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diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h
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+/*
+ V4L2 device support header.
+
+ Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _V4L2_DEVICE_H
+#define _V4L2_DEVICE_H
+
+#include <media/v4l2-subdev.h>
+
+/* Each instance of a V4L2 device should create the v4l2_device struct,
+ either stand-alone or embedded in a larger struct.
+
+ It allows easy access to sub-devices (see v4l2-subdev.h) and provides
+ basic V4L2 device-level support.
+ */
+
+#define V4L2_DEVICE_NAME_SIZE (BUS_ID_SIZE + 16)
+
+struct v4l2_device {
+ /* dev->driver_data points to this struct */
+ struct device *dev;
+ /* used to keep track of the registered subdevs */
+ struct list_head subdevs;
+ /* lock this struct; can be used by the driver as well if this
+ struct is embedded into a larger struct. */
+ spinlock_t lock;
+ /* unique device name, by default the driver name + bus ID */
+ char name[V4L2_DEVICE_NAME_SIZE];
+};
+
+/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev */
+int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
+/* Set v4l2_dev->dev->driver_data to NULL and unregister all sub-devices */
+void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
+
+/* Register a subdev with a v4l2 device. While registered the subdev module
+ is marked as in-use. An error is returned if the module is no longer
+ loaded when you attempt to register it. */
+int __must_check v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd);
+/* Unregister a subdev with a v4l2 device. Can also be called if the subdev
+ wasn't registered. In that case it will do nothing. */
+void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
+
+/* Iterate over all subdevs. */
+#define v4l2_device_for_each_subdev(sd, dev) \
+ list_for_each_entry(sd, &(dev)->subdevs, list)
+
+/* Call the specified callback for all subdevs matching the condition.
+ Ignore any errors. Note that you cannot add or delete a subdev
+ while walking the subdevs list. */
+#define __v4l2_device_call_subdevs(dev, cond, o, f, args...) \
+ do { \
+ struct v4l2_subdev *sd; \
+ \
+ list_for_each_entry(sd, &(dev)->subdevs, list) \
+ if ((cond) && sd->ops->o && sd->ops->o->f) \
+ sd->ops->o->f(sd , ##args); \
+ } while (0)
+
+/* Call the specified callback for all subdevs matching the condition.
+ If the callback returns an error other than 0 or -ENOIOCTLCMD, then
+ return with that error code. Note that you cannot add or delete a
+ subdev while walking the subdevs list. */
+#define __v4l2_device_call_subdevs_until_err(dev, cond, o, f, args...) \
+({ \
+ struct v4l2_subdev *sd; \
+ int err = 0; \
+ \
+ list_for_each_entry(sd, &(dev)->subdevs, list) { \
+ if ((cond) && sd->ops->o && sd->ops->o->f) \
+ err = sd->ops->o->f(sd , ##args); \
+ if (err && err != -ENOIOCTLCMD) \
+ break; \
+ } \
+ (err == -ENOIOCTLCMD) ? 0 : err; \
+})
+
+/* Call the specified callback for all subdevs matching grp_id (if 0, then
+ match them all). Ignore any errors. Note that you cannot add or delete
+ a subdev while walking the subdevs list. */
+#define v4l2_device_call_all(dev, grp_id, o, f, args...) \
+ __v4l2_device_call_subdevs(dev, \
+ !(grp_id) || sd->grp_id == (grp_id), o, f , ##args)
+
+/* Call the specified callback for all subdevs matching grp_id (if 0, then
+ match them all). If the callback returns an error other than 0 or
+ -ENOIOCTLCMD, then return with that error code. Note that you cannot
+ add or delete a subdev while walking the subdevs list. */
+#define v4l2_device_call_until_err(dev, grp_id, o, f, args...) \
+ __v4l2_device_call_subdevs_until_err(dev, \
+ !(grp_id) || sd->grp_id == (grp_id), o, f , ##args)
+
+#endif