IO-DOMAIN调试指南

IO-Domain用来配置X5部分模块的电压域，以RGMII接口为例，如果电路设计时外接电压域为3.3V，则需要配置RGMII模块的IO-DOMAIN为3.3V，如果电路设计时外接电压域为1.8V，则需要配置为1.8v，需要注意的是：

• 外接电压域为3.3V而对应的IO-DOMAIN配置为1.8V时，可能会对芯片有损伤；
• 外接电压域为1.8V而对应的IO-DOMAIN配置为3.3V时，相应的模块可能无法正常工作；

驱动代码

代码位置

drivers/pinctrl/hobot/ # pinctrl 驱动代码源文件所在文件夹
include/linux/platform_data/pinctrl-single.h # pinctrl 驱动代码头文件

IO-DOMAIN的DTS

X5的Pinctrl功能相关定义位于SDK包kernel文件夹下的arch/arm64/boot/dts/hobot/pinmux-func.dtsi文件内。

由于IO-Domain在pinctrl-single的框架下实现，因此其DTS和pinctrl的类似，在IO-Domain的DTS里已经列出了所有模块1.8V和3.3V的配置组，客户一般不需要修改，在具体开发时根据实际情况选择使用即可。

比较特殊的是SD和SDIO两组IO-Domain的配置。由于在芯片PAD上SD与SDIO的电压域会被同时配置，我们默认使用SD及SDIO的MMC控制器来独立控制SD/SDIO的PIN的电压域，配置选项为自定义的“power-source”宏，如下所示：

...
	pconf_sd_sdio_ds12_padctrl_3v3: pconf-sd-sdio-ds12-padctrl-3v3 {
		bias-pull-up;
		power-source = <HORIZON_IO_PAD_CTRL_VOLTAGE_3V3>;
		drive-strength = <12>;
	};

	pconf_sd_sdio_pu_ds12_padctrl_1v8: pconf-sd-sdio-ds12-padctrl-1v8 {
		bias-pull-up;
		power-source = <HORIZON_IO_PAD_CTRL_VOLTAGE_1V8>;
		drive-strength = <12>;
	};
...

	pinctrl_sd: sdgrp {
		horizon,pins = <
			HSIO_SD_WP		HSIO_PINMUX_2	BIT_OFFSET24	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SD_CLK		HSIO_PINMUX_2	BIT_OFFSET22	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SD_CMD		HSIO_PINMUX_2	BIT_OFFSET20	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SD_CDN		HSIO_PINMUX_2	BIT_OFFSET18	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SD_DATA0	HSIO_PINMUX_2	BIT_OFFSET16	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SD_DATA1	HSIO_PINMUX_2	BIT_OFFSET14	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SD_DATA2	HSIO_PINMUX_2	BIT_OFFSET12	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SD_DATA3	HSIO_PINMUX_2	BIT_OFFSET10	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
		>;
	};

	pinctrl_sdio: sdiogrp {
		horizon,pins = <
			HSIO_SDIO_WP	HSIO_PINMUX_2	BIT_OFFSET8	MUX_ALT0		&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SDIO_CLK	HSIO_PINMUX_0	BIT_OFFSET30	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SDIO_CMD	HSIO_PINMUX_0	BIT_OFFSET28	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SDIO_DATA0	HSIO_PINMUX_1	BIT_OFFSET0		MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SDIO_DATA1	HSIO_PINMUX_2	BIT_OFFSET30	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SDIO_DATA2	HSIO_PINMUX_2	BIT_OFFSET28	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
			HSIO_SDIO_DATA3	HSIO_PINMUX_2	BIT_OFFSET26	MUX_ALT0	&pconf_sd_sdio_pu_ds12_ipctrl
		>;
	};
...

驱动调用时DTS配置

首先，在DTS内定义当前硬件特殊的电压域配置，以配置pwm0 ch1为1.8V为例：

&lsio_iomuxc {
    pinctrl_pwm0_1_1v8: pinctrl-pwm0-1_1v8 {
        horizon,pins = <
            LSIO_SPI2_SSN	LSIO_PINMUX_1	BIT_OFFSET18	MUX_ALT3	&pconf_pwm_1v8
        >;
    };
}

和pinctrl的使用方法类似，驱动在自己的DTS中引用需要配置的IO-Domain，以pwm驱动为例，配置如下：

&pwm0 {
    ...
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_pwm0_1_1v8>; /* 将pwm0 Ch1 配置为1.8V电压域，PWM0功能 */
    ...
};

驱动调用示例代码

和Pinctrl调用方法一致，驱动先通过Pinctrl-names查找对应的pinctrl state，然后再切换到对应的state。

static int hobot_xxx_probe(struct platform_device *pdev)
{
    ...
    g_xxx_dev->pinctrl = devm_pinctrl_get(&pdev->dev);
    if (IS_ERR(g_xxx_dev->pinctrl)) {
        dev_warn(&pdev->dev, "pinctrl get none\n");
        g_xxx_dev->pins_voltage = NULL;
    }
    ...
        /* 按照pinctrl-names lookup state */
        g_xxx_dev->pins_voltage = pinctrl_lookup_state(g_xxx_dev->pinctrl,
                "xxx_voltage_func");
    if (IS_ERR(g_xxx_dev->pins_voltage)) {
        dev_info(&pdev->dev, "xxx_voltage_func get error %ld\n",
                PTR_ERR(g_xxx_dev->pins_voltage));
        g_xxx_dev->pins_voltage = NULL;
    }
    ...
        /* select state */
        if (g_xxx_dev->pins_voltage) {
            ret = pinctrl_select_state(g_xxx_dev->pinctrl, g_xxx_dev->pins_voltage);
            if (ret) {
                dev_info(&pdev->dev, "xxx_voltage_func set error %d\n", ret);
            }
        }
    ...
}

uboot下修改电压域

X5的Uboot内已实现了Pinctrl驱动，使用方法与内核一致，均通过DTS来定义具体的Pin的属性。