On Tue, Mar 15, 2016 at 12:54:13PM -0400, Jaret Cantu wrote: > The TX settings can be calibrated for particular hardware. The > phy is reset by Linux, so this cannot be handled by the bootloader. > > The TRM mentions that the maximum resistance should be used for the > DN/DP calibration in order to pass USB certification. > > The values for the TX registers are poorly described in the TRM. > The meanings of the register values were taken from another > Freescale-provided document: > https://community.freescale.com/message/566147#comment-566912 > > Signed-off-by: Jaret Cantu <jaret.cantu@xxxxxxxxxxx> > --- > v2. Copying devicetree list > Removed prettifying extra whitespace > Removed unnecessary register rewrite on resume > Use min and max constants for clarity > > .../devicetree/bindings/phy/mxs-usb-phy.txt | 10 ++++ > drivers/usb/phy/phy-mxs-usb.c | 58 ++++++++++++++++++++ > 2 files changed, 68 insertions(+) > > diff --git a/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt b/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt > index 379b84a..2f11e27 100644 > --- a/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt > +++ b/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt > @@ -12,6 +12,16 @@ Required properties: > - interrupts: Should contain phy interrupt > - fsl,anatop: phandle for anatop register, it is only for imx6 SoC series > > +Optional properties: > +- fsl,tx-cal-45-dn: Integer [30-55]. Resistance (in ohms) of switchable > + high-speed trimming resistor connected in parallel with the 45 ohm resistor > + that terminates the DN output signal. Default: 45 > +- fsl,tx-cal-45-dp: Integer [30-55]. Resistance (in ohms) of switchable > + high-speed trimming resistor connected in parallel with the 45 ohm resistor > + that terminates the DP output signal. Default: 45 Add unit suffix (-ohms) > +- fsl,tx-d-cal: Integer [79-119]. Current trimming value (as a percentage) of > + the 17.78mA TX reference current. Default: 100 > + > Example: > usbphy1: usbphy@020c9000 { > compatible = "fsl,imx6q-usbphy", "fsl,imx23-usbphy"; -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
