[PATCH v3 2/3] usb: typec: USB Power Deliver helpers for ports and partners

Heikki Krogerus
2022-04-25T12:50:13Z

All the USB Type-C Connector Class devices are protected, so
the drivers can not directly access them. This will adds a
few helpers that can be used to link the ports and partners
to the correct USB Power Delivery objects.

For ports a new optional sysfs attribute file is also added
that can be used to select the USB Power Delivery
capabilities that the port will advertise to the partner.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
Documentation/ABI/testing/sysfs-class-typec | 8 ++
drivers/usb/typec/class.c | 148 ++++++++++++++++++++
drivers/usb/typec/class.h | 4 +
include/linux/usb/typec.h | 12 ++
4 files changed, 172 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
index 75088ecad2029..281b995beb05a 100644
--- a/Documentation/ABI/testing/sysfs-class-typec
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -141,6 +141,14 @@ Description:
- "reverse": CC2 orientation
- "unknown": Orientation cannot be determined.

+What: /sys/class/typec/<port>/select_usb_power_delivery
+Date: May 2022
+Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+ Lists the USB Power Delivery Capabilities that the port can
+ advertise to the partner. The currently used capabilities are in
+ brackets. Selection happens by writing to the file.
+
USB Type-C partner devices (eg. /sys/class/typec/port0-partner/)

What: /sys/class/typec/<port>-partner/accessory_mode
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index ee0e520707dd7..bd087389fc510 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -15,6 +15,7 @@

#include "bus.h"
#include "class.h"
+#include "pd.h"

static DEFINE_IDA(typec_index_ida);

@@ -720,6 +721,38 @@ void typec_partner_set_pd_revision(struct typec_partner *partner, u16 pd_revisio
}
EXPORT_SYMBOL_GPL(typec_partner_set_pd_revision);

+/**
+ * typec_partner_set_pd - Declare USB Power Delivery Contract.
+ * @partner: The partner device.
+ * @pd: The USB PD instance.
+ *
+ * This routine can be used to declare USB Power Delivery Contract with @partner
+ * by linking @partner to @pd which contains the objects that were used during the
+ * negotiation of the contract.
+ *
+ * If @pd is NULL, the link is removed and the contract with @partner has ended.
+ */
+int typec_partner_set_pd(struct typec_partner *partner, struct pd *pd)
+{
+ int ret;
+
+ if (IS_ERR_OR_NULL(partner) || partner->pd == pd)
+ return 0;
+
+ if (pd) {
+ ret = pd_link_device(pd, &partner->dev);
+ if (ret)
+ return ret;
+ } else {
+ pd_unlink_device(partner->pd, &partner->dev);
+ }
+
+ partner->pd = pd;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(typec_partner_set_pd);
+
/**
* typec_partner_set_num_altmodes - Set the number of available partner altmodes
* @partner: The partner to be updated.
@@ -1170,6 +1203,104 @@ EXPORT_SYMBOL_GPL(typec_unregister_cable);
/* ------------------------------------------------------------------------- */
/* USB Type-C ports */

+/**
+ * typec_port_set_pd - Assign USB PD for port.
+ * @port: USB Type-C port.
+ * @pd: USB PD instance.
+ *
+ * This routine can be used to set the USB Power Delivery Capabilities for @port
+ * that it will advertise to the partner.
+ *
+ * If @pd is NULL, the assignment is removed.
+ */
+int typec_port_set_pd(struct typec_port *port, struct pd *pd)
+{
+ int ret;
+
+ if (IS_ERR_OR_NULL(port) || port->pd == pd)
+ return 0;
+
+ if (pd) {
+ ret = pd_link_device(pd, &port->dev);
+ if (ret)
+ return ret;
+ } else {
+ pd_unlink_device(port->pd, &port->dev);
+ }
+
+ port->pd = pd;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(typec_port_set_pd);
+
+static ssize_t select_usb_power_delivery_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct typec_port *port = to_typec_port(dev);
+ struct pd *pd;
+
+ if (!port->ops || !port->ops->pd_set)
+ return -EOPNOTSUPP;
+
+ pd = pd_find(buf);
+ if (!pd)
+ return -EINVAL;
+
+ return port->ops->pd_set(port, pd);
+}
+
+static ssize_t select_usb_power_delivery_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct typec_port *port = to_typec_port(dev);
+ struct pd **pds;
+ struct pd *pd;
+ int ret = 0;
+
+ if (!port->ops || !port->ops->pd_get)
+ return -EOPNOTSUPP;
+
+ pds = port->ops->pd_get(port);
+ if (!pds)
+ return 0;
+
+ for (pd = pds[0]; pd; pd++) {
+ if (pd == port->pd)
+ ret += sysfs_emit(buf + ret, "[%s] ", dev_name(&pd->dev));
+ else
+ ret += sysfs_emit(buf + ret, "%s ", dev_name(&pd->dev));
+ }
+
+ buf[ret - 1] = '\n';
+
+ return ret;
+}
+static DEVICE_ATTR_RW(select_usb_power_delivery);
+
+static struct attribute *port_attrs[] = {
+ &dev_attr_select_usb_power_delivery.attr,
+ NULL
+};
+
+static umode_t port_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+ struct typec_port *port = to_typec_port(kobj_to_dev(kobj));
+
+ if (!port->pd || !port->ops || !port->ops->pd_get)
+ return 0;
+ if (!port->ops->pd_set)
+ return 0444;
+
+ return attr->mode;
+}
+
+static const struct attribute_group pd_group = {
+ .is_visible = port_attr_is_visible,
+ .attrs = port_attrs,
+};
+
static const char * const typec_orientations[] = {
[TYPEC_ORIENTATION_NONE] = "unknown",
[TYPEC_ORIENTATION_NORMAL] = "normal",
@@ -1581,6 +1712,7 @@ static const struct attribute_group typec_group = {

