V4L/DVB (9820): v4l2: add v4l2_device and v4l2_subdev structs to the v4l2 framework.

Start implementing a proper v4l2 framework as discussed during the
Linux Plumbers Conference 2008.

Introduces v4l2_device (for device instances) and v4l2_subdev (representing
sub-device instances).

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Reviewed-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Reviewed-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Reviewed-by: Andy Walls <awalls@radix.net>
Reviewed-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 109 insertions, 0 deletions

diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h
new file mode 100644
index 000000000000..97b283a04289
--- /dev/null
+++ b/include/media/v4l2-device.h
@@ -0,0 +1,109 @@
+/*
+    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