initialize (multiple) PHYs for a HCD

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}

With this new wrapper the USB PHYs can be specified directly in the USB controller's devicetree node (just like on the drivers listed above). This allows SoCs like the Amlogic Meson GXL family to operate correctly once this is wired up correctly. These SoCs use a dwc3 controller and require all USB PHYs to be initialized (if one of the USB PHYs it not initialized then none of USB port works at all).

Signed-off-by Martin Blumenstingl <[email protected]>

Tested-by Yixun Lan <[email protected]>

Cc Neil Armstrong <[email protected]>

Cc Chunfeng Yun <[email protected]>

---
 drivers/usb/core/Makefile |   2 +-
 drivers/usb/core/phy.c    | 158 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/core/phy.h    |   7 ++
 3 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/core/phy.c
 create mode 100644 drivers/usb/core/phy.h

drivers/usb/core/Makefile +1 -1

index 92c9cefb4317..18e874b0441e 100644
@@ -6,7 +6,7 @@
 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

drivers/usb/core/phy.c new file +71 -0

new file mode 100644
index 000000000000..09b7c43c0ea4
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * A wrapper for multiple PHYs which passes all phy_* function calls to
+ * multiple (actual) PHY devices. This is comes handy when initializing
+ * all PHYs on a HCD and to keep them all in the same state.
+ *
+ * Copyright (C) 2018 Martin Blumenstingl <[email protected]>
+ */
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/phy/phy.h>
+#include <linux/of.h>
+
+#include "phy.h"
+
+struct usb_phy_roothub {
+       struct phy              *phy;
+       struct list_head        list;
+};
+
+static struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
+{
+       struct usb_phy_roothub *roothub_entry;
+
+       roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
+       if (!roothub_entry)
+               return ERR_PTR(-ENOMEM);
+
+       INIT_LIST_HEAD(&roothub_entry->list);
+
+       return roothub_entry;
+}
+
+static int usb_phy_roothub_add_phy(struct device *dev, int index,
+                                  struct list_head *list)
+{
+       struct usb_phy_roothub *roothub_entry;
+       struct phy *phy = devm_of_phy_get_by_index(dev, dev->of_node, index);
+
+       if (IS_ERR_OR_NULL(phy)) {
+               if (!phy || PTR_ERR(phy) == -ENODEV)
+                       return 0;
+               else
+                       return PTR_ERR(phy);
+       }
+
+       roothub_entry = usb_phy_roothub_alloc(dev);
+       if (IS_ERR(roothub_entry))
+               return PTR_ERR(roothub_entry);
+
+       roothub_entry->phy = phy;
+
+       list_add_tail(&roothub_entry->list, list);
+
+       return 0;
+}
+
+struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev)
+{
+       struct usb_phy_roothub *phy_roothub;
+       struct usb_phy_roothub *roothub_entry;
+       struct list_head *head;
+       int i, num_phys, err;
+
+       num_phys = of_count_phandle_with_args(dev->of_node, "phys",
+                                             "#phy-cells");
+       if (num_phys <= 0)
+               return NULL;
+
+       phy_roothub = usb_phy_roothub_alloc(dev);

2018-03-04 6:43 GMT+09:00 Martin Blumenstingl
<[email protected]>:

Quoted 121 lines

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}

With this new wrapper the USB PHYs can be specified directly in the USB controller's devicetree node (just like on the drivers listed above). This allows SoCs like the Amlogic Meson GXL family to operate correctly once this is wired up correctly. These SoCs use a dwc3 controller and require all USB PHYs to be initialized (if one of the USB PHYs it not initialized then none of USB port works at all).

