Re: [PATCHv4 1/2] usb: USB Type-C connector class

[Guenter Roeck]

On Wed, Jun 29, 2016 at 04:38:37PM +0300, Heikki Krogerus wrote:
> The purpose of USB Type-C connector class is to provide
> unified interface for the user space to get the status and
> basic information about USB Type-C connectors on a system,
> control over data role swapping, and when the port supports
> USB Power Delivery, also control over power role swapping
> and Alternate Modes.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
>  Documentation/ABI/testing/sysfs-class-typec |  236 +++++
>  Documentation/usb/typec.txt                 |  103 +++
>  MAINTAINERS                                 |    9 +
>  drivers/usb/Kconfig                         |    2 +
>  drivers/usb/Makefile                        |    2 +
>  drivers/usb/typec/Kconfig                   |    7 +
>  drivers/usb/typec/Makefile                  |    1 +
>  drivers/usb/typec/typec.c                   | 1277 +++++++++++++++++++++++++++
>  include/linux/usb/typec.h                   |  260 ++++++
>  9 files changed, 1897 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-typec
>  create mode 100644 Documentation/usb/typec.txt
>  create mode 100644 drivers/usb/typec/Kconfig
>  create mode 100644 drivers/usb/typec/Makefile
>  create mode 100644 drivers/usb/typec/typec.c
>  create mode 100644 include/linux/usb/typec.h
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
> new file mode 100644
> index 0000000..7cd40e5
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-typec
> @@ -0,0 +1,236 @@
> +USB Type-C port devices (eg. /sys/class/typec/usbc0/)
> +
> +What:		/sys/class/typec/<port>/current_data_role
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		The current USB data role the port is operating in. This
> +		attribute can be used for requesting data role swapping on the
> +		port.
> +
> +		Valid values:
> +		- host
> +		- device
> +
> +What:		/sys/class/typec/<port>/current_power_role
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		The current power role of the port. This attribute can be used
> +		to request power role swap on the port when the port supports
> +		USB Power Delivery.
> +
> +		Valid values:
> +		- source
> +		- sink
> +
> +What:		/sys/class/typec/<port>/current_vconn_role
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows the current VCONN role of the port. This attribute can be
> +		used to request VCONN role swap on the port when the port
> +		supports USB Power Delivery.
> +
> +		Valid values are:
> +		- source
> +		- sink
> +
> +What:		/sys/class/typec/<port>/power_operation_mode
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows the current power operational mode the port is in.
> +
> +		Valid values:
> +		- USB - Normal power levels defined in USB specifications
> +		- BC1.2 - Power levels defined in Battery Charging Specification
> +			  v1.2
> +		- USB Type-C 1.5A - Higher 1.5A current defined in USB Type-C
> +				    specification.
> +		- USB Type-C 3.0A - Higher 3A current defined in USB Type-C
> +				    specification.
> +                - USB Power Delivery - The voltages and currents defined in USB
> +				       Power Delivery specification
> +
> +What:		/sys/class/typec/<port>/preferred_role
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		The user space can notify the driver about the preferred role.
> +		It should be handled as enabling of Try.SRC or Try.SNK, as
> +		defined in USB Type-C specification, in the port drivers. By
> +		default there is no preferred role.
> +
> +		Valid values:
> +		- host
> +		- device
> +		- For example "none" to remove preference (anything else except
> +		  "host" or "device")
> +
> +What:		/sys/class/typec/<port>/supported_accessory_modes
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Lists the Accessory Modes, defined in the USB Type-C
> +		specification, the port supports.
> +
> +What:		/sys/class/typec/<port>/supported_data_roles
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Lists the USB data roles the port is capable of supporting.
> +
> +		Valid values:
> +		- device
> +		- host
> +		- device, host (DRD as defined in USB Type-C specification v1.2)
> +
> +What:		/sys/class/typec/<port>/supported_power_roles
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Lists the power roles the port is capable of supporting.
> +
> +		Valid values:
> +		- source
> +		- sink
> +
> +What:		/sys/class/typec/<port>/supports_usb_power_delivery
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows if the port supports USB Power Delivery.
> +		- 1 if USB Power Delivery is supported
> +		- 0 when it's not
> +
> +
> +USB Type-C partner devices (eg. /sys/class/typec/usbc0-partner/)
> +
> +What:		/sys/class/typec/<port>-partner/accessory
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		The attribute is visible only when the partner's type is
> +		"Accessory". The type can be read from its own attribute.
> +
> +		Shows the name of the Accessory Mode. The Accessory Modes are
> +		defined in USB Type-C Specification.
> +
> +What:		/sys/class/typec/<port>-partner/type
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows the type of the partner. Can be one of the following:
> +		- USB - When the partner is normal USB host/peripheral.
> +		- Charger - When the partner has been identified as dedicated
> +			    charger.
> +		- Alternate Mode - When the partner supports Alternate Modes.
> +		- Accessory - When the partner is one of the accessories with
> +			      specific Accessory Mode defined in USB Type-C
> +			      specification.
> +
> +What:		/sys/class/typec/<port>-partner/supports_usb_power_delivery
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows if the partner supports USB Power Delivery.
> +		- 1 if USB Power Delivery is supported
> +		- 0 when it's not
> +
> +
> +What:		/sys/class/typec/<port>-partner/id_header_vdo
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		If the partner supports USB Power Deliver, shows the VDO
> +		returned from Discover Identity USB Power Delivery command.
> +
> +		If the partner does not support USB Power Delivery, the
> +		attribute is hidden.
> +
> +
> +USB Type-C cable devices (eg. /sys/class/typec/usbc0-cable/)
> +
> +Note: Electronically Marked Cables will have a device also for one cable plug
> +(eg. /sys/class/typec/usbc0-plug0). If the cable is active and has also SOP
> +Double Prime controller (USB Power Deliver specification ch. 2.4) it will have
> +second device also for the other plug. Both plugs may have their alternate modes
> +as described in USB Type-C and USB Power Delivery specifications.
> +
> +What:		/sys/class/typec/<port>-cable/active
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows if the cable is active or passive.
> +
> +		Valid values:
> +		- 0 when the cable is passive
> +		- 1 when the cable is active
> +
> +What:		/sys/class/typec/<port>-cable/plug_type
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows type of the plug on the cable:
> +		- Type-A - Standard A
> +		- Type-B - Standard B
> +		- Type-C - USB Type-C
> +		- Captive - Non-standard
> +
> +What:		/sys/class/typec/<port>-cable/supports_usb_power_delivery
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows if the cable supports USB Power Delivery communication.
> +		- 1 if USB Power Delivery is supported
> +		- 0 when it's not
> +
> +What:		/sys/class/typec/<port>-cable/id_header_vdo
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		If the cable supports USB Power Deliver, shows the VDO
> +		returned from Discover Identity USB Power Delivery command.
> +
> +		If the cable does not support USB Power Delivery, the
> +		attribute is hidden.
> +
> +
> +Alternate Mode devices (For example,
> +/sys/class/typec/usbc0-partner/usbc0-partner.svid:xxxx/). The ports, partners
> +and cable plugs can have alternate modes.
> +
> +What:		/sys/class/typec/<dev>/<dev>.svid:<svid>/<mode>/active
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows if the mode is active or not. The attribute can be used
> +		for entering/exiting the mode with partners and cable plugs, and
> +		with the port alternate modes it can be used for disabling
> +		support for specific alternate modes.
> +
> +What:		/sys/class/typec/<dev>/<dev>.svid:<svid>/<mode>/description
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows description of the mode. The description is optional for
> +		the drivers, just like with the Billboard Devices.
> +
> +What:		/sys/class/typec/<dev>/<dev>.svid:<svid>/<mode>/vdo
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows the VDO in hexadecimal returned from the Discover Modes
> +		command.
> +
> +What:		/sys/class/typec/<port>/<port>.svid:<svid>/<mode>/supported_roles
> +Date:		June 2016
> +Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description:
> +		Shows the roles, source or sink, the mode is supported with.
