Re: Multiple device attachments

[Frank Zerangue <frank.zerangue%gmail.com@localhost>]

I have a hardware configuration with a cmos camera sensor on an i2c bus (for 
configuring the camera) and connected to an (ipu) image processing controller 
that acts as a hub for all things video. I envisioned (naturally I think) a 
camera driver inheriting from two parents 1) i2c bus driver and 2) ipu 
controller driver. 

This does not seem like such a strange hardware configuration to me that would 
not be found on other embedded systems. Does anyone have a suggestion for an 
appropriate driver hierarchy for such a configuration?

Frank

On Jul 22, 2011, at 12:07 PM, Eduardo Horvath wrote:

> On Thu, 21 Jul 2011, Frank Zerangue wrote:
> 
>> The examples you site seem to indicate that for example the le device may 
>> attach to many
>> alternative devices (e.g. pci, tc, …), but only one attachment is made when 
>> autoconf is complete. I may have 
>> read the code examples incorrectly -- please pardon me if I did; but what I 
>> want to know is --  can a 
>> device have multiple attachments (more than one parent device) when autoconf 
>> is complete. 
> 
> What we have is a device tree.  That means a device instance can only have 
> one parent.  Once it has been instantiated, that instance, with its 
> associated instance number, cannot appear anywhere else in the device 
> tree.
> 
> It might be good to extend the device tree to a directed graph at some 
> point to support multi-pathed devices on fabrics like SAS, Fibre-channel, 
> or PCIe that allow that sort of thing, but that's a different issue.
> 
> Eduardo