Re: [PATCH v3 1/3] soc: devicetree: bindings: Add Qualcomm RPM DT binding

[Stephen Boyd]

On 06/18/14 01:34, Srinivas Kandagatla wrote:
>
>
> On 18/06/14 00:59, Stephen Boyd wrote:
>> On 06/16/14 11:46, Bjorn Andersson wrote:
>>> diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,rpm.txt
>>> b/Documentation/devicetree/bindings/soc/qcom/qcom,rpm.txt
>>> new file mode 100644
>>> index 0000000..0366533
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,rpm.txt
>>> @@ -0,0 +1,260 @@
>>> +Qualcomm Resource Power Manager (RPM)
>>> +
>> [...]
>>> +
>>> +- reg:
>>> +    Usage: required
>>> +    Value type: <prop-encoded-array>
>>> +    Definition: two entries specifying the RPM's message ram and
>>> ipc register
>>> +
>>> +- reg-names:
>>> +    Usage: required
>>> +    Value type: <string-array>
>>> +    Definition: must contain the following, in order:
>>> +            "msg_ram"
>>> +            "ipc"
>>
>> ipc is concerning....
>>
>>> +    rpm@108000 {
>>> +        compatible = "qcom,rpm-msm8960";
>>> +        reg = <0x108000 0x1000 0x2011008 0x4>;
>>> +
>>
>> (reg-names is missing from the example)
>>
>> because ipc is actually a register inside the Krait complex's global
>> clock control/distribution hardware block (it's located at 0x2011000).
>>  From what I can tell, this is the only non-clock/power register inside
>> there. I plan to send out a driver for this hardware block so that I can
>> switch the L2 aux source mux over to PLL8 instead of PXO (done with a
>> single register write to 0x2011028) and this mapping/use here is going
>> to conflict with that unless I only map the single register like is done
>> here.
>>
>> I wonder if we'd be better off making this region a separate node and
>> having some phandle to it here in the RPM node? That way we have a
>
> Can't we use syscon based on regmap here?  syscon is a better way to
> share a common register space across multiple drivers.

How would the mux clock be registered? I'd like it to be registered by
the driver associated with this device with something like
devm_clk_register(). From what I can tell syscon wouldn't allow that
unless we extend the syscon driver to handle more specific compatible
strings.

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