> +
> +		This attribute is available for the devices describing the
> +		alternate modes a port supports, and it will not be exposed with
> +		the devices presenting the alternate modes the partners or cable
> +		plugs support.
> diff --git a/Documentation/usb/typec.txt b/Documentation/usb/typec.txt
> new file mode 100644
> index 0000000..dce5f07
> --- /dev/null
> +++ b/Documentation/usb/typec.txt
> @@ -0,0 +1,103 @@
> +USB Type-C connector class
> +==========================
> +
> +Introduction
> +------------
> +The typec class is meant for describing the USB Type-C ports in a system to the
> +user space in unified fashion. The class is designed to provide nothing else
> +except the user space interface implementation in hope that it can be utilized
> +on as many platforms as possible.
> +
> +The platforms are expected to register every USB Type-C port they have with the
> +class. In a normal case the registration will be done by a USB Type-C or PD PHY
> +driver, but it may be a driver for firmware interface such as UCSI, driver for
> +USB PD controller or even driver for Thunderbolt3 controller. This document
> +considers the component registering the USB Type-C ports with the class as "port
> +driver".
> +
> +On top of showing the capabilities, the class also offer the user space control
> +over the roles and alternate modes they support when the port driver is capable
> +of supporting those features.
> +
> +The class provides an API for the port drivers described in this document. The
> +attributes are described in Documentation/ABI/testing/sysfs-class-typec.
> +
> +
> +Interface
> +---------
> +Every port will be presented as its own device under /sys/class/typec/. The
> +first port will be named "usbc0", the second "usbc1" and so on.
> +
> +When connected, the partner will be presented also as its own device under
> +/sys/class/typec/. The parent of the partner device will always be the port. The
> +partner attached to port "usbc0" will be named "usbc0-partner". Full patch to
> +the device would be /sys/class/typec/usb0/usb0-partner/.
> +
> +The cable and the two plugs on it may also be optionally presented as their own
> +devices under /sys/class/typec/. The cable attached to the port "usbc0" port
> +will be named usbc0-cable and the plug on the SOP Prime end (see USB Power
> +Delivery Specification ch. 2.4) will be named "usbc-plug0" and on the SOP Double
> +Prime end "usbc0-plug1". The parent of a cable will always be the port, and the
> +parent of the cable plugs will always be the cable.
> +
> +If the port, partner or cable plug support Alternate Modes, every Alternate Mode
> +SVID will have their own device describing them. The Alternate Modes will not be
> +attached to the typec class. For the port's "usbc0" partner, the Alternate Modes
> +would have devices presented under /sys/class/typec/usbc0-partner/. Every mode
> +that is supported will have its own group under the Alternate Mode device named
> +"mode<id>". For example /sys/class/typec/usbc0/usbc0.svid:xxxx/mode0/. The
> +requests for entering/exiting the modes happens with the "active" attribute in
> +that group.
> +
> +
> +API
> +---
> +
> +* Registering the ports
> +
> +The port drivers will describe every Type-C port they control with struct
> +typec_capability data structure, and register them with the following API:
> +
> +struct typec_port *typec_register_port(struct device *dev,
> +				       const struct typec_capability *cap);
> +
> +The class will provide handle to struct typec_port on success and ERR_PTR on
> +failure. The un-registration of the port happens with the following API:
> +
> +void typec_unregister_port(struct typec_port *port);
> +
> +
> +* Notifications
> +
> +When connection happens on a port, the port driver fills struct typec_connection
> +which is passed to the class. The class provides the following API for reporting
> +connection/disconnection:
> +
> +int typec_connect(struct typec_port *port, struct typec_connection *);
> +void typec_disconnect(struct typec_port *);
> +
> +When the partner end has executed a role change, the port driver uses the
> +following APIs to report it to the class:
> +
> +void typec_set_data_role(struct typec_port *, enum typec_data_role);
> +void typec_set_pwr_role(struct typec_port *, enum typec_role);
> +void typec_set_vconn_role(struct typec_port *, enum typec_role);
> +void typec_set_pwr_opmode(struct typec_port *, enum typec_pwr_opmode);
> +
> +
> +* Alternate Modes
> +
> +After connection, the port drivers register the alternate modes the partner
> +and/or cable plugs support. And before reporting disconnection, the port driver
> +_must_ unregister all the alternate modes registered for the partner and cable
> +plugs. The API takes the struct device of the partner or the cable plug as
> +parameter:
> +
> +int typec_register_altmodes(struct device *, struct typec_altmode *);
> +void typec_unregister_altmodes(struct device *);
> +
> +When the partner end enters or exits the modes, the port driver needs to notify
> +the class with the following API:
> +
> +void typec_altmode_update_active(struct typec_altmode *alt, int mode,
> +				 bool active);
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 952fd2a..8fe0977 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11983,6 +11983,15 @@ F:	drivers/usb/
>  F:	include/linux/usb.h
>  F:	include/linux/usb/
>  
> +USB TYPEC SUBSYSTEM
> +M:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +L:	linux-usb@xxxxxxxxxxxxxxx
> +S:	Maintained
> +F:	Documentation/ABI/testing/sysfs-class-typec
> +F:	Documentation/usb/typec.txt
> +F:	drivers/usb/typec/
> +F:	include/linux/usb/typec.h
> +
>  USB UHCI DRIVER
>  M:	Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
>  L:	linux-usb@xxxxxxxxxxxxxxx
> diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
> index 8689dcb..f42a3d3 100644
> --- a/drivers/usb/Kconfig
> +++ b/drivers/usb/Kconfig
> @@ -150,6 +150,8 @@ source "drivers/usb/phy/Kconfig"
>  
>  source "drivers/usb/gadget/Kconfig"
>  
> +source "drivers/usb/typec/Kconfig"
> +
>  config USB_LED_TRIG
>  	bool "USB LED Triggers"
>  	depends on LEDS_CLASS && USB_COMMON && LEDS_TRIGGERS
> diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
> index dca7856..51e381e 100644
> --- a/drivers/usb/Makefile
> +++ b/drivers/usb/Makefile
> @@ -61,3 +61,5 @@ obj-$(CONFIG_USB_GADGET)	+= gadget/
>  obj-$(CONFIG_USB_COMMON)	+= common/
>  
>  obj-$(CONFIG_USBIP_CORE)	+= usbip/
> +
> +obj-$(CONFIG_TYPEC)		+= typec/
> diff --git a/drivers/usb/typec/Kconfig b/drivers/usb/typec/Kconfig
> new file mode 100644
> index 0000000..b229fb9
> --- /dev/null
> +++ b/drivers/usb/typec/Kconfig
> @@ -0,0 +1,7 @@
> +
> +menu "USB PD and Type-C drivers"
> +
> +config TYPEC
> +	tristate
> +
> +endmenu
> diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
> new file mode 100644
> index 0000000..1012a8b
> --- /dev/null
> +++ b/drivers/usb/typec/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_TYPEC)		+= typec.o
> diff --git a/drivers/usb/typec/typec.c b/drivers/usb/typec/typec.c
> new file mode 100644
> index 0000000..bbfd6e5
