8 files changed, 158 insertions, 22 deletions

diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index f22f35c271f3..8b358710b2f7 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -319,6 +319,22 @@ controlled through GPIO pins. This distinction is only relevant when setting
 up the device, but once the subdev is registered it is completely transparent.
 
 
+V4L2 sub-device userspace API
+-----------------------------
+
+Beside exposing a kernel API through the v4l2_subdev_ops structure, V4L2
+sub-devices can also be controlled directly by userspace applications.
+
+Device nodes named v4l-subdevX can be created in /dev to access sub-devices
+directly. If a sub-device supports direct userspace configuration it must set
+the V4L2_SUBDEV_FL_HAS_DEVNODE flag before being registered.
+
+After registering sub-devices, the v4l2_device driver can create device nodes
+for all registered sub-devices marked with V4L2_SUBDEV_FL_HAS_DEVNODE by calling
+v4l2_device_register_subdev_nodes(). Those device nodes will be automatically
+removed when sub-devices are unregistered.
+
+
 I2C sub-device drivers
 ----------------------
 
diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
index ac54652396e3..7ea65163090e 100644
--- a/drivers/media/video/Makefile
+++ b/drivers/media/video/Makefile
@@ -11,7 +11,7 @@ stkwebcam-objs	:=	stk-webcam.o stk-sensor.o
 omap2cam-objs   :=      omap24xxcam.o omap24xxcam-dma.o
 
 videodev-objs   :=      v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \
-                        v4l2-event.o v4l2-ctrls.o
+                        v4l2-event.o v4l2-ctrls.o v4l2-subdev.o
 
 # V4L2 core modules
 
diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
index 341764a3a990..abe04ef38066 100644
--- a/drivers/media/video/v4l2-dev.c
+++ b/drivers/media/video/v4l2-dev.c
@@ -408,13 +408,14 @@ static int get_index(struct video_device *vdev)
 }
 
 /**
- *      video_register_device - register video4linux devices
+ *      __video_register_device - register video4linux devices
  *      @vdev: video device structure we want to register
  *      @type: type of device to register
  *      @nr:   which device node number (0 == /dev/video0, 1 == /dev/video1, ...
  *             -1 == first free)
  *      @warn_if_nr_in_use: warn if the desired device node number
  *             was already in use and another number was chosen instead.
+ *      @owner: module that owns the video device node
  *
  *      The registration code assigns minor numbers and device node numbers
  *      based on the requested type and registers the new device node with
@@ -435,9 +436,11 @@ static int get_index(struct video_device *vdev)
  *      %VFL_TYPE_VBI - Vertical blank data (undecoded)
  *
  *      %VFL_TYPE_RADIO - A radio card
+ *
+ *      %VFL_TYPE_SUBDEV - A subdevice
  */
-static int __video_register_device(struct video_device *vdev, int type, int nr,
-                int warn_if_nr_in_use)
+int __video_register_device(struct video_device *vdev, int type, int nr,
+                int warn_if_nr_in_use, struct module *owner)
 {
         int i = 0;
         int ret;
@@ -469,6 +472,9 @@ static int __video_register_device(struct video_device *vdev, int type, int nr,
         case VFL_TYPE_RADIO:
                 name_base = "radio";
                 break;
+        case VFL_TYPE_SUBDEV:
+                name_base = "v4l-subdev";
+                break;
         default:
                 printk(KERN_ERR "%s called with unknown type: %d\n",
                        __func__, type);
@@ -552,7 +558,7 @@ static int __video_register_device(struct video_device *vdev, int type, int nr,
                 goto cleanup;
         }
         vdev->cdev->ops = &v4l2_fops;
-        vdev->cdev->owner = vdev->fops->owner;
+        vdev->cdev->owner = owner;
         ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
         if (ret < 0) {
                 printk(KERN_ERR "%s: cdev_add failed\n", __func__);
@@ -597,18 +603,7 @@ cleanup:
         vdev->minor = -1;
         return ret;
 }
-
-int video_register_device(struct video_device *vdev, int type, int nr)
-{
-        return __video_register_device(vdev, type, nr, 1);
-}
-EXPORT_SYMBOL(video_register_device);
-
-int video_register_device_no_warn(struct video_device *vdev, int type, int nr)
-{
-        return __video_register_device(vdev, type, nr, 0);
-}
-EXPORT_SYMBOL(video_register_device_no_warn);
+EXPORT_SYMBOL(__video_register_device);
 
