Re: [PATCH v2 2/3] dt-binding: net: sfp binding documentation

[Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>]

On 08/30/2017 02:25 PM, Baruch Siach wrote:

>>>>> Add device-tree binding documentation SFP transceivers. Support for SFP
>>>>> transceivers has been recently introduced (drivers/net/phy/sfp.c).
>>>>>
>>>>> Signed-off-by: Baruch Siach <baruch@tkos.co.il>
>>>>> ---
>>>>> v2:
>>>>>      Rename -gpio properties to -gpios
>>>>>      Rename the rate-select-gpio property to rate-select0-gpios
>>>>>      Add the rate-select1-gpios property
>>>>>      Add examples
>>>>> ---
>>>>>     Documentation/devicetree/bindings/net/sff,sfp.txt | 74 +++++++++++++++++++++++
>>>>>     1 file changed, 74 insertions(+)
>>>>>     create mode 100644 Documentation/devicetree/bindings/net/sff,sfp.txt
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/net/sff,sfp.txt b/Documentation/devicetree/bindings/net/sff,sfp.txt
>>>>> new file mode 100644
>>>>> index 000000000000..1d9c786d6287
>>>>> --- /dev/null
>>>>> +++ b/Documentation/devicetree/bindings/net/sff,sfp.txt
>>>>> @@ -0,0 +1,74 @@
>>>>> +Small Form Factor (SFF) Committee Small Form-factor Pluggable (SFP)
>>>>> +Transceiver
>>>>> +
>>>>> +Required properties:
>>>>> +
>>>>> +- compatible : must be "sff,sfp"
>>>>> +
>>>>> +Optional Properties:
>>>>> +
>>>>> +- i2c-bus : phandle of an I2C bus controller for the SFP two wire serial
>>>>> +  interface
>>>>> +
>>>>> +- moddef0-gpios : phandle of the MOD-DEF0 (AKA Mod_ABS) module presence input
>>>>> +  gpio signal
>>>>
>>>>      Your example shows there's GPIO phandle *and* specifier.
>>>
>>> Would "GPIO specifier" be enough here?
>>
>>     No, specifier is the cells following GPIO (or any other) phandle.
> 
> So this should be "GPIO phandle and specifier of ...", is that correct?

    Exactly. The length of the GPIO specifier is determined by the 
"#gpio-cells" prop of the GPIO node your phandle refers to.

> I have found very few (< 4) occurrences of this language in (lots of) '-gpios'
> property descriptions under Documentation/devicetree/bindings/.

    You better see Documentation/devicetree/bindings/gpio/gpio.txt.

> Is this a new
> requirement?

    Not at all, and it's not limited to GPIOs. Nobody reads the specs. :-)

> baruch

MBR, Sergei