TMDX654IDKEVM: GPIOs in Linux

Hi Johannes,

ICSSG ethernet LEDs might need more configuration.

If the intent is just to test GPIO toggling you can check:

arch/arm64/boot/dts/ti/k3-am654-base-board.dts

gpio-keys {
compatible = "gpio-keys";
autorepeat;
pinctrl-names = "default";
pinctrl-0 = <&push_button_pins_default>;

sw5 {
label = "GPIO Key USER1";
linux,code = <BTN_0>;
gpios = <&wkup_gpio0 24 GPIO_ACTIVE_LOW>;
};

sw6 {
label = "GPIO Key USER2";
linux,code = <BTN_1>;
gpios = <&wkup_gpio0 27 GPIO_ACTIVE_LOW>;
};
};

There are 2 push buttons on the IDK and they can generate interrupts as well.

Also on the free GPIOs. Try the below from Linux command promt:

echo 0 > /sys/class/gpio/export
devmem 0x11c000 32 0x08050007
echo out > /sys/class/gpio/gpio0/direction
echo 1 > /sys/class/gpio/gpio0/value

echo 2 > /sys/class/gpio/export
devmem 0x11c008 32 0x08050007
echo out > /sys/class/gpio/gpio2/direction
echo 1 > /sys/class/gpio/gpio2/value

echo 5 > /sys/class/gpio/export
devmem 0x11c014 32 0x08050007
echo out > /sys/class/gpio/gpio5/direction
echo 1 > /sys/class/gpio/gpio5/value

You need to ensure that Pin Mux is also rightly set.

Best Regards,
Keerthy

Hi Keerthy,

thanks for your fast and detailed feedback.

But I have one remaining question: How do I find out to which Pin/Pad of the chip a GPIO is assigned to?

Here is what I could by executing 'cat /sys/kernel/debug/gpio':

root@am65xx-evm:~# cat /sys/kernel/debug/gpio
gpiochip4: GPIOs 246-253, parent: i2c/0-0039, 0-0039, can sleep:
 gpio-250 (                    |fixedregulator-sd   ) out hi

gpiochip3: GPIOs 254-343, parent: platform/601000.gpio, 601000.gpio:
 gpio-301 (                    |standby             ) out lo ACTIVE LOW
 gpio-321 (                    |standby             ) out lo ACTIVE LOW

gpiochip2: GPIOs 344-439, parent: platform/600000.gpio, 600000.gpio:

gpiochip1: GPIOs 440-495, parent: platform/42110000.gpio, 42110000.gpio:
 gpio-464 (                    |GPIO Key USER1      ) in  hi ACTIVE LOW
 gpio-467 (                    |GPIO Key USER2      ) in  hi ACTIVE LOW

gpiochip0: GPIOs 496-511, parent: i2c/2-0021, 2-0021, can sleep:
 gpio-501 (                    |reset               ) out hi

Behind gpiochip2 are the GPIOs of the AM64x which can be controlled over the GPIO IP at physical address 0x000600000 (GPIO0). So, with

echo 344 > export

echo out > gpio344/direction

I am setting up GPIO0_0 up for use. But to what Pad is this GPIO releated too?

Can you help me out here?

Best regards,

Johannes