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From:   Igor Plyatov <plyatov@gmail.com>
Subject: Initialisation of SOC USB pads
To:     linux-usb@vger.kernel.org
Cc:     Alan Stern <stern@rowland.harvard.edu>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Message-ID: <607c6b4c-d53a-8115-aa60-2a8461607d40@gmail.com>
Date:   Mon, 13 May 2019 18:39:34 +0300
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Dear developers,

can you please explain who must configure AT91SAM9G20 SOC pads to 
operate as USB Host port? Is it AT91Bootstrap, U-Boot bootloader, Linux 
kernel or this is not required at all?

I ask, because during connection of USB disk, my board complains

usb 1-1: device descriptor read/64, error -62
usb 1-1: device descriptor read/64, error -62
usb 1-1: device descriptor read/64, error -62
usb 1-1: device descriptor read/64, error -62
usb 1-1: device not accepting address 4, error -62
usb 1-1: device not accepting address 5, error -62
usb usb1-port1: unable to enumerate USB device


Looks like there is no connectivity between USB Host module of SOC and 
USB device. Or am I wrong?


My setup is:


* AT91SAM9G20 based custom board;
* Linux kernel 4.9.36, from LINUX4SAM project.
* USB disk connected to USB Host port 0 (HDPA, HDMA pins of SOC). 39 Ohm 
series resistors and 15 Kohm pull-down resistors added at these lines. 
Connectivity between SOC and USB device confirmed by Ohmmeter.
* USB_VBUS voltage measured at USB connector = 4.96 VDC.

Best wishes
--
Igor Plyatov