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Subject: Re: [PATCH 1/4] arm64: dts: ti: k3-am65*: Cleanup disabled nodes at
 SoC dtsi level
To:     Nishanth Menon <nm@ti.com>, Roger Quadros <rogerq@ti.com>,
        Keerthy <j-keerthy@ti.com>, Jyri Sarha <jsarha@ti.com>,
        Peter Ujfalusi <peter.ujfalusi@ti.com>,
        Lokesh Vutla <lokeshvutla@ti.com>,
        Rob Herring <robh+dt@kernel.org>,
        Tony Lindgren <tony@atomide.com>, Tero Kristo <t-kristo@ti.com>
CC:     <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>
References: <20201104224356.18040-1-nm@ti.com>
 <20201104224356.18040-2-nm@ti.com>
From:   Tomi Valkeinen <tomi.valkeinen@ti.com>
Message-ID: <3cc234ac-ea7a-fe3e-e485-ee3123048fec@ti.com>
Date:   Thu, 5 Nov 2020 09:25:01 +0200
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On 05/11/2020 00:43, Nishanth Menon wrote:
> The device tree standard sets the default node behavior when status
> property as enabled. There are many reasons for doing the same, number
> of strings in device tree, default power management functionality etc
> are few of the reasons.
> 
> In general, after a few rounds of discussions [1] there are few
> options one could take when dealing with SoC dtsi and board dts
> 
> a. SoC dtsi provide nodes as a super-set default (aka enabled) state and
>    to prevent messy board files, when more boards are added per SoC, we
>    optimize and disable commonly un-used nodes in board-common.dtsi
> b. SoC dtsi disables all hardware dependent nodes by default and board
>    dts files enable nodes based on a need basis.
> c. Subjectively pick and choose which nodes we will disable by default
>    in SoC dtsi and over the years we can optimize things and change
>    default state depending on the need.
> 
> While there are pros and cons on each of these approaches, the right
> thing to do will be to stick with device tree default standards and
> work within those established rules. So, we choose to go with option
> (a).
> 
> Lets cleanup defaults of am654 SoC dtsi before this gets more harder
> to cleanup later on and new SoCs are added.
> 
> The dtb generated is identical with the patch and it is just cleanup to
> ensure we have a clean usage model
> 
> [1] https://lore.kernel.org/linux-arm-kernel/20201027130701.GE5639@atomide.com/
> 
> Fixes: 9bcb631e9953 ("arm64: dts: ti: k3-am654-main: Add McASP nodes")
> Fixes: fc539b90eda2 ("arm64: dts: ti: am654: Add DSS node")
> Cc: Jyri Sarha <jsarha@ti.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
> Cc: Tony Lindgren <tony@atomide.com>
> Signed-off-by: Nishanth Menon <nm@ti.com>
> ---
>  arch/arm64/boot/dts/ti/k3-am65-main.dtsi       |  8 --------
>  arch/arm64/boot/dts/ti/k3-am654-base-board.dts | 16 ++++++++++++++++
>  2 files changed, 16 insertions(+), 8 deletions(-)

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

 Tomi

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