请教 软件I2C如何配置？

• wjh

  Posts: 16

  Joined: 2025-08-06 2:29

  2025-09-05 3:13

  lyra plus开发板
  
  kernel配置开了软件I2C：
  <*> GPIO-based bitbanging I2C
  [ ] GPIO-based fault injector
  
  一开始设置了有6个类似这样的软件I2C，在rk3506g-luckfox-lyra-plus.dts里，rk3502.dtsi内aliases加了对应的I2C，可以在/dev下挂载I2C设备。

  Code: Select all

  aliases {
  		gpio0 = &gpio0;
  		gpio1 = &gpio1;
  		gpio2 = &gpio2;
  		gpio3 = &gpio3;
  		gpio4 = &gpio4;
  		i2c0 = &i2c0;
  		i2c1 = &i2c1;
  		i2c2 = &i2c2;
  		i2c3 = &i2c3;
  		i2c4 = &i2c4;
  		i2c5 = &i2c5;
  		i2c6 = &i2c6;
  		i2c7 = &i2c7;
  		i2c8 = &i2c8;
  		serial0 = &uart0;
  		serial1 = &uart1;
  		serial2 = &uart2;
  		serial3 = &uart3;
  		serial4 = &uart4;
  		serial5 = &uart5;
  		spi0 = &spi0;
  		spi1 = &spi1;
  		spi2 = &fspi;
  		spi3 = &flexbus_fspi;
  		spi4 = &flexbus_spi;
  	};

  Code: Select all

  i2c3: i2c-gpio-3 {
  		compatible = "i2c-gpio";
  		gpios = <&gpio4 1 GPIO_ACTIVE_HIGH>, /* PT1_SDA = GPIO4_A1_z  */
  				<&gpio4 0 GPIO_ACTIVE_HIGH>; /* PT1_SCL = GPIO4_A0_z  */
  
  		i2c-gpio,delay-us = <2>;
  		#address-cells = <1>;
  		#size-cells = <0>;
  		status = "okay";
  	};

  但是实测发现有部分I2C引脚电平没有上拉，有些又是正常的，硬件上均有4.7k上拉电阻。
  想设置软件上拉，就在rk3506-luckfox-lyra.dtsi文件里就加了pinctrl。

  Code: Select all

  i2c3: i2c-gpio-3 {
  		compatible = "i2c-gpio";
  		gpios = <&gpio4 1 GPIO_ACTIVE_HIGH>, /* PT1_SDA = GPIO4_A1_z  */
  				<&gpio4 0 GPIO_ACTIVE_HIGH>; /* PT1_SCL = GPIO4_A0_z  */
  
  		i2c-gpio,delay-us = <2>;
  		#address-cells = <1>;
  		#size-cells = <0>;
          pinctrl-names = "default";
  	    pinctrl-0 = <&gpio_i2c3_scl &gpio_i2c3_sda>;
  		status = "okay";
  	};

  Code: Select all

  &pinctrl {
  	gpio_i2c3 {
  		gpio_i2c3_sda: gpio-i2c3-sda {
  			rockchip,pins =
  				<4 RK_PA1 35 &pcfg_pull_up>;
  		};
  	};
  
  	gpio_i2c3 {
  		gpio_i2c3_scl: gpio-i2c3-scl {
  			rockchip,pins =
  				<4 RK_PA0 34 &pcfg_pull_up>;
  		};
  	};
  };

  然后再刷镜像这个I2C3就没有挂载了
  
  请问有没有完整的软件I2C配置示例可以参考一下，请教上述步骤有哪里搞错了

  • Quote

&pinctrl {
	gpio_i2c3 {
		gpio_i2c3_sda: gpio-i2c3-sda {
			rockchip,pins =
				<4 RK_PA1 35 &pcfg_pull_up>;
		};
	};

	gpio_i2c3 {
		gpio_i2c3_scl: gpio-i2c3-scl {
			rockchip,pins =
				<4 RK_PA0 34 &pcfg_pull_up>;
		};
	};
};

&pinctrl {
	i2c_pcfg_pull_up: i2c-pcfg-pull-up {
        bias-pull-up;
        drive-open-drain;
    };

	rm_io0 {
		rm_io0_i2c2_sda: rm-io0-i2c2-sda {
			rockchip,pins =
				<0 RK_PA0 35 &pcfg_pull_up>;
		};
	};

	rm_io1 {
		rm_io1_i2c2_scl: rm-io1-i2c2-scl {
			rockchip,pins =
				<0 RK_PA1 34 &pcfg_pull_up>;
		};
	};

	i2c3_gpio: i2c3-gpio {
		rockchip,pins =
			<4 RK_PA1 RK_FUNC_GPIO &i2c_pcfg_pull_up>,
			<4 RK_PA0 RK_FUNC_GPIO &i2c_pcfg_pull_up>;
	};
};

i2c3: i2c-gpio-3 {
		compatible = "i2c-gpio";
		gpios = <&gpio4 1 GPIO_ACTIVE_HIGH>, /* PT1_SDA = GPIO4_A1_z  */
				<&gpio4 0 GPIO_ACTIVE_HIGH>; /* PT1_SCL = GPIO4_A0_z  */

		i2c-gpio,delay-us = <2>;
		#address-cells = <1>;
		#size-cells = <0>;
        pinctrl-names = "default";
        pinctrl-0 = <&i2c3_gpio>;
		status = "okay";
	};

&pinctrl {
    i2c3 {
        i2c3_gpio: i2c3-gpio {
            rockchip,pins =
                <4 RK_PA1 0 &i2c_pcfg_pull_up>, /* SCL */
                <4 RK_PA0 0 &i2c_pcfg_pull_up>; /* SDA */
        };
    };
};

wjh

Posts: 16

Joined: 2025-08-06 2:29

2025-09-08 9:58

Crocodile wrote: ↑2025-09-08 2:26 您的pinctrl应该添加group去消除 unable to find group for node i2c3-gpio 报错,

Code: Select all

&pinctrl {
    i2c3 {
        i2c3_gpio: i2c3-gpio {
            rockchip,pins =
                <4 RK_PA1 0 &i2c_pcfg_pull_up>, /* SCL */
                <4 RK_PA0 0 &i2c_pcfg_pull_up>; /* SDA */
        };
    };
};

好的，谢谢哥

• Quote