[media] media: Media device

The media_device structure abstracts functions common to all kind of
media devices (v4l2, dvb, alsa, ...). It manages media entities and
offers a userspace API to discover and configure the media device
internal topology.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
new file mode 100644
index 000000000000..bcd3985d415a
--- /dev/null
+++ b/drivers/media/media-device.c
@@ -0,0 +1,100 @@
+/*
+ * Media device
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ *
+ * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ *           Sakari Ailus <sakari.ailus@iki.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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 <media/media-device.h>
+#include <media/media-devnode.h>
+
+static const struct media_file_operations media_device_fops = {
+        .owner = THIS_MODULE,
+};
+
+/* -----------------------------------------------------------------------------
+ * sysfs
+ */
+
+static ssize_t show_model(struct device *cd,
+                          struct device_attribute *attr, char *buf)
+{
+        struct media_device *mdev = to_media_device(to_media_devnode(cd));
+
+        return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
+}
+
+static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);
+
+/* -----------------------------------------------------------------------------
+ * Registration/unregistration
+ */
+
+static void media_device_release(struct media_devnode *mdev)
+{
+}
+
+/**
+ * media_device_register - register a media device
+ * @mdev:       The media device
+ *
+ * The caller is responsible for initializing the media device before
+ * registration. The following fields must be set:
+ *
+ * - dev must point to the parent device
+ * - model must be filled with the device model name
+ */
+int __must_check media_device_register(struct media_device *mdev)
+{
+        int ret;
+
+        if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0))
+                return -EINVAL;
+
+        /* Register the device node. */
+        mdev->devnode.fops = &media_device_fops;
+        mdev->devnode.parent = mdev->dev;
+        mdev->devnode.release = media_device_release;
+        ret = media_devnode_register(&mdev->devnode);
+        if (ret < 0)
+                return ret;
+
+        ret = device_create_file(&mdev->devnode.dev, &dev_attr_model);
+        if (ret < 0) {
+                media_devnode_unregister(&mdev->devnode);
+                return ret;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(media_device_register);
+
+/**
+ * media_device_unregister - unregister a media device
+ * @mdev:       The media device
+ *
+ */
+void media_device_unregister(struct media_device *mdev)
+{
+        device_remove_file(&mdev->devnode.dev, &dev_attr_model);
+        media_devnode_unregister(&mdev->devnode);
+}
+EXPORT_SYMBOL_GPL(media_device_unregister);