On 13.08.2019 17:06, Rob Herring wrote:
> On Mon, Aug 12, 2019 at 7:32 PM Leonard Crestez <leonard.crestez@xxxxxxx> wrote:
>> On 8/12/2019 10:47 PM, Rob Herring wrote:
>>> On Mon, Aug 12, 2019 at 12:49 PM Leonard Crestez <leonard.crestez@xxxxxxx> wrote:
>>>> Add initial dt bindings for the interconnects inside i.MX chips.
>>>> Multiple external IPs are involved but SOC integration means the
>>>> software controllable interfaces are very similar.
>>>>
>>>> +description: |
>>>> + The i.MX SoC family has multiple buses for which clock frequency (and sometimes
>>>> + voltage) can be adjusted.
>>>> +
>>>> + Some of those buses expose register areas mentioned in the memory maps as GPV
>>>> + ("Global Programmers View") but not all. Access to this area might be denied for
>>>> + normal world.
>>>> +
>>>> + The buses are based on externally licensed IPs such as ARM NIC-301 and Arteris
>>>> + FlexNOC but DT bindings are specific to the integration of these bus
>>>> + interconnect IPs into imx SOCs.
>>>
>>> No need to use the interconnect binding?
>>
>> The interconnect is represented by a separate "virtual" node which might
>> not be OK. There was also a recent RFC from samsung which turns devfreq
>> nodes into interconnect providers:
>>
>> Is that preferable?
>
> Virtual nodes are not OK.
Then I'll try to make the "interconnect" device probe from a soc driver
and turn devfreq nodes into interconnect providers backed by this same
singleton device.
Still separate from this series.
>>>> +required:
>>>> + - compatible
>>>> + - clocks
>>>
>>> reg?
>>
>> This is deliberately optional: for some NICs the GPV register area is
>> not exposed in the memory map. This is unusual but an accurate
>> description of the hardware.
>
> Different h/w blocks should have different compatibles. GPV is an Arm
> thing and I'd expect FlexNOC to be different.
The imx reference manuals call them both "GPV" though layout is indeed
quite different (and for FlexNoC it's not even documented).
The h/w blocks do have different compat strings (imx8m-nic and
imx8m-noc). They have a single binding document because didn't want to
create two nearly-identical bindings, I assume it would be fine to split
later if needed.
--
Regards,
Leonard
