Re: [PATCH v7 usb-next 2/4] usb: core: add a wrapper for the USB PHYs on the root-hub

Many SoC platforms have separate devices for the USB PHY which are
registered through the generic PHY framework. These PHYs have to be
enabled to make the USB controller actually work. They also have to be
disabled again on shutdown/suspend.

Currently (at least) the following HCI platform drivers are using custom
code to obtain all PHYs via devicetree for the roothub/controller and
disable/enable them when required:
- ehci-platform.c has ehci_platform_power_{on,off}
- xhci-mtk.c has xhci_mtk_phy_{init,exit,power_on,power_off}
- ohci-platform.c has ohci_platform_power_{on,off}

These drivers are not using the generic devicetree USB device bindings
(for the root-hub) yet which were only introduced recently (documentation
is available in devicetree/bindings/usb/usb-device.txt).

With this new wrapper the usb2-phy and usb3-phy can be specified directly
in the child-node of the corresponding port of the roothub via
devicetree.
This allows SoCs like the Amlogic Meson GXL family to operate correctly
because all USB PHYs are initialized (instead of the first USB PHY
only).

Signed-off-by: Martin Blumenstingl <martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
Tested-by: Neil Armstrong <narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
---
 drivers/usb/core/Makefile |   2 +-
 drivers/usb/core/phy.c    | 176 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/core/phy.h    |   7 ++
 3 files changed, 184 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/core/phy.c
 create mode 100644 drivers/usb/core/phy.h

diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
index 250ec1d662d9..b6e181d08bf6 100644
--- a/drivers/usb/core/Makefile
+++ b/drivers/usb/core/Makefile

@@ -5,7 +5,7 @@
 usbcore-y := usb.o hub.o hcd.o urb.o message.o driver.o
 usbcore-y += config.o file.o buffer.o sysfs.o endpoint.o
 usbcore-y += devio.o notify.o generic.o quirks.o devices.o
-usbcore-y += port.o
+usbcore-y += phy.o port.o
 
 usbcore-$(CONFIG_OF)		+= of.o
 usbcore-$(CONFIG_USB_PCI)		+= hcd-pci.o

diff --git a/drivers/usb/core/phy.c b/drivers/usb/core/phy.c
new file mode 100644
index 000000000000..31245b4abdbf
--- /dev/null
+++ b/drivers/usb/core/phy.c

diff --git a/drivers/usb/core/phy.h b/drivers/usb/core/phy.h
new file mode 100644
index 000000000000..6fde59bfbff8
--- /dev/null
+++ b/drivers/usb/core/phy.h

@@ -0,0 +1,7 @@
+struct usb_phy_roothub;
+
+struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev);
+int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub);
+
+int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub);
+void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub);