[RFC,2/3] usb: typec: Add product_type sysfs attribute file for partners and cables

diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
index b7794e02ad205..4c09e327c62be 100644
--- a/Documentation/ABI/testing/sysfs-class-typec
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -139,6 +139,42 @@  Description:
 		Shows if the partner supports USB Power Delivery communication:
 		Valid values: yes, no
 
+What:		/sys/class/typec/<port>-partner/product_type
+Date:		December 2020
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:	USB Power Delivery Specification defines a set of product types
+		for the partner devices. This file will show the product type of
+		the partner if it is known. Dual-role capable partners will have
+		both UFP and DFP product types defined, but only one that
+		matches the current role will be active at the time. If the
+		product type of the partner is not visible to the device driver,
+		this file will not exist.
+
+		When the partner product type is detected, or changed with role
+		swap, uvevent is also raised that contains PRODUCT_TYPE=<product
+		type> (for example PRODUCT_TYPE=hub).
+
+		Valid values:
+
+		UFP / device role
+		========================  ==========================
+		undefined		  -
+		hub			  PDUSB Hub
+		peripheral		  PDUSB Peripheral
+		psd			  Power Bank
+		ama			  Alternate Mode Adapter
+		vpd			  VCONN Powered USB Device
+		========================  ==========================
+
+		DFP / host role
+		========================  ==========================
+		undefined		  -
+		hub			  PDUSB Hub
+		host			  PDUSB Host
+		power_brick		  Power Brick
+		amc			  Alternate Mode Controller
+		========================  ==========================
+
 What:		/sys/class/typec/<port>-partner>/identity/
 Date:		April 2017
 Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
@@ -202,6 +238,25 @@  Description:
 		- type-c
 		- captive
 
+What:		/sys/class/typec/<port>-cable/product_type
+Date:		December 2020
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:	USB Power Delivery Specification defines a set of product types
+		for the cables. This file will show the product type of the
+		cable if it is known. If the product type of the cable is not
+		visible to the device driver, this file will not exist.
+
+		When the cable product type is detected, uvevent is also raised
+		with PRODUCT_TYPE showing the product type of the cable.
+
+		Valid values:
+
+		========================  ==========================
+		undefined		  -
+		active			  Active Cable
+		passive			  Passive Cable
+		========================  ==========================
+
 What:		/sys/class/typec/<port>-cable/identity/
 Date:		April 2017
 Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 35eec707cb512..303f054181ff7 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -11,6 +11,7 @@ 
 #include <linux/mutex.h>
 #include <linux/property.h>
 #include <linux/slab.h>
+#include <linux/usb/pd_vdo.h>
 
 #include "bus.h"
 
@@ -81,6 +82,30 @@  static const char * const typec_accessory_modes[] = {
 	[TYPEC_ACCESSORY_DEBUG]		= "debug",
 };
 
+/* Product types defined in USB PD Specification R3.0 V2.0 */
+static const char * const product_type_ufp[8] = {
+	[IDH_PTYPE_UNDEF]		= "undefined",
+	[IDH_PTYPE_HUB]			= "hub",
+	[IDH_PTYPE_PERIPH]		= "peripheral",
+	[IDH_PTYPE_PSD]			= "psd",
+	[IDH_PTYPE_AMA]			= "ama",
+	[IDH_PTYPE_VPD]			= "vpd",
+};
+
+static const char * const product_type_dfp[8] = {
+	[IDH_PTYPE_DFP_UNDEF]		= "undefined",
+	[IDH_PTYPE_DFP_HUB]		= "hub",
+	[IDH_PTYPE_DFP_HOST]		= "host",
+	[IDH_PTYPE_DFP_PB]		= "power_brick",
+	[IDH_PTYPE_DFP_AMC]		= "amc",
+};
+
+static const char * const product_type_cable[8] = {
+	[IDH_PTYPE_UNDEF]		= "undefined",
+	[IDH_PTYPE_PCABLE]		= "passive",
+	[IDH_PTYPE_ACABLE]		= "active",
+};
+
 static struct usb_pd_identity *get_pd_identity(struct device *dev)
 {
 	if (is_typec_partner(dev)) {
@@ -95,6 +120,24 @@  static struct usb_pd_identity *get_pd_identity(struct device *dev)
 	return NULL;
 }
 
+static const char *get_pd_product_type(struct device *dev)
+{
+	struct typec_port *port = to_typec_port(dev->parent);
+	struct usb_pd_identity *id = get_pd_identity(dev);
+	const char *ptype = NULL;
+
+	if (is_typec_partner(dev)) {
+		if (port->data_role == TYPEC_HOST)
+			ptype = product_type_ufp[PD_IDH_PTYPE(id->id_header)];
+		else
+			ptype = product_type_dfp[PD_IDH_DFP_PTYPE(id->id_header)];
+	} else if (is_typec_cable(dev)) {
+		ptype = product_type_cable[PD_IDH_PTYPE(id->id_header)];
+	}
+
+	return ptype;
+}
+
 static ssize_t id_header_show(struct device *dev, struct device_attribute *attr,
 			      char *buf)
 {
@@ -139,11 +182,55 @@  static const struct attribute_group *usb_pd_id_groups[] = {
 	NULL,
 };
 
