f133 挖坑2 ，修改 uart0 -> uart3 设置

[axw_fae]

按很多大老的分享！ https://bbs.aw-ol.com/topic/1673/全志芯片tina-linux-修改-uart-引脚-uart端口?lang=zh-CN

按其操作！ 结果卡死在这儿

自已一顿操作！ 发现一些和一些大老分享不一样的地方

       uart3_pins_a: uart3_pins@0 {  /* for mq-r uart3 */
                pins = "PB6", "PB7";
                function = "uart3";
                muxsel = <7>;
                drive-strength = <10>;
                bias-pull-up;
        };

        uart3_pins_b: uart3_pins@1 {  /* For mq-r uart3 */
                pins = "PB6", "PB7";
                function = "gpio_in";
        };

function 很多大老指向 uart0 ，但是这个明明是给 uart3 用的！
再者 muxsel 必需要改成 7 ，这个才是 uart3 功能

/*

&uart0 {
        pinctrl-names = "default", "sleep";
        pinctrl-0 = <&uart0_pins_a>;
        pinctrl-1 = <&uart0_pins_b>;
        status = "okay";
};

&uart3 {
        compatible = "allwinner,sun20iw1-dsp-uart";
        pinctrl-names = "default", "sleep";
        pinctrl-0 = <&uart3_pins_a>;
        pinctrl-1 = <&uart3_pins_a>;
        status = "disabled";
};

mq-r
*/

&uart0 {
        pinctrl-names = "default", "sleep";
        pinctrl-0 = <&uart0_pins_a>;
        pinctrl-1 = <&uart0_pins_b>;
        status = "disabled";
};

&uart3 {
        pinctrl-names = "default", "sleep";
        pinctrl-0 = <&uart3_pins_a>;
        pinctrl-1 = <&uart3_pins_b>;
        status = "okay";
};

这一句一定要删掉，要不然就开不起来
compatible = "allwinner,sun20iw1-dsp-uart";

目前坑还在接著挖！ 有新坑再上来 po 文