From 005759613b95264fba9138010f112bc138c857c2 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Fri, 13 Mar 2009 10:03:04 -0300 Subject: V4L/DVB (10988): v4l2-dev: use parent field if the v4l2_device has no parent set. Normally the parent device of v4l2_device is used as the video device node's parent. But if it was not set, then use the parent field in the video_device struct. This is needed in the cx88 driver, which has one core v4l2_device but creates multiple pci devices (one each for raw and mpeg video). So you cannot associate the core v4l2_device with a particular PCI device, but you can do that for each video_device. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/v4l2-framework.txt | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'Documentation/video4linux/v4l2-framework.txt') diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index 51a7b6db118f..df0247ed13d8 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -91,7 +91,8 @@ NULL, then you *must* setup v4l2_dev->name before calling v4l2_device_register. The first 'dev' argument is normally the struct device pointer of a pci_dev, usb_device or platform_device. It is rare for dev to be NULL, but it happens -with ISA devices, for example. +with ISA devices or when one device creates multiple PCI devices, thus making +it impossible to associate v4l2_dev with a particular parent. You unregister with: @@ -414,6 +415,15 @@ You should also set these fields: - ioctl_ops: if you use the v4l2_ioctl_ops to simplify ioctl maintenance (highly recommended to use this and it might become compulsory in the future!), then set this to your v4l2_ioctl_ops struct. +- parent: you only set this if v4l2_device was registered with NULL as + the parent device struct. This only happens in cases where one hardware + device has multiple PCI devices that all share the same v4l2_device core. + + The cx88 driver is an example of this: one core v4l2_device struct, but + it is used by both an raw video PCI device (cx8800) and a MPEG PCI device + (cx8802). Since the v4l2_device cannot be associated with a particular + PCI device it is setup without a parent device. But when the struct + video_device is setup you do know which parent PCI device to use. If you use v4l2_ioctl_ops, then you should set either .unlocked_ioctl or .ioctl to video_ioctl2 in your v4l2_file_operations struct. -- cgit v1.2.3