_to_a;
> > +             if (!list_is_last(&buf->link, &fb->bufs))
> > +                     chv3_fb_next_frame(fb, list_next_entry(buf, link)=
);
> > +     } else {
> > +             writel(0, fb->iobase + FB_EN);
> > +     }
> > +empty:
> > +     spin_unlock(&fb->bufs_lock);
> > +}
> > +
> > +static void chv3_fb_error_irq(struct chv3_fb *fb)
> > +{
> > +     if (vb2_is_streaming(&fb->queue))
> > +             vb2_queue_error(&fb->queue);
> > +}
> > +
> > +static void chv3_fb_resolution_irq(struct chv3_fb *fb)
> > +{
> > +     static const struct v4l2_event event =3D {
> > +             .type =3D V4L2_EVENT_SOURCE_CHANGE,
> > +             .u.src_change.changes =3D V4L2_EVENT_SRC_CH_RESOLUTION,
> > +     };
> > +
> > +     v4l2_event_queue(&fb->vdev, &event);
> > +     chv3_fb_error_irq(fb);
> > +}
> > +
> > +static irqreturn_t chv3_fb_isr(int irq, void *data)
> > +{
> > +     struct chv3_fb *fb =3D data;
> > +     unsigned int reg;
> > +
> > +     reg =3D readl(fb->iobase_irq + FB_IRQ_CLR);
> > +     if (!reg)
> > +             return IRQ_NONE;
> > +
> > +     if (reg & FB_IRQ_BUFF0)
> > +             chv3_fb_frame_irq(fb);
> > +     if (reg & FB_IRQ_BUFF1)
> > +             chv3_fb_frame_irq(fb);
> > +     if (reg & FB_IRQ_RESOLUTION)
> > +             chv3_fb_resolution_irq(fb);
> > +     if (reg & FB_IRQ_ERROR) {
> > +             dev_warn(fb->dev, "framebuffer error: 0x%x\n",
> > +                      readl(fb->iobase + FB_ERRORSTATUS));
> > +             chv3_fb_error_irq(fb);
> > +     }
> > +
> > +     writel(reg, fb->iobase_irq + FB_IRQ_CLR);
> > +
> > +     return IRQ_HANDLED;
> > +}
> > +
> > +static int chv3_fb_check_version(struct chv3_fb *fb)
> > +{
> > +     u32 version;
> > +
> > +     version =3D readl(fb->iobase + FB_VERSION);
> > +     if (version !=3D FB_VERSION_CURRENT) {
> > +             dev_err(fb->dev,
> > +                     "wrong framebuffer version: expected %x, got %x\n=
",
> > +                     FB_VERSION_CURRENT, version);
> > +             return -ENODEV;
> > +     }
> > +     return 0;
> > +}
> > +
> > +static void chv3_fb_set_default_format(struct chv3_fb *fb, bool legacy=
_format)
> > +{
> > +     struct v4l2_pix_format *pix =3D &fb->pix_fmt;
> > +
> > +     if (legacy_format)
> > +             pix->pixelformat =3D V4L2_PIX_FMT_BGRX32;
> > +     else
> > +             pix->pixelformat =3D V4L2_PIX_FMT_RGB24;
> > +     pix->field =3D V4L2_FIELD_NONE;
> > +     pix->colorspace =3D V4L2_COLORSPACE_SRGB;
> > +
> > +     chv3_fb_set_format_resolution(fb, DEFAULT_WIDTH, DEFAULT_HEIGHT);
> > +}
> > +
> > +static void chv3_fb_set_default_timings(struct chv3_fb *fb)
> > +{
> > +     memset(&fb->timings, 0, sizeof(fb->timings));
> > +     fb->timings.type =3D V4L2_DV_BT_656_1120;
> > +     fb->timings.bt.width  =3D DEFAULT_WIDTH;
> > +     fb->timings.bt.height =3D DEFAULT_HEIGHT;
>
> Wouldn't it be better to say: fb->timings =3D V4L2_DV_BT_CEA_1920X1080P60=
;

Yes, that would work.

>
> > +}
> > +
> > +#define notifier_to_fb(nf) container_of(nf, struct chv3_fb, notifier)
> > +
> > +static int chv3_fb_async_notify_bound(struct v4l2_async_notifier *noti=
fier,
> > +                                   struct v4l2_subdev *subdev,
> > +                                   struct v4l2_async_connection *asc)
> > +{
> > +     struct chv3_fb *fb =3D notifier_to_fb(notifier);
> > +     int pad;
> > +
> > +     pad =3D media_entity_get_fwnode_pad(&subdev->entity, asc->match.f=
wnode,
> > +                                       MEDIA_PAD_FL_SOURCE);
> > +     if (pad < 0)
> > +             return pad;
> > +
> > +     fb->subdev =3D subdev;
> > +     fb->subdev_source_pad =3D pad;
> > +
> > +     return 0;
> > +}
> > +
> > +static void chv3_fb_async_notify_unbind(struct v4l2_async_notifier *no=
tifier,
> > +                                     struct v4l2_subdev *subdev,
> > +                                     struct v4l2_async_connection *asc=
)
> > +{
> > +     struct chv3_fb *fb =3D notifier_to_fb(notifier);
> > +
> > +     video_unregister_device(&fb->vdev);
>
> Use vb2_video_unregister_device. See documentation in include/media/video=
buf2-v4l2.h.

