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| 2024/01/30 | DESK-MX9-L-5.0.0 release | ||
Contents
Peripheral USB1 OTGEdit
AURA SOM supports OTG/Host/Peripheral modes: on AURA Evaluation Kit the USB1 OTG port is configured as peripheral.
Device tree configurationEdit
Here below is an example of device tree configuration used on standard DAVE's kit for the AURA SOM:
From kernel device tree imx93-aura.dtsi:
...
&usbotg1 {
dr_mode = "peripheral";
hnp-disable;
srp-disable;
adp-disable;
disable-over-current;
samsung,picophy-pre-emp-curr-control = <3>;
samsung,picophy-dc-vol-level-adjust = <7>;
status = "disabled";
};
...
From kernel device tree imx93-aura-cb2001.dts:
/ {
...
&usbotg1 {
dr_mode = "peripheral";
status = "okay";
};
...
Accessing the peripheralEdit
Usage with mass-storageEdit
root@desk-mx93:~# dd if=/dev/zero of=mass_storage count=256 bs=1M 256+0 records in 256+0 records out 268435456 bytes (268 MB, 256 MiB) copied, 0.774426 s, 347 MB/s root@desk-mx93:~# mkfs.msdos mass_storage mkfs.fat 4.2 (2021-01-31) root@desk-mx93:~# mkdir loop root@desk-mx93:~# mount -o loop mass_storage loop [ 2309.051910] loop0: detected capacity change from 0 to 524288 root@desk-mx93:~# echo "Test USB OTG with mass storage device" > loop/usb.txt root@desk-mx93:~# umount loop root@desk-mx93:~#
then insert the g_mass_storage kernel module driver enabling an Windows PC to see it as a removable device
root@desk-mx93:~# modprobe g_mass_storage removable=y file=mass_storage [ 2366.224448] Mass Storage Function, version: 2009/09/11 [ 2366.229698] LUN: removable file: (no medium) [ 2366.234576] LUN: removable file: /home/root/mass_storage [ 2366.239928] Number of LUNs=1 [ 2366.242990] g_mass_storage gadget.0: Mass Storage Gadget, version: 2009/09/11 [ 2366.250151] g_mass_storage gadget.0: userspace failed to provide iSerialNumber [ 2366.257373] g_mass_storage gadget.0: g_mass_storage ready root@desk-mx93:~#
Once the USB cable is connected to the PC, the kernel prints the following messages:
[32262.935133] usb 1-1: new high-speed USB device number 2 using ehci-pci [32263.305571] usb 1-1: New USB device found, idVendor=0525, idProduct=a4a5, bcdDevice= 6.01 [32263.305574] usb 1-1: New USB device strings: Mfr=3, Product=4, SerialNumber=0 [32263.305575] usb 1-1: Product: Mass Storage Gadget [32263.305577] usb 1-1: Manufacturer: Linux 6.1.55-desk-mx9-l-5.0.0+g8942d3259e9b with 4c100000.usb [32263.337697] usb-storage 1-1:1.0: USB Mass Storage device detected [32263.337819] usb-storage 1-1:1.0: Quirks match for vid 0525 pid a4a5: 10000 [32263.337867] scsi host4: usb-storage 1-1:1.0 [32263.337968] usbcore: registered new interface driver usb-storage [32263.340492] usbcore: registered new interface driver uas [32264.367940] scsi 4:0:0:0: Direct-Access Linux File-Stor Gadget 0601 PQ: 0 ANSI: 2 [32264.368435] sd 4:0:0:0: Attached scsi generic sg2 type 0 [32264.385398] sd 4:0:0:0: Power-on or device reset occurred [32264.404893] sd 4:0:0:0: [sdb] 524288 512-byte logical blocks: (268 MB/256 MiB) [32264.519991] sd 4:0:0:0: [sdb] Write Protect is off [32264.519993] sd 4:0:0:0: [sdb] Mode Sense: 0f 00 00 00 [32264.637756] sd 4:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [32264.942269] sdb: [32265.225654] sd 4:0:0:0: [sdb] Attached SCSI removable disk