lkml.org 
[lkml]   [2012]   [Dec]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] serial: tegra: add serial driver
On 12/17/2012 11:36 AM, Stephen Warren wrote:
> On 12/17/2012 05:10 AM, Laxman Dewangan wrote:
>> Nvidia's Tegra has multiple uart controller which supports:
>> - APB dma based controller fifo read/write.
>> - End Of Data interrupt in incoming data to know whether end
>> of frame achieve or not.
>> - Hw controlled RTS and CTS flow control to reduce SW overhead.
>
>> diff --git a/Documentation/devicetree/bindings/serial/nvidia,serial-tegra.txt b/Documentation/devicetree/bindings/serial/nvidia,serial-tegra.txt
>
>> +NVIDIA Tegra20/Tegra30 high speed (dma based) UART controller driver.
>> +
>> +Required properties:
>> +- compatible : should be "nvidia,tegra20-hsuart", "nvidia,tegra30-hsuart".
>
> One question that isn't addressed here is:
>
> Tegra has 5 UARTs. All of them can use the existing 8250.c by specifying
> compatible = "nvidia,tegra20-uart".

The way it is supposed to work is that the compatible property should
list "nvidia,tegra30-hsuart" first, followed by a fallback name that
refers to the generic 8250 compatibility. Having the 8250.c driver bind
to the more-specific tegra30-hsuart name is wrong.

However, the 8250.c driver doesn't
> support the DMA features of this driver. This driver is an alternate
> driver for the same HW that allows DMA to be used with it, etc.
>
> Since DT is supposed to describe the HW, modifying the DT to change the
> compatible value in order to select a different driver in Linux doesn't
> seem correct, or is it? Is there any kind of precedent for how to select
> different drivers for the same HW at run-time? I'd wondered about using
> the sysfs bind/unbind "methods" from user-space as the driver selection
> mechanism...
> _______________________________________________
> devicetree-discuss mailing list
> devicetree-discuss@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/devicetree-discuss
>


\
 
 \ /
  Last update: 2012-12-17 23:41    [W:0.084 / U:0.484 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site