So if I understand the docs correctly, I should just change this line to
'vb2_video_unregister_device(&fb->vdev);'?

>
> > +}
> > +
> > +static int chv3_fb_async_notify_complete(struct v4l2_async_notifier *n=
otifier)
> > +{
> > +     struct chv3_fb *fb =3D notifier_to_fb(notifier);
> > +
> > +     return video_register_device(&fb->vdev, VFL_TYPE_VIDEO, -1);
> > +}
> > +
> > +static const struct v4l2_async_notifier_operations chv3_fb_async_notif=
y_ops =3D {
> > +     .bound =3D chv3_fb_async_notify_bound,
> > +     .unbind =3D chv3_fb_async_notify_unbind,
> > +     .complete =3D chv3_fb_async_notify_complete,
> > +};
> > +
> > +static int chv3_fb_fallback_init(struct chv3_fb *fb)
> > +{
> > +     fb->subdev =3D NULL;
> > +     fb->subdev_source_pad =3D 0;
> > +
> > +     return video_register_device(&fb->vdev, VFL_TYPE_VIDEO, -1);
> > +}
> > +
> > +static int chv3_fb_fwnode_init(struct chv3_fb *fb)
> > +{
> > +     struct v4l2_async_connection *asc;
> > +     struct fwnode_handle *endpoint;
> > +     int res;
> > +
> > +     endpoint =3D fwnode_graph_get_next_endpoint(dev_fwnode(fb->dev), =
NULL);
> > +     if (!endpoint)
> > +             return -EINVAL;
> > +
> > +     v4l2_async_nf_init(&fb->notifier, &fb->v4l2_dev);
> > +
> > +     asc =3D v4l2_async_nf_add_fwnode_remote(&fb->notifier, endpoint,
> > +                                           struct v4l2_async_connectio=
n);
> > +     fwnode_handle_put(endpoint);
> > +
> > +     if (IS_ERR(asc))
> > +             return PTR_ERR(asc);
> > +
> > +     fb->notifier.ops =3D &chv3_fb_async_notify_ops;
> > +     res =3D v4l2_async_nf_register(&fb->notifier);
> > +     if (res) {
> > +             v4l2_async_nf_cleanup(&fb->notifier);
> > +             return res;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int chv3_fb_probe(struct platform_device *pdev)
> > +{
> > +     struct chv3_fb *fb;
> > +     bool legacy_format;
> > +     int res;
> > +     int irq;
> > +
> > +     fb =3D devm_kzalloc(&pdev->dev, sizeof(*fb), GFP_KERNEL);
> > +     if (!fb)
> > +             return -ENOMEM;
> > +     fb->dev =3D &pdev->dev;
> > +     platform_set_drvdata(pdev, fb);
> > +
> > +     /* map register space */
> > +     fb->iobase =3D devm_platform_ioremap_resource(pdev, 0);
> > +     if (IS_ERR(fb->iobase))
> > +             return PTR_ERR(fb->iobase);
> > +
> > +     fb->iobase_irq =3D devm_platform_ioremap_resource(pdev, 1);
> > +     if (IS_ERR(fb->iobase_irq))
> > +             return PTR_ERR(fb->iobase_irq);
> > +
> > +     /* check hw version */
> > +     res =3D chv3_fb_check_version(fb);
> > +     if (res)
> > +             return res;
> > +
> > +     /* setup interrupts */
> > +     irq =3D platform_get_irq(pdev, 0);
> > +     if (irq < 0)
> > +             return -ENXIO;
> > +     res =3D devm_request_irq(&pdev->dev, irq, chv3_fb_isr, 0, DEVICE_=
NAME, fb);
> > +     if (res)
> > +             return res;
> > +
> > +     /* initialize v4l2_device */
> > +     res =3D v4l2_device_register(&pdev->dev, &fb->v4l2_dev);
> > +     if (res)
> > +             return res;
> > +
> > +     /* initialize vb2 queue */
> > +     fb->queue.type =3D V4L2_BUF_TYPE_VIDEO_CAPTURE;
> > +     fb->queue.io_modes =3D VB2_MMAP | VB2_DMABUF;
> > +     fb->queue.dev =3D &pdev->dev;
> > +     fb->queue.lock =3D &fb->fb_lock;
> > +     fb->queue.ops =3D &chv3_fb_vb2_ops;
> > +     fb->queue.mem_ops =3D &vb2_dma_contig_memops;
