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 <[email protected]>
> ---
> 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 [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
