DESK-MX6-L/Peripherals/USB Host

History
Issue Date	Notes
2021/07/16	First DESK-MX6-L release
2022/03/03	DESK-MX6-L 3.0.0 release
2023/04/11	DESK-MX6-L 4.0.0 release

Peripheral USB Host

The USB Host port requires to configure the USB VBUS regulator and the gpio used for enabling the 5V USB power switch.

Device tree configuration

Here below an example of device tree configuration used on standard DAVE's kit for the AXEL Lite SOM:

From imx6qdl-axelcommon.dtsi:

    regulators {
        compatible = "simple-bus";
 
        reg_usb_h1_vbus: usb_h1_vbus {
            compatible = "regulator-fixed";
            regulator-name = "usb_h1_vbus";
            regulator-min-microvolt = <5000000>;
            regulator-max-microvolt = <5000000>;
            gpio = <&gpio2 11 0>;
            enable-active-high;
        };
    };
...
...
&usbh1 {
    vbus-supply = <&reg_usb_h1_vbus>;
    status = "okay";
};

Accessing the peripheral

Linux messages at boot time

When a USB peripheral is inserted, in the following example a memory mass storage device, the kernel recognizes the device (i.e. xlass, vendor id, product id, etc.)

[  949.174288] usb 1-1: New USB device found, idVendor=13fe, idProduct=6700, bcdDevice= 1.10
[  949.182598] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  949.192339] usb 1-1: Product: USB DISK 3.0
[  949.196474] usb 1-1: Manufacturer: Wilk
[  949.202608] usb 1-1: SerialNumber: 07012533C2BE5935
[  949.216478] usb-storage 1-1:1.0: USB Mass Storage device detected
[  949.234501] scsi host0: usb-storage 1-1:1.0
[  950.319317] scsi 0:0:0:0: Direct-Access     Wilk     USB DISK 3.0     PMAP PQ: 0 ANSI: 6
[  950.334575] sd 0:0:0:0: [sda] 60628992 512-byte logical blocks: (31.0 GB/28.9 GiB)
[  950.343311] sd 0:0:0:0: [sda] Write Protect is off
[  950.357023] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[  950.421972]  sda: sda1 sda2
[  950.433822] sd 0:0:0:0: [sda] Attached SCSI removable disk

Additional information

If the root file system configuration does not automatically mount the partition, it is possible to mount the device using the following command:

root@desk-mx6:~# mkdir -p /mnt/usb
root@desk-mx6:~# mount /dev/sda1 /mnt/usb/
root@desk-mx6:~# ls -la /mnt/usb/
total 24
drwxrwx--- 3 root disk    16384 Jan  1  1970 .
drwxr-xr-x 6 root root     4096 Apr  4 07:11 ..
drwxrwx--- 3 root disk     2048 Apr  5  2011 EFI
-rwxrwx--- 1 root disk 10193056 Apr  5  2011 uImage

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