[i2c] [PATCH 3/5] powerpc: Document device nodes for I2C devices.

[Kumar Gala]

On May 18, 2007, at 11:35 AM, Scott Wood wrote:

> Kumar Gala wrote:
>> I guess my gripe is about proposing a solution and not willing to   
>> extend it in light of people providing issues with it.
>
> I'm perfectly willing to extend it if you let me know what you  
> think is needed, rather than just saying "switches and muxes".   
> What *specifically* would they need beyond what I proposed?

I provided you an example device and asked you to explain how it  
would be described in what you are proposing.

>> Last time I  check we don't put things into the kernel w/o any  
>> review and if  people have issues that are reasonable they get  
>> hashed out.  It seems  that the onus is on the initial submitter  
>> to either show that what  they are providing is sufficient and w/o  
>> issue or incorporate the  feedback.
>
> Give me something I can incorporate, then.  My gripe is when the  
> feedback is "don't bother" based on unspecified problems with a  
> configuration more complex than what it was intended to address  
> (but still, AFAICT, not outside its ability to address).

I never said don't bother because you didn't cover the switch/mux  
case.  I said don't bother because I don't see what the value is  
creating a namespace that no one is going to manage and thus will end  
up most likely being linux specific, and linux already provides a  
solution for the problem.

>> More specifically, we have a way to specify what devices are  
>> connect  on I2C today.  I'm not convinced there is any value in  
>> creating yet  another mechanism, especially in an interface that  
>> in theory should  be linux agnostic.
>
> We had a way to specify platform devices before, too.  If the  
> device tree isn't worthwhile for i2c devices, why is it worthwhile  
> for soc devices?  It seems to me that non-probable chips like i2c  
> devices are precisely the kind of thing that the device tree is  
> useful for.

I dont believe anyone has ever said that platform devices have to be  
in the device tree.  We've been putting them their because we are  
going to act as the registry for the devices.  The number of devices  
on all the various Freescale/AMCC/IBM PPC SoCs is likely a very small  
number compared to all I2C devices.

For I2C specifically we already have both a dynamic way (kernel cmd  
line) and static (i2c_board_info) to specify the i2c devices, why do  
we need yet another?

- k