Signed-off-by Martin Blumenstingl <[email protected]>

Tested-by Yixun Lan <[email protected]>

Cc Neil Armstrong <[email protected]>

Cc Chunfeng Yun <[email protected]>

---
 drivers/usb/core/Makefile |   2 +-
 drivers/usb/core/phy.c    | 158 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/core/phy.h    |   7 ++
 3 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/core/phy.c
 create mode 100644 drivers/usb/core/phy.h

drivers/usb/core/Makefile +1 -1

index 92c9cefb4317..18e874b0441e 100644
@@ -6,7 +6,7 @@
 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

drivers/usb/core/phy.c new file +71 -0

new file mode 100644
index 000000000000..09b7c43c0ea4
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * A wrapper for multiple PHYs which passes all phy_* function calls to
+ * multiple (actual) PHY devices. This is comes handy when initializing
+ * all PHYs on a HCD and to keep them all in the same state.
+ *
+ * Copyright (C) 2018 Martin Blumenstingl <[email protected]>
+ */
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/phy/phy.h>
+#include <linux/of.h>
+
+#include "phy.h"
+
+struct usb_phy_roothub {
+       struct phy              *phy;
+       struct list_head        list;
+};
+
+static struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
+{
+       struct usb_phy_roothub *roothub_entry;
+
+       roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
+       if (!roothub_entry)
+               return ERR_PTR(-ENOMEM);
+
+       INIT_LIST_HEAD(&roothub_entry->list);
+
+       return roothub_entry;
+}
+
+static int usb_phy_roothub_add_phy(struct device *dev, int index,
+                                  struct list_head *list)
+{
+       struct usb_phy_roothub *roothub_entry;
+       struct phy *phy = devm_of_phy_get_by_index(dev, dev->of_node, index);
+
+       if (IS_ERR_OR_NULL(phy)) {
+               if (!phy || PTR_ERR(phy) == -ENODEV)
+                       return 0;
+               else
+                       return PTR_ERR(phy);
+       }
+
+       roothub_entry = usb_phy_roothub_alloc(dev);
+       if (IS_ERR(roothub_entry))
+               return PTR_ERR(roothub_entry);
+
+       roothub_entry->phy = phy;
+
+       list_add_tail(&roothub_entry->list, list);
+
+       return 0;
+}
+
+struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev)
+{
+       struct usb_phy_roothub *phy_roothub;
+       struct usb_phy_roothub *roothub_entry;
+       struct list_head *head;
+       int i, num_phys, err;
+
+       num_phys = of_count_phandle_with_args(dev->of_node, "phys",
+                                             "#phy-cells");
+       if (num_phys <= 0)
+               return NULL;
+
+       phy_roothub = usb_phy_roothub_alloc(dev);

drivers/usb/core/phy.c line 81

Quoted 10 lines

drivers/usb/core/phy.c new file +10 -0

+       if (IS_ERR(phy_roothub))
+               return phy_roothub;
+
+       for (i = 0; i < num_phys; i++) {
+               err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
+               if (err)
+                       goto err_out;
+       }
+
+       head = &phy_roothub->list;

I think phy_roothub->phy is always empty,
and only phy_roothub->list is used.

I just wondered if we can directly put 'struct list_head' into 'struct usb_hcd'.

drivers/usb/core/phy.h line 1

Quoted 7 lines

drivers/usb/core/phy.h new file +1 -0

new file mode 100644
index 000000000000..6fde59bfbff8
@@ -0,0 +1,7 @@
+struct usb_phy_roothub;

struct device;

is also needed for usb_phy_roothub_init().

drivers/usb/core/phy.h line 7

Quoted 5 lines

drivers/usb/core/phy.h new file +5 -0

+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);

Better to add an include guard?
SPDX-License-Identifier for this header too?

Hello,

(great to hear that this might be useful on Socionext SoCs as well :))

Quoted 139 lines · Masahiro Yamada

2018-03-04 6:43 GMT+09:00 Martin Blumenstingl
<[email protected]>:

Quoted 121 lines

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}

With this new wrapper the USB PHYs can be specified directly in the USB controller's devicetree node (just like on the drivers listed above). This allows SoCs like the Amlogic Meson GXL family to operate correctly once this is wired up correctly. These SoCs use a dwc3 controller and require all USB PHYs to be initialized (if one of the USB PHYs it not initialized then none of USB port works at all).

