Hi Tomi,
On 3/1/22 11:55, Tomi Valkeinen wrote:
> Add v4l2_subdev_call_state_active() macro to help calling subdev ops
> that take a subdev state as a parameter. Normally the v4l2 framework
> will lock and pass the correct subdev state to the subdev ops, but there
> are legacy situations where this is not the case (e.g. non-MC video
> device driver calling set_fmt in a source subdev).
>
> As this macro is only needed for legacy use cases, the macro is added in
> a new header file, v4l2-subdev-legacy.h.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> ---
> include/media/v4l2-subdev-legacy.h | 42 ++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
> create mode 100644 include/media/v4l2-subdev-legacy.h
>
> diff --git a/include/media/v4l2-subdev-legacy.h b/include/media/v4l2-subdev-legacy.h
> new file mode 100644
> index 000000000000..6a61e579b629
> --- /dev/null
> +++ b/include/media/v4l2-subdev-legacy.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * V4L2 sub-device legacy support header.
> + *
> + * Copyright (C) 2022 Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> + */
> +
> +#ifndef _V4L2_SUBDEV_LEGACY_H
> +#define _V4L2_SUBDEV_LEGACY_H
> +
> +/**
> + * v4l2_subdev_call_state_active - call an operation of a v4l2_subdev which
> + * takes state as a parameter, passing the
> + * subdev its active state.
> + *
> + * @sd: pointer to the &struct v4l2_subdev
> + * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
> + * Each element there groups a set of callbacks functions.
> + * @f: callback function to be called.
> + * The callback functions are defined in groups, according to
> + * each element at &struct v4l2_subdev_ops.
> + * @args: arguments for @f.
> + *
> + * This is similar to v4l2_subdev_call(), except that this version can only be
> + * used for ops that take a subdev state as a parameter. The macro will get the
> + * active state and lock it before calling the op, and unlock it after the
> + * call.
> + */
You should explain why this is a legacy macro and, ideally, what would need to
be done to get rid of it. The first is in the commit log, but nobody reads that :-)
But if just using it in a non-MC video device driver constitutes 'legacy' use,
then I disagree with that. There are many non-MC video device drivers, nothing
legacy about that.
Regards,
Hans
> +#define v4l2_subdev_call_state_active(sd, o, f, args...) \
> + ({ \
> + int __result; \
> + struct v4l2_subdev_state *state; \
> + state = v4l2_subdev_get_active_state(sd); \
> + if (state) \
> + v4l2_subdev_lock_state(state); \
> + __result = v4l2_subdev_call(sd, o, f, state, ##args); \
> + if (state) \
> + v4l2_subdev_unlock_state(state); \
> + __result; \
> + })
> +
> +#endif
