When I enable pull ups in the device tree, it is not reported in the gpioinfo?

[mfide]

Hello,

I’m working with a TI AM62-based Linux board running Kernel v6.12 and libgpiod v2.2.2.

The issue I’m facing is that when I configure some GPIOs with pull-up settings directly in the Device Tree, it works as expected—I can measure a logic high (1) on the input pins.

Below is the relevant part of the Device Tree that defines GPIO_1 as an input with a pull-up resistor:

&mcu_pmx0 {
	/* Baseboard GPIO_1 */
	pinctrl_gpio_1: mcu-gpio0-1-default-pins {
		pinctrl-single,pins = <
			AM62X_MCU_IOPAD(0x0004, PIN_INPUT_PULLUP, 7) /* (B8) MCU_GPIO0_1 */
		>;
	};
..
}

However, when I later check the pin status using gpioinfo -c1, it only reports the pin as an input (without showing the pull-up configuration).

root@am62:~# gpioinfo -c1
gpiochip1 - 24 lines:
        line   0:       "GPIO_9"                input
        line   1:       "GPIO_1"                input     <<<-- pull-up enabled in device tree, but not shown here
        line   2:       "GPIO_2"                input
        line   3:       "GPIO_3"                input
        line   4:       "GPIO_4"                input
        line   5:       "GPIO_10"               input
        line   6:       "GPIO_11"               input
        line   7:       "GPIO_12"               input
        line   8:       "GPIO_13"               input
        line   9:       unnamed                 input
        line  10:       unnamed                 input
        line  11:       unnamed                 input
        line  12:       unnamed                 input
        line  13:       unnamed                 input
        line  14:       unnamed                 input
        line  15:       unnamed                 input
        line  16:       "GPIO_14"               input
        line  17:       unnamed                 input
        line  18:       unnamed                 input
        line  19:       unnamed                 input
        line  20:       unnamed                 input
        line  21:       unnamed                 input
        line  22:       unnamed                 input
        line  23:       unnamed                 input

Does the Linux kernel expose an interface that allows libgpiod to retrieve the current pull-up/pull-down configuration of a GPIO pin?

Thanks.

[brgl]

That would typically be reported once someone requests this GPIO using the gpiod in-kernel API. Pinctrl and GPIO subsystems are somewhat related but not tightly integrated so for a free GPIO it does not look into the pinctrl internals and the flags it sets. Please assign it to some dummy driver (gpio-virtuser for instance) and see if it's reported then.