> --- /dev/null
> +++ b/drivers/usb/typec/typec.c
> @@ -0,0 +1,1277 @@
> +/*
> + * USB Type-C Connector Class
> + *
> + * Copyright (C) 2016, Intel Corporation
> + * Author: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> + *
> + * 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.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/usb/typec.h>
> +
> +struct typec_port {
> +	unsigned int		id;
> +	struct device		dev;
> +	struct mutex		lock; /* device lock */
> +
> +	int			prefer_role;
> +
> +	enum typec_data_role	data_role;
> +	enum typec_role		pwr_role;
> +	enum typec_role		vconn_role;
> +	enum typec_pwr_opmode	pwr_opmode;
> +
> +	struct typec_partner	*partner;
> +	struct typec_cable	*cable;
> +
> +	unsigned int		connected:1;
> +
> +	const struct typec_capability *cap;
> +};
> +
> +#define to_typec_port(p) container_of(p, struct typec_port, dev)
> +
> +static DEFINE_IDA(typec_index_ida);
> +
> +static struct class typec_class = {
> +	.name = "typec",
> +};
> +
> +static const char * const typec_accessory_modes[] = {
> +	[TYPEC_ACCESSORY_NONE]		= "none",
> +	[TYPEC_ACCESSORY_AUDIO]		= "Audio",
> +	[TYPEC_ACCESSORY_DEBUG]		= "Debug",
> +	[TYPEC_ACCESSORY_DAUDIO]	= "Digital Audio",
> +};
> +
> +/* ------------------------------------------------------------------------- */
> +/* Type-C Partners */
> +
> +static void typec_dev_release(struct device *dev)
> +{
> +}
> +
> +static const char * const typec_partner_types[] = {
> +	[TYPEC_PARTNER_USB]		= "USB",
> +	[TYPEC_PARTNER_CHARGER]		= "Charger",
> +	[TYPEC_PARTNER_ALTMODE]		= "Alternate Mode",
> +	[TYPEC_PARTNER_ACCESSORY]	= "Accessory",
> +};
> +
> +static ssize_t partner_type_show(struct device *dev,
> +				 struct device_attribute *attr, char *buf)
> +{
> +	struct typec_partner *partner = container_of(dev, struct typec_partner,
> +						     dev);
> +
> +	return sprintf(buf, "%s\n", typec_partner_types[partner->type]);
> +}
> +
> +static struct device_attribute dev_attr_partner_type = {
> +	.attr = {
> +		.name = "type",
> +		.mode = S_IRUGO,
> +	},
> +	.show = partner_type_show,
> +};
> +
> +static ssize_t
> +partner_accessory_mode_show(struct device *dev, struct device_attribute *attr,
> +			    char *buf)
> +{
> +	struct typec_partner *partner = container_of(dev, struct typec_partner,
> +						     dev);
> +
> +	return sprintf(buf, "%s\n", typec_accessory_modes[partner->accessory]);
> +}
> +
> +static struct device_attribute dev_attr_partner_accessory = {
> +	.attr = {
> +		.name = "accessory",
> +		.mode = S_IRUGO,
> +	},
> +	.show = partner_accessory_mode_show,
> +};
> +
> +static ssize_t partner_usb_pd_show(struct device *dev,
> +				   struct device_attribute *attr, char *buf)
> +{
> +	struct typec_partner *partner = container_of(dev, struct typec_partner,
> +						     dev);
> +
> +	return sprintf(buf, "%d\n", partner->usb_pd);
> +}
> +
> +static struct device_attribute dev_attr_partner_usb_pd = {
> +	.attr = {
> +		.name = "supports_usb_power_delivery",
> +		.mode = S_IRUGO,
> +	},
> +	.show = partner_usb_pd_show,
> +};
> +
> +static ssize_t partner_vdo_show(struct device *dev,
> +				struct device_attribute *attr, char *buf)
> +{
> +	struct typec_partner *partner = container_of(dev, struct typec_partner,
> +						     dev);
> +
> +	return sprintf(buf, "0x%08x\n", partner->vdo);
> +}
> +
> +static struct device_attribute dev_attr_partner_vdo = {
> +	.attr = {
> +		.name = "id_header_vdo",
> +		.mode = S_IRUGO,
> +	},
> +	.show = partner_vdo_show,
> +};
> +
> +static struct attribute *typec_partner_attrs[] = {
> +	&dev_attr_partner_accessory.attr,
> +	&dev_attr_partner_type.attr,
> +	&dev_attr_partner_usb_pd.attr,
> +	&dev_attr_partner_vdo.attr,
> +	NULL
> +};
> +
> +static umode_t partner_is_visible(struct kobject *kobj, struct attribute *attr,
> +				  int n)
> +{
> +	struct device *dev = container_of(kobj, struct device, kobj);
> +	struct typec_partner *partner = container_of(dev, struct typec_partner,
> +						     dev);
> +
> +	if (attr == &dev_attr_partner_accessory.attr &&
> +	    partner->type != TYPEC_PARTNER_ACCESSORY)
> +		return 0;
> +
> +	if (attr == &dev_attr_partner_vdo.attr && !partner->usb_pd)
> +		return 0;
> +
> +	return attr->mode;
> +}
> +
> +static struct attribute_group typec_partner_group = {
> +	.attrs = typec_partner_attrs,
> +	.is_visible = partner_is_visible,
> +};
> +
> +static const struct attribute_group *typec_partner_groups[] = {
> +	&typec_partner_group,
> +	NULL
> +};
> +
> +static struct device_type typec_partner_dev_type = {
> +	.name = "typec_partner_device",
> +	.groups = typec_partner_groups,
> +	.release = typec_dev_release,
> +};
> +
> +static int
> +typec_add_partner(struct typec_port *port, struct typec_partner *partner)
> +{
> +	struct device *dev = &partner->dev;
> +	int ret;
> +
> +	dev->class = &typec_class;
> +	dev->parent = &port->dev;
> +	dev->type = &typec_partner_dev_type;
> +	dev_set_name(dev, "%s-partner", dev_name(&port->dev));
> +
> +	ret = device_register(dev);
> +	if (ret) {
> +		put_device(dev);
> +		return ret;
> +	}
> +
> +	port->partner = partner;
> +	return 0;
> +}
> +
> +static void typec_remove_partner(struct typec_port *port)
> +{
> +	WARN_ON(port->partner->alt_modes);
> +	device_unregister(&port->partner->dev);
> +}
> +
> +/* ------------------------------------------------------------------------- */
> +/* Type-C Cable Plugs */
> +
> +static struct device_type typec_plug_dev_type = {
> +	.name = "type_plug_device",
> +	.release = typec_dev_release,
> +};
> +
> +static int
> +typec_add_plug(struct typec_port *port, struct typec_plug *plug)
> +{
> +	struct device *dev = &plug->dev;
> +	char name[8];
> +	int ret;
> +
> +	sprintf(name, "plug%d", plug->index);
> +
> +	dev->class = &typec_class;
> +	dev->parent = &port->cable->dev;
> +	dev->type = &typec_plug_dev_type;
> +	dev_set_name(dev, "%s-%s", dev_name(&port->dev), name);
> +
> +	ret = device_register(dev);
> +	if (ret) {
> +		put_device(dev);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void typec_remove_plug(struct typec_plug *plug)
> +{
> +	WARN_ON(plug->alt_modes);
> +	device_unregister(&plug->dev);
> +}
> +
> +/* Type-C Cables */
> +
> +static ssize_t
> +cable_active_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct typec_cable *cable = container_of(dev, struct typec_cable, dev);
> +
> +	return sprintf(buf, "%d\n", cable->active);
> +}
> +
> +static struct device_attribute dev_attr_cable_active = {
> +	.attr = {
> +		.name = "active",
> +		.mode = S_IRUGO,
> +	},
> +	.show = cable_active_show,
> +};
> +
> +static ssize_t cable_usb_pd_show(struct device *dev,
> +				 struct device_attribute *attr, char *buf)
> +{
> +	struct typec_cable *cable = container_of(dev, struct typec_cable, dev);
> +
> +	return sprintf(buf, "%d\n", cable->usb_pd);
> +}
> +
> +static struct device_attribute dev_attr_cable_usb_pd = {
> +	.attr = {
> +		.name = "supports_usb_power_delivery",
> +		.mode = S_IRUGO,
> +	},
> +	.show = cable_usb_pd_show,
> +};
> +
> +static ssize_t cable_vdo_show(struct device *dev, struct device_attribute *attr,
> +			      char *buf)
> +{
