usb: dwc3: make HIRD threshold configurable

HIRD threshold should be configurable by different platforms.

From DesignWare databook:
When HIRD_Threshold[4] is set to 1b1 and HIRD value is greater than or
equal to the value in HIRD_Threshold[3:0], dwc3 asserts output signals
utmi_l1_suspend_n to put PHY into Deep Low-Power mode in L1.

When HIRD_Threshold[4] is set to 1b0 or the HIRD value is less than
HIRD_Threshold[3:0], dwc3 asserts output signals utmi_sleep_n on L1.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
index f200ecc1f0dc..cd7f0454e13a 100644
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ b/Documentation/devicetree/bindings/usb/dwc3.txt
@@ -34,6 +34,9 @@ Optional properties:
                         LTSSM during USB3 Compliance mode.
  - snps,dis_u3_susphy_quirk: when set core will disable USB3 suspend phy.
  - snps,dis_u2_susphy_quirk: when set core will disable USB2 suspend phy.
+ - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal
+                        utmi_l1_suspend_n, false when asserts utmi_sleep_n
+ - snps,hird-threshold: HIRD threshold
 
 This is usually a subnode to DWC3 glue to which it is connected.