How to access SCU_GPIO0_00 from core A35 (u-boot or Linux)?

[Juanma1]

Hello

I'm working with a custom board based on iMX8DXL and I need to access to SCU_GPIO0_00 and SCU_GPIO0_01 from the core A35 (u-boot or linux).

In scfw I have changed the mux from defaul scu_uart to scu_gpio, select as digital input and changed the owner partition.

I did this:

void init_scu_gpio_pins(void)

{

  rgpio_pin_config_t config;
  config.pinDirection = kRGPIO_DigitalInput;

  rm_set_pad_movable(SC_PT, SC_P_SCU_GPIO0_00, SC_P_SCU_GPIO0_01, SC_TRUE);

  pad_set_all(SC_PT, SC_P_SCU_GPIO0_00, 4U, SC_PAD_CONFIG_NORMAL, SC_PAD_ISO_OFF, 0x60, SC_PAD_WAKEUP_OFF);

  pad_set_all(SC_PT, SC_P_SCU_GPIO0_01, 4U, SC_PAD_CONFIG_NORMAL, SC_PAD_ISO_OFF, 0x60, SC_PAD_WAKEUP_OFF);

  RGPIO_PinInit(RGPIOA, 0U, &config);
  RGPIO_PinInit(RGPIOA, 1U, &config);

  rm_assign_pad (SC_PT, BOOT_PT, SC_P_SCU_GPIO0_00);

  rm_assign_pad (SC_PT, BOOT_PT, SC_P_SCU_GPIO0_01);

}

I don't know if I missed something to do here or there are something wrong.

If it is correct, how can I access these pins (SCU pins) from linux or u-boot?

Thanks for your help!

Regards

[josephzhou1]

good , where did u put  pmic_init() ? 

[Juanma1]

pmic_init() is in its default place: in board_init() when phase == BOOT_PHASE_FINAL_INIT

[Juanma1 · Accepted solution]

Solved!

It seems that pmic must be initialized before call init_scu_gpio_pins() to work properly.

I do not why, but calling de gpio init function afterwards pmic_init() I can read values from scu_gpios.

[Juanma1]

Hello again,

I've seen that these pins are only accesible from SCU, and I have to add/modify ioctl api to get "access" from A35, i.e. to read their values.

My problem now is that I only get 0's from that pins even though I have an '1' put on them.

I used that code in scfw board.c:

/*--------------------------------------------------------------------------*/
/* Init SCU pins                                                            */
/*--------------------------------------------------------------------------*/
static void init_scu_gpio_pins(void)
{      
sc_err_t err;
    rgpio_pin_config_t config;
    config.pinDirection = kRGPIO_DigitalInput;

/* To disable uart-scu default gpios mux and set pins as normal gpios */
    err=pad_set_all(SC_PT, SC_P_SCU_GPIO0_00, 4U, SC_PAD_CONFIG_NORMAL, SC_PAD_ISO_OFF, 0x60, SC_PAD_WAKEUP_OFF);
    err=pad_set_all(SC_PT, SC_P_SCU_GPIO0_01, 4U, SC_PAD_CONFIG_NORMAL, SC_PAD_ISO_OFF, 0x60, SC_PAD_WAKEUP_OFF);

    /* Init SCU_GPIO0_00 and SCU_GPIO0_01 as digital input */
    RGPIO_PinInit(RGPIOA, 0U, &config);
    RGPIO_PinInit(RGPIOA, 1U, &config);
}


static uint32_t ReadSCUPins (void)
{
    uint32_t retval = 0U;
    uint32_t gpio0_val = 0U, gpio1_val = 0U;   
   
    gpio0_val = RGPIO_PinRead(RGPIOA, 0U);
    gpio1_val = RGPIO_PinRead(RGPIOA, 1U);
   
    retval = (gpio0_val & 0x01) | ((gpio1_val & 0x01) <<1);
   
    board_print(1, "SCU_GPIO0_00: %u, SCU_GPIO0_01: %u, retval: %u\n", gpio0_val, gpio1_val, retval);
   
    return retval;
}