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media: v4l: async: Remove re-probing support 

Remove V4L2 async re-probing support. The re-probing support has been
there to support cases where the sub-devices require resources provided by
the main driver's hardware to function, such as clocks.

Reprobing has allowed unbinding and again binding the main driver without
explicitly unbinding the sub-device drivers. This is certainly not a
common need, and the responsibility will be the user's going forward.

An alternative could have been to introduce notifier specific locks.
Considering the complexity of the re-probing and that it isn't really a
solution to a problem but a workaround, remove re-probing instead.

If there is a need to support the clock provider unregister/register cycle
while keeping the clock references in the consumers in the future, this
should be implemented in the clock framework instead, not in V4L2.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Sakari Ailus 2017-09-05 08:11:59 -04:00 committed by Mauro Carvalho Chehab
parent f283c01b80
commit de8dd7b2af
1 changed files with 1 additions and 53 deletions
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54
drivers/media/v4l2-core/v4l2-async.c
View File

@ -198,78 +198,26 @@ EXPORT_SYMBOL(v4l2_async_notifier_register);
void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
{
struct v4l2_subdev *sd, *tmp;
unsigned int notif_n_subdev = notifier->num_subdevs;
unsigned int n_subdev = min(notif_n_subdev, V4L2_MAX_SUBDEVS);
struct device **dev;
int i = 0;
if (!notifier->v4l2_dev)
return;
dev = kvmalloc_array(n_subdev, sizeof(*dev), GFP_KERNEL);
if (!dev) {
dev_err(notifier->v4l2_dev->dev,
"Failed to allocate device cache!\n");
}
mutex_lock(&list_lock);
list_del(&notifier->list);
list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
struct device *d;
d = get_device(sd->dev);
v4l2_async_cleanup(sd);
/* If we handled USB devices, we'd have to lock the parent too */
device_release_driver(d);
if (notifier->unbind)
notifier->unbind(notifier, sd, sd->asd);
/*
* Store device at the device cache, in order to call
* put_device() on the final step
*/
if (dev)
dev[i++] = d;
else
put_device(d);
list_move(&sd->async_list, &subdev_list);
}
mutex_unlock(&list_lock);
/*
* Call device_attach() to reprobe devices
*
* NOTE: If dev allocation fails, i is 0, and the whole loop won't be
* executed.
*/
while (i--) {
struct device *d = dev[i];
if (d && device_attach(d) < 0) {
const char *name = "(none)";
int lock = device_trylock(d);
if (lock && d->driver)
name = d->driver->name;
dev_err(d, "Failed to re-probe to %s\n", name);
if (lock)
device_unlock(d);
}
put_device(d);
}
kvfree(dev);
notifier->v4l2_dev = NULL;
/*
* Don't care about the waiting list, it is initialised and populated
* upon notifier registration.
*/
}
EXPORT_SYMBOL(v4l2_async_notifier_unregister);