UIO node not found in /dev

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UIO node not found in /dev

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bhupindersinghk
Contributor I

I am trying to handle GPIO interrupt in userspace on Linux with UIO

I am using imx6dl-sabresd development board with kernel version 4.1.15

I have added uio in imx6qdl-sabresd.dtsi as given below, and built imx6dl-sabresd.dtb

user_io@0 {
            compatible = "mydevice,generic-uio,ui_pdrv";
            status = "okay";
            interrupt-parent = <&gpio1>;
            interrupts = <4 IRQ_TYPE_EDGE_RISING>;
            pinctrl-names = "default";
            pinctrl-0 = <&pinctrl_user_io>;
        };

&iomuxc {

.

.

pinctrl_user_io: user_io-0 {
            fsl,pins = <
                
                MX6QDL_PAD_GPIO_4__KEY_COL7    0x1b0b1
            >;
        };

.

.

}

Then I built kernel with:

CONFIG_UIO=y
CONFIG_UIO_PDRV_GENIRQ=m

CONFIG_UIO_DMEM_GENIRQ is not set

(I also tried CONFIG_UIO=m,CONFIG_UIO_PDRV_GENIRQ=m

              and CONFIG_UIO=y, CONFIG_UIO_PDRV_GENIRQ=y)

After boot I tried to load generic IRQ with,

modprobe uio_pdrv_genirq uio_pdrv_genirq.of_id="mydevice,generic-uio,ui_pdrv"

Still I do not found /dev/uio0##

Thanks in advance!

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igorpadykov
NXP Employee
NXP Employee

Hi Bhupinder

one can check in menuconfig
* userspace io platform driver

may be useful some uio examples on

COM iMX6 Linux - Wiki-DB 

Solved: UIO: Device Tree confusion, no UIO created - Community Forums 

Best regards
igor
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bhupindersinghk
Contributor I

Hi Igor,

Thank you for your response.

I have tried making "userspace io platform driver" as built-in in menuconfig,

* userspace io platform driver

But it doesn't work.

I checked links given by you, there is reg field in which address is mentioned like,

reg = < 0x43C00000 0x1000 >;

Do I also need to do the same?

Is there any other dependency for UIO?

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