> +	struct typec_cable *cable = container_of(dev, struct typec_cable, dev);
> +
> +	return sprintf(buf, "0x%08x\n", cable->vdo);
> +}
> +
> +static struct device_attribute dev_attr_cable_vdo = {
> +	.attr = {
> +		.name = "id_header_vdo",
> +		.mode = S_IRUGO,
> +	},
> +	.show = cable_vdo_show,
> +};
> +
> +static const char * const typec_plug_types[] = {
> +	[USB_PLUG_NONE]		= "unknown",
> +	[USB_PLUG_TYPE_A]	= "Type-A",
> +	[USB_PLUG_TYPE_B]	= "Type-B",
> +	[USB_PLUG_TYPE_C]	= "Type-C",
> +	[USB_PLUG_CAPTIVE]	= "Captive",
> +};
> +
> +static ssize_t
> +cable_plug_type_show(struct device *dev, struct device_attribute *attr,
> +		     char *buf)
> +{
> +	struct typec_cable *cable = container_of(dev, struct typec_cable, dev);
> +
> +	return sprintf(buf, "%s\n", typec_plug_types[cable->type]);
> +}
> +
> +static struct device_attribute dev_attr_plug_type = {
> +	.attr = {
> +		.name = "plug_type",
> +		.mode = S_IRUGO,
> +	},
> +	.show = cable_plug_type_show,
> +};
> +
> +static struct attribute *typec_cable_attrs[] = {
> +	&dev_attr_cable_active.attr,
> +	&dev_attr_cable_usb_pd.attr,
> +	&dev_attr_cable_vdo.attr,
> +	&dev_attr_plug_type.attr,
> +	NULL
> +};
> +
> +static umode_t cable_is_visible(struct kobject *kobj, struct attribute *attr,
> +				int n)
> +{
> +	struct device *dev = container_of(kobj, struct device, kobj);
> +	struct typec_cable *cable = container_of(dev, struct typec_cable, dev);
> +
> +	if (attr == &dev_attr_cable_vdo.attr && !cable->usb_pd)
> +		return 0;
> +
> +	return attr->mode;
> +}
> +
> +static struct attribute_group typec_cable_group = {
> +	.attrs = typec_cable_attrs,
> +	.is_visible = cable_is_visible,
> +};
> +
> +static const struct attribute_group *typec_cable_groups[] = {
> +	&typec_cable_group,
> +	NULL
> +};
> +
> +static struct device_type typec_cable_dev_type = {
> +	.name = "typec_cable_device",
> +	.groups = typec_cable_groups,
> +	.release = typec_dev_release,
> +};
> +
> +static int typec_add_cable(struct typec_port *port, struct typec_cable *cable)
> +{
> +	struct device *dev = &cable->dev;
> +	int ret;
> +
> +	dev->class = &typec_class;
> +	dev->parent = &port->dev;
> +	dev->type = &typec_cable_dev_type;
> +	dev_set_name(dev, "%s-cable", dev_name(&port->dev));
> +
> +	ret = device_register(dev);
> +	if (ret) {
> +		put_device(dev);
> +		return ret;
> +	}
> +
> +	/* Plug1 */
> +	if (!cable->usb_pd)
> +		return 0;
> +
> +	cable->plug[0].index = 1;
> +	ret = typec_add_plug(port, &cable->plug[0]);
> +	if (ret) {
> +		device_unregister(dev);
> +		return ret;
> +	}
> +
> +	/* Plug2 */
> +	if (!cable->active || !cable->sop_pp_controller)
> +		return 0;
> +
> +	cable->plug[1].index = 2;
> +	ret = typec_add_plug(port, &cable->plug[1]);
> +	if (ret) {
> +		typec_remove_plug(&cable->plug[0]);
> +		device_unregister(dev);
> +		return ret;
> +	}
> +
> +	port->cable = cable;
> +	return 0;
> +}
> +
> +static void typec_remove_cable(struct typec_port *port)
> +{
> +	if (port->cable->active) {
> +		typec_remove_plug(&port->cable->plug[0]);
> +		if (port->cable->sop_pp_controller)
> +			typec_remove_plug(&port->cable->plug[1]);
> +	}
> +	device_unregister(&port->cable->dev);
> +}
> +
> +/* ------------------------------------------------------------------------- */
> +/* API for the port drivers */
> +
> +static void typec_init_roles(struct typec_port *port)
> +{
> +	if (port->prefer_role < 0)
> +		return;
> +
> +	if (port->prefer_role == TYPEC_SOURCE) {
> +		port->data_role = TYPEC_HOST;
> +		port->pwr_role = TYPEC_SOURCE;
> +		port->vconn_role = TYPEC_SOURCE;
> +	} else {
> +		/* Device mode as default also by default with DRP ports */
> +		port->data_role = TYPEC_DEVICE;
> +		port->pwr_role = TYPEC_SINK;
> +		port->vconn_role = TYPEC_SINK;
> +	}
> +}
> +
> +int typec_connect(struct typec_port *port, struct typec_connection *con)
> +{
> +	int ret;
> +
> +	if (!con->partner && !con->cable)
> +		return -EINVAL;
> +
> +	port->connected = 1;
> +	port->data_role = con->data_role;
> +	port->pwr_role = con->pwr_role;
> +	port->vconn_role = con->vconn_role;
> +	port->pwr_opmode = con->pwr_opmode;
> +
> +	kobject_uevent(&port->dev.kobj, KOBJ_CHANGE);
> +
> +	if (con->cable) {
> +		ret = typec_add_cable(port, con->cable);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	if (con->partner) {
> +		ret = typec_add_partner(port, con->partner);
> +		if (ret) {
> +			if (con->cable)
> +				typec_remove_cable(port);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_connect);
> +
> +void typec_disconnect(struct typec_port *port)
> +{
> +	if (port->partner)
> +		typec_remove_partner(port);
> +
> +	if (port->cable)
> +		typec_remove_cable(port);
> +
> +	port->connected = 0;
> +	port->partner = NULL;
> +	port->cable = NULL;
> +
> +	port->pwr_opmode = TYPEC_PWR_MODE_USB;
> +
> +	typec_init_roles(port);
> +
> +	kobject_uevent(&port->dev.kobj, KOBJ_CHANGE);
> +}
> +EXPORT_SYMBOL_GPL(typec_disconnect);
> +
> +/* --------------------------------------- */
> +/* Driver callbacks to report role updates */
> +
> +void typec_set_data_role(struct typec_port *port, enum typec_data_role role)
> +{
> +	mutex_lock(&port->lock);
> +	port->data_role = role;
> +	sysfs_notify(&port->dev.kobj, NULL, "current_data_role");
> +	mutex_unlock(&port->lock);
> +}
> +EXPORT_SYMBOL(typec_set_data_role);
> +
> +void typec_set_pwr_role(struct typec_port *port, enum typec_role role)
> +{
> +	mutex_lock(&port->lock);
> +	port->pwr_role = role;
> +	sysfs_notify(&port->dev.kobj, NULL, "current_power_role");
> +	mutex_unlock(&port->lock);
> +}
> +EXPORT_SYMBOL(typec_set_pwr_role);
> +
> +void typec_set_vconn_role(struct typec_port *port, enum typec_role role)
> +{
> +	mutex_lock(&port->lock);
> +	port->vconn_role = role;
> +	sysfs_notify(&port->dev.kobj, NULL, "current_vconn_role");
> +	mutex_unlock(&port->lock);
> +}
> +EXPORT_SYMBOL(typec_set_vconn_role);
> +
> +void typec_set_pwr_opmode(struct typec_port *port,
> +			  enum typec_pwr_opmode opmode)
> +{
> +	mutex_lock(&port->lock);
> +	port->pwr_opmode = opmode;
> +	sysfs_notify(&port->dev.kobj, NULL, "power_operation_mode");
> +	mutex_unlock(&port->lock);
> +}
> +EXPORT_SYMBOL(typec_set_pwr_opmode);
> +
> +/* -------------------------------- */
> +/* Alternate Modes */
> +
> +/*
> + * typec_altmode_update_active - Notify about Enter/Exit mode
> + * @alt: Handle to the Alternate Mode
> + * @mode: Mode id
> + * @active: True when the mode has been enterred
> + */
> +void typec_altmode_update_active(struct typec_altmode *alt, int mode,
> +				 bool active)
> +{
> +	struct typec_port *port = typec_altmode2port(alt);
> +	struct typec_mode *m = alt->modes + mode;
> +	char dir[6];
> +
> +	mutex_lock(&port->lock);
> +	m->active = active;
> +	sprintf(dir, "mode%d", mode);
> +	sysfs_notify(&alt->dev.kobj, dir, "active");
> +	mutex_unlock(&port->lock);
> +}
> +EXPORT_SYMBOL(typec_altmode_update_active);
> +
> +static struct device_type typec_port_dev_type;
> +
> +/*
> + * typec_altmode2port - Alternate Mode to USB Type-C port
> + * @alt: The Alternate Mode
> + *
> + * Returns the port that the cable plug or partner with @alt is connected to.
