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References: <20191211032802.83309-1-jian.hu@amlogic.com>
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From:   Jerome Brunet <jbrunet@baylibre.com>
To:     Jian Hu <jian.hu@amlogic.com>,
        Neil Armstrong <narmstrong@baylibre.com>
Cc:     Kevin Hilman <khilman@baylibre.com>,
        "Rob Herring" <robh@kernel.org>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Wolfram Sang <wsa@the-dreams.de>,
        Mark Rutland <mark.rutland@arm.com>,
        Jianxin Pan <jianxin.pan@amlogic.com>,
        linux-amlogic@lists.infradead.org, linux-i2c@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
Subject: Re: [PATCH v2] arm64: dts: meson-a1: add I2C nodes
In-reply-to: <20191211032802.83309-1-jian.hu@amlogic.com>
Date:   Wed, 11 Dec 2019 10:34:16 +0100
Message-ID: <1jk173kxyf.fsf@starbuckisacylon.baylibre.com>
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On Wed 11 Dec 2019 at 04:28, Jian Hu <jian.hu@amlogic.com> wrote:

> There are four I2C controllers in A1 series,
> Share the same comptible with AXG. Compared to AXG,
> Drive strength feature is newly added in A1.

Until here, OK

> This patch depends on A1 clock driver.

This last sentence is a valuable piece of information for the maintainer
but should not appear is the commit description as it is something we
want is the history

Please move this bellow the '---' *AND*
Add a link like " https://lkml.kernel.org/r/..." to help the maintainer
locate the related series


>
> Signed-off-by: Jian Hu <jian.hu@amlogic.com>
>
> ---
> This patch depends on A1 clock patchset at[0]
>
> Changes since v1 at [1]:
> -change reg length to 0x20
> -assign i2c bus alias in dts file
> -add new feature note compared to AXG in changelog
>
> [0] https://lkml.kernel.org/r/20191206074052.15557-1-jian.hu@amlogic.com
> [1] https://lkml.kernel.org/r/20191202111253.94872-1-jian.hu@amlogic.com
> ---
> ---
>  .../arm64/boot/dts/amlogic/meson-a1-ad401.dts |   4 +
>  arch/arm64/boot/dts/amlogic/meson-a1.dtsi     | 142 ++++++++++++++++++
>  2 files changed, 146 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/amlogic/meson-a1-ad401.dts b/arch/arm64/boot/dts/amlogic/meson-a1-ad401.dts
> index 69c25c68c358..2d0457976233 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-a1-ad401.dts
> +++ b/arch/arm64/boot/dts/amlogic/meson-a1-ad401.dts
> @@ -13,6 +13,10 @@
>  
>  	aliases {
>  		serial0 = &uart_AO_B;
> +		i2c0 = &i2c0;
> +		i2c1 = &i2c1;
> +		i2c2 = &i2c2;
> +		i2c3 = &i2c3;

It is not necessary to define alias for all the possible buses,
especially it some won't be used on the platform.

Will this platform use all 4 busses ?

In any case, the aliases can added later, as needed when the related i2c
bus is enabled on the board

>  	};
>  
>  	chosen {
> diff --git a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
> index eab2ecd36aa8..66d5206a57de 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
> @@ -117,6 +117,46 @@
>  				};
>  			};
>  
> +			i2c0: i2c@1400 {
> +				compatible = "amlogic,meson-axg-i2c";
> +				reg = <0x0 0x1400 0x0 0x20>;
> +				interrupts = <GIC_SPI 32 IRQ_TYPE_EDGE_RISING>;
> +				#address-cells = <1>;
> +				#size-cells = <0>;
> +				clocks = <&clkc_periphs CLKID_I2C_M_A>;
> +				status = "disabled";
> +			};
> +
> +			i2c1: i2c@5c00 {

Please order nodes by address when then have one.
The 3 following i2c busses should appear after the uarts

> +				compatible = "amlogic,meson-axg-i2c";
> +				reg = <0x0 0x5c00 0x0 0x20>;
> +				interrupts = <GIC_SPI 68 IRQ_TYPE_EDGE_RISING>;
> +				#address-cells = <1>;
> +				#size-cells = <0>;
> +				clocks = <&clkc_periphs CLKID_I2C_M_B>;
> +				status = "disabled";
> +			};
> +
> +			i2c2: i2c@6800 {
> +				compatible = "amlogic,meson-axg-i2c";
> +				reg = <0x0 0x6800 0x0 0x20>;
> +				interrupts = <GIC_SPI 76 IRQ_TYPE_EDGE_RISING>;
> +				#address-cells = <1>;
> +				#size-cells = <0>;
> +				clocks = <&clkc_periphs CLKID_I2C_M_C>;
> +				status = "disabled";
> +			};
> +
> +			i2c3: i2c@6c00 {
> +				compatible = "amlogic,meson-axg-i2c";
> +				reg = <0x0 0x6c00 0x0 0x20>;
> +				interrupts = <GIC_SPI 78 IRQ_TYPE_EDGE_RISING>;
> +				#address-cells = <1>;
> +				#size-cells = <0>;
> +				clocks = <&clkc_periphs CLKID_I2C_M_D>;
> +				status = "disabled";
> +			};
> +
>  			uart_AO: serial@1c00 {
>  				compatible = "amlogic,meson-gx-uart",
>  					     "amlogic,meson-ao-uart";
> @@ -171,3 +211,105 @@
>  		#clock-cells = <0>;
>  	};
>  };
> +
> +&periphs_pinctrl {
> +	i2c0_f11_pins:i2c0-f11 {
> +		mux {
> +			groups = "i2c0_sck_f11",
> +				"i2c0_sda_f12";
> +			function = "i2c0";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c0_f9_pins:i2c0-f9 {

When the nodes don't have an address, please order them
alpha-numerically by node name.

> +		mux {
> +			groups = "i2c0_sck_f9",
> +				"i2c0_sda_f10";
> +			function = "i2c0";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c1_x_pins:i2c1-x {
> +		mux {
> +			groups = "i2c1_sck_x",
> +				"i2c1_sda_x";
> +			function = "i2c1";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c1_a_pins:i2c1-a {
> +		mux {
> +			groups = "i2c1_sck_a",
> +				"i2c1_sda_a";
> +			function = "i2c1";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c2_x0_pins:i2c2-x0 {
> +		mux {
> +			groups = "i2c2_sck_x0",
> +				"i2c2_sda_x1";
> +			function = "i2c2";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c2_x15_pins:i2c2-x15 {
> +		mux {
> +			groups = "i2c2_sck_x15",
> +				"i2c2_sda_x16";
> +			function = "i2c2";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c2_a4_pins:i2c2-a4 {
> +		mux {
> +			groups = "i2c2_sck_a4",
> +				"i2c2_sda_a5";
> +			function = "i2c2";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c2_a8_pins:i2c2-a8 {
> +		mux {
> +			groups = "i2c2_sck_a8",
> +				"i2c2_sda_a9";
> +			function = "i2c2";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c3_x_pins:i2c3-x {
> +		mux {
> +			groups = "i2c3_sck_x",
> +				"i2c3_sda_x";
> +			function = "i2c3";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +
> +	i2c3_f_pins:i2c3-f {
> +		mux {
> +			groups = "i2c3_sck_f",
> +				"i2c3_sda_f";
> +			function = "i2c3";
> +			bias-pull-up;
> +			drive-strength-microamp = <3000>;
> +		};
> +	};
> +};