From patchwork Tue Jun 7 15:05:19 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans Verkuil X-Patchwork-Id: 857312 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p57F5e6O010205 for ; Tue, 7 Jun 2011 15:05:44 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755493Ab1FGPFl (ORCPT ); Tue, 7 Jun 2011 11:05:41 -0400 Received: from smtp-vbr1.xs4all.nl ([194.109.24.21]:1325 "EHLO smtp-vbr1.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755332Ab1FGPFi (ORCPT ); Tue, 7 Jun 2011 11:05:38 -0400 Received: from tschai.lan (215.80-203-102.nextgentel.com [80.203.102.215]) (authenticated bits=0) by smtp-vbr1.xs4all.nl (8.13.8/8.13.8) with ESMTP id p57F5QqY037616 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 7 Jun 2011 17:05:35 +0200 (CEST) (envelope-from hverkuil@xs4all.nl) From: Hans Verkuil To: linux-media@vger.kernel.org Cc: Hans Verkuil Subject: [RFCv3 PATCH 14/18] v4l2-ctrls: simplify event subscription. Date: Tue, 7 Jun 2011 17:05:19 +0200 Message-Id: <802aafb5bb2f6a0c35ba477b3ced7a070283ef64.1307458245.git.hans.verkuil@cisco.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1307459123-17810-1-git-send-email-hverkuil@xs4all.nl> References: <1307459123-17810-1-git-send-email-hverkuil@xs4all.nl> In-Reply-To: References: X-Virus-Scanned: by XS4ALL Virus Scanner Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Tue, 07 Jun 2011 15:05:45 +0000 (UTC) From: Hans Verkuil Signed-off-by: Hans Verkuil --- drivers/media/video/v4l2-ctrls.c | 27 +++++++++++++++++++++++++++ include/media/v4l2-ctrls.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+), 0 deletions(-) diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c index 99987fe..bf649cf 100644 --- a/drivers/media/video/v4l2-ctrls.c +++ b/drivers/media/video/v4l2-ctrls.c @@ -862,6 +862,13 @@ int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl, } EXPORT_SYMBOL(v4l2_ctrl_handler_init); +/* Count the number of controls */ +unsigned v4l2_ctrl_handler_cnt(const struct v4l2_ctrl_handler *hdl) +{ + return hdl ? hdl->nr_of_refs : 0; +} +EXPORT_SYMBOL(v4l2_ctrl_handler_cnt); + /* Free all controls and control refs */ void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl) { @@ -1013,6 +1020,7 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl, insertion is an O(1) operation. */ if (list_empty(&hdl->ctrl_refs) || id > node2id(hdl->ctrl_refs.prev)) { list_add_tail(&new_ref->node, &hdl->ctrl_refs); + hdl->nr_of_refs++; goto insert_in_hash; } @@ -2061,3 +2069,22 @@ void v4l2_ctrl_del_fh(struct v4l2_ctrl *ctrl, struct v4l2_fh *fh) v4l2_ctrl_unlock(ctrl); } EXPORT_SYMBOL(v4l2_ctrl_del_fh); + +int v4l2_ctrl_subscribe_fh(struct v4l2_fh *fh, + struct v4l2_event_subscription *sub, unsigned n) +{ + struct v4l2_ctrl_handler *hdl = fh->ctrl_handler; + int ret = 0; + + if (!fh->events) + ret = v4l2_event_init(fh); + if (!ret) { + if (v4l2_ctrl_handler_cnt(hdl) * 2 > n) + n = v4l2_ctrl_handler_cnt(hdl) * 2; + ret = v4l2_event_alloc(fh, n); + } + if (!ret) + ret = v4l2_event_subscribe(fh, sub); + return ret; +} +EXPORT_SYMBOL(v4l2_ctrl_subscribe_fh); diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h index c45bf40..72dafcf 100644 --- a/include/media/v4l2-ctrls.h +++ b/include/media/v4l2-ctrls.h @@ -169,6 +169,7 @@ struct v4l2_ctrl_ref { * control is needed multiple times, so this is a simple * optimization. * @buckets: Buckets for the hashing. Allows for quick control lookup. + * @nr_of_refs: Total number of control references in the list. * @nr_of_buckets: Total number of buckets in the array. * @error: The error code of the first failed control addition. */ @@ -178,6 +179,7 @@ struct v4l2_ctrl_handler { struct list_head ctrl_refs; struct v4l2_ctrl_ref *cached; struct v4l2_ctrl_ref **buckets; + u16 nr_of_refs; u16 nr_of_buckets; int error; }; @@ -263,6 +265,14 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type, int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl, unsigned nr_of_controls_hint); +/** v4l2_ctrl_handler_cnt() - Count the number of controls in the handler. + * @hdl: The control handler. + * + * Returns the number of controls referenced by this handler. + * Returns 0 if @hdl == NULL. + */ +unsigned v4l2_ctrl_handler_cnt(const struct v4l2_ctrl_handler *hdl); + /** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free * the control list. * @hdl: The control handler. @@ -494,11 +504,29 @@ s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl); */ int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val); +/* Internal helper functions that deal with control events. */ void v4l2_ctrl_add_fh(struct v4l2_ctrl_handler *hdl, struct v4l2_ctrl_fh *ctrl_fh, struct v4l2_event_subscription *sub); void v4l2_ctrl_del_fh(struct v4l2_ctrl *ctrl, struct v4l2_fh *fh); +/** v4l2_ctrl_subscribe_fh() - Helper function that subscribes a control event. + * @fh: The file handler that subscribed the control event. + * @sub: The event to subscribe (type must be V4L2_EVENT_CTRL). + * @n: How many events should be allocated? (Passed to v4l2_event_alloc). + * Recommended to set to twice the number of controls plus whatever + * is needed for other events. This function will set n to + * max(n, 2 * v4l2_ctrl_handler_cnt(fh->ctrl_handler)). + * + * A helper function that initializes the fh for events, allocates the + * list of events and subscribes the control event. + * + * Typically called in the handler of VIDIOC_SUBSCRIBE_EVENT in the + * V4L2_EVENT_CTRL case. + */ +int v4l2_ctrl_subscribe_fh(struct v4l2_fh *fh, + struct v4l2_event_subscription *sub, unsigned n); + /* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */ int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc); int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);