 /**
  *      video_unregister_device - unregister a video4linux device
diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c
index ce64fe16bc60..8c0ad8b372d8 100644
--- a/drivers/media/video/v4l2-device.c
+++ b/drivers/media/video/v4l2-device.c
@@ -124,16 +124,20 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
         /* Check for valid input */
         if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
                 return -EINVAL;
+
         /* Warn if we apparently re-register a subdev */
         WARN_ON(sd->v4l2_dev != NULL);
+
         if (!try_module_get(sd->owner))
                 return -ENODEV;
+
         sd->v4l2_dev = v4l2_dev;
         if (sd->internal_ops && sd->internal_ops->registered) {
                 err = sd->internal_ops->registered(sd);
                 if (err)
                         return err;
         }
+
         /* This just returns 0 if either of the two args is NULL */
         err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler);
         if (err) {
@@ -141,24 +145,57 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
                         sd->internal_ops->unregistered(sd);
                 return err;
         }
+
         spin_lock(&v4l2_dev->lock);
         list_add_tail(&sd->list, &v4l2_dev->subdevs);
         spin_unlock(&v4l2_dev->lock);
+
         return 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
 
+int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
+{
+        struct video_device *vdev;
+        struct v4l2_subdev *sd;
+        int err;
+
+        /* Register a device node for every subdev marked with the
+         * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
+         */
+        list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
+                if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
+                        continue;
+
+                vdev = &sd->devnode;
+                strlcpy(vdev->name, sd->name, sizeof(vdev->name));
+                vdev->v4l2_dev = v4l2_dev;
+                vdev->fops = &v4l2_subdev_fops;
+                vdev->release = video_device_release_empty;
+                err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
+                                              sd->owner);
+                if (err < 0)
+                        return err;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
+
 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 {
         /* return if it isn't registered */
         if (sd == NULL || sd->v4l2_dev == NULL)
                 return;
+
         spin_lock(&sd->v4l2_dev->lock);
         list_del(&sd->list);
         spin_unlock(&sd->v4l2_dev->lock);
         if (sd->internal_ops && sd->internal_ops->unregistered)
                 sd->internal_ops->unregistered(sd);
         sd->v4l2_dev = NULL;
+
+        video_unregister_device(&sd->devnode);
         module_put(sd->owner);
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
diff --git a/drivers/media/video/v4l2-subdev.c b/drivers/media/video/v4l2-subdev.c
new file mode 100644
index 000000000000..037aa28a5ed1
--- /dev/null
+++ b/drivers/media/video/v4l2-subdev.c
@@ -0,0 +1,60 @@
+/*
+ *  V4L2 subdevice support.
+ *
+ *  Copyright (C) 2010 Nokia Corporation
+ *
+ *  Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ *
+ *  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.
+ *
+ *  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/videodev2.h>
+
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+
+static int subdev_open(struct file *file)
+{
+        return 0;
+}
+
+static int subdev_close(struct file *file)
+{
+        return 0;
+}
+
+static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
+{
+        switch (cmd) {
+        default:
+                return -ENOIOCTLCMD;
+        }
+
+        return 0;
+}
+
+static long subdev_ioctl(struct file *file, unsigned int cmd,
+        unsigned long arg)
+{
+        return video_usercopy(file, cmd, arg, subdev_do_ioctl);
+}
+
+const struct v4l2_file_operations v4l2_subdev_fops = {
+        .owner = THIS_MODULE,
+        .open = subdev_open,
+        .unlocked_ioctl = subdev_ioctl,
+        .release = subdev_close,
+};
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index 15802a067a12..4fe6831b1851 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -21,7 +21,8 @@
 #define VFL_TYPE_GRABBER        0
 #define VFL_TYPE_VBI            1
 #define VFL_TYPE_RADIO          2
-#define VFL_TYPE_MAX            3
+#define VFL_TYPE_SUBDEV         3
+#define VFL_TYPE_MAX            4
 
