information needed

[srinivas_123]

i am using imx8mplus custom board . i want to blink the leds which are connected to my board
gpio3 port , pin19,20,21,25
the below changes i made in my dts file , leds are blinking fine . i want to know what is 0x400000.
which register they are configuring and how it behaves gpio . please let me know .

&gpio3 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_gpio3>;

status = "okay";
};

Then, inside of the &iomuxc:

pinctrl_gpio3: gpio3grp {
fsl,pins = <
MX8MP_IOMUXC_SAI5_RXFS__GPIO3_IO19 0x40000
MX8MP_IOMUXC_SAI5_RXC__GPIO3_IO20 0x40000
MX8MP_IOMUXC_SAI5_RXD0__GPIO3_IO21 0x40000
MX8MP_IOMUXC_SAI5_MCLK__GPIO3_IO25 0x40000
>;
};

[Chavira]

HI @srinivas_123!

Thank you for contacting NXP Support!

The next line configures 2 Registers:

MX8MP_IOMUXC_SAI5_RXFS__GPIO3_IO19 0x40000

1. SW_MUX_CTL_PAD_SAI5_RXFS

2. SW_PAD_CTL_PAD_SAI5_RXFS

The first element of the configuration is :

MX8MP_IOMUXC_SAI5_RXFS__GPIO3_IO19

this part configures the SW_MUX_CTL_PAD_SAI5_RXFS register and is divided in two parts:

1. Pad name:  MX8MP_IOMUXC_SAI5_RXFS

2. Function name: __GPIO3_IO19

You can consult each function of each pin in the Reference Manual of the device.

This functions are declared on the pinfunc.h of each device in this case is imx8mp-pinfunc.h 

The second element of the configuration is :

0x40000

This value is directly the value that we write in SW_PAD_CTL_PAD_SAI5_RXFS.

Best Regards!

Chavira