It would be useful to mark instances of v4l2_subdev_state structures as
const when code needs to access them read-only. This isn't currently
possible, as the v4l2_subdev_state_get_*() accessor functions take a
non-const pointer to the state.
Use _Generic() to provide two different versions of the accessors, for
const and non-const states respectively. The former returns a const
pointer to the requested format, rectangle or interval, implementing
const-correctness. The latter returns a non-const pointer, preserving
the current behaviour for drivers.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
---
Bike-shedding about names and the 4 leading underscores is allowed (and
expected).
---
drivers/media/v4l2-core/v4l2-subdev.c | 24 +++++-----
include/media/v4l2-subdev.h | 66 ++++++++++++++++++---------
2 files changed, 57 insertions(+), 33 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 83c6d1e36871..af1fbc28c8f0 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -1616,8 +1616,8 @@ void v4l2_subdev_cleanup(struct v4l2_subdev *sd)
EXPORT_SYMBOL_GPL(v4l2_subdev_cleanup);
struct v4l2_mbus_framefmt *
-__v4l2_subdev_state_get_format(struct v4l2_subdev_state *state,
- unsigned int pad, u32 stream)
+____v4l2_subdev_state_get_format(struct v4l2_subdev_state *state,
+ unsigned int pad, u32 stream)
{
struct v4l2_subdev_stream_configs *stream_configs;
unsigned int i;
@@ -1647,11 +1647,11 @@ __v4l2_subdev_state_get_format(struct v4l2_subdev_state *state,
return NULL;
}
-EXPORT_SYMBOL_GPL(__v4l2_subdev_state_get_format);
+EXPORT_SYMBOL_GPL(____v4l2_subdev_state_get_format);
struct v4l2_rect *
-__v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad,
- u32 stream)
+____v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad,
+ u32 stream)
{
struct v4l2_subdev_stream_configs *stream_configs;
unsigned int i;
@@ -1681,11 +1681,11 @@ __v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad,
return NULL;
}
-EXPORT_SYMBOL_GPL(__v4l2_subdev_state_get_crop);
+EXPORT_SYMBOL_GPL(____v4l2_subdev_state_get_crop);
struct v4l2_rect *
-__v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state,
- unsigned int pad, u32 stream)
+____v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state,
+ unsigned int pad, u32 stream)
{
struct v4l2_subdev_stream_configs *stream_configs;
unsigned int i;
@@ -1715,11 +1715,11 @@ __v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state,
return NULL;
}
-EXPORT_SYMBOL_GPL(__v4l2_subdev_state_get_compose);
+EXPORT_SYMBOL_GPL(____v4l2_subdev_state_get_compose);
struct v4l2_fract *
-__v4l2_subdev_state_get_interval(struct v4l2_subdev_state *state,
- unsigned int pad, u32 stream)
+____v4l2_subdev_state_get_interval(struct v4l2_subdev_state *state,
+ unsigned int pad, u32 stream)
{
struct v4l2_subdev_stream_configs *stream_configs;
unsigned int i;
@@ -1751,7 +1751,7 @@ __v4l2_subdev_state_get_interval(struct v4l2_subdev_state *state,
return NULL;
}
-EXPORT_SYMBOL_GPL(__v4l2_subdev_state_get_interval);
+EXPORT_SYMBOL_GPL(____v4l2_subdev_state_get_interval);
#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index e30c463d90e5..ba722ab501c1 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1340,21 +1340,27 @@ void v4l2_subdev_cleanup(struct v4l2_subdev *sd);
*/
/*
* Wrap v4l2_subdev_state_get_format(), allowing the function to be called with
- * two or three arguments. The purpose of the __v4l2_subdev_state_get_format()
+ * two or three arguments. The purpose of the __v4l2_subdev_state_gen_call()
* macro below is to come up with the name of the function or macro to call,
* using the last two arguments (_stream and _pad). The selected function or
* macro is then called using the arguments specified by the caller. A similar
* arrangement is used for v4l2_subdev_state_crop() and
* v4l2_subdev_state_compose() below.
*/
-#define v4l2_subdev_state_get_format(state, pad, ...) \
- __v4l2_subdev_state_gen_call(format, ##__VA_ARGS__, , _pad) \
+#define v4l2_subdev_state_get_format(state, pad, ...) \
+ __v4l2_subdev_state_gen_call(format, ##__VA_ARGS__, , _pad) \
(state, pad, ##__VA_ARGS__)
-#define __v4l2_subdev_state_get_format_pad(state, pad) \
+#define __v4l2_subdev_state_get_format_pad(state, pad) \
__v4l2_subdev_state_get_format(state, pad, 0)
+#define __v4l2_subdev_state_get_format(state, pad, stream) \
+ _Generic(state, \
+ const struct v4l2_subdev_state *: ((const struct v4l2_mbus_framefmt *) \
+ ____v4l2_subdev_state_get_format((struct v4l2_subdev_state *)state, pad, stream)), \
+ default: ____v4l2_subdev_state_get_format((struct v4l2_subdev_state *)state, pad, stream) \
+ )
struct v4l2_mbus_framefmt *
-__v4l2_subdev_state_get_format(struct v4l2_subdev_state *state,
- unsigned int pad, u32 stream);
+____v4l2_subdev_state_get_format(struct v4l2_subdev_state *state,
+ unsigned int pad, u32 stream);
/**
* v4l2_subdev_state_get_crop() - Get pointer to a stream crop rectangle
@@ -1368,14 +1374,20 @@ __v4l2_subdev_state_get_format(struct v4l2_subdev_state *state,
* For stream-unaware drivers the crop rectangle for the corresponding pad is
* returned. If the pad does not exist, NULL is returned.
