[RFCv2 usb-next 2/3] usb: host: add a generic platform USB roothub driver

[Chunfeng Yun]

On Thu, 2017-07-13 at 12:59 +0200, Martin Blumenstingl wrote:
> 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
> yet which were only introduced recently (documentation is available in
> devicetree/bindings/usb/usb-device.txt).
> With this new driver the usb2-phy and usb3-phy can be specified directly
> in the child-node of the corresponding port of the roothub via
> devicetree. This can be extended by not just parsing PHYs (some of the
> other drivers listed above are for example also parsing a list of clocks
> as well) when required.
> 
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl at googlemail.com>
> ---
>  drivers/usb/host/Kconfig            |   3 +
>  drivers/usb/host/Makefile           |   2 +
>  drivers/usb/host/platform-roothub.c | 146 ++++++++++++++++++++++++++++++++++++
>  drivers/usb/host/platform-roothub.h |  14 ++++
>  4 files changed, 165 insertions(+)
>  create mode 100644 drivers/usb/host/platform-roothub.c
>  create mode 100644 drivers/usb/host/platform-roothub.h
> 
> diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
> index fa5692dec832..b8b05c786b2a 100644
> --- a/drivers/usb/host/Kconfig
> +++ b/drivers/usb/host/Kconfig
> @@ -805,6 +805,9 @@ config USB_HCD_SSB
>  
>  	  If unsure, say N.
>  
> +config USB_PLATFORM_ROOTHUB
> +	bool
> +
>  config USB_HCD_TEST_MODE
>  	bool "HCD test mode support"
>  	---help---
> diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
> index cf2691fffcc0..dc817f82d632 100644
> --- a/drivers/usb/host/Makefile
> +++ b/drivers/usb/host/Makefile
> @@ -29,6 +29,8 @@ obj-$(CONFIG_USB_WHCI_HCD)	+= whci/
>  
>  obj-$(CONFIG_USB_PCI)	+= pci-quirks.o
>  
> +obj-$(CONFIG_USB_PLATFORM_ROOTHUB)	+= platform-roothub.o
> +
>  obj-$(CONFIG_USB_EHCI_HCD)	+= ehci-hcd.o
>  obj-$(CONFIG_USB_EHCI_PCI)	+= ehci-pci.o
>  obj-$(CONFIG_USB_EHCI_HCD_PLATFORM)	+= ehci-platform.o
> diff --git a/drivers/usb/host/platform-roothub.c b/drivers/usb/host/platform-roothub.c
> new file mode 100644
> index 000000000000..84837e42b006
> --- /dev/null
> +++ b/drivers/usb/host/platform-roothub.c
> @@ -0,0 +1,146 @@
> +/*
> + * platform roothub driver - a virtual PHY device which passes all phy_*
> + * function calls to multiple (actual) PHY devices. This is comes handy when
> + * initializing all PHYs on a root-hub (to keep them all in the same state).
> + *
> + * Copyright (C) 2017 Martin Blumenstingl <martin.blumenstingl at googlemail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/list.h>
> +#include <linux/phy/phy.h>
> +#include <linux/of.h>
> +#include <linux/usb/of.h>
> +
> +#include "platform-roothub.h"
> +
> +#define ROOTHUB_PORTNUM		0
> +
> +struct platform_roothub {
> +	struct phy		*phy;
> +	struct list_head	list;
> +};
> +
> +static struct platform_roothub *platform_roothub_alloc(struct device *dev)
> +{
> +	struct platform_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 platform_roothub_add_phy(struct device *dev,
> +				    struct device_node *port_np,
> +				    const char *con_id, struct list_head *list)
> +{
> +	struct platform_roothub *roothub_entry;
> +	struct phy *phy = devm_of_phy_get(dev, port_np, con_id);
> +
> +	if (IS_ERR_OR_NULL(phy)) {
> +		if (!phy || PTR_ERR(phy) == -ENODEV)
> +			return 0;
> +		else
> +			return PTR_ERR(phy);
> +	}
> +
> +	roothub_entry = platform_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 platform_roothub *platform_roothub_init(struct device *dev)
> +{
> +	struct device_node *roothub_np, *port_np;
> +	struct platform_roothub *plat_roothub;
> +	int err;
> +
> +	roothub_np = usb_of_get_child_node(dev->of_node, ROOTHUB_PORTNUM);
> +	if (!of_device_is_available(roothub_np))
> +		return NULL;
> +
> +	plat_roothub = platform_roothub_alloc(dev);
> +	if (IS_ERR(plat_roothub))
> +		return plat_roothub;
> +
> +	for_each_available_child_of_node(roothub_np, port_np) {
> +		err = platform_roothub_add_phy(dev, port_np, "usb2-phy",
> +					       &plat_roothub->list);
> +		if (err)
> +			return ERR_PTR(err);
> +
> +		err = platform_roothub_add_phy(dev, port_np, "usb3-phy",
> +					       &plat_roothub->list);
> +		if (err)
> +			return ERR_PTR(err);
> +	}
> +
> +	return plat_roothub;
> +}
> +EXPORT_SYMBOL_GPL(platform_roothub_init);
Can we process the case without phy-names property?
as following one, phy-names may be redundant, because the phy type is
informed in phys property.

