From 1cbd53c8cd85a63383a075347abee8f6e3f14fbe Mon Sep 17 00:00:00 2001 From: Richard Leitner Date: Tue, 20 Mar 2018 11:17:13 +0100 Subject: usb: core: introduce per-port over-current counters For some userspace applications information on the number of over-current conditions at specific USB hub ports is relevant. In our case we have a series of USB hardware (using the cp210x driver) which communicates using a proprietary protocol. These devices sometimes trigger an over-current situation on some hubs. In case of such an over-current situation the USB devices offer an interface for reducing the max used power. As these conditions are quite rare and imply performance reductions of the device we don't want to reduce the max power always. Therefore give user-space applications the possibility to react adequately by introducing an over_current_counter in the usb port struct which is exported via sysfs. Signed-off-by: Richard Leitner Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-bus-usb | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index 0bd731cbb50c..c702c78f24d8 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -189,6 +189,16 @@ Description: The file will read "hotplug", "wired" and "not used" if the information is available, and "unknown" otherwise. +What: /sys/bus/usb/devices/.../(hub interface)/portX/over_current_count +Date: February 2018 +Contact: Richard Leitner +Description: + Most hubs are able to detect over-current situations on their + ports and report them to the kernel. This attribute is to expose + the number of over-current situation occurred on a specific port + to user space. This file will contain an unsigned 32 bit value + which wraps to 0 after its maximum is reached. + What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit Date: November 2015 Contact: Lu Baolu -- cgit v1.2.3 From fde0aa6c175a4d8aa19e82b86ae0f9278bc8563b Mon Sep 17 00:00:00 2001 From: Heikki Krogerus Date: Tue, 20 Mar 2018 15:57:04 +0300 Subject: usb: common: Small class for USB role switches USB role switch is a device that can be used to choose the data role for USB connector. With dual-role capable USB controllers, the controller itself will be the switch, but on some platforms the USB host and device controllers are separate IPs and there is a mux between them and the connector. On those platforms the mux driver will need to register the switch. With USB Type-C connectors, the host-to-device relationship is negotiated over the Configuration Channel (CC). That means the USB Type-C drivers need to be in control of the role switch. The class provides a simple API for the USB Type-C drivers for the control. For other types of USB connectors (mainly microAB) the class provides user space control via sysfs attribute file that can be used to request role swapping from the switch. Reviewed-by: Hans de Goede Reviewed-by: Andy Shevchenko Signed-off-by: Heikki Krogerus Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-class-usb_role | 21 ++ drivers/usb/Kconfig | 3 + drivers/usb/common/Makefile | 1 + drivers/usb/common/roles.c | 305 +++++++++++++++++++++++++ include/linux/usb/role.h | 53 +++++ 5 files changed, 383 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-usb_role create mode 100644 drivers/usb/common/roles.c create mode 100644 include/linux/usb/role.h (limited to 'Documentation/ABI') 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 +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//role +Date: Jan 2018 +Contact: Heikki Krogerus +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 148f3ee70286..f278958e04ca 100644 --- a/drivers/usb/Kconfig +++ b/drivers/usb/Kconfig @@ -203,4 +203,7 @@ 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..15cc76e22123 --- /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 + * Hans de Goede + */ + +#include +#include +#include +#include +#include + +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 (IS_ERR_OR_NULL(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 device_connection *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_connection_find_match(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) + return ret; + + return size; +} +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 (!IS_ERR_OR_NULL(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 "); +MODULE_AUTHOR("Hans de Goede "); +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..edc51be4a77c --- /dev/null +++ b/include/linux/usb/role.h @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0 + +#ifndef __LINUX_USB_ROLE_H +#define __LINUX_USB_ROLE_H + +#include + +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 */ -- cgit v1.2.3