Re: [RFC 1/8] dt-bindings: mfd: Add Altera Arria10 System Resource Chip bindings

[Thor Thayer <tthayer@opensource.altera.com>]

Hi Lee,

On 04/18/2016 02:45 AM, Lee Jones wrote:
> On Fri, 15 Apr 2016, Thor Thayer wrote:
>> On 03/30/2016 06:35 AM, Lee Jones wrote:
>>> On Tue, 29 Mar 2016, tthayer@opensource.altera.com wrote:
>>>
>>>> From: Thor Thayer <tthayer@opensource.altera.com>
>>>>
>>>> The Altera Arria10 Devkit System Resource chip is a Multi-Function
>>>> Device, it has two subdevices:
>>>>       - GPIO
>>>>       - HWMON
>>>>
>>>> This patch adds documentation for the Altera A10-SR DT bindings.
>>>>
>>>> Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
>>>> ---
>>>>   .../devicetree/bindings/mfd/altera-a10sr.txt       |   35 ++++++++++++++++++++
>>>>   1 file changed, 35 insertions(+)
>>>>   create mode 100644 Documentation/devicetree/bindings/mfd/altera-a10sr.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/mfd/altera-a10sr.txt b/Documentation/devicetree/bindings/mfd/altera-a10sr.txt
>>>> new file mode 100644
>>>> index 0000000..564c761
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/mfd/altera-a10sr.txt
>>>> @@ -0,0 +1,35 @@
>>>> +* Altera Arria10 Development Kit System Resource Chip
>>>> +
>>>> +Required parent device properties:
>>>> +- compatible : "altr,altr_a10sr"
>>>> +- spi-max-frequency : Maximum SPI frequency.
>>>> +- reg : the SPI Chip Select address for the Arria10 System Resource chip
>
> [...]
>
>>>> +		a10sr_hwmon: a10sr_hwmon {
>>>
>>> Device type only please.
>>>
>> I need to revisit where this will live (hwmon does not seem to be
>> the correct place) so it will change but I can follow the format
>> above if it is correct.
>
> BTW, "hwmon" is a subsystem in Linux, therefore is a Linuxism and is
> not allowed in DT.  What does the device *actually* do?
>

OK. I'll be careful not to introduce the Linux subsystem name.

This module indicates whether the power supplies are at the correct 
voltage. It uses a boolean instead of giving an actual voltage value as 
required by HWMON. In other words it is a comparator instead of an 
Analog-to-Digital Converter.

I could call it a power supply supervisor or voltage status monitor but 
it only acts in a passive role. There is no output to trigger an error - 
only polling, so supervisor doesn't seem like a good name.

Maybe something like this?

	power_supply_status {
		compatible = "altr,a10sr-hwmon";
	}

Thanks for reviewing and helping me figure out the device tree naming.