DESK-MX6-L/Pheripherals/USB Host

History
ID#	Issue Date	Notes
14091	16/07/2021	First DESK release
17002	03/03/2022	DESK 3.0.0 release

Contents

Peripheral USB HostEdit

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

Device tree configurationEdit

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 peripheralEdit

Linux messages at boot timeEdit

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.)

[  293.085612] usb 1-1: new high-speed USB device number 2 using ci_hdrc
[  293.287458] usb 1-1: New USB device found, idVendor=0781, idProduct=5591, bcdDevice= 1.00
[  293.287490] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  293.287509] usb 1-1: Product:  SanDisk 3.2Gen1
[  293.287525] usb 1-1: Manufacturer:  USB
[  293.287541] usb 1-1: SerialNumber: 03017128082020175157
[  293.289195] usb-storage 1-1:1.0: USB Mass Storage device detected
[  293.302275] scsi host0: usb-storage 1-1:1.0
[  294.376862] scsi 0:0:0:0: Direct-Access      USB      SanDisk 3.2Gen1 1.00 PQ: 0 ANSI: 6
[  294.379701] sd 0:0:0:0: [sda] 30031872 512-byte logical blocks: (15.4 GB/14.3 GiB)
[  294.381105] sd 0:0:0:0: [sda] Write Protect is off
[  294.381122] sd 0:0:0:0: [sda] Mode Sense: 43 00 00 00
[  294.381838] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[  294.439432]  sda: sda1
[  294.446425] sd 0:0:0:0: [sda] Attached SCSI removable disk

Additional informationEdit

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
drwxr-xr-x 3 root root    4096 Feb 24 14:16 .
drwxr-xr-x 5 root root    4096 Feb 27 15:41 ..
drwx------ 2 root root   16384 Feb 24 14:16 lost+found
-rwxr-xr-x 1 root root 6881192 Feb 24 14:16 uImage

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