Re: [Linux-stm32] [PATCH] ARM: dts: stm32: Fill GPIO line names on AV96

From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: Christoph Niedermaier <cniedermaier@dh-electronics.com>,
	'Marek Vasut' <marex@denx.de>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linus.walleij@linaro.org" <linus.walleij@linaro.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	"linux-stm32@st-md-mailman.stormreply.com"
	<linux-stm32@st-md-mailman.stormreply.com>,
	Alexandre Torgue <alexandre.torgue@st.com>,
	Patrick Delaunay <patrick.delaunay@st.com>,
	Patrice Chotard <patrice.chotard@st.com>
Subject: Re: [Linux-stm32] [PATCH] ARM: dts: stm32: Fill GPIO line names on AV96
Date: Mon, 15 Mar 2021 13:05:05 +0100	[thread overview]
Message-ID: <d452b0ac-d11b-0e6e-56db-568d7c9238a0@pengutronix.de> (raw)
In-Reply-To: <788d7d182b13448c8afc4b99518daa34@dh-electronics.com>

On 15.03.21 12:41, Christoph Niedermaier wrote:
>> So I'll pose another question here to the GPIO maintainers.
>>
>> Is it OK to define gpio-line-names in SoM DTSI even for pins which will
>> not be used as GPIOs e.g. because they are muxed differently in the
>> carrier board DTS ?
>>
>> If that is OK, then the above approach is then also OK.
> 
> In our case, we cannot mux the GPIO pins in the carrier board DTS
> to another functions, because then we break our SOM standard (DHCOM).
> So in the case we relabel a GPIO in the carrier board e.g. "DHCOM-I"
> becomes "LED1" the mux function have to be GPIO.

For standards like SMARC, where the interface is predefined, I think it makes
much sense to have the SoM dtsi contain not only the line-names, but also
ready-to-use, pinmuxing settings.

Base boards can then either enable peripherals with just a status = "okay"
if they follow the standard or just override it if they choose to do
stuff differently.

Cheers,
Ahmad

> 
> Regards,
> Christoph
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