[Linux-stm32] [PATCH 07/22] ARM: dts: stm32: Add alternate pinmux for SDMMC2 pins 4-7

[Alexandre Torgue]

On 3/31/20 6:44 PM, Marek Vasut wrote:
> On 3/31/20 6:39 PM, Alexandre Torgue wrote:
> 
> Hi,
> 
> [...]
> 
>>>> I agree, and I prefer to keep pins groups definition in
>>>> stm32mp15-pinctrl.dtsi file. IMO, it is easier for users to find them in
>>>> only one file. Actually, I already had this discussions with some guys
>>>> "where pins groups have to be defined ?". For me (and maybe only for
>>>> me), muxing is SOC dependent, I mean SoC provides a bunch a possible
>>>> pinmux for each IPs. If we got enough memory spaces (and time to waste
>>>> also) we could define all possible pinmux (AFx....) for each devices and
>>>> let board users chose the good one (using stm32mp15-pictrl.dtsi as a
>>>> database). In board file, you select one possible pin configuration
>>>> (provided by the SoC) for your device according to your schematic.
>>>> However you could append pin groups in board file to update bias,
>>>> slewrate ...
>>>> If your concern it to embed a bunch of not used pin configuration for a
>>>> board, we could use /omit-if-no-ref/ tag on pin groups.
>>>
>>> Can we instead define pinmux the way e.g. iMX6 does , as separate pins ,
>>> instead of pinmux groups ?
>>>
>>
>> Sorry but what would the advantage to do so ?
> 
> You'd have per-board pinmux which would be perfect fit for that board,
> without potentially affecting other boards with changes, without hacking
> various things like drive-strengths in board files, and without having
> the combinatorial explosion of the current single pinmux file.
> 

It is something that we could analysis. Let's follow the way we 
currently use. I'll let u know, when I have a better view on your 
proposition.

thanks
alex