Hi Roger, On Mon, Feb 11, 2013 at 03:14:26PM +0000, Roger Quadros wrote: > On 02/11/2013 01:40 PM, Mark Rutland wrote: > > Hello, > > > > On Thu, Feb 07, 2013 at 04:02:41PM +0000, Roger Quadros wrote: > >> The PHY clock, clock rate, VCC regulator and RESET regulator > >> can now be provided via device tree. > >> > >> Signed-off-by: Roger Quadros <[email protected]> > >> Acked-by: Felipe Balbi <[email protected]> > >> --- > >> .../devicetree/bindings/usb/usb-nop-xceiv.txt | 34 > >> ++++++++++++++++++ > >> drivers/usb/otg/nop-usb-xceiv.c | 36 > >> +++++++++++++++---- > >> 2 files changed, 62 insertions(+), 8 deletions(-) > >> create mode 100644 Documentation/devicetree/bindings/usb/usb-nop-xceiv.txt > >> > >> diff --git a/Documentation/devicetree/bindings/usb/usb-nop-xceiv.txt > >> b/Documentation/devicetree/bindings/usb/usb-nop-xceiv.txt > >> new file mode 100644 > >> index 0000000..d7e2726 > >> --- /dev/null > >> +++ b/Documentation/devicetree/bindings/usb/usb-nop-xceiv.txt > >> @@ -0,0 +1,34 @@ > >> +USB NOP PHY > >> + > >> +Required properties: > >> +- compatible: should be usb-nop-xceiv > > > > This might be better as "linux,usb-no-xceiv", given this is a Linux-specific > > 'device'. > > > > Saying that, I'm not sure I understand why this device needs to be > > instantiated > > from devicetree. As I understand it from looking at the driver, it's purely > > a > > Linux implementation detail used in the case of autonomous PHYs, and not an > > actual piece of hardware or firmware system. I must admit to being > > unfamiliar > > with this area of hardware, have I misunderstood somethign here? > > The PHY is a physical device and may need resources like power and clock to > be functional. > The only reason that driver is named NOP is that many USB controllers know > how to talk to > the standard PHYs and don't need any interface/management software.
Ok. That makes sense. Apologies for the noise. > > The PHY driver you are looking at most likely doesn't have the recent changes > I wrote to > manage the PHY clock/reset/power. i.e. patches 3, 4 and 5 in the series > https://lkml.org/lkml/2013/1/28/275 > > Before this, the ehci-omap driver was trying to manage the PHY power and > reset, which was > wrong. Yes. That makes a lot more sense now. Thanks for the info! Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
