On 11/04/2024 08:34, Umang Jain wrote:
Hi Tomi,
On 10/04/24 6:05 pm, Tomi Valkeinen wrote:
Add some checks to verify that the subdev driver implements required
features.
A subdevice that supports streams (V4L2_SUBDEV_FL_STREAMS) must do one
of the following:
- Implement neither .enable/disable_streams() nor .s_stream(), if the
subdev is part of a video driver that uses an internal method to
enable the subdev.
- Implement only .enable/disable_streams(), if support for legacy
sink-side subdevices is not needed.
- Implement .enable/disable_streams() and .s_stream(), if support for
legacy sink-side subdevices is needed.
At the moment the framework doesn't check this requirement. Add the
check.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
The code looks aligned with the restrictions mentioned in the commit
message.
Only one question in case 3), does the .s_stream() needs to be helper
function I think, can we (or do we) need to check that as well?
Do you mean if in case 3, the s_stream should always be set to
v4l2_subdev_s_stream_helper()?
I don't think so. The helper only works for subdevices with a single
source pad. And even if the helper worked for multiple source pads, I
don't see any specific reason to prevent the drivers from having their
own implementation.
Tomi
Reviewed-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-subdev.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c
b/drivers/media/v4l2-core/v4l2-subdev.c
index 4a531c2b16c4..606a909cd778 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -1533,6 +1533,33 @@ int __v4l2_subdev_init_finalize(struct
v4l2_subdev *sd, const char *name,
struct lock_class_key *key)
{
struct v4l2_subdev_state *state;
+ struct device *dev = sd->dev;
+ bool has_disable_streams;
+ bool has_enable_streams;
+ bool has_s_stream;
+
+ /* Check that the subdevice implements the required features */
+
+ has_s_stream = v4l2_subdev_has_op(sd, video, s_stream);
+ has_enable_streams = v4l2_subdev_has_op(sd, pad, enable_streams);
+ has_disable_streams = v4l2_subdev_has_op(sd, pad, disable_streams);
+
+ if (has_enable_streams != has_disable_streams) {
+ dev_err(dev,
+ "subdev '%s' must implement both or neither of
.enable_streams() and .disable_streams()\n",
+ sd->name);
+ return -EINVAL;
+ }
+
+ if (sd->flags & V4L2_SUBDEV_FL_STREAMS) {
+ if (has_s_stream && !has_enable_streams) {
+ dev_err(dev,
+ "subdev '%s' must implement
.enable/disable_streams()\n",
+ sd->name);
+
+ return -EINVAL;
+ }
+ }
state = __v4l2_subdev_state_alloc(sd, name, key);
if (IS_ERR(state))