> + */
> +struct typec_port *typec_altmode2port(struct typec_altmode *alt)
> +{
> +	if (alt->dev.parent->type == &typec_plug_dev_type)
> +		return to_typec_port(alt->dev.parent->parent->parent);
> +	if (alt->dev.parent->type == &typec_partner_dev_type)
> +		return to_typec_port(alt->dev.parent->parent);
> +	if (alt->dev.parent->type == &typec_port_dev_type)
> +		return to_typec_port(alt->dev.parent);
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode2port);
> +
> +static void typec_altmode_release(struct device *dev)
> +{
> +	struct typec_altmode *alt = to_altmode(dev);
> +
> +	kfree(alt->mode_groups);
> +}
> +
> +static ssize_t
> +typec_altmode_vdo_show(struct device *dev, struct device_attribute *attr,
> +		       char *buf)
> +{
> +	struct typec_mode *mode = container_of(attr, struct typec_mode,
> +					       vdo_attr);
> +	struct typec_port *port = typec_altmode2port(mode->alt_mode);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	ret = sprintf(buf, "0x%08x\n", mode->vdo);
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t
> +typec_altmode_desc_show(struct device *dev, struct device_attribute *attr,
> +			char *buf)
> +{
> +	struct typec_mode *mode = container_of(attr, struct typec_mode,
> +					       desc_attr);
> +	struct typec_port *port = typec_altmode2port(mode->alt_mode);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	ret = sprintf(buf, "%s\n", mode->desc ? mode->desc : "");
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t
> +typec_altmode_active_show(struct device *dev, struct device_attribute *attr,
> +			  char *buf)
> +{
> +	struct typec_mode *mode = container_of(attr, struct typec_mode,
> +					       active_attr);
> +	struct typec_port *port = typec_altmode2port(mode->alt_mode);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	ret = sprintf(buf, "%d\n", mode->active);
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t
> +typec_altmode_active_store(struct device *dev, struct device_attribute *attr,
> +			   const char *buf, size_t size)
> +{
> +	struct typec_mode *mode = container_of(attr, struct typec_mode,
> +					       active_attr);
> +	struct typec_port *port = typec_altmode2port(mode->alt_mode);
> +	bool activate;
> +	int ret;
> +
> +	ret = kstrtobool(buf, &activate);
> +	if (ret)
> +		return ret;
> +
> +	if (activate > 1)
> +		return -EINVAL;
> +
> +	mutex_lock(&port->lock);
> +	ret = port->cap->activate_mode(mode->alt_mode, mode->index, activate);
> +	if (!ret) {
> +		mode->active = activate;
> +		ret = size;
> +	}
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t
> +typec_altmode_roles_show(struct device *dev, struct device_attribute *attr,
> +			 char *buf)
> +{
> +	struct typec_mode *mode = container_of(attr, struct typec_mode,
> +					       roles_attr);
> +	struct typec_port *port = typec_altmode2port(mode->alt_mode);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	switch (mode->roles) {
> +	case TYPEC_PORT_DFP:
> +		ret =  sprintf(buf, "source\n");
> +		break;
> +	case TYPEC_PORT_UFP:
> +		ret = sprintf(buf, "sink\n");
> +		break;
> +	case TYPEC_PORT_DRP:
> +	default:
> +		ret = sprintf(buf, "source, sink\n");
> +		break;
> +	}
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +
> +static void typec_init_modes(struct typec_altmode *alt, int is_port)
> +{
> +	struct typec_mode *mode = alt->modes;
> +	int i;
> +
> +	for (i = 0; i < alt->n_modes; i++, mode++) {
> +		mode->alt_mode = alt;
> +		mode->index = i;
> +		sprintf(mode->group_name, "mode%d", i);
> +
> +		sysfs_attr_init(&mode->vdo_attr.attr);
> +		mode->vdo_attr.attr.name = "vdo";
> +		mode->vdo_attr.attr.mode = S_IRUGO;
> +		mode->vdo_attr.show = typec_altmode_vdo_show;
> +
> +		sysfs_attr_init(&mode->desc_attr.attr);
> +		mode->desc_attr.attr.name = "description";
> +		mode->desc_attr.attr.mode = S_IRUGO;
> +		mode->desc_attr.show = typec_altmode_desc_show;
> +
> +		sysfs_attr_init(&mode->active_attr.attr);
> +		mode->active_attr.attr.name = "active";
> +		mode->active_attr.attr.mode = S_IWUSR | S_IRUGO;
> +		mode->active_attr.show = typec_altmode_active_show;
> +		mode->active_attr.store = typec_altmode_active_store;
> +
> +		mode->attrs[0] = &mode->vdo_attr.attr;
> +		mode->attrs[1] = &mode->desc_attr.attr;
> +		mode->attrs[2] = &mode->active_attr.attr;
> +
> +		/* With ports, list the roles that the mode is supported with */
> +		if (is_port) {
> +			sysfs_attr_init(&mode->roles_attr.attr);
> +			mode->roles_attr.attr.name = "supported_roles";
> +			mode->roles_attr.attr.mode = S_IRUGO;
> +			mode->roles_attr.show = typec_altmode_roles_show;
> +
> +			mode->attrs[3] = &mode->roles_attr.attr;
> +		}
> +
> +		mode->group.attrs = mode->attrs;
> +		mode->group.name = mode->group_name;
> +
> +		alt->mode_groups[i] = &mode->group;
> +	}
> +}
> +
> +static int
> +typec_add_altmode(struct device *parent, struct typec_altmode *alt, int is_port)
> +{
> +	struct device *dev = &alt->dev;
> +	int ret;
> +
> +	alt->mode_groups = kcalloc(alt->n_modes + 1,
> +				   sizeof(struct attibute_group *), GFP_KERNEL);
> +	if (!alt->mode_groups)
> +		return -ENOMEM;
> +
> +	typec_init_modes(alt, is_port);
> +
> +	dev->groups = alt->mode_groups;
> +	dev->release = typec_altmode_release;
> +	dev->parent = parent;
> +	/* TODO: if (!is_port) dev->bus = &typec_altmode_bus; */
> +
> +	dev_set_name(dev, "%s.svid:%04x", dev_name(parent), alt->svid);
> +
> +	ret = device_register(dev);
> +	if (ret) {
> +		put_device(dev);
> +		kfree(alt->mode_groups);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int __typec_register_altmodes(struct device *parent,
> +				     struct typec_altmode *alt_modes,
> +				     int is_port)
> +{
> +	struct typec_altmode *alt;
> +	int index;
> +	int ret;
> +
> +	if (!alt_modes)
> +		return 0;
> +
> +	for (alt = alt_modes, index = 0; alt->svid; alt++, index++) {
> +		ret = typec_add_altmode(parent, alt, is_port);
> +		if (ret)
> +			goto err;
> +	}
> +
> +	return 0;
> +err:
> +	for (alt = alt_modes + index; index; alt--, index--)
> +		device_unregister(&alt->dev);
> +
> +	return ret;
> +}
> +
> +int typec_register_altmodes(struct device *dev, struct typec_altmode *alt_modes)
> +{
> +	if (dev->type == &typec_partner_dev_type) {
> +		struct typec_partner *p = container_of(dev,
> +						       struct typec_partner,
> +						       dev);
> +		p->alt_modes = alt_modes;
> +	} else if (dev->type == &typec_plug_dev_type) {
> +		struct typec_plug *p = container_of(dev, struct typec_plug,
> +						    dev);
> +		p->alt_modes = alt_modes;
> +	} else {
> +		return -ENODEV;
> +	}
> +
> +	return __typec_register_altmodes(dev, alt_modes, false);
> +}
> +EXPORT_SYMBOL_GPL(typec_register_altmodes);
> +
> +void typec_unregister_altmodes(struct device *dev)
> +{
> +	struct typec_altmode *alt_modes = NULL;
> +	struct typec_altmode *alt;
> +
> +	if (dev->type == &typec_partner_dev_type) {
> +		struct typec_partner *p = container_of(dev,
> +						       struct typec_partner,
> +						       dev);
> +		alt_modes = p->alt_modes;
> +		p->alt_modes = NULL;
> +	} else if (dev->type == &typec_plug_dev_type) {
> +		struct typec_plug *p = container_of(dev, struct typec_plug,
