[04/12] usb: common: Small class for USB role switches

Message ID	20180216104751.8371-5-hdegoede@redhat.com (mailing list archive)
State	Changes Requested, archived
Delegated to:	Andy Shevchenko
Headers	show Return-Path: <platform-driver-x86-owner@kernel.org> From: Hans de Goede <hdegoede@redhat.com> To: Darren Hart <dvhart@infradead.org>, Andy Shevchenko <andy@infradead.org>, MyungJoo Ham <myungjoo.ham@samsung.com>, Chanwoo Choi <cw00.choi@samsung.com>, Mathias Nyman <mathias.nyman@intel.com>, Heikki Krogerus <heikki.krogerus@linux.intel.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hans de Goede <hdegoede@redhat.com>, platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Subject: [PATCH 04/12] usb: common: Small class for USB role switches Date: Fri, 16 Feb 2018 11:47:43 +0100 Message-Id: <20180216104751.8371-5-hdegoede@redhat.com> In-Reply-To: <20180216104751.8371-1-hdegoede@redhat.com> References: <20180216104751.8371-1-hdegoede@redhat.com> Sender: platform-driver-x86-owner@vger.kernel.org Precedence: bulk

diff --git a/Documentation/ABI/testing/sysfs-class-usb_role b/Documentation/ABI/testing/sysfs-class-usb_role new file mode 100644 index 000000000000..3b810a425a52 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-usb_role @@ -0,0 +1,21 @@ +What: /sys/class/usb_role/ +Date: Jan 2018 +Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> +Description: + Place in sysfs for USB Role Switches. USB Role Switch is a + device that can select the data role (host or device) for USB + port. + +What: /sys/class/usb_role/<switch>/role +Date: Jan 2018 +Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> +Description: + The current role of the switch. This attribute can be used for + requesting role swapping with non-USB Type-C ports. With USB + Type-C ports, the ABI defined for USB Type-C connector class + must be used. + + Valid values: + - none + - host + - device diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig index f699abab1787..a79198f5f1a6 100644 --- a/drivers/usb/Kconfig +++ b/drivers/usb/Kconfig @@ -197,4 +197,7 @@ config USB_ULPI_BUS To compile this driver as a module, choose M here: the module will be called ulpi. +config USB_ROLE_SWITCH + tristate + endif # USB_SUPPORT diff --git a/drivers/usb/common/Makefile b/drivers/usb/common/Makefile index 0a7c45e85481..fb4d5ef4165c 100644 --- a/drivers/usb/common/Makefile +++ b/drivers/usb/common/Makefile @@ -9,3 +9,4 @@ usb-common-$(CONFIG_USB_LED_TRIG) += led.o obj-$(CONFIG_USB_OTG_FSM) += usb-otg-fsm.o obj-$(CONFIG_USB_ULPI_BUS) += ulpi.o +obj-$(CONFIG_USB_ROLE_SWITCH) += roles.o diff --git a/drivers/usb/common/roles.c b/drivers/usb/common/roles.c new file mode 100644 index 000000000000..923e3721d183 --- /dev/null +++ b/drivers/usb/common/roles.c @@ -0,0 +1,305 @@ +// SPDX-License-Identifier: GPL-2.0 +/** + * USB Role Switch Support + * + * Copyright (C) 2018 Intel Corporation + * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com> + * Hans de Goede <hdegoede@redhat.com> + */ + +#include <linux/connection.h> +#include <linux/usb/role.h> +#include <linux/device.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> + +static struct class *role_class; + +struct usb_role_switch { + struct device dev; + struct mutex lock; /* device lock*/ + enum usb_role role; + + /* From descriptor */ + struct device *usb2_port; + struct device *usb3_port; + struct device *udc; + usb_role_switch_set_t set; + usb_role_switch_get_t get; + bool allow_userspace_control; +}; + +#define to_role_switch(d) container_of(d, struct usb_role_switch, dev) + +/** + * usb_role_switch_set_role - Set USB role for a switch + * @sw: USB role switch + * @role: USB role to be switched to + * + * Set USB role @role for @sw. + */ +int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role) +{ + int ret; + + if (!sw || IS_ERR(sw)) + return 0; + + mutex_lock(&sw->lock); + + ret = sw->set(sw->dev.parent, role); + if (!ret) + sw->role = role; + + mutex_unlock(&sw->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(usb_role_switch_set_role); + +/** + * usb_role_switch_get_role - Get the USB role for a switch + * @sw: USB role switch + * + * Depending on the role-switch-driver this function returns either a cached + * value of the last set role, or reads back the actual value from the hardware. + */ +enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw) +{ + enum usb_role role; + + if (IS_ERR_OR_NULL(sw)) + return USB_ROLE_NONE; + + mutex_lock(&sw->lock); + + if (sw->get) + role = sw->get(sw->dev.parent); + else + role = sw->role; + + mutex_unlock(&sw->lock); + + return role; +} +EXPORT_SYMBOL_GPL(usb_role_switch_get_role); + +static int __switch_match(struct device *dev, const void *name) +{ + return !strcmp((const char *)name, dev_name(dev)); +} + +static void *usb_role_switch_match(struct devcon *con, int ep, void *data) +{ + struct device *dev; + + dev = class_find_device(role_class, NULL, con->endpoint[ep], + __switch_match); + + return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER); +} + +/** + * usb_role_switch_get - Find USB role switch linked with the caller + * @dev: The caller device + * + * Finds and returns role switch linked with @dev. The reference count for the + * found switch is incremented. + */ +struct usb_role_switch *usb_role_switch_get(struct device *dev) +{ + return __device_find_connection(dev, "usb-role-switch", NULL, + usb_role_switch_match); +} +EXPORT_SYMBOL_GPL(usb_role_switch_get); + +/** + * usb_role_switch_put - Release handle to a switch + * @sw: USB Role Switch + * + * Decrement reference count for @sw. + */ +void usb_role_switch_put(struct usb_role_switch *sw) +{ + if (!IS_ERR_OR_NULL(sw)) + put_device(&sw->dev); +} +EXPORT_SYMBOL_GPL(usb_role_switch_put); + +static umode_t +usb_role_switch_is_visible(struct kobject *kobj, struct attribute *attr, int n) +{ + struct device *dev = container_of(kobj, typeof(*dev), kobj); + struct usb_role_switch *sw = to_role_switch(dev); + + if (sw->allow_userspace_control) + return attr->mode; + + return 0; +} + +static const char * const usb_roles[] = { + [USB_ROLE_NONE] = "none", + [USB_ROLE_HOST] = "host", + [USB_ROLE_DEVICE] = "device", +}; + +static ssize_t +role_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct usb_role_switch *sw = to_role_switch(dev); + enum usb_role role = usb_role_switch_get_role(sw); + + return sprintf(buf, "%s\n", usb_roles[role]); +} + +static ssize_t role_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t size) +{ + struct usb_role_switch *sw = to_role_switch(dev); + int ret; + + ret = sysfs_match_string(usb_roles, buf); + if (ret < 0) { + bool res; + + /* Extra check if the user wants to disable the switch */ + ret = kstrtobool(buf, &res); + if (ret || res) + return -EINVAL; + } + + ret = usb_role_switch_set_role(sw, ret); + if (!ret) + ret = size; + + return ret; +} +static DEVICE_ATTR_RW(role); + +static struct attribute *usb_role_switch_attrs[] = { + &dev_attr_role.attr, + NULL, +}; + +static const struct attribute_group usb_role_switch_group = { + .is_visible = usb_role_switch_is_visible, + .attrs = usb_role_switch_attrs, +}; + +static const struct attribute_group *usb_role_switch_groups[] = { + &usb_role_switch_group, + NULL, +}; + +static int +usb_role_switch_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + int ret; + + ret = add_uevent_var(env, "USB_ROLE_SWITCH=%s", dev_name(dev)); + if (ret) + dev_err(dev, "failed to add uevent USB_ROLE_SWITCH\n"); + + return ret; +} + +static void usb_role_switch_release(struct device *dev) +{ + struct usb_role_switch *sw = to_role_switch(dev); + + kfree(sw); +} + +static const struct device_type usb_role_dev_type = { + .name = "usb_role_switch", + .groups = usb_role_switch_groups, + .uevent = usb_role_switch_uevent, + .release = usb_role_switch_release, +}; + +/** + * usb_role_switch_register - Register USB Role Switch + * @parent: Parent device for the switch + * @desc: Description of the switch + * + * USB Role Switch is a device capable or choosing the role for USB connector. + * On platforms where the USB controller is dual-role capable, the controller + * driver will need to register the switch. On platforms