[v2,1/1] RFC: media: v4l2-subdev: add subdev-wide state struct

We have 'struct v4l2_subdev_pad_config' which contains configuration for
a single pad used for the TRY functionality, and an array of those
structs is passed to various v4l2_subdev_pad_ops.

I was working on subdev internal routing between pads, and realized that
there's no way to add TRY functionality for routes, which is not pad
specific configuration. Adding a separate struct for try-route config
wouldn't work either, as e.g. set-fmt needs to know the try-route
configuration to propagate the settings.

This patch adds a new struct, 'struct v4l2_subdev_state' (which at the
moment only contains the v4l2_subdev_pad_config array) and the new
struct is used in most of the places where v4l2_subdev_pad_config was
used. All v4l2_subdev_pad_ops functions taking v4l2_subdev_pad_config
are changed to instead take v4l2_subdev_state.

Two drivers are changed to work with the above changes (drivers for HW
which I have) as an example.

I worked on a semantic patch (included below, my first spatch...) to do
this change to all drivers, but hit lots of problems with non-trivial
uses of v4l2_subdev_pad_config.

As it looks like substantial amount of manual work is needed, I'm
posting this RFC to get an ack on the changes before continuing that
work.

@ v4l2_subdev_pad_ops @
identifier pad_ops;
identifier func;
@@

(
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .enum_mbus_code = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .enum_frame_size = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .enum_frame_interval = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .get_fmt = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .set_fmt = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .get_selection = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .set_selection = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .init_cfg = func,
        ...,
};
)

@@
identifier v4l2_subdev_pad_ops.func;
identifier sd;
identifier cfg;
@@

 func(struct v4l2_subdev *sd,
-	struct v4l2_subdev_pad_config *cfg,
+	struct v4l2_subdev_state *cfg,
	...
      )
 {
    ...
 }

@@
identifier v4l2_subdev_pad_ops.func;
identifier sd;
identifier cfg;
@@

 func(struct v4l2_subdev *sd,
-   struct v4l2_subdev_pad_config *cfg
+   struct v4l2_subdev_state *cfg
      )
 {
    ...
 }

@@
struct v4l2_subdev_fh *fh;
@@
-    fh->pad
+    &fh->cfg

@@
identifier func;
identifier cfg;
@@

func(...,
- struct v4l2_subdev_pad_config *cfg,
+ struct v4l2_subdev_state *cfg,
 ...)
{
    ...
}

@@
struct v4l2_subdev_state *cfg;
@@
 {
    <...
(
-   cfg->try_fmt
+   cfg->pad->try_fmt
|
-   cfg->try_crop
+   cfg->pad->try_crop
|
-   cfg->try_compose
+   cfg->pad->try_compose
)
    ...>
 }

@@
identifier pad_cfg;
@@
{
    ...
    struct v4l2_subdev_pad_config pad_cfg;
+   struct v4l2_subdev_state cfg = { .pad = &pad_cfg };
    <...
-   &pad_cfg
+   &cfg
    ...>
}

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 141 +++++++++++++++-----------
 include/media/v4l2-subdev.h           |  72 +++++++------
 2 files changed, 120 insertions(+), 93 deletions(-)

Message ID	20210423102952.137638-2-tomi.valkeinen@ideasonboard.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-media-owner@kernel.org> From: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> To: Mauro Carvalho Chehab <mchehab@kernel.org>, Hans Verkuil <hans.verkuil@cisco.com>, linux-media@vger.kernel.org, Laurent Pinchart <laurent.pinchart@ideasonboard.com>, Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Subject: [PATCH v2 1/1] RFC: media: v4l2-subdev: add subdev-wide state struct Date: Fri, 23 Apr 2021 13:29:52 +0300 Message-Id: <20210423102952.137638-2-tomi.valkeinen@ideasonboard.com> In-Reply-To: <20210423102952.137638-1-tomi.valkeinen@ideasonboard.com> References: <20210423102952.137638-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	RFC: media: v4l2-subdev: add subdev-wide config struct \| expand [v2,0/1] RFC: media: v4l2-subdev: add subdev-wide config struct [v2,1/1] RFC: media: v4l2-subdev: add subdev-wide state struct

[v2,1/1] RFC: media: v4l2-subdev: add subdev-wide state struct

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