summaryrefslogtreecommitdiff
path: root/Documentation
diff options
context:
space:
mode:
authorJaret Cantu <jaret.cantu@timesys.com>2016-08-17 01:31:48 +0300
committerFelipe Balbi <felipe.balbi@linux.intel.com>2016-08-25 12:13:18 +0300
commitda605f5f842163921f851e34402da6f5829a6328 (patch)
tree2e2f2eef3a4f339a96874547d53c01ed5a817956 /Documentation
parente51163690eaa6fd36abca2878bd6c53dcd423fd1 (diff)
downloadlinux-da605f5f842163921f851e34402da6f5829a6328.tar.xz
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/phy/mxs-usb-phy.txt10
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt b/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt
index 379b84a567cc..1d25b04cd05e 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-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";