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V4L/DVB (12128): v4l2: update framework documentation.

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Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2009-06-09 17:29:29 -03:00 committed by Mauro Carvalho Chehab
parent f0222c7d86
commit 2c0b19ac3b
1 changed files with 24 additions and 0 deletions
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24
Documentation/video4linux/v4l2-framework.txt
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@ -390,6 +390,30 @@ later date. It differs between i2c drivers and as such can be confusing.
To see which chip variants are supported you can look in the i2c driver code
for the i2c_device_id table. This lists all the possibilities.
There are two more helper functions:
v4l2_i2c_new_subdev_cfg: this function adds new irq and platform_data
arguments and has both 'addr' and 'probed_addrs' arguments: if addr is not
0 then that will be used (non-probing variant), otherwise the probed_addrs
are probed.
For example: this will probe for address 0x10:
struct v4l2_subdev *sd = v4l2_i2c_new_subdev_cfg(v4l2_dev, adapter,
"module_foo", "chipid", 0, NULL, 0, I2C_ADDRS(0x10));
v4l2_i2c_new_subdev_board uses an i2c_board_info struct which is passed
to the i2c driver and replaces the irq, platform_data and addr arguments.
If the subdev supports the s_config core ops, then that op is called with
the irq and platform_data arguments after the subdev was setup. The older
v4l2_i2c_new_(probed_)subdev functions will call s_config as well, but with
irq set to 0 and platform_data set to NULL.
Note that in the next kernel release the functions v4l2_i2c_new_subdev,
v4l2_i2c_new_probed_subdev and v4l2_i2c_new_probed_subdev_addr will all be
replaced by a single v4l2_i2c_new_subdev that is identical to
v4l2_i2c_new_subdev_cfg but without the irq and platform_data arguments.
struct video_device
-------------------