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Date: Thu, 19 Mar 2015 09:42:35 -0600
From: Stephen Warren <swarren@wwwdotorg.org>
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To: Paul Walmsley <paul@pwsan.com>
CC: Russell King - ARM Linux <linux@arm.linux.org.uk>,
        linux-tegra@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Mark Rutland <mark.rutland@arm.com>,
        Alexandre Courbot <gnurou@gmail.com>, Pawel Moll <pawel.moll@arm.com>,
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        linux-kernel@vger.kernel.org, Eduardo Valentin <edubezval@gmail.com>,
        devicetree@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Paul Walmsley <pwalmsley@nvidia.com>,
        Kumar Gala <galak@codeaurora.org>, Hiroshi DOYU <hdoyu@nvidia.com>
Subject: Re: [PATCHv2 3/3] Documentation: DT bindings: Tegra AHB: note base
 address change
References: <20150317083221.32662.14647.stgit@baseline> <20150317083221.32662.96822.stgit@baseline> <20150317103806.GU8656@n2100.arm.linux.org.uk> <alpine.DEB.2.02.1503191525450.9480@utopia.booyaka.com>
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On 03/19/2015 09:26 AM, Paul Walmsley wrote:
> On Tue, 17 Mar 2015, Russell King - ARM Linux wrote:
>
>> On Tue, Mar 17, 2015 at 01:32:21AM -0700, Paul Walmsley wrote:
>>>   Required properties:
>>>   - compatible : For Tegra20, must contain "nvidia,tegra20-ahb".  For
>>> -  Tegra30, must contain "nvidia,tegra30-ahb".  Otherwise, must contain
>>> -  '"nvidia,<chip>-ahb", "nvidia,tegra30-ahb"' where <chip> is tegra124,
>>> -  tegra132, or tegra210.
>>> -- reg : Should contain 1 register ranges(address and length)
>>> +  Tegra30, must contain "nvidia,tegra30-ahb".  For Tegra114 and Tegra124, must
>>> +  contain '"nvidia,<chip>-ahb", "nvidia,tegra30-ahb"' where <chip> is tegra114
>>> +  or tegra124.  For Tegra132, the compatible string must contain
>>> +  "nvidia,tegra132-ahb".
>>> +
>>> +- reg : Should contain 1 register ranges(address and length).  On Tegra20,
>>> +  Tegra30, Tegra114, and Tegra124 chips, the low byte of the physical base
>>> +  address of the IP block must end in 0x04.  On DT files for later chips, the
>>> +  actual hardware base address of the IP block should be used.
>>
>> You could check that in the driver.  If you can check it in the driver,
>> you can also decide to ignore it if it were offset by 0x04 (possibly
>> printing a warning.)  That opens up the ability to fix the older Tegra
>> DT files going forward while still remaining compatible with existing
>> DT files, and avoiding the need for a complex note about this.
>
> That's fine, I'll do that and drop this patch.

Don't we still want to update the DT binding documentation to state what 
the preferred base address (or at least set of legal base addresses) is/are?