PIPE4 spec defines an 18bit de-emphasis setting to be passed from
controller to the PHY.
TxDeemph[17:0] is split as [5:0] C-1, [11:6] C0, [17:12] C+1 for 3 tap
filter used for USB Gen2(10GT/s).

Signed-off-by: Joy Chakraborty <joychakr@google.com>
---
 Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
index 1cd0ca90127d..a1f1bbcf1467 100644
--- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
+++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
@@ -190,6 +190,18 @@ properties:
       - 1 # -3.5dB de-emphasis
       - 2 # No de-emphasis
 
+  snps,tx_gen2_de_emphasis_quirk:
+    description: When set core will set Tx de-emphasis for USB Gen2
+    type: boolean
+
+  snps,tx_gen2_de_emphasis:
+    description:
+      The 18bit value of Tx deemphasis defined in PIPE4 spec driven to PHY
+      for normal operation.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 0
+    maximum: 0x3ffff
+
   snps,dis_u3_susphy_quirk:
     description: When set core will disable USB3 suspend phy
     type: boolean
-- 
2.47.0.rc0.187.ge670bccf7e-goog