diff options
Diffstat (limited to 'Documentation/video4linux/v4l2-framework.txt')
| -rw-r--r-- | Documentation/video4linux/v4l2-framework.txt | 21 |
1 files changed, 4 insertions, 17 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index a31177390e55..854808b67fae 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -90,7 +90,7 @@ up before calling v4l2_device_register then it will be untouched. If dev is 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 +usb_interface or platform_device. It is rare for dev to be NULL, but it happens with ISA devices or when one device creates multiple PCI devices, thus making it impossible to associate v4l2_dev with a particular parent. @@ -351,17 +351,6 @@ And this to go from an i2c_client to a v4l2_subdev struct: struct v4l2_subdev *sd = i2c_get_clientdata(client); -Finally you need to make a command function to make driver->command() -call the right subdev_ops functions: - -static int subdev_command(struct i2c_client *client, unsigned cmd, void *arg) -{ - return v4l2_subdev_command(i2c_get_clientdata(client), cmd, arg); -} - -If driver->command is never used then you can leave this out. Eventually the -driver->command usage should be removed from v4l. - Make sure to call v4l2_device_unregister_subdev(sd) when the remove() callback is called. This will unregister the sub-device from the bridge driver. It is safe to call this even if the sub-device was never registered. @@ -375,14 +364,12 @@ from the remove() callback ensures that this is always done correctly. The bridge driver also has some helper functions it can use: -struct v4l2_subdev *sd = v4l2_i2c_new_subdev(adapter, "module_foo", "chipid", 0x36); +struct v4l2_subdev *sd = v4l2_i2c_new_subdev(v4l2_dev, adapter, + "module_foo", "chipid", 0x36); This loads the given module (can be NULL if no module needs to be loaded) and calls i2c_new_device() with the given i2c_adapter and chip/address arguments. -If all goes well, then it registers the subdev with the v4l2_device. It gets -the v4l2_device by calling i2c_get_adapdata(adapter), so you should make sure -to call i2c_set_adapdata(adapter, v4l2_device) when you setup the i2c_adapter -in your driver. +If all goes well, then it registers the subdev with the v4l2_device. You can also use v4l2_i2c_new_probed_subdev() which is very similar to v4l2_i2c_new_subdev(), except that it has an array of possible I2C addresses |