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

Masahiro Yamada
2018-04-06T03:48:12Z

2018-04-06 5:04 GMT+09:00 Martin Blumenstingl
<martin.blumenstingl@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@socionext.com> wrote:
>> 2018-03-04 6:43 GMT+09:00 Martin Blumenstingl
>> <martin.blumenstingl@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@googlemail.com>
>>> Tested-by: Yixun Lan <yixun.lan@amlogic.com>
>>> Cc: Neil Armstrong <narmstrong@baylibre.com>
>>> Cc: Chunfeng Yun <chunfeng.yun@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@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?

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

--
Best Regards
Masahiro Yamada