> +						    dev);
> +		alt_modes = p->alt_modes;
> +		p->alt_modes = NULL;
> +	}
> +
> +	if (!alt_modes)
> +		return;
> +
> +	for (alt = alt_modes; alt->svid; alt++)
> +		device_unregister(&alt->dev);
> +}
> +EXPORT_SYMBOL_GPL(typec_unregister_altmodes);
> +
> +/* ------------------------------------------------------------------------- */
> +
> +static const char * const typec_roles[] = {
> +	[TYPEC_SINK]	= "sink",
> +	[TYPEC_SOURCE]	= "source",
> +};
> +
> +static const char * const typec_data_roles[] = {
> +	[TYPEC_DEVICE]	= "device",
> +	[TYPEC_HOST]	= "host",
> +};
> +
> +static ssize_t
> +preferred_role_store(struct device *dev, struct device_attribute *attr,
> +		     const char *buf, size_t size)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	enum typec_role role;
> +	int ret;
> +
> +	mutex_lock(&port->lock);
> +
> +	if (port->cap->type != TYPEC_PORT_DRP) {
> +		dev_dbg(dev, "Preferred role only supported with DRP ports\n");
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	if (!port->cap->try_role) {
> +		dev_dbg(dev, "Setting preferred role not supported\n");
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	ret = match_string(typec_roles, ARRAY_SIZE(typec_roles), buf);

With this, 'echo "sink" > preferred_role' no longer works because
match_string() tries to match the entire string, including the newline
generated by the echo command. One has to use "echo -n" instead.
Is this on purpose ? It is quite unusual.

> +	if (ret < 0) {
> +		port->prefer_role = -1;
> +		ret = size;
> +		goto out;
> +	}
> +
> +	role = ret;
> +
> +	ret = port->cap->try_role(port->cap, role);
> +	if (ret)
> +		goto out;
> +
> +	port->prefer_role = role;
> +	ret = size;
> +out:
> +	mutex_unlock(&port->lock);
> +	return ret;
> +}
> +
> +static ssize_t
> +preferred_role_show(struct device *dev, struct device_attribute *attr,
> +		    char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	ssize_t ret = 0;
> +
> +	mutex_lock(&port->lock);
> +
> +	if (port->prefer_role < 0)
> +		goto out;
> +
> +	ret = sprintf(buf, "%s\n", typec_roles[port->prefer_role]);
> +out:
> +	mutex_unlock(&port->lock);
> +	return ret;
> +}
> +static DEVICE_ATTR_RW(preferred_role);
> +
> +static ssize_t
> +current_data_role_store(struct device *dev, struct device_attribute *attr,
> +			const char *buf, size_t size)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	int ret = size;
> +
> +	mutex_lock(&port->lock);
> +
With this lock, the code in the driver can no longer call any state updates
during the call to dr_set(), because those (eg typec_set_data_role()) set
the lock as well. This means that the dr_set call and all other similar calls
now have to be asynchronous. As a result, those calls can not return an error
if the role change request fails. Is this on purpose ? I see it as a major
drawback, not only because errors can no longer be returned, but also because
I very much preferred the call to be synchronous.

> +	if (port->cap->type != TYPEC_PORT_DRP) {
> +		dev_dbg(dev, "data role swap only supported with DRP ports\n");
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	if (!port->cap->dr_set) {
> +		dev_dbg(dev, "data role swapping not supported\n");
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	if (!port->connected)
> +		goto out;
> +
> +	ret = match_string(typec_data_roles, ARRAY_SIZE(typec_data_roles), buf);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = port->cap->dr_set(port->cap, ret);
> +	if (ret)
> +		goto out;
> +
> +	ret = size;
> +out:
> +	mutex_unlock(&port->lock);
> +	return ret;
> +}
> +
> +static ssize_t
> +current_data_role_show(struct device *dev, struct device_attribute *attr,
> +		       char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	ret = sprintf(buf, "%s\n", typec_data_roles[port->data_role]);
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +static DEVICE_ATTR_RW(current_data_role);
> +
> +static ssize_t supported_data_roles_show(struct device *dev,
> +					 struct device_attribute *attr,
> +					 char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	size_t ret;
> +
> +	mutex_lock(&port->lock);
> +
> +	if (port->cap->type == TYPEC_PORT_DRP) {
> +		ret = sprintf(buf, "host, device\n");
> +		goto out;
> +	}
> +
> +	ret = sprintf(buf, "%s\n", typec_data_roles[port->data_role]);
> +out:
> +	mutex_unlock(&port->lock);
> +	return ret;
> +}
> +static DEVICE_ATTR_RO(supported_data_roles);
> +
> +static ssize_t current_power_role_store(struct device *dev,
> +					struct device_attribute *attr,
> +					const char *buf, size_t size)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	int ret = size;
> +
> +	mutex_lock(&port->lock);
> +
> +	if (!port->cap->usb_pd) {
> +		dev_dbg(dev, "power role swap only supported with USB PD\n");
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	if (!port->cap->pr_set) {
> +		dev_dbg(dev, "power role swapping not supported\n");
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	if (port->pwr_opmode != TYPEC_PWR_MODE_PD) {
> +		dev_dbg(dev, "partner unable to swap power role\n");
> +		ret = -EIO;
> +		goto out;
> +	}
> +
> +	if (!port->connected)
> +		goto out;
> +
> +	ret = match_string(typec_roles, ARRAY_SIZE(typec_roles), buf);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = port->cap->pr_set(port->cap, ret);
> +	if (ret)
> +		goto out;
> +
> +	ret = size;
> +out:
> +	mutex_unlock(&port->lock);
> +	return ret;
> +}
> +
> +static ssize_t current_power_role_show(struct device *dev,
> +				       struct device_attribute *attr, char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	ret = sprintf(buf, "%s\n", typec_roles[port->pwr_role]);
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +static DEVICE_ATTR_RW(current_power_role);
> +
> +static ssize_t supported_power_roles_show(struct device *dev,
> +					  struct device_attribute *attr,
> +					  char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	size_t ret;
> +
> +	mutex_lock(&port->lock);
> +
> +	if (port->cap->usb_pd || port->cap->type == TYPEC_PORT_DRP) {
> +		ret = sprintf(buf, "source, sink\n");
> +		goto out;
> +	}
> +
> +	ret = sprintf(buf, "%s\n", typec_roles[port->pwr_role]);
> +out:
> +	mutex_unlock(&port->lock);
> +	return ret;
> +}
> +static DEVICE_ATTR_RO(supported_power_roles);
> +
> +static const char * const typec_pwr_opmodes[] = {
> +	[TYPEC_PWR_MODE_USB]	= "USB",
> +	[TYPEC_PWR_MODE_1_5A]	= "USB Type-C 1.5A",
> +	[TYPEC_PWR_MODE_3_0A]	= "USB Type-C 3.0A",
> +	[TYPEC_PWR_MODE_PD]	= "USB Power Delivery",
> +};
> +
> +static ssize_t power_operation_mode_show(struct device *dev,
> +					 struct device_attribute *attr,
> +					 char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	ret = sprintf(buf, "%s\n", typec_pwr_opmodes[port->pwr_opmode]);
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +static DEVICE_ATTR_RO(power_operation_mode);
> +
> +static ssize_t current_vconn_role_store(struct device *dev,
> +					struct device_attribute *attr,
> +					const char *buf, size_t size)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	int ret;
> +
> +	mutex_lock(&port->lock);
> +
> +	if (!port->cap->usb_pd) {