Signed-off-by Martin Blumenstingl <[email protected]>

Tested-by Yixun Lan <[email protected]>

Cc Neil Armstrong <[email protected]>

Cc Chunfeng Yun <[email protected]>

---
 drivers/usb/core/Makefile |   2 +-
 drivers/usb/core/phy.c    | 158 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/core/phy.h    |   7 ++
 3 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/core/phy.c
 create mode 100644 drivers/usb/core/phy.h

drivers/usb/core/Makefile +1 -1

index 92c9cefb4317..18e874b0441e 100644
@@ -6,7 +6,7 @@
 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

drivers/usb/core/phy.c new file +71 -0

new file mode 100644
index 000000000000..09b7c43c0ea4
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * A wrapper for multiple PHYs which passes all phy_* function calls to
+ * multiple (actual) PHY devices. This is comes handy when initializing
+ * all PHYs on a HCD and to keep them all in the same state.
+ *
+ * Copyright (C) 2018 Martin Blumenstingl <[email protected]>
+ */
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/phy/phy.h>
+#include <linux/of.h>
+
+#include "phy.h"
+
+struct usb_phy_roothub {
+       struct phy              *phy;
+       struct list_head        list;
+};
+
+static struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
+{
+       struct usb_phy_roothub *roothub_entry;
+
+       roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
+       if (!roothub_entry)
+               return ERR_PTR(-ENOMEM);
+
+       INIT_LIST_HEAD(&roothub_entry->list);
+
+       return roothub_entry;
+}
+
+static int usb_phy_roothub_add_phy(struct device *dev, int index,
+                                  struct list_head *list)
+{
+       struct usb_phy_roothub *roothub_entry;
+       struct phy *phy = devm_of_phy_get_by_index(dev, dev->of_node, index);
+
+       if (IS_ERR_OR_NULL(phy)) {
+               if (!phy || PTR_ERR(phy) == -ENODEV)
+                       return 0;
+               else
+                       return PTR_ERR(phy);
+       }
+
+       roothub_entry = usb_phy_roothub_alloc(dev);
+       if (IS_ERR(roothub_entry))
+               return PTR_ERR(roothub_entry);
+
+       roothub_entry->phy = phy;
+
+       list_add_tail(&roothub_entry->list, list);
+
+       return 0;
+}
+
+struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev)
+{
+       struct usb_phy_roothub *phy_roothub;
+       struct usb_phy_roothub *roothub_entry;
+       struct list_head *head;
+       int i, num_phys, err;
+
+       num_phys = of_count_phandle_with_args(dev->of_node, "phys",
+                                             "#phy-cells");
+       if (num_phys <= 0)
+               return NULL;
+
+       phy_roothub = usb_phy_roothub_alloc(dev);

drivers/usb/core/phy.c line 81

Quoted 10 lines

drivers/usb/core/phy.c new file +10 -0

+       if (IS_ERR(phy_roothub))
+               return phy_roothub;
+
+       for (i = 0; i < num_phys; i++) {
+               err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
+               if (err)
+                       goto err_out;
+       }
+
+       head = &phy_roothub->list;

I think phy_roothub->phy is always empty,
and only phy_roothub->list is used.

Quoted 2 lines

I just wondered if we can directly put 'struct list_head' into 'struct usb_hcd'.

maybe you can try it and send a patch (note: please wait until v4.17-rc2-ish because there are some fixes that will be applied by Greg after v4.17-rc1 is out, as well as the issues you noted below)? I believe it's not critical so there's plenty of time to get it into v4.18

2018-04-06 5:04 GMT+09:00 Martin Blumenstingl
<[email protected]>:

Quoted 145 lines

Hello,

(great to hear that this might be useful on Socionext SoCs as well :))

Quoted 139 lines · Masahiro Yamada

2018-03-04 6:43 GMT+09:00 Martin Blumenstingl
<[email protected]>:

Quoted 121 lines

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}

With this new wrapper the USB PHYs can be specified directly in the USB controller's devicetree node (just like on the drivers listed above). This allows SoCs like the Amlogic Meson GXL family to operate correctly once this is wired up correctly. These SoCs use a dwc3 controller and require all USB PHYs to be initialized (if one of the USB PHYs it not initialized then none of USB port works at all).

