i.MX 8X GPIOs

Each GPIO should be mapped on the device tree as:

XX_YY_ZZ_LSIO_GPIO#_IO#

<details>
<summary>Click here</summary>

imx8qxp-qx8x {
        pinctrl_hog: hoggrp {
            fsl,pins = <
                SC_P_SPI2_SDO_LSIO_GPIO1_IO01                0x00000021    /* GPIO 0 (449) */
                SC_P_SPI2_CS0_LSIO_GPIO1_IO00                0x00000021    /* GPIO 1 (448) */
                SC_P_SPI2_SDI_LSIO_GPIO1_IO02                0x00000021    /* GPIO 2 (450) */
                SC_P_SPI2_SCK_LSIO_GPIO1_IO03                0x00000021    /* GPIO 3 (451)*/
                SC_P_SPI0_CS0_LSIO_GPIO1_IO08                0x00000021    /* GPIO 4 (456) */
                SC_P_FLEXCAN2_RX_LSIO_GPIO1_IO19            0x00000021    /* GPIO 5 (467) */
                SC_P_SPI0_SDI_LSIO_GPIO1_IO05                0x00000021    /* GPIO 6 (453) */
                SC_P_FLEXCAN2_TX_LSIO_GPIO1_IO20             0x00000021    /* GPIO 7 (468) */
                SC_P_MIPI_DSI0_GPIO0_01_LSIO_GPIO1_IO28            0x00000021    /* LVDS0_PPEN (476) */
                SC_P_MIPI_DSI1_GPIO0_01_LSIO_GPIO2_IO00            0x00000021    /* LVDS0_BLEN (416) */
            >;
        };

</details>

the GPIO# matches the gpiochip

the IO# is the specific GPIO number into the chip

To calculate the number where the GPIO is mapped into the userspace this are the correspondence:

GPIO	#user space

GPIO	#user space
--	--
0	480
1	448
2	416
3	384
4	352
5	320
6	288
7	256

Then add the specific number of the IO to the gpiochip and this will be the GPIO number into the userspace

e.g: SC_P_M40_GPIO0_01_LSIO_GPIO0_IO09

GPIO chip 0 → 480

IO number → 9

gpio number → 480+9 = 489

To have access to it do the following

cd /sys/class/gpio
echo 489 > export
cd gpio489
echo out > direction
echo 1 > value
echo 0 > value
echo in > direction