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Message-ID: <CAL411-qpW4dNUMTwh4gP_M+i_UOzc7q84gH+qJWeAYaSCgBCJg@mail.gmail.com>
Date: Wed, 9 Nov 2011 14:15:43 +0800
From: Peter Chen <hzpeterchen@...il.com>
To: balbi@...com
Cc: Peter Chen <peter.chen@...escale.com>,
"ABRAHAM, KISHON VIJAY" <kishon@...com>,
Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
Greg KH <gregkh@...e.de>, linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org, Sascha Hauer <s.hauer@...gutronix.de>
Subject: Re: [PATCHv6 01/19] usb: otg: Rename otg_transceiver to usb_phy
> > > > Includes fixes to IMX code from Sascha Hauer.
> > >
> > > I tend to defer with your opinion of renaming otg_transceiver to
> > > usb_phy. According to me otg_transceiver should program hardware
> > > mechanisms associated to VBUS, ID lines, etc.. and phy is responsible
> > > for transmitting data over differential data lines (with its own
> > > programming of phy_init, phy_shutdown, setting phy clocks etc..). So
> > > in my opinion otg_transceiver and usb_phy should be two different and
> > > separate entities.
> > >
> > I am a little puzzled, are there two separate analog usb parts at OMap
> > 's usb part? What the transceiver do? And what the phy do?
>
> Kinda... there's one which is mostly digital inside the SoC handling
> data lines and also comunicating VBUS/ID levels to the link but the
> actual VBUS/ID comparators are outside of the SoC, inside the PMIC.
>
> It's a bit of a pain, but I understand why they did it that way. It's
> mostly for power management, although the same is likely to be
> achievable by keeping everything in the PMIC.
>
So, in that way, the users must choose specific PMICs which have USB
interface if
they want to use OMAP
> --
> balbi
--
BR,
Peter Chen
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