I.MX6UL 增加ADC

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项目需要，需要增加ADC功能，通道数量是8个

因为中间GPIO06和GPIO07没有对应IO，且不知道如何跳过这两个IO，所以配置中使用了10通道。

 

 

 

 

1. 修改设备树

&adc1 {pinctrl-names = "default";pinctrl-0 = <&pinctrl_adc1>;num-channels = <10>;vref-supply = <&reg_vref_3v3>;status = "okay";
};

上图使用了10通道

 

 regulators {compatible = "simple-bus";#address-cells = <1>;#size-cells = <0>;reg_can_3v3: regulator@0 {compatible = "regulator-fixed";reg = <0>;regulator-name = "can-3v3";regulator-min-microvolt = <3300000>;regulator-max-microvolt = <3300000>;};reg_vref_3v3: regulator@3 {compatible = "regulator-fixed";regulator-name = "vref-3v3";regulator-min-microvolt = <3300000>;regulator-max-microvolt = <3300000>;};reg_usb_ltemodule: regulator@1 {compatible = "regulator-fixed";regulator-name = "ltemodule-pwr";regulator-min-microvolt = <3800000>;regulator-max-microvolt = <3800000>;gpios = <&gpio5 5 GPIO_ACTIVE_HIGH>;enable-active-high;regulator-boot-on;};reg_gpio_wifi: regulator@2 {compatible = "regulator-fixed";regulator-name = "wifi-pwr";regulator-min-microvolt = <3300000>;regulator-max-microvolt = <3300000>;gpios = <&gpio1 10 GPIO_ACTIVE_LOW>;regulator-boot-on;};};

                pinctrl_adc1: adc1grp {fsl,pins = <MX6UL_PAD_GPIO1_IO00__GPIO1_IO00        0xb0    /*ADC1*/MX6UL_PAD_GPIO1_IO01__GPIO1_IO01        0xb0MX6UL_PAD_GPIO1_IO02__GPIO1_IO02        0xb0MX6UL_PAD_GPIO1_IO03__GPIO1_IO03        0xb0MX6UL_PAD_GPIO1_IO04__GPIO1_IO04        0xb0MX6UL_PAD_GPIO1_IO05__GPIO1_IO05        0xb0                                MX6UL_PAD_GPIO1_IO06__GPIO1_IO06        0xb0    /*NULL*/MX6UL_PAD_GPIO1_IO07__GPIO1_IO07        0xb0    /*NULL*/MX6UL_PAD_GPIO1_IO08__GPIO1_IO08        0xb0    /*ADC7*/MX6UL_PAD_GPIO1_IO09__GPIO1_IO09        0xb0    /*ADC8*/>;};

ADC6和7实际没用上，但是也要加上去，否者读不了ADC8和9。这个问题应该是可以解决的吧，有空再说吧。

 

2. 升级后

[root@SCU iio:device0]# cd /sys/bus/iio/devices/iio\:device0/
[root@SCU iio:device0]# ls 
dev                            in_voltage6_raw                of_node
in_voltage0_raw                in_voltage7_raw                power
in_voltage1_raw                in_voltage8_raw                sampling_frequency_available
in_voltage2_raw                in_voltage9_raw                subsystem
in_voltage3_raw                in_voltage_sampling_frequency  uevent
in_voltage4_raw                in_voltage_scale
in_voltage5_raw                name
[root@SCU iio:device0]# 

直接到/sys/bus/iio/devices/iio\:device0/目录下，就可以看到新增的10个ADC通道，in_voltage0_raw ~ in_voltage9_raw

直接cat就可以读到对应的ADC值了。

后话：如何跳过ADC6 ADC7通道？

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