Re: [PATCH v1 1/5] dt-bindings: cpufreq: Add binding for NVIDIA Tegra20/30

Dmitry Osipenko
2018-10-17T12:43:03Z

On 10/17/18 3:37 PM, Dmitry Osipenko wrote:
> On 10/17/18 11:40 AM, Jon Hunter wrote:
>>
>> On 30/08/2018 20:43, Dmitry Osipenko wrote:
>>> Add device-tree binding that describes CPU frequency-scaling hardware
>>> found on NVIDIA Tegra20/30 SoC's.
>>>
>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>>> ---
>>> .../cpufreq/nvidia,tegra20-cpufreq.txt | 38 +++++++++++++++++++
>>> 1 file changed, 38 insertions(+)
>>> create mode 100644 Documentation/devicetree/bindings/cpufreq/nvidia,tegra20-cpufreq.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/cpufreq/nvidia,tegra20-cpufreq.txt b/Documentation/devicetree/bindings/cpufreq/nvidia,tegra20-cpufreq.txt
>>> new file mode 100644
>>> index 000000000000..2c51f676e958
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/cpufreq/nvidia,tegra20-cpufreq.txt
>>> @@ -0,0 +1,38 @@
>>> +Binding for NVIDIA Tegra20 CPUFreq
>>> +==================================
>>> +
>>> +Required properties:
>>> +- clocks: Must contain an entry for each entry in clock-names.
>>> + See ../clocks/clock-bindings.txt for details.
>>> +- clock-names: Must include the following entries:
>>> + - pll_x: main-parent for CPU clock, must be the first entry
>>> + - backup: intermediate-parent for CPU clock
>>> + - cpu: the CPU clock
>>
>> Is it likely that 'backup' will be anything other that pll_p? If not why
>> not just call it pll_p? Personally, I don't 'backup' to descriptive even
>> though I can see what you mean.
>>
>> I can see that you want to make this flexible, but if the likelihood is
>> that we will just use pll_p then I am not sure it is warranted at this
>> point.
>
> That won't describe HW, but software. And device tree should describe HW.
>

Though indeed it is unlikely that anything else other than pll_p will be used, so it is a software/firmware description anyway.