where the USB host and + * USB device controllers behind the connector are separate, there will be a + * mux, and the driver for that mux will need to register the switch. + * + * Returns handle to a new role switch or ERR_PTR. The content of @desc is + * copied. + */ +struct usb_role_switch * +usb_role_switch_register(struct device *parent, + const struct usb_role_switch_desc *desc) +{ + struct usb_role_switch *sw; + int ret; + + if (!desc || !desc->set) + return ERR_PTR(-EINVAL); + + sw = kzalloc(sizeof(*sw), GFP_KERNEL); + if (!sw) + return ERR_PTR(-ENOMEM); + + mutex_init(&sw->lock); + + sw->allow_userspace_control = desc->allow_userspace_control; + sw->usb2_port = desc->usb2_port; + sw->usb3_port = desc->usb3_port; + sw->udc = desc->udc; + sw->set = desc->set; + sw->get = desc->get; + + sw->dev.parent = parent; + sw->dev.class = role_class; + sw->dev.type = &usb_role_dev_type; + dev_set_name(&sw->dev, "%s-role-switch", dev_name(parent)); + + ret = device_register(&sw->dev); + if (ret) { + put_device(&sw->dev); + return ERR_PTR(ret); + } + + /* TODO: Symlinks for the host port and the device controller. */ + + return sw; +} +EXPORT_SYMBOL_GPL(usb_role_switch_register); + +/** + * usb_role_switch_unregister - Unregsiter USB Role Switch + * @sw: USB Role Switch + * + * Unregister switch that was registered with usb_role_switch_register(). + */ +void usb_role_switch_unregister(struct usb_role_switch *sw) +{ + if (sw && !IS_ERR(sw)) + device_unregister(&sw->dev); +} +EXPORT_SYMBOL_GPL(usb_role_switch_unregister); + +static int __init usb_roles_init(void) +{ + role_class = class_create(THIS_MODULE, "usb_role"); + return PTR_ERR_OR_ZERO(role_class); +} +subsys_initcall(usb_roles_init); + +static void __exit usb_roles_exit(void) +{ + class_destroy(role_class); +} +module_exit(usb_roles_exit); + +MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>"); +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("USB Role Class"); diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h new file mode 100644 index 000000000000..2ef347bd1fdb --- /dev/null +++ b/include/linux/usb/role.h @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 + +#ifndef __LINUX_USB_ROLE_H +#define __LINUX_USB_ROLE_H + +struct usb_role_switch; + +enum usb_role { + USB_ROLE_NONE, + USB_ROLE_HOST, + USB_ROLE_DEVICE, +}; + +typedef int (*usb_role_switch_set_t)(struct device *dev, enum usb_role role); +typedef enum usb_role (*usb_role_switch_get_t)(struct device *dev); + +/** + * struct usb_role_switch_desc - USB Role Switch Descriptor + * @usb2_port: Optional reference to the host controller port device (USB2) + * @usb3_port: Optional reference to the host controller port device (USB3) + * @udc: Optional reference to the peripheral controller device + * @set: Callback for setting the role + * @get: Callback for getting the role (optional) + * @allow_userspace_control: If true userspace may change the role through sysfs + * + * @usb2_port and @usb3_port will point to the USB host port and @udc to the USB + * device controller behind the USB connector with the role switch. If + * @usb2_port, @usb3_port and @udc are included in the description, the + * reference count for them should be incremented by the caller of + * usb_role_switch_register() before registering the switch. + */ +struct usb_role_switch_desc { + struct device *usb2_port; + struct device *usb3_port; + struct device *udc; + usb_role_switch_set_t set; + usb_role_switch_get_t get; + bool allow_userspace_control; +}; + +int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role); +enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw); +struct usb_role_switch *usb_role_switch_get(struct device *dev); +void usb_role_switch_put(struct usb_role_switch *sw); + +struct usb_role_switch * +usb_role_switch_register(struct device *parent, + const struct usb_role_switch_desc *desc); +void usb_role_switch_unregister(struct usb_role_switch *sw); + +#endif /* __LINUX_USB_ROLE_H */

[04/12] usb: common: Small class for USB role switches

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