From: Peter Chen <peter.chen@nxp.com>
To: "Pali Rohár" <pali@kernel.org>
Cc: Mathias Nyman <mathias.nyman@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Gregory CLEMENT <gregory.clement@bootlin.com>,
Miquel Raynal <miquel.raynal@bootlin.com>,
Tomasz Maciej Nowak <tmn505@gmail.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] usb: host: xhci: mvebu: make USB 3.0 PHY optional for Armada 3720
Date: Fri, 25 Dec 2020 00:16:48 +0000 [thread overview]
Message-ID: <DBBPR04MB7979925F193F7D5AE4454C328BDC0@DBBPR04MB7979.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20201224132944.5odphwxtnzhvkeg7@pali>
> > >
> > > If not supported by ATF, then where to power on and off PHY since no other
> place calls PHY APIs? Is it always on?
> >
> > Yes, in this case (when -EOPNOTSUPP is returned) SMC API is not
> > supported by ATF, and PHY is always on.
>
> To make it clear, core/hcd.c function usb_add_hcd() when
> hcd->skip_phy_initialization is false is calling
> usb_phy_roothub_power_on() which calls phy_power_on(). If this call fails then
> error is propagated back to the usb_add_hcd() and this function fails too.
>
> But on boards with older ATF (which do not support PHY power on SMC API) is
> phy_power_on() returning error -EOPNOTSUPP and therefore whole USB
> 3.0 initialization fails.
>
> This patch is adding init hook to detect if ATF supports PHY power on/off
> functions and in case it does not support it, code sets XHCI_SKIP_PHY_INIT flag
> to instruct xhci-plat code to set
> hcd->skip_phy_initialization flag to instruct core/hcd.c to skip calling
> usb_phy_roothub_power_on() function as it is know that it would fail.
Thanks for clarity, clear now.
Peter
next prev parent reply other threads:[~2020-12-25 0:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-23 16:24 [PATCH] usb: host: xhci: mvebu: make USB 3.0 PHY optional for Armada 3720 Pali Rohár
2020-12-24 5:54 ` Peter Chen
2020-12-24 12:53 ` Pali Rohár
2020-12-24 13:15 ` Peter Chen
2020-12-24 13:24 ` Pali Rohár
2020-12-24 13:29 ` Pali Rohár
2020-12-25 0:16 ` Peter Chen [this message]
2020-12-28 12:11 ` Marek Behun
2020-12-28 13:22 ` Pali Rohár
2021-01-30 16:31 ` Tomasz Maciej Nowak
2021-01-30 16:35 ` Pali Rohár
2021-01-30 16:37 ` Tomasz Maciej Nowak
2021-02-01 15:08 ` [PATCH v2] " Pali Rohár
2021-02-02 1:53 ` Yoshihiro Shimoda
2021-02-02 18:41 ` Greg Kroah-Hartman
2021-02-03 9:46 ` Mathias Nyman
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