v4l2: add v4l2_device and v4l2_subdev structs to the v4l2 framework.

From: Hans Verkuil <hverkuil@xs4all.nl>

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).

Priority: normal

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>

1 files changed, 86 insertions, 0 deletions

diff --git a/linux/drivers/media/video/v4l2-device.c b/linux/drivers/media/video/v4l2-device.c
new file mode 100644
index 000000000..9eefde031
--- /dev/null
+++ b/linux/drivers/media/video/v4l2-device.c
@@ -0,0 +1,86 @@
+/*
+    V4L2 device support.
+
+    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
+ */
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+#include <linux/i2c.h>
+#include <linux/videodev2.h>
+#include <media/v4l2-device.h>
+
+int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
+{
+	if (dev == NULL || v4l2_dev == NULL)
+		return -EINVAL;
+	/* Warn if we apparently re-register a device */
+	WARN_ON(dev_get_drvdata(dev));
+	INIT_LIST_HEAD(&v4l2_dev->subdevs);
+	spin_lock_init(&v4l2_dev->lock);
+	v4l2_dev->dev = dev;
+	snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
+			dev->driver->name, dev->bus_id);
+	dev_set_drvdata(dev, v4l2_dev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_register);
+
+void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
+{
+	struct v4l2_subdev *sd, *next;
+
+	if (v4l2_dev == NULL || v4l2_dev->dev == NULL)
+		return;
+	dev_set_drvdata(v4l2_dev->dev, NULL);
+	/* unregister subdevs */
+	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list)
+		v4l2_device_unregister_subdev(sd);
+
+	v4l2_dev->dev = NULL;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_unregister);
+
+int v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd)
+{
+	/* Check for valid input */
+	if (dev == NULL || sd == NULL || !sd->name[0])
+		return -EINVAL;
+	/* Warn if we apparently re-register a subdev */
+	WARN_ON(sd->dev);
+	if (!try_module_get(sd->owner))
+		return -ENODEV;
+	sd->dev = dev;
+	spin_lock(&dev->lock);
+	list_add_tail(&sd->list, &dev->subdevs);
+	spin_unlock(&dev->lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
+
+void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
+{
+	/* return if it isn't registered */
+	if (sd == NULL || sd->dev == NULL)
+		return;
+	spin_lock(&sd->dev->lock);
+	list_del(&sd->list);
+	spin_unlock(&sd->dev->lock);
+	sd->dev = NULL;
+	module_put(sd->owner);
+}
+EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);