在按照《linux驱动入门》书中添加I2C到设备树发现nano里并没有
sys/devices/platform/soc/1c27000.i2c/i2c-0/0-0050/
I2C-0这一目录，本书甚至给出代码
&i2c0 {
clock-frequency = <100000>; //时钟设置为 100KHz
status = "okay";
at24c02: at24c02@50 {
compatible = "test,at24c0x";
reg = <0x50>;
};
};这样一般笔带，随后我只能开船畅游百度。
第一天无果
第二天我试图在原有的内核中找线索，我在arch/arm/boot/dts/sun4i-a10.dtsi中找到这么一串代码
i2c0: i2c@1c2ac00 {
compatible = "allwinner,sun4i-a10-i2c";
reg = <0x01c2ac00 0x400>;
interrupts = <7>;
clocks = <&ccu CLK_APB1_I2C0>;
pinctrl-names = "default";
pinctrl-0 = <&i2c0_pins>;
status = "disabled";
#address-cells = <1>;
#size-cells = <0>;
};将其拷贝粘贴debug,神奇的一幕发现了
ls sys/devices/platform/soc/1c27000.i2c/i2c-0/0-0050
已经生成了i2c-0
/ # insmod /home/zr/i2c.ko
[ 144.167822] i2c: loading out-of-tree module taints kernel.
/ # ls sys/devices/platform/soc/1c27000.i2c/i2c-0/0-0050/of_node/
compatible name reg
/ # ls sys/devices/platform/soc/1c27000.i2c/i2c-0/0-0050/
at24c02 modalias of_node/ subsystem/
driver/ name power/ uevent究其原因是因为compatible属性没有适配，将compatible填写成sun4i-a10-i2c就可以了。
这是我的设备树
dtsi
i2c0: i2c@1c27000 {
compatible = "allwinner,sun4i-a10-i2c";
reg = <0x01c27000 0x400>;
interrupts = <7>;
clocks = <&ccu CLK_BUS_I2C0>;
resets = <&ccu RST_BUS_I2C0>;
pinctrl-names = "default";
pinctrl-0 = <&i2c0_pins>;
status = "okay";
#address-cells = <1>;
#size-cells = <0>;
};dts
&i2c0 {
clock-frequency = <100000>; //时钟设置为 100KHz
pinctrl-names = "default";
pinctrl-0 = <&i2c0_pins>;
status = "okay";
at24c02@50 {
compatible = "test,at24c0x";
reg = <0x50>;
};
};下面继续调试i2c
最近编辑记录 744219909 (2023-03-02 10:08:19)
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