IMX8M-EVK M.2 PCIE port does not detect USB

[rahmanuh]

Hello,

I have been trying to bringing up 88W8997-based wireless card with PCIE-USB interface. WLAN on PCIE, and BT on USB. The PCIe is detected by the board, i.e. lspci list the WiFi card. But when I do lsusb, the board does not detect the USB. I am sure the WiFi module is working perfectly on IMX6-EVK.

For a sanity check, I have tried to plug a USB stick onto USB port of the board, and it is detected. But why the USB-part of the WiFi module is not detected on its M.2 port.

Anyone have an idea? I wonder if i miss a device tree setup or kernel config.

My platform:

IMX8M-EVK, running Linux kernel 4.14.98-2.3.3

root@imx8mqevk:~# uname -r
4.14.98-2.3.3+gdc4ba17dfdb7
root@imx8mqevk:~# lspci
0000:00:00.0 PCI bridge: Synopsys, Inc. Device abcd (rev 01)
0000:01:00.0 Network controller: Broadcom Limited BCM4356 802.11ac Wireless Network Adapter (rev 02)
0001:00:00.0 PCI bridge: Synopsys, Inc. Device abcd (rev 01)
0001:01:00.0 Ethernet controller: Marvell Technology Group Ltd. Device 2b42 (rev 11)
root@imx8mqevk:~# lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Best regards,
Rahmanu

[weidong_sun]

Hello rahmanuh,

See the schematic of i.MX8M-EVK,please!

Resisters in RED circle are DNP status, DNP means Do Not Place.  So if you want to enable USB for WIFI card and SDIO card, you should populate/depopulate relevant resistors .

Try it, please!

Have a nice day!

B.R,

weidong

[rahmanuh]

Hi again Weidong,

I have just found R1417 and R1817. There are no resistors there, so I need to place 0 ohm resistors there, right?

But I have not found R926 and R927, could you give a hint of where are they?

Many thanks.

Best regards,
Rahmanu

[weidong_sun · Accepted solution]

See below, please!

these 2 resistors should be removed.  R1417 and R1817 should be placed with 0 OHM .

Have a nice day!

B.R,

weidong

[rahmanuh]

Thanks a lot for sharing this. 

Another question, if I want to use a PCIE-UART WiFi card over the M.2 PCIE port, it will work out of the box, right? It does need a modification like PCIE-USB.

Best regards,
Rahmanu

[rahmanuh]

Hello Weidong,

Thanks for your reply.

So in order to activate USB on M.2 port, I only need to remove both R1417 and R1418, right?

I do not need to remove R926 and R927, right?

Could you also share where is the location of the resistors on the board? I cannot open the .brd file.

Best regards,
Rahmanu