Signed-off-by Martin Blumenstingl <[email protected]>

Tested-by Yixun Lan <[email protected]>

Cc Neil Armstrong <[email protected]>

Cc Chunfeng Yun <[email protected]>

---
 drivers/usb/core/Makefile |   2 +-
 drivers/usb/core/phy.c    | 158 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/core/phy.h    |   7 ++
 3 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/core/phy.c
 create mode 100644 drivers/usb/core/phy.h

drivers/usb/core/Makefile +1 -1

index 92c9cefb4317..18e874b0441e 100644
@@ -6,7 +6,7 @@
 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

drivers/usb/core/phy.c new file +71 -0

new file mode 100644
index 000000000000..09b7c43c0ea4
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * A wrapper for multiple PHYs which passes all phy_* function calls to
+ * multiple (actual) PHY devices. This is comes handy when initializing
+ * all PHYs on a HCD and to keep them all in the same state.
+ *
+ * Copyright (C) 2018 Martin Blumenstingl <[email protected]>
+ */
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/phy/phy.h>
+#include <linux/of.h>
+
+#include "phy.h"
+
+struct usb_phy_roothub {
+       struct phy              *phy;
+       struct list_head        list;
+};
+
+static struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
+{
+       struct usb_phy_roothub *roothub_entry;
+
+       roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
+       if (!roothub_entry)
+               return ERR_PTR(-ENOMEM);
+
+       INIT_LIST_HEAD(&roothub_entry->list);
+
+       return roothub_entry;
+}
+
+static int usb_phy_roothub_add_phy(struct device *dev, int index,
+                                  struct list_head *list)
+{
+       struct usb_phy_roothub *roothub_entry;
+       struct phy *phy = devm_of_phy_get_by_index(dev, dev->of_node, index);
+
+       if (IS_ERR_OR_NULL(phy)) {
+               if (!phy || PTR_ERR(phy) == -ENODEV)
+                       return 0;
+               else
+                       return PTR_ERR(phy);
+       }
+
+       roothub_entry = usb_phy_roothub_alloc(dev);
+       if (IS_ERR(roothub_entry))
+               return PTR_ERR(roothub_entry);
+
+       roothub_entry->phy = phy;
+
+       list_add_tail(&roothub_entry->list, list);
+
+       return 0;
+}
+
+struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev)
+{
+       struct usb_phy_roothub *phy_roothub;
+       struct usb_phy_roothub *roothub_entry;
+       struct list_head *head;
+       int i, num_phys, err;
+
+       num_phys = of_count_phandle_with_args(dev->of_node, "phys",
+                                             "#phy-cells");
+       if (num_phys <= 0)
+               return NULL;
+
+       phy_roothub = usb_phy_roothub_alloc(dev);

drivers/usb/core/phy.c line 81

Quoted 10 lines

drivers/usb/core/phy.c new file +10 -0

+       if (IS_ERR(phy_roothub))
+               return phy_roothub;
+
+       for (i = 0; i < num_phys; i++) {
+               err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
+               if (err)
+                       goto err_out;
+       }
+
+       head = &phy_roothub->list;

I think phy_roothub->phy is always empty,
and only phy_roothub->list is used.

Quoted 6 lines

Quoted 2 lines

I just wondered if we can directly put 'struct list_head' into 'struct usb_hcd'.

maybe you can try it and send a patch (note: please wait until v4.17-rc2-ish because there are some fixes that will be applied by Greg after v4.17-rc1 is out, as well as the issues you noted below)? I believe it's not critical so there's plenty of time to get it into v4.18

Oh, I was misunderstanding - I thought this patch series was under review. (Greg does not post patch-apply announce to ML.)

I see this in linux-next now.

When will this be available in Linus' tree? In the current MW?

Sure, I can send a patch after some flaws are ironed-out.

Quoted 2 lines

When will this be available in Linus' tree? In the current MW?

this is already available in Linus' tree. the commit for this specific patch (#3) is known as 07dbff0ddbd86c

Quoted 1 line

Sure, I can send a patch after some flaws are ironed-out.

great, thank you!
could you also let me know once you have tested this on one of your SoCs?

The new PHY wrapper is now wired up in the core HCD code. This means that PHYs are now controlled (initialized, enabled, disabled, exited) without requiring any host-driver specific code.
Remove the custom USB PHY handling from the xhci-mtk driver as the core HCD code now handles this.

