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[media] v4l: Allow changing control handler lock

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Allow choosing the lock used by the control handler. This may be handy
sometimes when a driver providing multiple subdevs does not want to use
several locks to serialise its functions.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Sakari Ailus
2012-01-24 21:05:34 -03:00
committed by Mauro Carvalho Chehab
parent 8227c92b69
commit 77e7c4e624
4 changed files with 32 additions and 28 deletions
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9
include/media/v4l2-ctrls.h
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@@ -167,7 +167,9 @@ struct v4l2_ctrl_ref {
/** struct v4l2_ctrl_handler - The control handler keeps track of all the
* controls: both the controls owned by the handler and those inherited
* from other handlers.
* @_lock: Default for "lock".
* @lock: Lock to control access to this handler and its controls.
* May be replaced by the user right after init.
* @ctrls: The list of controls owned by this handler.
* @ctrl_refs: The list of control references.
* @cached: The last found control reference. It is common that the same
@@ -178,7 +180,8 @@ struct v4l2_ctrl_ref {
* @error: The error code of the first failed control addition.
*/
struct v4l2_ctrl_handler {
struct mutex lock;
struct mutex _lock;
struct mutex *lock;
struct list_head ctrls;
struct list_head ctrl_refs;
struct v4l2_ctrl_ref *cached;
@@ -455,7 +458,7 @@ void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
*/
static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
{
mutex_lock(&ctrl->handler->lock);
mutex_lock(ctrl->handler->lock);
}
/** v4l2_ctrl_lock() - Helper function to unlock the handler
@@ -464,7 +467,7 @@ static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
*/
static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
{
mutex_unlock(&ctrl->handler->lock);
mutex_unlock(ctrl->handler->lock);
}
/** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.