Linux/am5728: The problem about setting gpio output value in u-boot

Tool/software: Linux

Hi,

On my custom board, I want to set gpio3_12 as output pin and output high level. Based on the SDK ti-processor-sdk-linux-am57xx-evm-03.01.00.06, I modified \board\ti\am57xx\mux_data.h:

    const struct pad_conf_entry core_padconf_array_essential_x15[] = {

    ......

    {VIN1A_D8, (M14 | PIN_OUTPUT_PULLUP)},    /* vin1a_d8.gpio3_12 */

    ......

    }

and in board.c file, I added the codes:

    gpio_request(108, "pr2_mii0_rst");
    gpio_direction_output(108, 1);
    gpio_set_value(108, 1);

Then I start the u-boot, the result is it didn't work. when I use "gpio status -a", the gpio3_12 is "input, 0".

Why? How do I modify it correctly?

Thanks.