Signed-off-by Martin Blumenstingl <[email protected]>

---
 drivers/usb/host/xhci-mtk.c | 98 +--------------------------------------------
 1 file changed, 2 insertions(+), 96 deletions(-)

drivers/usb/host/xhci-mtk.c +2 -96

index b0ab4d5e2751..7334da9e9779 100644
@@ -14,7 +14,6 @@
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
-#include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>

@@ -352,62 +351,6 @@ static const struct xhci_driver_overrides xhci_mtk_overrides __initconst = {
 
 static struct hc_driver __read_mostly xhci_mtk_hc_driver;
 
-static int xhci_mtk_phy_init(struct xhci_hcd_mtk *mtk)
-{
-	int i;
-	int ret;
-
-	for (i = 0; i < mtk->num_phys; i++) {
-		ret = phy_init(mtk->phys[i]);
-		if (ret)
-			goto exit_phy;
-	}
-	return 0;
-
-exit_phy:
-	for (; i > 0; i--)
-		phy_exit(mtk->phys[i - 1]);
-
-	return ret;
-}
-
-static int xhci_mtk_phy_exit(struct xhci_hcd_mtk *mtk)
-{
-	int i;
-
-	for (i = 0; i < mtk->num_phys; i++)
-		phy_exit(mtk->phys[i]);
-
-	return 0;
-}
-
-static int xhci_mtk_phy_power_on(struct xhci_hcd_mtk *mtk)
-{
-	int i;
-	int ret;
-
-	for (i = 0; i < mtk->num_phys; i++) {
-		ret = phy_power_on(mtk->phys[i]);
-		if (ret)
-			goto power_off_phy;
-	}
-	return 0;
-
-power_off_phy:
-	for (; i > 0; i--)
-		phy_power_off(mtk->phys[i - 1]);
-
-	return ret;
-}
-
-static void xhci_mtk_phy_power_off(struct xhci_hcd_mtk *mtk)
-{
-	unsigned int i;
-
-	for (i = 0; i < mtk->num_phys; i++)
-		phy_power_off(mtk->phys[i]);
-}
-
 static int xhci_mtk_ldos_enable(struct xhci_hcd_mtk *mtk)
 {
 	int ret;

@@ -488,8 +431,6 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 	struct xhci_hcd *xhci;
 	struct resource *res;
 	struct usb_hcd *hcd;
-	struct phy *phy;
-	int phy_num;
 	int ret = -ENODEV;
 	int irq;
 

@@ -529,16 +470,6 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	mtk->num_phys = of_count_phandle_with_args(node,
-			"phys", "#phy-cells");
-	if (mtk->num_phys > 0) {
-		mtk->phys = devm_kcalloc(dev, mtk->num_phys,
-					sizeof(*mtk->phys), GFP_KERNEL);
-		if (!mtk->phys)
-			return -ENOMEM;
-	} else {
-		mtk->num_phys = 0;
-	}
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
 	device_enable_async_suspend(dev);

@@ -596,23 +527,6 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 		mtk->has_ippc = false;
 	}
 
-	for (phy_num = 0; phy_num < mtk->num_phys; phy_num++) {
-		phy = devm_of_phy_get_by_index(dev, node, phy_num);
-		if (IS_ERR(phy)) {
-			ret = PTR_ERR(phy);
-			goto put_usb2_hcd;
-		}
-		mtk->phys[phy_num] = phy;
-	}
-
-	ret = xhci_mtk_phy_init(mtk);
-	if (ret)
-		goto put_usb2_hcd;
-
-	ret = xhci_mtk_phy_power_on(mtk);
-	if (ret)
-		goto exit_phys;
-
 	device_init_wakeup(dev, true);
 
 	xhci = hcd_to_xhci(hcd);

@@ -630,7 +544,7 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 			dev_name(dev), hcd);
 	if (!xhci->shared_hcd) {
 		ret = -ENOMEM;
-		goto power_off_phys;
+		goto disable_device_wakeup;
 	}
 
 	ret = usb_add_hcd(hcd, irq, IRQF_SHARED);

@@ -653,13 +567,9 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 	xhci_mtk_sch_exit(mtk);
 	usb_put_hcd(xhci->shared_hcd);
 
-power_off_phys:
-	xhci_mtk_phy_power_off(mtk);
+disable_device_wakeup:
 	device_init_wakeup(dev, false);
 
-exit_phys:
-	xhci_mtk_phy_exit(mtk);
-
 put_usb2_hcd:
 	usb_put_hcd(hcd);
 