> > +     fb->queue.drv_priv =3D fb;
> > +     fb->queue.buf_struct_size =3D sizeof(struct chv3_fb_buffer);
> > +     fb->queue.timestamp_flags =3D V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> > +     res =3D vb2_queue_init(&fb->queue);
> > +     if (res)
> > +             goto error;
> > +
> > +     /* initialize video_device */
> > +     strscpy(fb->vdev.name, DEVICE_NAME, sizeof(fb->vdev.name));
> > +     fb->vdev.fops =3D &chv3_fb_v4l2_fops;
> > +     fb->vdev.ioctl_ops =3D &chv3_fb_v4l2_ioctl_ops;
> > +     fb->vdev.lock =3D &fb->fb_lock;
> > +     fb->vdev.release =3D video_device_release_empty;
> > +     fb->vdev.device_caps =3D V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAM=
ING;
> > +     fb->vdev.v4l2_dev =3D &fb->v4l2_dev;
> > +     fb->vdev.queue =3D &fb->queue;
> > +     video_set_drvdata(&fb->vdev, fb);
> > +
> > +     /* read other DT properties */
> > +     legacy_format =3D device_property_read_bool(&pdev->dev, "google,l=
egacy-format");
> > +
> > +     if (device_get_named_child_node(&pdev->dev, "port"))
> > +             res =3D chv3_fb_fwnode_init(fb);
> > +     else
> > +             res =3D chv3_fb_fallback_init(fb);
> > +     if (res)
> > +             goto error;
> > +
> > +     /* initialize rest of driver struct */
> > +     INIT_LIST_HEAD(&fb->bufs);
> > +     spin_lock_init(&fb->bufs_lock);
> > +     mutex_init(&fb->fb_lock);
> > +
> > +     chv3_fb_set_default_format(fb, legacy_format);
> > +     chv3_fb_set_default_timings(fb);
> > +
> > +     /* initialize hw */
> > +     writel(FB_RESET_BIT, fb->iobase + FB_RESET);
> > +     writel(FB_DATARATE_DOUBLE, fb->iobase + FB_DATARATE);
> > +     writel(FB_PIXELMODE_DOUBLE, fb->iobase + FB_PIXELMODE);
> > +     if (legacy_format)
> > +             writel(FB_DMAFORMAT_8BPC_LEGACY, fb->iobase + FB_DMAFORMA=
T);
> > +     else
> > +             writel(FB_DMAFORMAT_8BPC, fb->iobase + FB_DMAFORMAT);
> > +
> > +     writel(FB_IRQ_ALL, fb->iobase_irq + FB_IRQ_MASK);
> > +
> > +     return 0;
> > +
> > +error:
> > +     v4l2_device_unregister(&fb->v4l2_dev);
> > +
> > +     return res;
> > +}
> > +
> > +static void chv3_fb_remove(struct platform_device *pdev)
> > +{
> > +     struct chv3_fb *fb =3D platform_get_drvdata(pdev);
> > +
> > +     /* disable interrupts */
> > +     writel(0, fb->iobase_irq + FB_IRQ_MASK);
> > +
> > +     v4l2_async_nf_unregister(&fb->notifier);
> > +     v4l2_async_nf_cleanup(&fb->notifier);
> > +     v4l2_device_unregister(&fb->v4l2_dev);
> > +}
> > +
> > +static const struct of_device_id chv3_fb_match_table[] =3D {
> > +     { .compatible =3D "google,chv3-fb" },
> > +     { },
> > +};
> > +
> > +static struct platform_driver chv3_fb_platform_driver =3D {
> > +     .probe =3D chv3_fb_probe,
> > +     .remove_new =3D chv3_fb_remove,
> > +     .driver =3D {
> > +             .name =3D DEVICE_NAME,
> > +             .of_match_table =3D chv3_fb_match_table,
> > +     },
> > +};
> > +
> > +module_platform_driver(chv3_fb_platform_driver);
> > +
> > +MODULE_AUTHOR("Pawe=C5=82 Anikiel <panikiel@google.com>");
> > +MODULE_DESCRIPTION("Google Chameleon v3 video framebuffer driver");
> > +MODULE_LICENSE("GPL");
>
> For the v3, can you also provide the output of 'v4l2-compliance -s'
> in the cover letter? Make sure you compile v4l2-compliance directly
> from the git repo https://git.linuxtv.org/v4l-utils.git/ since the versio=
n
> from distros is usually too old.

Okay, I'll do that.