Re: [PATCH v3 2/3] dt-bindings: Add pinctrl bindings for mt65xx/mt81xx.

[Linus Walleij <linus.walleij@linaro.org>]

On Fri, Jan 16, 2015 at 11:23 AM, Yingjoe Chen
<yingjoe.chen@mediatek.com> wrote:
> On Fri, 2015-01-16 at 10:53 +0100, Linus Walleij wrote:
>> On Tue, Jan 13, 2015 at 5:16 PM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
>> > On Tue, Jan 13, 2015 at 11:05:22AM +0100, Linus Walleij wrote:
>>
>> >> > You often talk about ambiguities. Could you give an example what
>> >> > ambiguities you mean?
>> >>
>> >> What happened was this pins = ; arguments were sometimes
>> >> strings and sometimes integers, that becomes strange to handle
>> >> in code, ambiguous.
>> >
>> > I see. I like naming it 'pinmux' because that's what it is: pins and
>> > mux settings. A plain 'pinno' suggests that it contains only pin mubers,
>> > without mux setting. How about 'pin-no-mux'? We also could add an
>> > explicit "pins-are-numbered" property instead of distinguishing this
>> > by property names.
>>
>> I kind of like this "pins-are-numbered" thing.
>>
>> The other property for the pin, whether pinmux or pin-no-mux or
>> pin-num-and-mux etc is no such big deal, as long as it's
>> consistent and documented with the generic bindings.
>
> Hi Linus,
>
> To make sure I understand it correct, you think something like this is
> OK?
>
>         pinctrl@01c20800 {
>                 compatible = "mediatek,mt8135-pinctrl";
> [...]
>                 pins-are-numbered;
>
>                 i2c0_pins_a: i2c0@0 {
>                         pins1 {
>                                 pins = <MT8135_PIN_100_SDA0__FUNC_SDA0>,
>                                         <MT8135_PIN_101_SCL0__FUNC_SCL0>;
>                                 bias-disable;
>                         };
>                 };

As discussed with Sascha Hauer it is ambigous to use "pins" for
a numerical value indicating both a mux setting and a pin. Sascha
suggests using "pinmux" and adding this as a secondary generic
binding for this type of pin controllers that use numbers and #defines
to set up bindings.

We should still move these parsing functions to the core.

See this discussion earlier in this thread:
http://marc.info/?l=linux-kernel&m=142116581226500&w=2

Yours,
Linus Walleij