[usb-next PATCH v11 3/8] usb: core: add a wrapper for the USB PHYs on the HCD

[Martin Blumenstingl]

On Fri, Apr 6, 2018 at 5:48 AM, Masahiro Yamada
<yamada.masahiro at socionext.com> wrote:
> 2018-04-06 5:04 GMT+09:00 Martin Blumenstingl
> <martin.blumenstingl at googlemail.com>:
>> Hello,
>>
>> (great to hear that this might be useful on Socionext SoCs as well :))
>>
>> On Wed, Apr 4, 2018 at 2:10 PM, Masahiro Yamada
>> <yamada.masahiro at socionext.com> wrote:
>>> 2018-03-04 6:43 GMT+09:00 Martin Blumenstingl
>>> <martin.blumenstingl at googlemail.com>:
>>>> 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 <martin.blumenstingl at googlemail.com>
>>>> Tested-by: Yixun Lan <yixun.lan at amlogic.com>
>>>> Cc: Neil Armstrong <narmstrong at baylibre.com>
>>>> Cc: Chunfeng Yun <chunfeng.yun at mediatek.com>
>>>> ---
>>>>  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
>>>>
>>>> diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
>>>> index 92c9cefb4317..18e874b0441e 100644
>>>> --- a/drivers/usb/core/Makefile
>>>> +++ b/drivers/usb/core/Makefile
>>>> @@ -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
>>>> diff --git a/drivers/usb/core/phy.c b/drivers/usb/core/phy.c
>>>> new file mode 100644
>>>> index 000000000000..09b7c43c0ea4
>>>> --- /dev/null
>>>> +++ b/drivers/usb/core/phy.c
>>>> @@ -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 <martin.blumenstingl at googlemail.com>
>>>> + */
>>>> +
>>>> +#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);
>>>> +       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'.
>> 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?
this is already available in Linus' tree. the commit for this specific
patch (#3) is known as 07dbff0ddbd86c

> 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?


Regards
Martin