@@ -682,8 +592,6 @@ static int xhci_mtk_remove(struct platform_device *dev)
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
 
 	usb_remove_hcd(xhci->shared_hcd);
-	xhci_mtk_phy_power_off(mtk);
-	xhci_mtk_phy_exit(mtk);
 	device_init_wakeup(&dev->dev, false);
 
 	usb_remove_hcd(hcd);

@@ -718,7 +626,6 @@ static int __maybe_unused xhci_mtk_suspend(struct device *dev)
 	del_timer_sync(&xhci->shared_hcd->rh_timer);
 
 	xhci_mtk_host_disable(mtk);
-	xhci_mtk_phy_power_off(mtk);
 	xhci_mtk_clks_disable(mtk);
 	usb_wakeup_set(mtk, true);
 	return 0;

@@ -732,7 +639,6 @@ static int __maybe_unused xhci_mtk_resume(struct device *dev)
 
 	usb_wakeup_set(mtk, false);
 	xhci_mtk_clks_enable(mtk);
-	xhci_mtk_phy_power_on(mtk);
 	xhci_mtk_host_enable(mtk);
 
 	xhci_dbg(xhci, "%s: restart port polling\n", __func__);

The goal of this series is to initialize multiple PHYs on a USB host controller, which is needed on Amlogic Meson GXL and GXM SoCs.
- Amlogic Meson GXL and GXM SoCs come with a dwc3 IP block which has two or three USB2 ports enabled on the internal root-hub. The SoCs also provide separate USB2 PHYs, one per port. All USB2 PHYs (which are internally "connected" to the dwc3 roothub) need to be powered on, otherwise USB devices cannot be enumerated (even if just one PHY is disabled and if the device is plugged into another, enabled port)
- dwc3 already takes one USB2 and one USB3 PHY and initializes these correctly
- some other HCI platform drivers (like ehci-platform.c, xhci-mtk.c and ohci-platform.c) do not have a limitation on the number of PHYs - they support any number of USB PHYs (typically one PHY per actual port)

This series adds a new "PHY wrapper". This can be configured through devicetree by passing a "phys" property (with any number of PHY handles) to the USB controller.
Additionally it this integrates this new PHY wrapper into hcd.c which automatically enables it for all USB controller drivers (tested on an Amlogic Meson GXL SoC which uses a dwc3 controller). Since this leaves some duplicate code (which now becomes obsolete!) in various drivers this is being cleaned up as well.

Changes since v10 at [13]:
- added Peter Chen's Acked-by to patch #2 (thank you!)
- rebased to usb-next (134d1fd44221614 "Merge 4.16-rc3 into usb-next")

Changes since v9 at [12]:
- changed "skip_phy_initialization" from PATCH #2 into a bitfield and moved it below the "remove_phy" bitfield as suggested by Alan Stern (thanks!)
- rebased against usb-next (which is currently identical to v4.16-rc1)

Changes since v8 at [10]:
- add new patch #2 which allows disabling "USB PHY management" in the USB HCD core driver. this also affects patch #4 which now checks the skip_phy_initialization flag before calling usb_phy_roothub_{init,power_on} (other functions don't need to be guarded since they are null-safe - see patch #3)
- integrated my other series 'remove driver-specific "multiple PHY" handling' from [11] into this one so the result of this "generic" code (= removing duplicate code in various drivers) can be seen directly. affects patches #5-8. (note: patch #1 "usb: mtu3: remove custom USB PHY handling" from that series was dropped, because it broke device mode support - Chunfeng Yun will come up with a separate patch later. patch #5 "usb: chipidea: do not set the "phy" field in struct usb_hcd" from that series was rewritten and is now integrated into the new patch #2 from this series)
- collected all {Reviewed,Tested,Acked}-by
- dropped RfC prefix since this v8 was out for review for two weeks and it only got Reviewed-by's and Tested-by's since then