*/
-#define v4l2_subdev_state_get_crop(state, pad, ...) \
- __v4l2_subdev_state_gen_call(crop, ##__VA_ARGS__, , _pad) \
+#define v4l2_subdev_state_get_crop(state, pad, ...) \
+ __v4l2_subdev_state_gen_call(crop, ##__VA_ARGS__, , _pad) \
(state, pad, ##__VA_ARGS__)
-#define __v4l2_subdev_state_get_crop_pad(state, pad) \
+#define __v4l2_subdev_state_get_crop_pad(state, pad) \
__v4l2_subdev_state_get_crop(state, pad, 0)
+#define __v4l2_subdev_state_get_crop(state, pad, stream) \
+ _Generic(state, \
+ const struct v4l2_subdev_state *: ((const struct v4l2_rect *) \
+ ____v4l2_subdev_state_get_crop((struct v4l2_subdev_state *)state, pad, stream)), \
+ default: ____v4l2_subdev_state_get_crop((struct v4l2_subdev_state *)state, pad, stream) \
+ )
struct v4l2_rect *
-__v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad,
- u32 stream);
+____v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad,
+ u32 stream);
/**
* v4l2_subdev_state_get_compose() - Get pointer to a stream compose rectangle
@@ -1389,14 +1401,20 @@ __v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad,
* For stream-unaware drivers the compose rectangle for the corresponding pad is
* returned. If the pad does not exist, NULL is returned.
*/
-#define v4l2_subdev_state_get_compose(state, pad, ...) \
- __v4l2_subdev_state_gen_call(compose, ##__VA_ARGS__, , _pad) \
+#define v4l2_subdev_state_get_compose(state, pad, ...) \
+ __v4l2_subdev_state_gen_call(compose, ##__VA_ARGS__, , _pad) \
(state, pad, ##__VA_ARGS__)
-#define __v4l2_subdev_state_get_compose_pad(state, pad) \
+#define __v4l2_subdev_state_get_compose_pad(state, pad) \
__v4l2_subdev_state_get_compose(state, pad, 0)
+#define __v4l2_subdev_state_get_compose(state, pad, stream) \
+ _Generic(state, \
+ const struct v4l2_subdev_state *: ((const struct v4l2_rect *) \
+ ____v4l2_subdev_state_get_compose((struct v4l2_subdev_state *)state, pad, stream)), \
+ default: ____v4l2_subdev_state_get_compose((struct v4l2_subdev_state *)state, pad, stream) \
+ )
struct v4l2_rect *
-__v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state,
- unsigned int pad, u32 stream);
+____v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state,
+ unsigned int pad, u32 stream);
/**
* v4l2_subdev_state_get_interval() - Get pointer to a stream frame interval
@@ -1410,14 +1428,20 @@ __v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state,
* For stream-unaware drivers the frame interval for the corresponding pad is
* returned. If the pad does not exist, NULL is returned.
*/
-#define v4l2_subdev_state_get_interval(state, pad, ...) \
- __v4l2_subdev_state_gen_call(interval, ##__VA_ARGS__, , _pad) \
+#define v4l2_subdev_state_get_interval(state, pad, ...) \
+ __v4l2_subdev_state_gen_call(interval, ##__VA_ARGS__, , _pad) \
(state, pad, ##__VA_ARGS__)
-#define __v4l2_subdev_state_get_interval_pad(state, pad) \
+#define __v4l2_subdev_state_get_interval_pad(state, pad) \
__v4l2_subdev_state_get_interval(state, pad, 0)
+#define __v4l2_subdev_state_get_interval(state, pad, stream) \
+ _Generic(state, \
+ const struct v4l2_subdev_state *: ((const struct v4l2_frac *) \
+ ____v4l2_subdev_state_get_interval((struct v4l2_subdev_state *)state, pad, stream)), \
+ default: ____v4l2_subdev_state_get_interval((struct v4l2_subdev_state *)state, pad, stream) \
+ )
struct v4l2_fract *
-__v4l2_subdev_state_get_interval(struct v4l2_subdev_state *state,
- unsigned int pad, u32 stream);
+____v4l2_subdev_state_get_interval(struct v4l2_subdev_state *state,
+ unsigned int pad, u32 stream);
#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
--
Regards,
Laurent Pinchart