> +		dev_dbg(dev, "vconn swap only supported with USB PD\n");
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	if (!port->cap->vconn_set) {
> +		dev_dbg(dev, "vconn swapping not supported\n");
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	ret = match_string(typec_roles, ARRAY_SIZE(typec_roles), buf);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = port->cap->vconn_set(port->cap, ret);
> +	if (ret)
> +		goto out;
> +
> +	ret = size;
> +out:
> +	mutex_unlock(&port->lock);
> +	return ret;
> +}
> +
> +static ssize_t current_vconn_role_show(struct device *dev,
> +				       struct device_attribute *attr, char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	ret = sprintf(buf, "%s\n", typec_roles[port->vconn_role]);
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +static DEVICE_ATTR_RW(current_vconn_role);
> +
> +static ssize_t supported_accessory_modes_show(struct device *dev,
> +					      struct device_attribute *attr,
> +					      char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	enum typec_accessory *accessory;
> +	ssize_t ret = 0;
> +	int i;
> +
> +	mutex_lock(&port->lock);
> +	if (port->cap->accessory)
> +		for (accessory = port->cap->accessory, i = 0;
> +		     i < port->cap->num_accessory; accessory++, i++)
> +			ret += sprintf(buf, "%s\n",
> +				       typec_accessory_modes[*accessory]);
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +static DEVICE_ATTR_RO(supported_accessory_modes);
> +
> +static ssize_t supports_usb_power_delivery_show(struct device *dev,
> +						struct device_attribute *attr,
> +						char *buf)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +	ssize_t ret;
> +
> +	mutex_lock(&port->lock);
> +	ret = sprintf(buf, "%d\n", port->cap->usb_pd);
> +	mutex_unlock(&port->lock);
> +
> +	return ret;
> +}
> +static DEVICE_ATTR_RO(supports_usb_power_delivery);
> +
> +static struct attribute *typec_attrs[] = {
> +	&dev_attr_current_power_role.attr,
> +	&dev_attr_current_vconn_role.attr,
> +	&dev_attr_current_data_role.attr,
> +	&dev_attr_power_operation_mode.attr,
> +	&dev_attr_preferred_role.attr,
> +	&dev_attr_supported_accessory_modes.attr,
> +	&dev_attr_supported_data_roles.attr,
> +	&dev_attr_supported_power_roles.attr,
> +	&dev_attr_supports_usb_power_delivery.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group typec_group = {
> +	.attrs = typec_attrs,
> +};
> +
> +static const struct attribute_group *typec_groups[] = {
> +	&typec_group,
> +	NULL,
> +};
> +
> +static int typec_uevent(struct device *dev, struct kobj_uevent_env *env)
> +{
> +	int ret;
> +
> +	ret = add_uevent_var(env, "TYPEC_PORT=%s", dev_name(dev));
> +	if (ret)
> +		dev_err(dev, "failed to add uevent TYPEC_PORT\n");
> +
> +	return ret;
> +}
> +
> +static void typec_release(struct device *dev)
> +{
> +	struct typec_port *port = to_typec_port(dev);
> +
> +	ida_simple_remove(&typec_index_ida, port->id);
> +	kfree(port);
> +}
> +
> +static struct device_type typec_port_dev_type = {
> +	.name = "typec_port",
> +	.groups = typec_groups,
> +	.uevent = typec_uevent,
> +	.release = typec_release,
> +};
> +
> +struct typec_port *typec_register_port(struct device *dev,
> +				       const struct typec_capability *cap)
> +{
> +	struct typec_port *port;
> +	int ret;
> +	int id;
> +
> +	port = kzalloc(sizeof(*port), GFP_KERNEL);
> +	if (!port)
> +		return ERR_PTR(-ENOMEM);
> +
> +	id = ida_simple_get(&typec_index_ida, 0, 0, GFP_KERNEL);
> +	if (id < 0) {
> +		kfree(port);
> +		return ERR_PTR(id);
> +	}
> +
> +	/* FIXME: a better approach for this */
> +	port->prefer_role = -1;
> +
> +	port->id = id;
> +	port->cap = cap;
> +	port->dev.type = &typec_port_dev_type;
> +	port->dev.class = &typec_class;
> +	port->dev.parent = dev;
> +	dev_set_name(&port->dev, "usbc%d", id);
> +	mutex_init(&port->lock);
> +
> +	typec_init_roles(port);
> +
> +	ret = device_register(&port->dev);
> +	if (ret)
> +		goto reg_err;
> +
> +	ret = __typec_register_altmodes(&port->dev, cap->alt_modes, true);
> +	if (ret)
> +		goto alt_err;
> +
> +	return port;
> +alt_err:
> +	device_unregister(&port->dev);
> +reg_err:
> +	ida_simple_remove(&typec_index_ida, id);
> +	put_device(&port->dev);
> +	kfree(port);
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(typec_register_port);
> +
> +void typec_unregister_port(struct typec_port *port)
> +{
> +	struct typec_altmode *alt;
> +
> +	WARN_ON(port->connected);
> +
> +	if (port->cap->alt_modes)
> +		for (alt = port->cap->alt_modes; alt->svid; alt++)
> +			device_unregister(&alt->dev);
> +	device_unregister(&port->dev);
> +}
> +EXPORT_SYMBOL_GPL(typec_unregister_port);
> +
> +static int __init typec_init(void)
> +{
> +	return class_register(&typec_class);
> +}
> +subsys_initcall(typec_init);
> +
> +static void __exit typec_exit(void)
> +{
> +	class_unregister(&typec_class);
> +}
> +module_exit(typec_exit);
> +
> +MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("USB Type-C Connector Class");
> diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
> new file mode 100644
> index 0000000..eda6747
> --- /dev/null
> +++ b/include/linux/usb/typec.h
> @@ -0,0 +1,260 @@
> +
> +#ifndef __LINUX_USB_TYPEC_H
> +#define __LINUX_USB_TYPEC_H
> +
> +#include <linux/device.h>
> +#include <linux/types.h>
> +
> +struct typec_port;
> +
> +enum typec_port_type {
> +	TYPEC_PORT_DFP,
> +	TYPEC_PORT_UFP,
> +	TYPEC_PORT_DRP,
> +};
> +
> +enum typec_partner_type {
> +	TYPEC_PARTNER_USB,
> +	TYPEC_PARTNER_CHARGER,
> +	TYPEC_PARTNER_ALTMODE,
> +	TYPEC_PARTNER_ACCESSORY,
> +};
> +
> +enum typec_plug_type {
> +	USB_PLUG_NONE,
> +	USB_PLUG_TYPE_A,
> +	USB_PLUG_TYPE_B,
> +	USB_PLUG_TYPE_C,
> +	USB_PLUG_CAPTIVE,
> +};
> +
> +enum typec_data_role {
> +	TYPEC_DEVICE,
> +	TYPEC_HOST,
> +};
> +
> +enum typec_role {
> +	TYPEC_SINK,
> +	TYPEC_SOURCE,
> +};
> +
> +enum typec_pwr_opmode {
> +	TYPEC_PWR_MODE_USB,
> +	TYPEC_PWR_MODE_1_5A,
> +	TYPEC_PWR_MODE_3_0A,
> +	TYPEC_PWR_MODE_PD,
> +};
> +
> +enum typec_accessory {
> +	TYPEC_ACCESSORY_NONE,
> +	TYPEC_ACCESSORY_AUDIO,
> +	TYPEC_ACCESSORY_DEBUG,
> +	TYPEC_ACCESSORY_DAUDIO,
> +};
> +
> +/*
> + * struct typec_mode - Individual Mode of an Alternate Mode
> + * @vdo: VDO returned by Discover Modes USB PD command
> + * @desc: Mode description
> + * @active: Tells if the mode is currently entered or not
> + * @index: Index of the mode
> + * @group_name: Name for the sysfs folder in form "mode<index>"
> + * @group: The sysfs group (folder) for the mode
> + * @attrs: The attributes for the sysfs group
> + * @vdo_attr: Device attribute to expose the VDO of the mode
> + * @desc_attr: Device attribute to expose the description of the mode
> + * @active_attr: Device attribute to expose active of the mode
> + * @roles: Only for ports. DRP if the mode is awailable in both roles
> + * @roles_attr: Device attribute, only for ports, to expose the supported roles
> + *
> + * Details about a mode of an Alternate Mode which a connector, cable plug or
> + * partner supports. Every mode will have it's own sysfs group. The details are
> + * the VDO returned by discover modes command, description for the mode and
> + * active flag telling is the mode currently active or not.
