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

[Ahmad Fatoum]

Hi Marek,

On 3/30/20 1:22 PM, Marek Vasut wrote:
> On 3/30/20 1:17 PM, Ahmad Fatoum wrote:
>> Hello Patrice,
> 
> Hi,
> 
>> On 3/30/20 1:11 PM, Patrice CHOTARD wrote:
>>> For your information, another submitted patch uses the same pinctrl sdmmc2_d47_pins_b node with different muxing (SDMMC2_D5)
>>>
>>> see https://lore.kernel.org/patchwork/patch/1216452/
>>>
>>> I haven't checked other muxing if there are other conflict.
>>
>> (author of linked patch here)
>>
>> I don't like the central stm32mp15-pinctrl.dtsi. I'd have preferred if each
>> file defined the pinctrl groups it is using.
> 
> I'm not a big fan of that either, because this is gonna be a
> combinatorial explosion of various pinmux options. But if you have each
> board define it's pinmux, it's also gonna become a massive amount of
> duplication (like iMX). So I cannot tell which one is better ...

Mhm. A middle ground could be keeping stm32mp15-pinctrl, but only for the
official ST eval kits as HW designers are expected to copy off those and have
board specifics in the board/SoM device tree?

If it has to be either one or the other, I prefer duplication in the device
tree. When the HW misses pull ups or needs to adjust slew rates, you probably
don't want a new, slightly different, pinctrl group in the stm32mp15-pinctrl.dtsi
for each variant.

So you are left with doctoring around with overrides and /delete-property/,
while just duplicating the node with the correct properties would've been
better for readability IMO.

> So, just apply one patch or the other, let me know what got applied and
> I'll rebase on top of that and resubmit if needed.

Same.

Cheers
Ahmad

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