problem usb mass storage and custom kernel

Hy Everybody :)

For a Week, i try to configure my custom kernel, to allow the usb mass storage.

I am a newbie and i like to learn, looking for informations and by practicing.
but even if i have found some informations with my friend google :p, i don't manage to find where is my error.

Here a part of my dmesg, select the line with the word usb ou storage :

Code: dmesg | grep 'USB'
[ 4.262180] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 4.268827] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
# dmesg | grep 'usb'
[ 3.434106] usbcore: registered new interface driver usbfs
[ 3.439816] usbcore: registered new interface driver hub
[ 3.445303] usbcore: registered new device driver usb
[ 4.275393] usbcore: registered new interface driver usb-storage
# dmesg | grep 'controller''
> ^C
# dmesg | grep 'controller'
[ 5.733047] mmc0: SDHCI controller on d00d0000.sdhci [d00d0000.sdhci] using ADMA
[ 5.780795] mmc1: SDHCI controller on d00d8000.sdhci [d00d8000.sdhci] using ADMA
# dmesg | grep 'mass'
# dmesg | grep 'storage'
[ 4.275393] usbcore: registered new interface driver usb-storage
When i do the line command lsusb, nothing appears.
and no driver usb found in /lib/modules/5.9.0/kernel/drivers

More informations about my project :

My support is a Turris Mox.

I shape my kernel from the kernel net-next 5.9.

I use Buildroot to build a custom Linux,
and i have included exfat fuse and exfat-utils.

thank by advance :)