From 2c79252326421dd49c059aceec0880d2cf15b17a Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 12 Mar 2009 18:34:19 -0300 Subject: 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 Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/v4l2-framework.txt | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'Documentation/video4linux') 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 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 -that adapdata is set to v4l2_device when you setup the i2c_adapter in your -driver. +to call i2c_set_adapdata(adapter, v4l2_device) when you setup the i2c_adapter +in your driver. 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 @@ -368,6 +368,14 @@ that it should probe. Internally it calls i2c_new_probed_device(). Both functions return NULL if something went wrong. +Note that the chipid you pass to v4l2_i2c_new_(probed_)subdev() is usually +the same as the module name. It allows you to specify a chip variant, e.g. +"saa7114" or "saa7115". In general though the i2c driver autodetects this. +The use of chipid is something that needs to be looked at more closely at a +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. + struct video_device ------------------- -- cgit v1.2.2