V4L/DVB (11044): v4l2-device: add v4l2_device_disconnect
Call v4l2_device_disconnect when the parent of a hotpluggable device disconnects. This ensures that you do not have a pointer to a device that is no longer present. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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@ -157,4 +157,3 @@
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156 -> IVCE-8784 [0000:f050,0001:f050,0002:f050,0003:f050]
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157 -> Geovision GV-800(S) (master) [800a:763d]
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158 -> Geovision GV-800(S) (slave) [800b:763d,800c:763d,800d:763d]
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159 -> ProVideo PV183 [1830:1540,1831:1540,1832:1540,1833:1540,1834:1540,1835:1540,1836:1540,1837:1540]
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@ -105,6 +105,17 @@ You unregister with:
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Unregistering will also automatically unregister all subdevs from the device.
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If you have a hotpluggable device (e.g. a USB device), then when a disconnect
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happens the parent device becomes invalid. Since v4l2_device has a pointer to
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that parent device it has to be cleared as well to mark that the parent is
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gone. To do this call:
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v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
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This does *not* unregister the subdevs, so you still need to call the
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v4l2_device_unregister() function for that. If your driver is not hotpluggable,
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then there is no need to call v4l2_device_disconnect().
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Sometimes you need to iterate over all devices registered by a specific
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driver. This is usually the case if multiple device drivers use the same
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hardware. E.g. the ivtvfb driver is a framebuffer driver that uses the ivtv
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@ -49,19 +49,26 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
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}
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EXPORT_SYMBOL_GPL(v4l2_device_register);
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void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
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{
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if (v4l2_dev->dev) {
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dev_set_drvdata(v4l2_dev->dev, NULL);
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v4l2_dev->dev = NULL;
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}
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}
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EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
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void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
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{
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struct v4l2_subdev *sd, *next;
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if (v4l2_dev == NULL)
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return;
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if (v4l2_dev->dev)
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dev_set_drvdata(v4l2_dev->dev, NULL);
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v4l2_device_disconnect(v4l2_dev);
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/* Unregister subdevs */
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list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list)
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v4l2_device_unregister_subdev(sd);
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v4l2_dev->dev = NULL;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_unregister);
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@ -53,7 +53,11 @@ struct v4l2_device {
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dev may be NULL in rare cases (ISA devices). In that case you
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must fill in the v4l2_dev->name field before calling this function. */
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int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
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/* Set v4l2_dev->dev->driver_data to NULL and unregister all sub-devices */
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/* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
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Since the parent disappears this ensures that v4l2_dev doesn't have an
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invalid parent pointer. */
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void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
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/* Unregister all sub-devices and any other resources related to v4l2_dev. */
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void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
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/* Register a subdev with a v4l2 device. While registered the subdev module
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