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

Masahiro Yamada
2018-04-04T12:10:28Z

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'.

> 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 device;

is also needed for usb_phy_roothub_init().

> +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?

--
Best Regards
Masahiro Yamada