Changes since v7 at [8]:
- updated the description in the cover-letter
- wrapped the only call usb_phy_roothub_power_{on,off} in hcd_bus_{resume,suspend} during system-suspend (excluding it from being called during runtime/auto suspend). this also fixes a problem on Meson GXL which does not detect that a new device has been connected if the PHYs are powered off. Thanks to Manu Gautam for suggesting this! (affects patch #3)
- after a discussion about the dt-bindings of this patch I went back to simply specifying a "phys" property (without a corresponding phy-names property) to pass all PHYs directly in the node of the USB controller. From my understanding the root hub node was "artificial" and we should describe it's properties as part of the controller, rather than introducing a sub-node. see also the discussion with Arnd in [9] (this affects patch #1 and #2)
- dropped patch #4 ("dt-bindings: usb: xhci: include the roothub and a device in the example") because we're back to just specifying a "phys" property directly within the controller.
NOTE: some HCI platform drivers are using the "phys" property as well. With this series phy_{init,power_on,power_off,exit} will be called twice for each PHY when using a ehci-platform.c or xhci-mtk.c USB controller (because the controller driver and our new, generic code now manage the PHYs). the PHY framework handles this gracefully (by ref-counting all operations). a follow-up series will be sent which removes the custom handling from the affected drivers (so only the new PHY wrapper will manage the PHYs state after that follow-up series).
- fixed an unnecessary whitespace change spotted by Alan Stern (thanks!) in patch #3
- removed all Tested-by's since we're changing code again

Changes since v6 at [6]:
- fixed unnecessary whitespace change (noticed by Alan Stern - thanks)
- added PATCH #4 to clarify (with an example) how I understood how Rob wanted the dt-binding to look like (see [0]). please wait for an ACK from Rob on this one to make sure that we're not introducing some broken binding (as discussed with Arnd: [7])
- added Alan Stern's ACK on PATCH #3
- added Neil's Tested-by on PATCH #2 and #3

Changes since RfC v5 at [5]:
- dropped RfC prefix
- removed noisy dev_err if no roothub node was found (spotted by Xiaolong Ye's kbuild test robot - thank you for that!)
- moved the call to usb_phy_roothub_power_off() within hcd_bus_suspend() to make sure that the PHYs are turned off if the "race with a root-hub wakeup event" condition is met (in this case the PHYs are turned on again, with the old code we did break the PHYs internal ref-counting because we never turned the PHYs off before turning them on again in case of that special "race with a root-hub wakeup event").
additionally we're not handling the status returned by usb_phy_roothub_power_off() anymore (the bus is already turned off and we tried to turn off all PHYs as well - only the PHYs which failed to power off will stay in the current state). thanks to Alan Stern for the suggestion
- removed return value from usb_phy_roothub_power_off() because none of my code uses it anymore. thanks to Alan Stern for the suggestion

Changes since v4 at [4]:
- renamed the subject of the cover-letter (old name was:
"initialize (multiple) PHYs in xhci-plat")
- back into RFC status (see below for the reasons)
- dropped Tested-by from Chunfeng Yun (same reasons as RFC status)
- reworded cover-letter and commit messages from "platform-roothub" to "roothub PHY wrapper"
- moved code from drivers/usb/host/platform-roothub.* to drivers/usb/core/phy.* and the changes to drivers/usb/host/xhci-plat.c to drivers/usb/core/hcd.c as suggested by Mathias Nyman (as a benefit this will enable the new logic for non-xHCI controllers as well - however this was not tested yet)
- rename the structs, function names, etc from platform_roothub_* to usb_phy_roothub*

Changes since RFCv3 at [3]:
- moved the DT binding change from patch #3 to patch #1 as suggested by Rob Herring (and slightly adjusted the commit message to account for that)
- added Tested-by from Chunfeng Yun (who confirmed that the whole concept and implementation works fine on Mediatek SoCs - many thanks again!) to patch #2
- added Rob Herring's ACK to patches 1 and 3
- dropped RFC status (RFCv3 -> PATCH v4)

Changes since RFCv2 at [2]:
- split phy_{init,exit} and phy_power_{on,off} handling. up until RFCv2 I called phy_init plus phy_power_on in platform_roothub_power_on and phy_power_off plus phy_exit in platform_roothub_power_off. However, Chunfeng Yun (a Mediatek SoC developer - many thanks for testing my series and providing great feedback) reported that only using phy_power_off (and omitting phy_exit) during system suspend fixes an issue where USB devices would be re-enumerated when resuming. His original problem description: "In order to keep link state on mt8173, we just power off all phys(not exit) when system enter suspend, then power on them again (needn't init, otherwise device will be disconnected) when system resume, this can avoid re-enumerating device.". This fix affects patch #2 and #3 as we now have platform_roothub_init (which calls phy_init internally), platform_roothub_power_on (which calls phy_power_on internally), platform_roothub_power_off (which calls phy_power_off internally) and platform_roothub_exit (which calls phy_exit internally). suspend and resume only call platform_roothub_power_{on,off} to prevent the issue described by Chunfeng Yun (unfortunately I cannot test this because the Amlogic platform currently does not support system suspend).
- dropped two struct forward declarations from platform-roothub.h which are not used in the header file (thanks to Chunfeng Yun for spotting this)