> + */
> +struct typec_mode {
> +	u32			vdo;
> +	char			*desc;
> +	unsigned int		active:1;
> +	/* Only for ports */
> +	enum typec_port_type	roles;
> +
> +	struct typec_altmode	*alt_mode;
> +
> +	int			index;
> +	char			group_name[8];
> +	struct attribute_group	group;
> +	struct attribute	*attrs[5];
> +	struct device_attribute vdo_attr;
> +	struct device_attribute desc_attr;
> +	struct device_attribute active_attr;
> +	/* Only for ports */
> +	struct device_attribute roles_attr;
> +};
> +
> +/*
> + * struct typec_altmode - USB Type-C Alternate Mode
> + * @dev: struct device instance
> + * @name: Name for the Alternate Mode (optional)
> + * @svid: Standard or Vendor ID
> + * @n_modes: Number of modes
> + * @modes: Array of modes supported by the Alternat Mode
> + * @mode_groups: The modes as attribute groups to be exposed in sysfs
> + *
> + * Representation of an Alternate Mode that has SVID assigned by USB-IF. The
> + * array of modes will list the modes of a particular SVID that are supported by
> + * a connector, partner of a cable plug.
> + */
> +struct typec_altmode {
> +	struct device		dev;
> +	char			*name;
> +
> +	u16			svid;
> +	int			n_modes;
> +	struct typec_mode	*modes;
> +
> +	const struct attribute_group **mode_groups;
> +};
> +
> +#define to_altmode(d) container_of(d, struct typec_altmode, dev)
> +
> +struct typec_port *typec_altmode2port(struct typec_altmode *);
> +
> +void typec_altmode_update_active(struct typec_altmode *alt, int mode,
> +				 bool active);
> +
> +int typec_register_altmodes(struct device *, struct typec_altmode *);
> +void typec_unregister_altmodes(struct device *);
> +
> +/*
> + * struct typec_plug - USB Type-C Cable Plug
> + * @dev: struct device instance
> + * @index: 1 for the plug connected to DFP and 2 for the plug connected to UFP
> + * @alt_modes: Alternate Modes the cable plug supports (null terminated)
> + *
> + * Represents USB Type-C Cable Plug.
> + */
> +struct typec_plug {
> +	struct device		dev;
> +	int			index;
> +	struct typec_altmode	*alt_modes;
> +};
> +
> +/*
> + * struct typec_cable - USB Type-C Cable
> + * @dev: struct device instance
> + * @type: The plug type from USB PD Cable VDO
> + * @usb_pd: Electronically Marked Cable
> + * @active: Is the cable active or passive
> + * @sop_pp_controller: Tells whether both cable plugs are configurable or not
> + * @plug: The two plugs in the cable.
> + *
> + * Represents USB Type-C Cable attached to USB Type-C port. Two plugs are
> + * created if the cable has SOP Double Prime controller as defined in USB PD
> + * specification. Otherwise only one will be created if the cable is active. For
> + * passive cables no plugs are created.
> + */
> +struct typec_cable {
> +	struct device		dev;
> +	enum typec_plug_type	type;
> +	u32			vdo;
> +	unsigned int		usb_pd:1;
> +	unsigned int		active:1;
> +	unsigned int		sop_pp_controller:1;
> +
> +	struct typec_plug	plug[2];
> +};
> +
> +/*
> + * struct typec_partner - USB Type-C Partner
> + * @dev: struct device instance
> + * @type: Normal USB device, charger, Alternate Mode or Accessory
> + * @usb_pd: USB Power Delivery support
> + * @vdo: VDO returned by Discover Identity USB PD command
> + * @alt_modes: Alternate Modes the partner supports (null terminated)
> + *
> + * Details about a partner that is attached to USB Type-C port.
> + */
> +struct typec_partner {
> +	struct device		dev;
> +	enum typec_partner_type	type;
> +	unsigned int		usb_pd:1;
> +	u32			vdo;
> +	enum typec_accessory	accessory;
> +	struct typec_altmode	*alt_modes;
> +};
> +
> +/*
> + * struct typec_capability - USB Type-C Port Capabilities
> + * @role: DFP (Host-only), UFP (Device-only) or DRP (Dual Role)
> + * @usb_pd: USB Power Delivery support
> + * @accessory: Supported Accessory Modes
> + * @num_accessory: Number of supported Accessory Modes
> + * @alt_modes: Alternate Modes the connector supports (null terminated)
> + * @try_role: Set a fixed data role for DRP port
> + * @dr_set: Set Data Role
> + * @pr_set: Set Power Role
> + * @vconn_set: Set VCONN Role
> + * @activate_mode: Enter/exit given Alternate Mode
> + *
> + * Static capabilities of a single USB Type-C port.
> + */
> +struct typec_capability {
> +	enum typec_port_type	type;
> +	unsigned int		usb_pd:1;
> +	enum typec_accessory	*accessory;
> +	unsigned int		num_accessory;
> +	struct typec_altmode	*alt_modes;
> +
> +	int			(*try_role)(const struct typec_capability *,
> +					    enum typec_role);
> +
> +	int			(*dr_set)(const struct typec_capability *,
> +					  enum typec_data_role);
> +	int			(*pr_set)(const struct typec_capability *,
> +					  enum typec_role);
> +	int			(*vconn_set)(const struct typec_capability *,
> +					     enum typec_role);
> +
> +	int			(*activate_mode)(struct typec_altmode *,
> +						 int mode, int activate);
> +};
> +
> +/*
> + * struct typec_connection - Details about USB Type-C port connection event
> + * @partner: The attached partner
> + * @cable: The attached cable
> + * @data_role: Initial USB data role (host or device)
> + * @pwr_role: Initial Power role (source or sink)
> + * @vconn_role: Initial VCONN role (source or sink)
> + * @pwr_opmode: The power mode of the connection
> + *
> + * All the relevant details about a connection event. Wrapper that is passed to
> + * typec_connect(). The context is copied when typec_connect() is called and the
> + * structure is not used for anything else.
> + */
> +struct typec_connection {
> +	struct typec_partner	*partner;
> +	struct typec_cable	*cable;
> +
> +	enum typec_data_role	data_role;
> +	enum typec_role		pwr_role;
> +	enum typec_role		vconn_role;
> +	enum typec_pwr_opmode	pwr_opmode;
> +};
> +
> +struct typec_port *typec_register_port(struct device *dev,
> +				       const struct typec_capability *cap);
> +void typec_unregister_port(struct typec_port *port);
> +
> +int typec_connect(struct typec_port *port, struct typec_connection *con);
> +void typec_disconnect(struct typec_port *port);
> +
> +/* Callbacks from driver */
> +
> +void typec_set_data_role(struct typec_port *, enum typec_data_role);
> +void typec_set_pwr_role(struct typec_port *, enum typec_role);
> +void typec_set_vconn_role(struct typec_port *, enum typec_role);
> +void typec_set_pwr_opmode(struct typec_port *, enum typec_pwr_opmode);
> +
> +#endif /* __LINUX_USB_TYPEC_H */
> -- 
> 2.8.1
>