On Wed, 4 Jan 2012, Laurent Pinchart wrote: > On Wednesday 04 January 2012 18:13:58 Guennadi Liakhovetski wrote: > > On Wed, 4 Jan 2012, Laurent Pinchart wrote: > > > On Wednesday 04 January 2012 17:35:27 Guennadi Liakhovetski wrote: > > > > On Wed, 4 Jan 2012, javier Martin wrote: > > > > > > > > [snip] > > > > > > > > > For ov7725 it is a natural thing to do since it was originally > > > > > developed for soc-camera and it can easily do the following to access > > > > > platform data: > > > > > > > > > > struct soc_camera_link *icl = soc_camera_i2c_to_link(client); > > > > > pdata = icl->priv; > > > > > > > > > > However, tvp5150 is not aware about soc_camera. I should be able to > > > > > tell whether it's being used with soc-camera or not. If soc camera > > > > > was used I would do the previous method to retrieve platform data. > > > > > But if soc-camera was not used I would do the classic method: > > > > > > > > > > struct tvp5150_platform_data *pdata = client->dev.platform_data; > > > > > > > > > > The problem is how to distinguish in tvp5150 whether I am using > > > > > soc_camera or not. > > > > > > > > Right, that _is_ the problem now. And we've known about it since the > > > > very first time we started to think about re-using the subdev drivers. > > > > The only solution I see so far is to introduce a standard platform > > > > data struct for all subdevices, similar to soc_camera_link. We could > > > > use it as a basis, of course, use a generic name, maybe reconsider > > > > fields - rename / remove / add, but the principle would be the same: a > > > > standard platform data struct with an optional private field. > > > > > > Why is that needed ? Why can't a tvp5150-specific platform data structure > > > do ? > > > > Javier has actually explained this already. > > Sorry for not having followed. > > > Ok, again: he wants to use tvp5150 with an soc-camera host driver, i.e., > > with the soc-camera subsystem. And the soc-camera core sets board_info-> > > platform_data itself to a pointer to the struct soc_camera_link instance. > > That looks to me like it's the part to be changed... Well, we could do this, but this would require changing a few soc-camera subdev drivers and respective platforms and (slightly) the core itself. The soc-camera core needs access to the struct soc_camera_link instance, supplied by the platform. It is passed in .platform_data of the soc-camera client platform device, there's no need to change that. struct soc_camera_link::board_info points to struct i2c_board_info, this is also ok. Basically, that's all the soc-camera core needs - access to these two structs. Next, subdevice drivers also need access to struct soc_camera_link and to their private data. If we let platforms pass subdevice driver private data in i2c_board_info::platform_data, then each driver will need to invent its own way how to also get to struct soc_camera_link. They would either have to point at it from their private data or embed it therein. So, yes, it is doable. AFAICS currently these subdevice drivers soc_camera_platform rj54n1cb0c tw9910 mt9t112 ov772x and these platforms sh/ecovec24 sh/kfr2r09 sh/migor sh/ap325rxa arm/mackerel are affected and have to be modified. After which the core can be fixed too. I could do that, but not sure when I find the time. Javier, if you like, feel free to give it a try. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