 struct v4l2_ioctl_callbacks;
 struct video_device;
@@ -102,15 +103,26 @@ struct video_device
 /* dev to video-device */
 #define to_video_device(cd) container_of(cd, struct video_device, dev)
 
+int __must_check __video_register_device(struct video_device *vdev, int type,
+                int nr, int warn_if_nr_in_use, struct module *owner);
+
 /* Register video devices. Note that if video_register_device fails,
    the release() callback of the video_device structure is *not* called, so
    the caller is responsible for freeing any data. Usually that means that
    you call video_device_release() on failure. */
-int __must_check video_register_device(struct video_device *vdev, int type, int nr);
+static inline int __must_check video_register_device(struct video_device *vdev,
+                int type, int nr)
+{
+        return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
+}
 
 /* Same as video_register_device, but no warning is issued if the desired
    device node number was already in use. */
-int __must_check video_register_device_no_warn(struct video_device *vdev, int type, int nr);
+static inline int __must_check video_register_device_no_warn(
+                struct video_device *vdev, int type, int nr)
+{
+        return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
+}
 
 /* Unregister video devices. Will do nothing if vdev == NULL or
    video_is_registered() returns false. */
diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h
index b16f307d471a..78b11e5a6db7 100644
--- a/include/media/v4l2-device.h
+++ b/include/media/v4l2-device.h
@@ -96,6 +96,12 @@ int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
    wasn't registered. In that case it will do nothing. */
 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
 
+/* Register device nodes for all subdev of the v4l2 device that are marked with
+ * the V4L2_SUBDEV_FL_HAS_DEVNODE flag.
+ */
+int __must_check
+v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
+
 /* Iterate over all subdevs. */
 #define v4l2_device_for_each_subdev(sd, v4l2_dev)                       \
         list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index da16d2f4a00b..474ef009fd3d 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -22,6 +22,7 @@
 #define _V4L2_SUBDEV_H
 
 #include <media/v4l2-common.h>
+#include <media/v4l2-dev.h>
 #include <media/v4l2-mediabus.h>
 
 /* generic v4l2_device notify callback notification values */
@@ -431,9 +432,11 @@ struct v4l2_subdev_internal_ops {
 #define V4L2_SUBDEV_NAME_SIZE 32
 
 /* Set this flag if this subdev is a i2c device. */
-#define V4L2_SUBDEV_FL_IS_I2C (1U << 0)
+#define V4L2_SUBDEV_FL_IS_I2C                   (1U << 0)
 /* Set this flag if this subdev is a spi device. */
-#define V4L2_SUBDEV_FL_IS_SPI (1U << 1)
+#define V4L2_SUBDEV_FL_IS_SPI                   (1U << 1)
+/* Set this flag if this subdev needs a device node. */
+#define V4L2_SUBDEV_FL_HAS_DEVNODE              (1U << 2)
 
 /* Each instance of a subdev driver should create this struct, either
    stand-alone or embedded in a larger struct.
@@ -455,8 +458,15 @@ struct v4l2_subdev {
         /* pointer to private data */
         void *dev_priv;
         void *host_priv;
+        /* subdev device node */
+        struct video_device devnode;
 };
 
+#define vdev_to_v4l2_subdev(vdev) \
+        container_of(vdev, struct v4l2_subdev, devnode)
+
+extern const struct v4l2_file_operations v4l2_subdev_fops;
+
 static inline void v4l2_set_subdevdata(struct v4l2_subdev *sd, void *p)
 {
         sd->dev_priv = p;