SK-AM62-SIP: Enabling UART5 from device tree compilation issue

Follow up. For the missing header file  #include <dt-bindings/pinctrl/k3.h> is this supposed to be generated by using the sysconfig tool? 

Hello Bin Lui, thank for looking into this. 

I removed the #includes I had and replaced them with the one you mentioned. Also, make linux-dtbs is helpful and faster than the steps I had. 

The following was built with make linux-dtbs

/dts-v1/;
/plugin/;

#include "k3-pinctrl.h"

&main_pmx0 {
    user_exp_uart5_pins_default: user-exp-uart5-pins-default {
        pinctrl-single,pins = <
            AM62X_IOPAD(0x01dc, PIN_OUTPUT, 1) /* E15 -> UART5_TXD */
            AM62X_IOPAD(0x01d8, PIN_INPUT,  1) /* C15 -> UART5_RXD */
        >;
    };
};

&main_uart5 {
    pinctrl-names = "default";
    pinctrl-0 = <&user_exp_uart5_pins_default>;
    status = "okay";
};

/*
&{/} {
    aliases { serial5 = &main_uart5; };
}
*/

/* power the 40-pin 3V3 rail 
&main_i2c1 {
    gpio@22 { /* TCA6424 at 0x22 *\/
        p05-hog {
            gpio-hog;
            gpios = <5 GPIO_ACTIVE_HIGH>; /* EXP_PS_3V3_EN *\/
            output-high;
            line-name = "EXP_PS_3V3_EN";
        };
    };
};
*/

I commented out the alias since that was producing syntax errors. 

After moving the .dtbo to dtb in boot/dtb/ti/ and adding ti to uEnv.txt Linux booted but I do not see the uart5 as active as shown here: 

root@sk-am62-sip:~# cat /proc/tty/driver/serial 
serinfo:1.0 driver revision:
0: uart:unknown port:00000000 irq:0
1: uart:unknown port:00000000 irq:0
2: uart:8250 mmio:0x02800000 irq:238 tx:23461 rx:153 RTS|DTR|DSR
3: uart:unknown port:00000000 irq:0
4: uart:unknown port:00000000 irq:0
5: uart:unknown port:00000000 irq:0
6: uart:unknown port:00000000 irq:0
7: uart:unknown port:00000000 irq:0
8: uart:unknown port:00000000 irq:0
9: uart:unknown port:00000000 irq:0
10: uart:unknown port:00000000 irq:0
11: uart:unknown port:00000000 irq:0

I believe it is not active because I did not assign an alias to uart5 as mentioned in this post 

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1372383/sk-am62-how-to-enable-userexpension-uart?utm_source=chatgpt.com 

Yes so at this point it should just be a syntax issue. I just need to enable the alias section without a syntax error. Will update soon..

Hi Bin Liu

Update: I just need to find the correct path for serial5 alias

I compiled the following dtso

/dts-v1/;
/plugin/;


#include "k3-pinctrl.h"

&main_pmx0 {
    user_exp_uart5_pins_default: user-exp-uart5-pins-default {
        pinctrl-single,pins = <
            AM62X_IOPAD(0x01dc, PIN_OUTPUT, 1) /* E15 -> UART5_TXD */
            AM62X_IOPAD(0x01d8, PIN_INPUT,  1) /* C15 -> UART5_RXD */
        >;
    };
};

&main_uart5 {
    pinctrl-names = "default";
    pinctrl-0 = <&user_exp_uart5_pins_default>;
    status = "okay";
};


&{/} {
    aliases {
        /* UART-5 lives at /bus@f0000/serial@2850000 in k3-am62-main.dtsi */
        serial5 = "/bus@f0000/serial@2850000";
    };
};


/*
&{/} {
    aliases { serial5 = &main_uart5; 
    };
};
*/

The results show the path I used for the alias is wrong

  DTC     arch/arm64/boot/dts/ti/k3-am62x-sk-uart5.dtbo
arch/arm64/boot/dts/ti/k3-am62x-sk-uart5.dtso:26.9-47: Warning (alias_paths): /fragment@2/__overlay__/aliases:serial5: aliases property is not a valid node (/bus@f0000/serial@2850000)

Where is one able to find the correct path for this alias?

I see under the k3-am62* examples  

k3-am62a7-sk-ethernet-dco1.dtso

has the following snippet

&{/} {

    aliases {

        ethernet1 = "/bus@f0000/ethernet@8000000/ethernet-ports/port@2";

    };

};

From the example, I see we need to find the correct path to complete a correct alias. 

Is the path generated from sysconfig tool?

Thank you again for taking the time. 

Hi David,

there are multiple ways to find the path. I guess the easy one for you is to search for *main_uart5* on your board under /sys/firmware/devicetree/fdt/base/ with your uart5 overlay loaded. 

sorry I am out of office and don’t have access to my EVM and kernel code to tell you the exact path.