linux/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt
Jaret Cantu da605f5f84 usb: phy: mxs: Add DT bindings to configure TX settings
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
NXP-provided document:
https://community.nxp.com/message/566147#comment-566912

Acked-by: Peter Chen <peter.chen@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jaret Cantu <jaret.cantu@timesys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
2016-08-25 12:13:18 +03:00

32 lines
1.2 KiB
Plaintext

* Freescale MXS USB Phy Device
Required properties:
- compatible: should contain:
* "fsl,imx23-usbphy" for imx23 and imx28
* "fsl,imx6q-usbphy" for imx6dq and imx6dl
* "fsl,imx6sl-usbphy" for imx6sl
* "fsl,vf610-usbphy" for Vybrid vf610
* "fsl,imx6sx-usbphy" for imx6sx
"fsl,imx23-usbphy" is still a fallback for other strings
- reg: Should contain registers location and length
- 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-ohms: 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-ohms: 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
- 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";
reg = <0x020c9000 0x1000>;
interrupts = <0 44 0x04>;
fsl,anatop = <&anatop>;
};