static const struct attribute_group *typec_groups[] = {
&typec_group,
+ &pd_group,
NULL
};

@@ -2123,6 +2255,13 @@ struct typec_port *typec_register_port(struct device *parent,
return ERR_PTR(ret);
}

+ ret = typec_port_set_pd(port, cap->pd);
+ if (ret) {
+ dev_err(&port->dev, "failed to link pd\n");
+ device_unregister(&port->dev);
+ return ERR_PTR(ret);
+ }
+
ret = typec_link_ports(port);
if (ret)
dev_warn(&port->dev, "failed to create symlinks (%d)\n", ret);
@@ -2141,6 +2280,7 @@ void typec_unregister_port(struct typec_port *port)
{
if (!IS_ERR_OR_NULL(port)) {
typec_unlink_ports(port);
+ typec_port_set_pd(port, NULL);
device_unregister(&port->dev);
}
}
@@ -2162,8 +2302,15 @@ static int __init typec_init(void)
if (ret)
goto err_unregister_mux_class;

+ ret = pd_init();
+ if (ret)
+ goto err_unregister_class;
+
return 0;

+err_unregister_class:
+ class_unregister(&typec_class);
+
err_unregister_mux_class:
class_unregister(&typec_mux_class);

@@ -2176,6 +2323,7 @@ subsys_initcall(typec_init);

static void __exit typec_exit(void)
{
+ pd_exit();
class_unregister(&typec_class);
ida_destroy(&typec_index_ida);
bus_unregister(&typec_bus);
diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
index 0f1bd6d19d67e..6c638fd8d85cb 100644
--- a/drivers/usb/typec/class.h
+++ b/drivers/usb/typec/class.h
@@ -33,6 +33,8 @@ struct typec_partner {
int num_altmodes;
u16 pd_revision; /* 0300H = "3.0" */
enum usb_pd_svdm_ver svdm_version;
+
+ struct pd *pd;
};

struct typec_port {
@@ -40,6 +42,8 @@ struct typec_port {
struct device dev;
struct ida mode_ids;

+ struct pd *pd;
+
int prefer_role;
enum typec_data_role data_role;
enum typec_role pwr_role;
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 45e28d14ae56e..3855cd07925d3 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -22,6 +22,8 @@ struct typec_altmode_ops;
struct fwnode_handle;
struct device;

+struct pd;
+
enum typec_port_type {
TYPEC_PORT_SRC,
TYPEC_PORT_SNK,
@@ -223,6 +225,8 @@ struct typec_partner_desc {
* @pr_set: Set Power Role
* @vconn_set: Source VCONN
* @port_type_set: Set port type
+ * @pd_get: Get available USB Power Delivery Capabilities.
+ * @pd_set: Set USB Power Delivery Capabilities.
*/
struct typec_operations {
int (*try_role)(struct typec_port *port, int role);
@@ -231,6 +235,8 @@ struct typec_operations {
int (*vconn_set)(struct typec_port *port, enum typec_role role);
int (*port_type_set)(struct typec_port *port,
enum typec_port_type type);
+ struct pd **(*pd_get)(struct typec_port *port);
+ int (*pd_set)(struct typec_port *port, struct pd *pd);
};

enum usb_pd_svdm_ver {
@@ -250,6 +256,7 @@ enum usb_pd_svdm_ver {
* @accessory: Supported Accessory Modes
* @fwnode: Optional fwnode of the port
* @driver_data: Private pointer for driver specific info
+ * @pd: Optional USB Power Delivery Support
* @ops: Port operations vector
*
* Static capabilities of a single USB Type-C port.
@@ -267,6 +274,8 @@ struct typec_capability {
struct fwnode_handle *fwnode;
void *driver_data;

+ struct pd *pd;
+
const struct typec_operations *ops;
};

@@ -318,4 +327,7 @@ void typec_partner_set_svdm_version(struct typec_partner *partner,
enum usb_pd_svdm_ver svdm_version);
int typec_get_negotiated_svdm_version(struct typec_port *port);

+int typec_port_set_pd(struct typec_port *port, struct pd *pd);
+int typec_partner_set_pd(struct typec_partner *partner, struct pd *pd);
+
#endif /* __LINUX_USB_TYPEC_H */
--
2.35.1