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

[Frank Rowand <frowand.list@gmail.com>]

On 5/29/2014 11:24 AM, Bjorn Andersson wrote:
> On Wed, May 28, 2014 at 9:34 AM, Kumar Gala <galak@codeaurora.org> wrote:
>>
>> On May 27, 2014, at 12:28 PM, Bjorn Andersson <bjorn.andersson@sonymobile.com> wrote:
>>
>>> Add binding for the Qualcomm Resource Power Manager (RPM) found in 8660, 8960
>>> and 8064 based devices. The binding currently describes the rpm itself and the
>>> regulator subnodes.
>>>
>>> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
>>> ---
>>> Documentation/devicetree/bindings/mfd/qcom,rpm.txt | 284 +++++++++++++++++++++
>>> include/dt-bindings/mfd/qcom_rpm.h                 | 142 +++++++++++
>>> 2 files changed, 426 insertions(+)
>>> create mode 100644 Documentation/devicetree/bindings/mfd/qcom,rpm.txt
>>> create mode 100644 include/dt-bindings/mfd/qcom_rpm.h
>>>
>>> diff --git a/Documentation/devicetree/bindings/mfd/qcom,rpm.txt b/Documentation/devicetree/bindings/mfd/qcom,rpm.txt
>>> new file mode 100644
>>> index 0000000..3908a5d
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/mfd/qcom,rpm.txt

< snip >

>>> +
>>> +- qcom,force-mode-none:
>>> +     Usage: optional (default if no other qcom,force-mode is specified)
>>> +     Value type: <empty>
>>> +     Defintion: indicates that the regulator should not be forced to any
>>> +                particular mode
>>> +
>>> +- qcom,force-mode-lpm:
>>> +     Usage: optional
>>> +     Value type: <empty>
>>> +     Definition: indicates that the regulator should be forced to operate in
>>> +                 low-power-mode
>>> +
>>> +- qcom,force-mode-auto:
>>> +     Usage: optional (only available for 8960/8064)
>>> +     Value type: <empty>
>>> +     Definition: indicates that the regulator should be automatically pick
>>> +                 operating mode
>>> +
>>> +- qcom,force-mode-hpm:
>>> +     Usage: optional (only available for 8960/8064)
>>> +     Value type: <empty>
>>> +     Definition: indicates that the regulator should be forced to operate in
>>> +                 high-power-mode
>>> +
>>> +- qcom,force-mode-bypass: (only for 8960/8064)
>>> +     Usage: optional (only available for 8960/8064)
>>> +     Value type: <empty>
>>> +     Definition: indicates that the regulator should be forced to operate in
>>> +                 bypass mode
>>> +
>>
>> Is force-mode really an enum?  Or can we really have multiple force-mode’s set?
>>
> 
> Force mode is an enum, you can only set one of these.
> 
> Looking around you can find three ways of doing this:
> 1) Make it an int and provide defines in a dt-bindings header file
> 2) Make it a string and list the possible values
> 3) Make it a set of boolean properties
> 
> I just spent some time in the pinctrl struff that implements 3), I
> like the feel of it and I like how the dts ended up looking like.
> 
> But if there's a strong opinion regarding this I could change it.

The problem with separate properties is that there is not a way to
detect the error of specifying multiple conflicting force-modes
at compile time.

It also means you can not override the default force-mode from one
.dts/.dtsi in another .dts/.dtsi.

< snip >

-Frank