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Subject: Re: [PATCH v9 2/3] PCI: Add tango PCIe host bridge support
To: Bjorn Helgaas <helgaas@kernel.org>
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From: Mason <slash.tmp@free.fr>
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Date: Wed, 5 Jul 2017 01:42:47 +0200
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On 04/07/2017 17:58, Bjorn Helgaas wrote:

> It's definitely a hassle to support chips with different register
> layouts.  Your hardware guys are really making your life hard :)

Now where did I put my foam bat...

> If the chips are fundamentally different, i.e., if they *operate*
> differently in addition to having a different register layout, you
> could make two separate drivers.

It's the exact same underlying IP. Revision 2 is only a
bug fix rev. IIUC, some of the fixes lead to adding a
register here, removing a register there... and I don't
think the HW dev ever considered the pain of supporting
both revs within a single driver.

This dual support explains some of the peculiarities
you noted in my submission.

Regards.