DEY 1.6 - GPIO assignement by kernel on imx28

Embedded Devices Linux
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1

I try to build an image in dey-1.6.5 for a custom board with the ccardimx28. I’ve already (un-)commented the used/unused features in the Platform Device Tree (arch/arm/boot/dts/imx28-ccardimx28js.dts)
I can build the images an the interfaces work like configured in the PDT. I can access the free GPIOs over sysfs but now I want an image where my GPIOs are configured at startup so I dont need to export and configure it first over sysfs.

I think this has also to be done over the dts files, but I’ve got no clue how to set it there for my needs.
For example i tried to set an output for a heartbeat-led and an input for a user button


led_pin_gpio0_19: led_gpio0_19@0 {
reg = <0>;
fsl,pinmux-ids = < 
0x0121 /* MX28_PAD_GPMI_CE2N__CAN1_TX */
>;
 fsl,drive-strength = <0>;
 fsl,voltage = <1>;
fsl,pull-up = <0>;
};
button_pin_gpio0_18: button_gpio0_18@0 {
reg = <0>;
fsl,pinmux-ids = < 
0x0131 /* MX28_PAD_GPMI_CE3N__CAN1_RX */
>;
 fsl,drive-strength = <0>;
 fsl,voltage = <1>;
fsl,pull-up = <0>;
};

But as I expected this isnt really working :slight_smile:

2

looks like you are in the right direction. Does this thread helps?

https://community.freescale.com/thread/314228

3

I found a helpful tutorial for the hole device tree thing. I’m now reading through it for better understanding of the FDT. Maybe this is is useful for someone other who want to dig in deeper in the FDT:
http://xillybus.com/tutorials/device-tree-zynq-1

Your link looks promising, I’ll give it a try the next days. thy