port at 2 {
    reg = <2>;
    phys = <&u2port1 PHY_TYPE_USB2>, <&u3port1 PHY_TYPE_USB3>;
    phy-names = "usb2-phy", "usb3-phy";
};


> +
> +int platform_roothub_power_on(struct platform_roothub *plat_roothub)
> +{
> +	struct platform_roothub *roothub_entry;
> +	struct list_head *head;
> +	int err;
> +
> +	if (!plat_roothub)
> +		return 0;
> +
> +	head = &plat_roothub->list;
> +
> +	list_for_each_entry(roothub_entry, head, list) {
> +		err = phy_init(roothub_entry->phy);
> +		if (err)
> +			goto err_out;
> +
> +		err = phy_power_on(roothub_entry->phy);
> +		if (err) {
> +			phy_exit(roothub_entry->phy);
> +			goto err_out;
> +		}
> +	}
> +
> +	return 0;
> +
> +err_out:
> +	list_for_each_entry_continue_reverse(roothub_entry, head, list) {
> +		phy_power_off(roothub_entry->phy);
> +		phy_exit(roothub_entry->phy);
> +	}
> +
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(platform_roothub_power_on);
> +
> +void platform_roothub_power_off(struct platform_roothub *plat_roothub)
> +{
> +	struct platform_roothub *roothub_entry;
> +
> +	if (!plat_roothub)
> +		return;
> +
> +	list_for_each_entry_reverse(roothub_entry, &plat_roothub->list, list) {
> +		phy_power_off(roothub_entry->phy);
> +		phy_exit(roothub_entry->phy);
> +	}
> +}
> +EXPORT_SYMBOL_GPL(platform_roothub_power_off);
I test it, and works fine on mt8173.
It will be flexible enough if some more APIs are provided, such as
porwer_on/off all phys but not init/exit them.
e.g. 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.

> diff --git a/drivers/usb/host/platform-roothub.h b/drivers/usb/host/platform-roothub.h
> new file mode 100644
> index 000000000000..bde0bf299e3b
> --- /dev/null
> +++ b/drivers/usb/host/platform-roothub.h
> @@ -0,0 +1,14 @@
> +#ifndef USB_HOST_PLATFORM_ROOTHUB_H
> +#define USB_HOST_PLATFORM_ROOTHUB_H
> +
> +struct phy;
> +struct device_node;
These two declarations are not needed, when I remove them, and still
compile pass.

> +
> +struct platform_roothub;
> +
> +struct platform_roothub *platform_roothub_init(struct device *dev);
> +
> +int platform_roothub_power_on(struct platform_roothub *plat_roothub);
> +void platform_roothub_power_off(struct platform_roothub *plat_roothub);
> +
> +#endif /* USB_HOST_PLATFORM_ROOTHUB_H */