struct v4l2_ctrl_ops — The control operations that the driver has to provide.
struct v4l2_ctrl_ops {
int (* g_volatile_ctrl) (struct v4l2_ctrl *ctrl);
int (* try_ctrl) (struct v4l2_ctrl *ctrl);
int (* s_ctrl) (struct v4l2_ctrl *ctrl);
}; Get a new value for this control. Generally only relevant for volatile (and usually read-only) controls such as a control that returns the current signal strength which changes continuously. If not set, then the currently cached value will be returned.
Test whether the control's value is valid. Only relevant when the usual min/max/step checks are not sufficient.
Actually set the new control value. s_ctrl is compulsory. The ctrl->handler->lock is held when these ops are called, so no one else can access controls owned by that handler.