phy: bcm-ns-usb3: new driver for USB 3.0 PHY on Northstar

Northstar is a family of SoCs used in home routers. They have USB 2.0
and 3.0 controllers with PHYs that need to be properly initialized.
This driver provides PHY init support in a generic way and can be bound
with XHCI controller driver.

There aren't any public datasheets from Broadcom so we can't have nice
defines for all used bits. It means we just follow Broadcom's
initialization procedure using their magic values. We were quite lucky
actually that Broadcom put some comments in their SDK reference code
explaining what given writes are responsible for.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/phy/bcm-ns-usb3-phy.txt b/Documentation/devicetree/bindings/phy/bcm-ns-usb3-phy.txt
new file mode 100644
index 000000000000..09aeba94538d
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/bcm-ns-usb3-phy.txt
@@ -0,0 +1,23 @@
+Driver for Broadcom Northstar USB 3.0 PHY
+
+Required properties:
+
+- compatible: one of: "brcm,ns-ax-usb3-phy", "brcm,ns-bx-usb3-phy".
+- reg: register mappings for DMP (Device Management Plugin) and ChipCommon B
+       MMI.
+- reg-names: "dmp" and "ccb-mii"
+
+Initialization of USB 3.0 PHY depends on Northstar version. There are currently
+three known series: Ax, Bx and Cx.
+Known A0: BCM4707 rev 0
+Known B0: BCM4707 rev 4, BCM53573 rev 2
+Known B1: BCM4707 rev 6
+Known C0: BCM47094 rev 0
+
+Example:
+	usb3-phy {
+		compatible = "brcm,ns-ax-usb3-phy";
+		reg = <0x18105000 0x1000>, <0x18003000 0x1000>;
+		reg-names = "dmp", "ccb-mii";
+		#phy-cells = <0>;
+	};