Subject: DTS parsing and kernel bus support query

From: [email-masked]
Date: Tue, 08 Dec 2009 13:53:41 +0000

Hi

I have following queries about DTS parsing and kernel bus support. I would  
really appreciate any help.

I have a PowerPC 440 core based board. We are porting Linux kernel – 2.6.31.

1) For other PowerPC 4xx based boards, what we found is devices like  
UART/I2C/GPIO are connected through PLB->OPB buses. Accordingly we specify  
the node structure inside a dts file. Does kernel uses the actual path to  
locate a node eg /plb/opb/i2c? or it uses the compatible property to locate  
a node?

2)In case of our board, instead of OPB and EBC we have buses like AI and  
APB. So our DTS node struct for UART looks like /plb/ai/apb/serial. For  
this do we need to add any extra support in kernel in order to recognize  
the devices on AI and APB buses? Similar question for Flash device. It's on  
the path /plb/ai/flash.
I need to access UART/I2C/GPIO/Flash devices over AI and APB bus. PLB is  
connected to AI bus. AI is further connected to APB.

3) Do we need to add extra support for AI/APB bus in kernel?

Thanks,
Vinayak