配置好设备树节点后插入sd卡无法检测。
设备树节点如下：
&sdmmc0 { bus-width = <4>; cap-sd-highspeed; cd-gpios = <&gpio0 RK_PA4 GPIO_ACTIVE_LOW>; disable-wp; pinctrl-names = "default"; pinctrl-0 = <&sdmmc0_bus4 &sdmmc0_clk &sdmmc0_cmd &sdmmc0_det>; sd-uhs-sdr104; vmmc-supply = <&vcc3v3_sd>; vqmmc-supply = <&vccio_sd>; status = "okay"; };
查看内核日志发现如下报错：
dmesg | grep mmc [ 12.226496] dwmmc_rockchip fe2b0000.mmc: Looking up vmmc-supply from device tree [ 12.226535] dwmmc_rockchip fe2b0000.mmc: Looking up vqmmc-supply from device tree
vmmc-supply和vqmmc-supply由rk809提供，rk809在该板子上连接到了i2c0, 设备树如下：
&i2c0 { status = "okay"; rk809: pmic@20 { compatible = "rockchip,rk809"; reg = <0x20>; interrupt-parent = <&gpio0>; interrupts = <RK_PA3 IRQ_TYPE_LEVEL_LOW>; assigned-clocks = <&cru I2S1_MCLKOUT_TX>; assigned-clock-parents = <&cru CLK_I2S1_8CH_TX>; #clock-cells = <1>; clock-names = "mclk"; clocks = <&cru I2S1_MCLKOUT_TX>; pinctrl-names = "default"; pinctrl-0 = <&pmic_int>; rockchip,system-power-controller; #sound-dai-cells = <0>; vcc1-supply = <&vcc3v3_sys>; vcc2-supply = <&vcc3v3_sys>; vcc3-supply = <&vcc3v3_sys>; vcc4-supply = <&vcc3v3_sys>; vcc5-supply = <&vcc3v3_sys>; vcc6-supply = <&vcc3v3_sys>; vcc7-supply = <&vcc3v3_sys>; vcc8-supply = <&vcc3v3_sys>; vcc9-supply = <&vcc3v3_sys>; wakeup-source; regulators { vdd_logic: DCDC_REG1 { regulator-name = "vdd_logic"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <500000>; regulator-max-microvolt = <1350000>; regulator-ramp-delay = <6001>; regulator-initial-mode = <0x2>; regulator-state-mem { regulator-off-in-suspend; }; }; vdd_gpu: DCDC_REG2 { regulator-name = "vdd_gpu"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <500000>; regulator-max-microvolt = <1350000>; regulator-ramp-delay = <6001>; regulator-initial-mode = <0x2>; regulator-state-mem { regulator-off-in-suspend; }; }; vcc_ddr: DCDC_REG3 { regulator-name = "vcc_ddr"; regulator-always-on; regulator-boot-on; regulator-initial-mode = <0x2>; regulator-state-mem { regulator-on-in-suspend; }; }; vdd_npu: DCDC_REG4 { regulator-name = "vdd_npu"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <500000>; regulator-max-microvolt = <1350000>; regulator-ramp-delay = <6001>; regulator-initial-mode = <0x2>; regulator-state-mem { regulator-off-in-suspend; }; }; vcc_1v8: DCDC_REG5 { regulator-name = "vcc_1v8"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; regulator-state-mem { regulator-off-in-suspend; }; }; vdda0v9_image: LDO_REG1 { regulator-name = "vdda0v9_image"; regulator-boot-on; regulator-always-on; regulator-min-microvolt = <900000>; regulator-max-microvolt = <900000>; regulator-state-mem { regulator-off-in-suspend; }; }; vdda_0v9: LDO_REG2 { regulator-name = "vdda_0v9"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <900000>; regulator-max-microvolt = <900000>; regulator-state-mem { regulator-off-in-suspend; }; }; vdda0v9_pmu: LDO_REG3 { regulator-name = "vdda0v9_pmu"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <900000>; regulator-max-microvolt = <900000>; regulator-state-mem { regulator-on-in-suspend; regulator-suspend-microvolt = <900000>; }; }; vccio_acodec: LDO_REG4 { regulator-name = "vccio_acodec"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <3300000>; regulator-max-microvolt = <3300000>; regulator-state-mem { regulator-off-in-suspend; }; }; vccio_sd: LDO_REG5 { regulator-name = "vccio_sd"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <3300000>; regulator-state-mem { regulator-off-in-suspend; }; }; vcc3v3_pmu: LDO_REG6 { regulator-name = "vcc3v3_pmu"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <3300000>; regulator-max-microvolt = <3300000>; regulator-state-mem { regulator-on-in-suspend; regulator-suspend-microvolt = <3300000>; }; }; vcca_1v8: LDO_REG7 { regulator-name = "vcca_1v8"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; regulator-state-mem { regulator-off-in-suspend; }; }; vcca1v8_pmu: LDO_REG8 { regulator-name = "vcca1v8_pmu"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; regulator-state-mem { regulator-on-in-suspend; regulator-suspend-microvolt = <1800000>; }; }; vcca1v8_image: LDO_REG9 { regulator-name = "vcca1v8_image"; regulator-always-on; regulator-boot-on; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; regulator-state-mem { regulator-off-in-suspend; }; }; vcc_3v3: SWITCH_REG1 { regulator-name = "vcc_3v3"; regulator-always-on; regulator-boot-on; regulator-state-mem { regulator-off-in-suspend; }; }; vcc3v3_sd: SWITCH_REG2 { regulator-name = "vcc3v3_sd"; regulator-always-on; regulator-boot-on; regulator-state-mem { regulator-off-in-suspend; }; }; }; }; };
查找rk809对应的compatiblec文件：
❯ find -name "*.c" -exec grep -nR "rockchip,rk809" {} + ./drivers/mfd/rk8xx-i2c.c:163: { .compatible = "rockchip,rk809" , .data = &rk809_data },
根据该目录下的Makefile找到对应配置选项：
1 obj-$(CONFIG_MFD_RK8XX) += rk8xx-core.o 225 obj-$(CONFIG_MFD_RK8XX_I2C) += rk8xx-i2c.o
menuconfig开启以下选项：
CONFIG_MFD_RK8XX CONFIG_MFD_RK8XX_I2C
重新编译内核发现还是无法检测到，经过查询发现RK809还有其他选项可以打开：
CONFIG_RTC_RK808 CONFIG_PINCTRL_RK805 CONFIG_REGULATOR_RK808 CONFIG_INPUT_RK805_PWRKEY CONFIG_COMMON_CLK_RK808
经过启用CONFIG_REGULATOR_RK808选项后，可以正常检测并挂载。
没有测试CONFIG_REGULATOR_RK808是否依赖于其他几个选项，直接全部开启了。
ref: https://blog.csdn.net/weixin_49303682/article/details/138390797
