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From: Arnd Bergmann <arnd@arndb.de>
To: Murali Karicheri <m-karicheri2@ti.com>
Cc: linux-arm-kernel@lists.infradead.org, Mark Rutland <mark.rutland@arm.com>,
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        Santosh Shilimkar <santosh.shilimkar@ti.com>,
        Kumar Gala <galak@codeaurora.org>, Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [PATCH] PCI: keystone: update to support multiple pci ports
Date: Tue, 09 Sep 2014 12:24:48 +0200
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On Monday 08 September 2014 11:52:47 Murali Karicheri wrote:
> On 09/05/2014 05:11 PM, Arnd Bergmann wrote:
> > But the driver can only do root complex mode, and we would probably
> > want a completely different driver if we were to start supporting
> > endpoint mode.
> 
> Good point! I will drop index#2 handling in the driver code and will 
> handle the same in boot loader. But I have a question though. The 
> original driver which is queued up for merge to v3.18 has index #2 for 
> this reg offset and is documented in the DT documentation as
> 
> 	index 2 is the base address and length of PCI mode configuration
> 	register.
> 	index 3 is the base address and length of PCI device ID register.
> 
> 
> Will this create any issue in terms of backward compatibility if I 
> remove it and move index3 to index2 and update the code for the same? I 
> assume since this patch also will likely be on the next branch soon, and 
> gets merged together with original driver to v3.18, this should be fine. 
> But for some reason, if this patch doesn't make to v3.18, then won't 
> this break the backward compatibility?
> 
> I think the other option is document index2 as obsolete and update the 
> document and remove the code for handling it. Any suggestion?

Since the driver is not merged into Linus' tree yet and (more importantly)
has not been in a release yet, we can still fix it. Please just send a
patch on top to remove it now, it's not too late yet.

	Arnd