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

[Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>]

Hi Rob,

2015-12-09 4:41 GMT+01:00 Rob Herring <robh@xxxxxxxxxx>:
> On Tue, Dec 08, 2015 at 01:45:04PM +0100, Maxime Coquelin wrote:
>> Signed-off-by: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
>> ---
>>  .../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.
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?
Do you have other ideas?

Thanks,
Maxime
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