[PATCH v3 2/9] Documentation: dt-bindings: Document STM32 pinctrl driver DT bindings

[Rob Herring]

On Wed, Dec 9, 2015 at 3:37 AM, Maxime Coquelin
<mcoquelin.stm32 at gmail.com> wrote:
> Hi Rob,
>
> 2015-12-09 4:41 GMT+01:00 Rob Herring <robh at kernel.org>:
>> On Tue, Dec 08, 2015 at 01:45:04PM +0100, Maxime Coquelin wrote:
>>> Signed-off-by: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
>>> ---
>>>  .../bindings/pinctrl/st,stm32-pinctrl.txt          | 126 +++++++++++++++++++++
>>>  1 file changed, 126 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt
>>> new file mode 100644
>>> index 0000000..7b4800c
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt
>>> @@ -0,0 +1,126 @@
>>> +* STM32 GPIO and Pin Mux/Config controller
>>> +
>>> +STMicroelectronics's STM32 MCUs intregrate a GPIO and Pin mux/config hardware
>>> +controller. It controls the input/output settings on the available pins and
>>> +also provides ability to multiplex and configure the output of various on-chip
>>> +controllers onto these pads.
>>> +
>>> +Pin controller node:
>>> +Required properies:
>>> + - compatible: value should be one of the following:
>>> +   (a) "st,stm32f429-pinctrl"
>>> + - #address-cells: The value of this property must be 1
>>> + - #size-cells       : The value of this property must be 1
>>> + - ranges    : defines mapping between pin controller node (parent) to
>>> +   gpio-bank node (children).
>>> + - pins-are-numbered: Specify the subnodes are using numbered pinmux to
>>> +   specify pins.
>>> +
>>> +GPIO controller/bank node:
>>> +Required properties:
>>> + - gpio-controller : Indicates this device is a GPIO controller
>>> + - #gpio-cells         : Should be two.
>>> +                     The first cell is the pin number
>>> +                     The second one is the polarity:
>>> +                             - 0 for active high
>>> +                             - 1 for active low
>>> + - reg                 : The gpio address range, relative to the pinctrl range
>>> + - clocks      : clock that drives this bank
>>> + - st,bank-name        : Should be a name string for this bank as specified in
>>> +   the datasheet
>>
>> How do you intend to use this? We should come up with something generic
>> or drop it.
> Good point.
> It is used to have a meaningful name set in gpio_chip's label.

Who cares about the gpio_chip name?

> I see two alternatives:
>  1. replace "st,bank-name" with label
>  2. use aliases, and construct label in driver with something like:
>      kasprintf(GFP_KERNEL, "GPIO%c", 'A' + of_alias_get_id(np, "gpio"));
>
> What do you prefer?

I prefer to not need it. Of these 2 though, probably using label.
However, I'm not convinced to say yes, we should use that because it
will only encourage others to do the same.

> Do you have other ideas?

We do need names on individual lines though. I'd rather not complicate
things by having labels for both unless we can define the need for it.

Rob