+static void typec_product_type_notify(struct device *dev)
+{
+	const char *ptype;
+	char *envp[2];
+
+	ptype = get_pd_product_type(dev);
+	if (!ptype)
+		return;
+
+	sysfs_notify(&dev->kobj, NULL, "product_type");
+
+	envp[0] = kasprintf(GFP_KERNEL, "PRODUCT_TYPE=%s", ptype);
+	if (!envp[0])
+		return;
+
+	envp[1] = NULL;
+	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
+	kfree(envp[0]);
+}
+
 static void typec_report_identity(struct device *dev)
 {
 	sysfs_notify(&dev->kobj, "identity", "id_header");
 	sysfs_notify(&dev->kobj, "identity", "cert_stat");
 	sysfs_notify(&dev->kobj, "identity", "product");
+	typec_product_type_notify(dev);
+}
+
+static ssize_t
+product_type_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	const char *ptype;
+
+	ptype = get_pd_product_type(dev);
+	if (!ptype)
+		return 0;
+
+	return sysfs_emit(buf, "%s\n", ptype);
+}
+static DEVICE_ATTR_RO(product_type);
+
+static umode_t typec_product_type_attr_is_visible(struct kobject *kobj,
+						  struct attribute *attr, int n)
+{
+	if (attr == &dev_attr_product_type.attr)
+		if (!get_pd_identity(kobj_to_dev(kobj)))
+			return 0;
+
+	return attr->mode;
 }
 
 /* ------------------------------------------------------------------------- */
@@ -534,10 +621,20 @@  static DEVICE_ATTR_RO(supports_usb_power_delivery);
 
 static struct attribute *typec_partner_attrs[] = {
 	&dev_attr_accessory_mode.attr,
+	&dev_attr_product_type.attr,
 	&dev_attr_supports_usb_power_delivery.attr,
 	NULL
 };
-ATTRIBUTE_GROUPS(typec_partner);
+
+static struct attribute_group typec_partner_group = {
+	.is_visible = typec_product_type_attr_is_visible,
+	.attrs = typec_partner_attrs,
+};
+
+static const struct attribute_group *typec_partner_groups[] = {
+	&typec_partner_group,
+	NULL
+};
 
 static void typec_partner_release(struct device *dev)
 {
@@ -773,9 +870,19 @@  static DEVICE_ATTR_RO(plug_type);
 static struct attribute *typec_cable_attrs[] = {
 	&dev_attr_type.attr,
 	&dev_attr_plug_type.attr,
+	&dev_attr_product_type.attr,
+	NULL
+};
+
+static struct attribute_group typec_cable_group = {
+	.is_visible = typec_product_type_attr_is_visible,
+	.attrs = typec_cable_attrs,
+};
+
+static const struct attribute_group *typec_cable_groups[] = {
+	&typec_cable_group,
 	NULL
 };
-ATTRIBUTE_GROUPS(typec_cable);
 
 static void typec_cable_release(struct device *dev)
 {
@@ -1352,6 +1459,11 @@  const struct device_type typec_port_dev_type = {
 /* --------------------------------------- */
 /* Driver callbacks to report role updates */
 
+static int partner_match(struct device *dev, void *data)
+{
+	return is_typec_partner(dev);
+}
+
 /**
  * typec_set_data_role - Report data role change
  * @port: The USB Type-C Port where the role was changed
@@ -1361,12 +1473,23 @@  const struct device_type typec_port_dev_type = {
  */
 void typec_set_data_role(struct typec_port *port, enum typec_data_role role)
 {
+	struct device *partner_dev;
+
 	if (port->data_role == role)
 		return;
 
 	port->data_role = role;
 	sysfs_notify(&port->dev.kobj, NULL, "data_role");
 	kobject_uevent(&port->dev.kobj, KOBJ_CHANGE);
+
+	partner_dev = device_find_child(&port->dev, NULL, partner_match);
+	if (!partner_dev)
+		return;
+
+	if (to_typec_partner(partner_dev)->identity)
+		typec_product_type_notify(partner_dev);
+
+	put_device(partner_dev);
 }
 EXPORT_SYMBOL_GPL(typec_set_data_role);
 
@@ -1407,11 +1530,6 @@  void typec_set_vconn_role(struct typec_port *port, enum typec_role role)
 }
 EXPORT_SYMBOL_GPL(typec_set_vconn_role);
 
-static int partner_match(struct device *dev, void *data)
-{
-	return is_typec_partner(dev);
-}
-
 /**
  * typec_set_pwr_opmode - Report changed power operation mode
  * @port: The USB Type-C Port where the mode was changed