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Subject: Re: [Linux-stm32] [PATCH 5/8] ARM: dts: stm32: introduce
 stm32h7-pinctrl.dtsi to support stm32h75x
To:     dillon min <dillon.minfei@gmail.com>,
        Alexandre TORGUE <alexandre.torgue@foss.st.com>
Cc:     "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Vladimir Murzin <vladimir.murzin@arm.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux@armlinux.org.uk, Rob Herring <robh+dt@kernel.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        afzal.mohd.ma@gmail.com, linux-stm32@st-md-mailman.stormreply.com,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
References: <1614758717-18223-1-git-send-email-dillon.minfei@gmail.com>
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From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
Message-ID: <d2549995-2b46-3f9a-e3d5-0e2bc21465d7@pengutronix.de>
Date:   Thu, 11 Mar 2021 13:54:48 +0100
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Hello Dillon,

On 11.03.21 13:23, dillon min wrote:
> For stm32h7's new board support , I guess following the stm32f7/stm32f4's style
> is a reasonable way to do it, but add a little optimization。
> which means :
> old structure
> stm32h7-pinctrl.dtsi --> stm32h743-pinctrl.dtsi  (referenced by
> stm32h743i-disco, -eval)
>                                 |--> stm32h750-pinctrl.dtsi
> (referenced by stm32h750i-art-pi, etc)
> add art-pi other board's pin definition in stm32h750-pinctrl.dtsi with
> xxx_pins_a, xxx_pins_b
> xxx_pins_a used for art-pi, xxx_pins_b used for other boards.
> 
> after more boards add in support, there will be more xxx_pin_c, .... defined
> 
> as the pin map is according to the hardware schematic diagram io connection.
> so, why not move xxx_pin_x to a board specific place. such as
> stm32h750i-art-pi.dts
> 
> new structure:
> 1, rename stm32h743-pinctrl.dtsi to stm32h7-pinctrl.dtsi (only
> preserve gpioa...k,)
> 2, move xxx_pins_x from stm32h7-pinctrl.dtsi to
> stm32h7xx-disco/eval/art-pi/etc.dts (as they depends on hardware
> schematic)
> 
> stm32h7-pinctrl.dtsi --> stm32h743i-discon.dts
>                                 |--> stm32h743i-eval.dts
>                                 |--> stm32h750i-art-pi.dts
>                                 |--> stm32h7xxx.dts
> would you agree this ?

If the optimization you intend is reducing DTB size, you can flag
all pinctrl groups with /omit-if-no-ref/ to have dtc throw them
away if they are unused.

(But in general, I am in favor of having board-specific configuration
 in the board dts)

Cheers,
Ahmad

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