On Mon, Mar 21, 2016 at 12:32:27PM -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> > --- > v3. Added unit suffix (-ohms) to tx-cal-45-d* > > 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..1d25b04 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 > > + > + if (!of_property_read_u32(np, "fsl,tx-d-cal", &val) && > + val >= MXS_PHY_TX_D_CAL_MIN && val <= MXS_PHY_TX_D_CAL_MAX) { > + /* scale to 4-bit value */ > + val = (MXS_PHY_TX_D_CAL_MAX - val) * 0xF > + / (MXS_PHY_TX_D_CAL_MAX - MXS_PHY_TX_D_CAL_MIN); > + mxs_phy->tx_reg_mask |= GM_USBPHY_TX_D_CAL(~0); > + mxs_phy->tx_reg_set |= GM_USBPHY_TX_D_CAL(val); > + } > + I have tested "tx-d-cal", but it seems incorrect according to the xls you have provided, would you please check it again or am I wrong? dts changes: +&usbphy1 { + fsl,tx-d-cal = <109>; +}; + +&usbphy2 { + fsl,tx-d-cal = <106>; +}; + The phy1's tx-d-cal is 0x3, and phy2's tx-d-cal is 0x4 after PHY initialization, but according to xls, it should be 0x4 and 0x5. -- Best Regards, Peter Chen -- 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
