Bureaucrats, dave_user, Administrators
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→Accessing the peripheral
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==== Usage in Host mode ====
When a USB peripheral is inserted, in the following example a memory mass storage device, the kernel recognizes the device (i.e. class, vendor id, product id, etc.)
<pre class="workstation-terminal">
root@desk-mx6ul-axelulite:~# [ 431.623145] usb 1-1: new high-speed USB device number 2 using ci_hdrc
[ 431.865699] usb 1-1: New USB device found, idVendor=0951, idProduct=1665
[ 431.872537] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 431.883302] usb 1-1: Product: DataTraveler 2.0
[ 431.887825] usb 1-1: Manufacturer: Kingston
[ 431.892114] usb 1-1: SerialNumber: 50E549C202681071F97202CB
[ 431.910893] usb-storage 1-1:1.0: USB Mass Storage device detected
[ 431.928942] scsi host0: usb-storage 1-1:1.0
[ 432.966408] scsi 0:0:0:0: Direct-Access Kingston DataTraveler 2.0 0000 PQ: 0 ANSI: 4
[ 432.995263] sd 0:0:0:0: [sda] 15151168 512-byte logical blocks: (7.76 GB/7.22 GiB)
[ 433.015350] sd 0:0:0:0: [sda] Write Protect is off
[ 433.031915] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 433.067380] sda: sda1
[ 433.089246] sd 0:0:0:0: [sda] Attached SCSI removable disk
root@desk-mx6ul-axelulite:~#
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<pre class="workstation-terminal">
root@imx6qdlxelkdesk-mx6ul-axelulite:~# dd if=/dev/zero of=mass_storage count=256 32 bs=1M25632+0 records in25632+0 records out268435456 33554432 bytes (268 34 MB, 256 32 MiB) copied, 153.924 62181 s, 169.9 3 MB/sroot@imx6qdlxelkdesk-mx6ul-axelulite:~# mkfs.msdos mass_storage
mkfs.fat 4.1 (2017-01-24)
root@imx6qdlxelkdesk-mx6ul-axelulite:~# mkdir looproot@imx6qdlxelkdesk-mx6ul-axelulite:~# mount -o loop mass_storage looproot@imx6qdlxelkdesk-mx6ul-axelulite:~# echo "Test USB OTG with mass storage device" > loop/usb.txtroot@imx6qdlxelkdesk-mx6ul-axelulite:~# umount loop
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<pre class="workstation-terminal">
root@imx6qdlxelkdesk-mx6ul-axelulite:~# modprobe g_mass_storage removable=y file=mass_storage[ 891137.807023706620] Mass Storage Function, version: 2009/09/11[ 891137.813145711809] LUN: removable file: (no medium)[ 891137.818901731390] LUN: removable file: /home/root/mass_storage[ 891137.824754737101] Number of LUNs=1[ 891137.827901740256] g_mass_storage gadget: Mass Storage Gadget, version: 2009/09/11[ 891137.834955751272] g_mass_storage gadget: userspace failed to provide iSerialNumber[ 891137.842109760299] g_mass_storage gadget: g_mass_storage readyroot@imx6qdlxelkdesk-mx6ul-axelulite:~#
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<pre class="workstation-terminal">
root@imx6qdlxelkdesk-mx6ul-axelulite:~# [ 892214.036840837430] g_mass_storage gadget: high-speed config #1: Linux File-Backed Storage
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