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From: "Shah, Nehal-bakulchandra" <nehal-bakulchandra.shah@amd.com>
To: Felipe Balbi <balbi@kernel.org>,
	linux-usb@vger.kernel.org,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>
Subject: Role Switch Driver on DWC3
Date: Wed, 8 Jul 2020 17:11:31 +0530	[thread overview]
Message-ID: <f3a4c488-a5bb-8698-dddb-7ab9cfc0f304@amd.com> (raw)

Hi,

As per my understanding, role switch interface for DWC3 controller will be called in dwc3_drd_init.

However, dwc3_drd_init is called only if mode is USB_DR_MODE_OTG. However for USB3 V3.3 and above the following code exists.

/*
         * DWC_usb31 and DWC_usb3 v3.30a and higher do not support OTG
         * mode. If the controller supports DRD but the dr_mode is not
         * specified or set to OTG, then set the mode to peripheral.
         */
        if (mode == USB_DR_MODE_OTG &&
            dwc->revision >= DWC3_REVISION_330A)
            mode = USB_DR_MODE_PERIPHERAL;
    }

Hence, in this case role switch interface will never will be called.


Please clear my understanding, and in such case how can i use the role switch driver?


Regards

Nehal Shah



             reply	other threads:[~2020-07-08 11:42 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-08 11:41 Shah, Nehal-bakulchandra [this message]
2020-07-08 12:44 ` Role Switch Driver on DWC3 Jun Li

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