linux-kernel - Re: [PATCH v2 1/2] arm64: dts: ti: k3-am65: disable optional peripherals by default

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Message-ID: <20220204143108.653qk2ihnlhsr5aa@prior>
Date:   Fri, 4 Feb 2022 08:31:08 -0600
From:   Nishanth Menon <nm@...com>
To:     Matthias Schiffer <matthias.schiffer@...tq-group.com>,
        Rob Herring <robh+dt@...nel.org>, <tony@...mide.com>,
        Arnd Bergmann <arnd@...db.de>, Olof Johansson <olof@...om.net>,
        <soc@...nel.org>
CC:     Vignesh Raghavendra <vigneshr@...com>,
        Tero Kristo <kristo@...nel.org>,
        Rob Herring <robh+dt@...nel.org>, <jan.kiszka@...mens.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] arm64: dts: ti: k3-am65: disable optional
 peripherals by default

Rob, Tony, Arnd, SoC maintainers,

On 15:02-20220203, Matthias Schiffer wrote:
> All peripherals that require pinmuxing or other configuration to work
> should be disabled by default. Dependent DTS are adjusted accordingly.

https://lore.kernel.org/linux-arm-kernel/20201112183538.6805-1-nm@ti.com/
reversal all over again.

Is there a specific pattern we are intending to use here? Because, if we
are going down this path (which would be a major churn across multiple
downstream trees as well) - I'd rather have this as a documented
standard and not just a TI approach and will need to be done across all
K3 devices.

Are you aware of such a documented guideline, rather than "word of
mouth"? Maybe I have'nt looked deep enough, but checking..

> 
> The following nodes are now "disabled" according to dtx_diff and were not
> overridden to "okay", as they define no pinctrl:


> k3-am654-base-board:
> - mcu_i2c0
> - mcu_spi0..2
> - mcu_uart0
> - cal
> - main_i2c3
> - ehrpwm0..5
> - main_uart1..2
> - main_spi1..4
> 
> k3-am65-iot2050*:
> - mci_spi1..2
> - cal
> - ehrpwm0..5
> - main_spi0..4
> 
> Signed-off-by: Matthias Schiffer <matthias.schiffer@...tq-group.com>
> ---
[...]

> diff --git a/arch/arm64/boot/dts/ti/k3-am65-main.dtsi b/arch/arm64/boot/dts/ti/k3-am65-main.dtsi
> index ce8bb4a61011e..5aa425d1ba802 100644
> --- a/arch/arm64/boot/dts/ti/k3-am65-main.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am65-main.dtsi
> @@ -64,6 +64,7 @@ serdes0: serdes@...000 {
>  		ti,serdes-clk = <&serdes0_clk>;

[...]

> @@ -1337,6 +1388,7 @@ icssg2_mdio: mdio@...00 {
>  			#address-cells = <1>;
>  			#size-cells = <0>;
>  			bus_freq = <1000000>;
> +			status = "disabled";
>  		};
>  	};
>  };
> diff --git a/arch/arm64/boot/dts/ti/k3-am65-mcu.dtsi b/arch/arm64/boot/dts/ti/k3-am65-mcu.dtsi
> index 8d592bf41d6f1..57ac3a493adbe 100644
> --- a/arch/arm64/boot/dts/ti/k3-am65-mcu.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am65-mcu.dtsi
> @@ -22,11 +22,12 @@ phy_gmii_sel: phy@...0 {
>  
>  	mcu_uart0: serial@...00000 {
>  		compatible = "ti,am654-uart";
> -			reg = <0x00 0x40a00000 0x00 0x100>;
> -			interrupts = <GIC_SPI 565 IRQ_TYPE_LEVEL_HIGH>;
> -			clock-frequency = <96000000>;
> -			current-speed = <115200>;
> -			power-domains = <&k3_pds 149 TI_SCI_PD_EXCLUSIVE>;
> +		reg = <0x00 0x40a00000 0x00 0x100>;
> +		interrupts = <GIC_SPI 565 IRQ_TYPE_LEVEL_HIGH>;
> +		clock-frequency = <96000000>;
> +		current-speed = <115200>;
> +		power-domains = <&k3_pds 149 TI_SCI_PD_EXCLUSIVE>;

When doing these kind of changes, do not include ancillary tab cleanups.
keep such cleanups separate patch.

> +		status = "disabled";

>  	};
>  
>  	mcu_ram: sram@...00000 {
> @@ -46,6 +47,7 @@ mcu_i2c0: i2c@...00000 {
>  		clock-names = "fck";
>  		clocks = <&k3_clks 114 1>;
>  		power-domains = <&k3_pds 114 TI_SCI_PD_EXCLUSIVE>;
> +		status = "disabled";
>  	};
>  
>  	mcu_spi0: spi@...00000 {
> @@ -56,6 +58,7 @@ mcu_spi0: spi@...00000 {
>  		power-domains = <&k3_pds 142 TI_SCI_PD_EXCLUSIVE>;
>  		#address-cells = <1>;
>  		#size-cells = <0>;
> +		status = "disabled";
>  	};
>  
-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D)/Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D