[Linux-Xtensa] Re: [RFC 6/6] xtensa: add xtavnet DTS

Max Filippov jcmvbkbc at gmail.com
Tue Nov 6 13:55:39 PST 2012


On Wed, Nov 7, 2012 at 1:18 AM, Marc Gauthier <marc at tensilica.com> wrote:
>> +     serial0: serial at fd050000 {
>> +             compatible = "ns16550a";
>> +             no-loopback-test;
>> +             reg = <0xfd050020 0x20>;
>> +             reg-shift = <2>;
>> +             interrupts = <0>;
>> +             clock-frequency = <100000000>;
>
>
> Is there any way with device trees, to have parameters
> (such as UART clock frequency here) be determined
> dynamically rather than be fixed?
> (eg. in this case, by reading the frequency from an FPGA register)

I see two options:
- either the driver must know where to get the parameter, or some other
  driver need to set it up;
- or the DTB needs to be updated.

Also in this particular case UART speed preset by the bootloader could
be kept by the serial driver (of_serial can do it).

-- 
Thanks.
-- Max


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