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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