Re: [PATCHv6 01/19] usb: otg: Rename otg_transceiver to usb_phy

From: Felipe Balbi
Date: Wed Nov 09 2011 - 01:06:57 EST


On Wed, Nov 09, 2011 at 09:22:38AM +0800, Peter Chen wrote:
> On Tue, Nov 08, 2011 at 11:27:12AM +0530, ABRAHAM, KISHON VIJAY wrote:
> > Hi Heikki,
> >
> > On Fri, Oct 28, 2011 at 6:05 PM, Heikki Krogerus
> > <heikki.krogerus@xxxxxxxxxxxxxxx> wrote:
> > > This is the first step in separating USB transceivers from
> > > USB OTG utilities.
> > >
> > > 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.

--
balbi

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