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authorHans Verkuil <hverkuil@xs4all.nl>2009-03-12 17:34:19 -0400
committerMauro Carvalho Chehab <mchehab@redhat.com>2009-03-30 11:43:19 -0400
commit2c79252326421dd49c059aceec0880d2cf15b17a (patch)
tree843430d8471a54dbe04a6363f7d2e30060ed7499 /Documentation/video4linux
parent5e585ef15b3633e1b0c022aa14bc88587827acd3 (diff)
V4L/DVB (10980): doc: improve the v4l2-framework documentation.
Emphasize the need to call i2c_set_adapdata and clarify the use of the chipid in v4l2_i2c_new_(probed_)device(). Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/video4linux')
-rw-r--r--Documentation/video4linux/v4l2-framework.txt12
1 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index accc376e93c..51a7b6db118 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -359,8 +359,8 @@ This loads the given module (can be NULL if no module needs to be loaded) and
359calls i2c_new_device() with the given i2c_adapter and chip/address arguments. 359calls i2c_new_device() with the given i2c_adapter and chip/address arguments.
360If all goes well, then it registers the subdev with the v4l2_device. It gets 360If all goes well, then it registers the subdev with the v4l2_device. It gets
361the v4l2_device by calling i2c_get_adapdata(adapter), so you should make sure 361the v4l2_device by calling i2c_get_adapdata(adapter), so you should make sure
362that adapdata is set to v4l2_device when you setup the i2c_adapter in your 362to call i2c_set_adapdata(adapter, v4l2_device) when you setup the i2c_adapter
363driver. 363in your driver.
364 364
365You can also use v4l2_i2c_new_probed_subdev() which is very similar to 365You can also use v4l2_i2c_new_probed_subdev() which is very similar to
366v4l2_i2c_new_subdev(), except that it has an array of possible I2C addresses 366v4l2_i2c_new_subdev(), except that it has an array of possible I2C addresses
@@ -368,6 +368,14 @@ that it should probe. Internally it calls i2c_new_probed_device().
368 368
369Both functions return NULL if something went wrong. 369Both functions return NULL if something went wrong.
370 370
371Note that the chipid you pass to v4l2_i2c_new_(probed_)subdev() is usually
372the same as the module name. It allows you to specify a chip variant, e.g.
373"saa7114" or "saa7115". In general though the i2c driver autodetects this.
374The use of chipid is something that needs to be looked at more closely at a
375later date. It differs between i2c drivers and as such can be confusing.
376To see which chip variants are supported you can look in the i2c driver code
377for the i2c_device_id table. This lists all the possibilities.
378
371 379
372struct video_device 380struct video_device
373------------------- 381-------------------