Re: [PATCH 3/3] Documentation: DT bindings: Tegra AHB: note base address change

Stephen Warren
2015-03-19T15:44:51Z

On 03/19/2015 09:33 AM, Paul Walmsley wrote:
> On Tue, 17 Mar 2015, Stephen Warren wrote:
>
>> On 03/17/2015 02:32 AM, Paul Walmsley wrote:
>>> For Tegra132 and later chips, we can now use the correct hardware base
>>> address for the Tegra AHB IP block in the DT data. Update the DT binding
>>> documentation to reflect this change.
>>
>>> diff --git
>>> a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt
>>> b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt
>>> index 067c979..7692b4c 100644
>>> --- a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt
>>> +++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt
>>> @@ -2,10 +2,15 @@ NVIDIA Tegra AHB
>>>
>>> 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.
>>
>> A table-based approach rather than prose might make this more legible?
>>
>> - compatible: Must contain the following:
>> Tegra20: "nvidia,tegra20-ahb"
>> Tegra30: "nvidia,tegra30-ahb"
>> Tegra114: "nvidia,tegra114-ahb", "nvidia,tegra30-ahb"
>> Tegra124: "nvidia,tegra124-ahb", "nvidia,tegra30-ahb"
>> Tegra132: "nvidia,tegra132-ahb"
>> Tegra210: "nvidia,tegra210-ahb", "nvidia,tegra132-ahb"
>>
>> With any luck, we can extend that final item for future chips to be:
>>
>> Tegra210, TegraNNN:
>> "nvidia,tegra<chip>-ahb", "nvidia,tegra132-ahb"
>>
>> Perhaps we format the 114/124 entry that way too.
>
> I think I'm just going to drop this patch, since Russell prefers that the
> workaround is applied in the driver.
>
> With regards to using tables rather than narrative descriptions: perhaps
> consider a patch to
> Documentation/devicetree/bindings/submitting-patches.txt ? I don't know
> what the DT binding documentation maintainers' future plans are with
> regards to automated documentation reflow, etc., but submitting a patch
> there would stimulate at least some coordination on the issue.

I don't think it's appropriate for that file to dictate that, in the
same way that coding style documentation generally doesn't address that
kind of detail regarding code structure. Rather, the code review process
hopefully homes in on the best representation case-by-case. A table
seems more succinct and unambiguous in this case. Most DT bindings don't
need to specify this level of detail since there aren't so many
inconsistent options; the generic rules apply.