Changes since RFCv1 at [1]:
- split the usb-xhci dt-binding documentation into a separate patch
- fixed a typo ("usb-phy" -> "phys" in the dt-binding example)
- rebased to apply against latest usb-next

[0] http://lists.infradead.org/pipermail/linux-amlogic/2016-November/001818.html
[1] http://marc.info/?l=linux-usb&m=148414866303604&w=2
[2] https://www.spinics.net/lists/linux-usb/msg158967.html
[3] https://www.spinics.net/lists/devicetree/msg190426.html
[4] http://lists.infradead.org/pipermail/linux-amlogic/2017-September/004685.html
[5] http://lists.infradead.org/pipermail/linux-amlogic/2017-October/004924.html
[6] http://lists.infradead.org/pipermail/linux-amlogic/2017-October/005049.html
[7] http://lists.infradead.org/pipermail/linux-amlogic/2017-October/005121.html
[8] http://lists.infradead.org/pipermail/linux-amlogic/2017-October/005124.html
[9] http://lists.infradead.org/pipermail/linux-amlogic/2017-October/005192.html
[10] http://lists.infradead.org/pipermail/linux-amlogic/2018-January/006274.html
[11] https://marc.info/?l=linux-usb&m=151683941207898&w=2
[12] http://lists.infradead.org/pipermail/linux-amlogic/2018-February/006412.html
[13] http://lists.infradead.org/pipermail/linux-amlogic/2018-February/006478.html

Martin Blumenstingl (8):
dt-bindings: usb: add the documentation for USB HCDs
usb: add a flag to skip PHY initialization to struct usb_hcd
usb: core: add a wrapper for the USB PHYs on the HCD
usb: core: hcd: integrate the PHY wrapper into the HCD core
usb: host: xhci-mtk: remove custom USB PHY handling
usb: host: ehci-platform: remove custom USB PHY handling
usb: host: ohci-platform: remove custom USB PHY handling
usb: core: hcd: remove support for initializing a single PHY

 .../devicetree/bindings/usb/mediatek,mtk-xhci.txt  |   5 +-
 .../devicetree/bindings/usb/mediatek,mtu3.txt      |   5 +-
 Documentation/devicetree/bindings/usb/usb-ehci.txt |   6 +-
 Documentation/devicetree/bindings/usb/usb-hcd.txt  |   9 ++
 Documentation/devicetree/bindings/usb/usb-ohci.txt |   6 +-
 Documentation/devicetree/bindings/usb/usb-uhci.txt |   3 +
 Documentation/devicetree/bindings/usb/usb-xhci.txt |   5 +
 drivers/usb/chipidea/host.c                        |   6 +-
 drivers/usb/core/Makefile                          |   2 +-
 drivers/usb/core/hcd.c                             |  64 ++++-----
 drivers/usb/core/phy.c                             | 158 +++++++++++++++++++++
 drivers/usb/core/phy.h                             |   7 +
 drivers/usb/host/ehci-fsl.c                        |   2 +
 drivers/usb/host/ehci-platform.c                   |  55 +------
 drivers/usb/host/ehci-tegra.c                      |   1 +
 drivers/usb/host/ohci-omap.c                       |   1 +

 drivers/usb/host/ohci-platform.c                   |  56 +-------
 drivers/usb/host/xhci-mtk.c                        |  98 +------------
 drivers/usb/host/xhci-plat.c                       |   1 +
 include/linux/usb/hcd.h                            |   8 +-
 20 files changed, 253 insertions(+), 245 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/usb/usb-hcd.txt
 create mode 100644 drivers/usb/core/phy.c
 create mode 100644 drivers/usb/core/phy.h