[PATCH V3 3/5] ARM: tegra:add aliases and DMA requestor for serial nodes of Tegra114

Laxman Dewangan ldewangan at nvidia.com
Fri Mar 15 15:03:12 EDT 2013


On Saturday 16 March 2013 12:28 AM, Stephen Warren wrote:
> On 03/15/2013 12:42 PM, Laxman Dewangan wrote:
>>
>>
>>
>> Simple uart driver use the uart clock divider and it is fine here.
>>
>> High speed uart driver uses the car register driver for better
>> flexibility and better resolution.
> OK, so I see that Tegra30 has an enhancement over Tegra20. However,
> given your description, that enhancement is optional; a driver could
> simply continue to use /just/ the in-UART divider, and ignore the CAR
> divider, and still work just fine, albeit with (entirely
> backwards-compatible) less accuracy than it might achieve if it used the
> new feature.
>
> As such, I think it's correct to mark the device as actually being
> compatible with all 3: 114 (precise HW model), 30 (base model w/ extra
> divider), 20 (base model that's compatible, albeit ignoring extra features).
>
> That might be a bit excessive though, so I guess I'll just go with the
> values in your patch. It'd be a good idea if you could post a follow-on
> patch that updates the DT binding to explain this, and then removes the
> comments from *.dtsi since this really should be explained in the
> binding document not the .dtsi files, I think.
>
> At most, I'd expect to see the following in the .dtsi files:
>
> These nodes can either be compatible with nvidia,tegra114-uart, or
> nvidia,tegra114-hsuart. See the bindings for details of the difference.

Sure, I will post a patch for this.




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