AM6421: Accessing GPIO in uboot

Hello, 

I noticed you have a partial dts configuration. To properly enable a GPIO in U-Boot please take a look at the following FAQ for initialization and accessing help: [FAQ] PROCESSOR-SDK-AM62X: How to Toggle GPIOs and LEDs from U-Boot Command Prompt - Processors forum - Processors - TI E2E support forums.

Regards,

Shriya 

Hi Shriya

      Thanks for the response.

         We have tried  as suggested in the link. but still not able to access the gpio.

      We have done the below modifications:

 in kernel dts file k3-am642-evm.dts added belwo

  &main_pmx0 {

customgpio1_pins_default: customgpio1-default-pins {
        pinctrl-single,pins = <
            
            AM64X_IOPAD(0x020c, PIN_INPUT, 7) /* (C13) SPI0_CS1.GPIO1_43 LCD_RST*/
        >;
    };

&main_gpio1 {
          status = "okay";
         pinctrl-names = "default";
         pinctrl-0 = <&customgpio1_pins_default>;
         gpio-controller;
          
};

IN uboot dts file k3-am642-evm-uboot.dtsi added below

&main_pmx0 {

      customgpio1_pins_default: customgpio1-default-pins {
                            pinctrl-single,pins = <
 
                                     AM64X_IOPAD(0x020c, PIN_OUTPUT, 7) /* (C13) SPI0_CS1.GPIO1_43 LCD_RST*/
                            >;
       };

};

&main_gpio1 {
                        bootph-all;

                        status = "okay";
                        pinctrl-names = "default";
                       pinctrl-0 = <&customgpio1_pins_default>;
                       gpio-controller;
};

/ {

       lcd_gpio_reset: lcd_gpio_reset{
                               gpios = <&main_gpio1 43 GPIO_ACTIVE_HIGH>;
          };

       aliases {
               GPIO1_43 = &lcd_gpio_reset;
       };
};

Iuboot source file evm.c added below code

int board_late_init(void)
{
    if (IS_ENABLED(CONFIG_TI_I2C_BOARD_DETECT)) {
        struct ti_am6_eeprom *ep = TI_AM6_EEPROM_DATA;

        setup_board_eeprom_env();
        setup_serial();
        /*
         * The first MAC address for ethernet a.k.a. ethernet0 comes from
         * efuse populated via the am654 gigabit eth switch subsystem driver.
         * All the other ones are populated via EEPROM, hence continue with
         * an index of 1.
         */
        board_ti_am6_set_ethaddr(1, ep->mac_addr_cnt);
    }

/* below added by UST for LCD reset pin*/

    struct gpio_desc lcdreset;
    int ret;
    

    ret = dm_gpio_lookup_name("GPIO1_43", &lcdreset);
    if (ret) {
        printf("Unable to lookup GPIO1_43\n");
        return ret;
    }
    
    ret = dm_gpio_request(&lcdreset, "lcd_reset");
    if (ret) {
        printf("Unable to request lcd_reset\n");
        return ret;
    }
    
    printf("Able to request lcd_reset GPIO1_43\n");
    
    /* set direction to output*/
    dm_gpio_set_dir_flags(&lcdreset, GPIOD_IS_OUT);
    
    /* Drive LCD reset low then high */
    dm_gpio_set_value(&lcdreset, 1);
    udelay(50);
    dm_gpio_set_value(&lcdreset, 0);
    udelay(150);
    dm_gpio_set_value(&lcdreset, 1);

    /*above added by UST  for LCD reset pin*/
    
    return 0;
}

while booting we are getting below errot

Unable to lookup GPIO1_43
 nitcall failed at call 00000000808064a4 (err=-22)
 ### ERROR ### Please RESET the board ###

Please check if we are doing any mistake.

Hi Narasimha, 

Would you be able to share the output of gpio status -a?

Regards,

Shriya