Linux/BEAGLEBK: Using IIO driver as a Loadable kernel module

Tool/software: Linux

I want use ti-ads8688 iio driver as a kernel module. I am using Beaglebone Black.

I wrote below Makefile for this work.

obj-m+=ti-ads8688.o
all:
    make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) modules
clean:
    make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) clean

ti-ads8688.ko file correctly generated and i load it with insmod command. But there is not module in iio devices, as you can see in below:

debian@beaglebone:~/work/phase1$ ls /sys/bus/iio/devices/iio\:device0
buffer           in_voltage1_raw  in_voltage4_raw  in_voltage7_raw  power          uevent
dev              in_voltage2_raw  in_voltage5_raw  name             scan_elements
in_voltage0_raw  in_voltage3_raw  in_voltage6_raw  of_node          subsystem

am i miss something? I also add in my devicetree below unit:

adc@0 {
    compatible = "ti,ads8688";
    reg = <0>;
    spi-cpha;
    spi-max-frequency = <100000>;
};