On Wed, Oct 9, 2024 at 8:46 AM Heikki Krogerus
<heikki.krogerus@xxxxxxxxxxxxxxx> wrote:
>
> This attribute file shows the supported USB modes (USB 2.0,
> USB 3.0 and USB4) of the partner, and the currently active
> mode.
>
> The active mode is determined primarily by checking the
> speed of the enumerated USB device. When USB Power Delivery
> is supported, the active USB mode should be always the mode
> that was used with the Enter_USB Message, regardless of the
> result of the USB enumeration. The port drivers can
> separately assign the mode with a dedicated API.
>
> If USB Power Delivery Identity is supplied for the partner
> device, the supported modes are extracted from it.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> Documentation/ABI/testing/sysfs-class-typec | 14 +++
> drivers/usb/typec/class.c | 123 +++++++++++++++++++-
> drivers/usb/typec/class.h | 2 +
> include/linux/usb/typec.h | 5 +
> 4 files changed, 140 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
> index 7c307f02d99e..866865ffeb66 100644
> --- a/Documentation/ABI/testing/sysfs-class-typec
> +++ b/Documentation/ABI/testing/sysfs-class-typec
> @@ -233,6 +233,20 @@ Description:
> directory exists, it will have an attribute file for every VDO
> in Discover Identity command result.
>
> +What: /sys/class/typec/<port>-partner/usb_mode
> +Date: February 2024
> +Contact: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description: The USB Modes that the partner device supports. The active mode
> + is disaplayed in brackets. The active USB mode can be changed by
spelling: displayed
> + writing to this file when the port driver is able to send Data
> + Reset Message to the partner. That requires USB Power Delivery
> + contract between the partner and the port.
> +
> + Valid values:
> + - usb2 (USB 2.0)
> + - usb3 (USB 3.2)
> + - usb4 (USB4)
> +
> USB Type-C cable devices (eg. /sys/class/typec/port0-cable/)
>
> Note: Electronically Marked Cables will have a device also for one cable plug
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 9c26d2ad40df..f25cc20a2024 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -618,6 +618,74 @@ EXPORT_SYMBOL_GPL(typec_unregister_altmode);
> /* ------------------------------------------------------------------------- */
> /* Type-C Partners */
>
> +/**
> + * typec_partner_set_usb_mode - Assign active USB Mode for the partner
> + * @partner: USB Type-C partner
> + * @mode: USB Mode (USB2, USB3 or USB4)
> + *
> + * The port drivers can use this function to assign the active USB Mode to
> + * @partner. The USB Mode can change for example due to Data Reset.
> + */
> +void typec_partner_set_usb_mode(struct typec_partner *partner, enum usb_mode mode)
> +{
> + if (!partner || partner->usb_mode == mode)
> + return;
> +
> + partner->usb_capability |= BIT(mode - 1);
> + partner->usb_mode = mode;
> + sysfs_notify(&partner->dev.kobj, NULL, "usb_mode");
> +}
> +EXPORT_SYMBOL_GPL(typec_partner_set_usb_mode);
> +
> +static ssize_t
> +usb_mode_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> + struct typec_partner *partner = to_typec_partner(dev);
> + int len = 0;
> + int i;
> +
> + for (i = USB_MODE_USB2; i < USB_MODE_USB4 + 1; i++) {
> + if (!(BIT(i - 1) & partner->usb_capability))
> + continue;
> +
> + if (i == partner->usb_mode)
> + len += sysfs_emit_at(buf, len, "[%s] ", usb_modes[i]);
> + else
> + len += sysfs_emit_at(buf, len, "%s ", usb_modes[i]);
> + }
> +
> + buf[len - 1] = '\n';
> + return len;
> +}
> +
> +static ssize_t usb_mode_store(struct device *dev, struct device_attribute *attr,
> + const char *buf, size_t size)
> +{
> + struct typec_partner *partner = to_typec_partner(dev);
> + struct typec_port *port = to_typec_port(dev->parent);
> + int mode;
> + int ret;
> +
> + if (!port->ops || !port->ops->data_reset)
> + return -EOPNOTSUPP;
> +
> + mode = sysfs_match_string(usb_modes, buf);
> + if (mode < 0)
> + return mode;
> +
> + if (mode == partner->usb_mode)
> + return size;
> +
> + ret = port->ops->data_reset(port, mode);
> + if (ret)
> + return ret;
> +
> + typec_partner_set_usb_mode(partner, mode);
> +
> + return size;
> +}
> +static DEVICE_ATTR_RW(usb_mode);
> +
> static ssize_t accessory_mode_show(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> @@ -664,6 +732,7 @@ static struct attribute *typec_partner_attrs[] = {
> &dev_attr_supports_usb_power_delivery.attr,
> &dev_attr_number_of_alternate_modes.attr,
> &dev_attr_type.attr,
> + &dev_attr_usb_mode.attr,
> &dev_attr_usb_power_delivery_revision.attr,
> NULL
> };
> @@ -671,6 +740,14 @@ static struct attribute *typec_partner_attrs[] = {
> static umode_t typec_partner_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
> {
> struct typec_partner *partner = to_typec_partner(kobj_to_dev(kobj));
> + struct typec_port *port = to_typec_port(partner->dev.parent);
> +
> + if (attr == &dev_attr_usb_mode.attr) {
> + if (!partner->usb_capability)
> + return 0;
> + if (!port->ops || !port->ops->data_reset)
> + return 0444;
> + }
>
> if (attr == &dev_attr_number_of_alternate_modes.attr) {
> if (partner->num_altmodes < 0)
> @@ -744,10 +821,33 @@ static void typec_partner_unlink_device(struct typec_partner *partner, struct de
> */
> int typec_partner_set_identity(struct typec_partner *partner)
> {
> - if (!partner->identity)
> + u8 usb_capability = partner->usb_capability;
> + struct device *dev = &partner->dev;
> + struct usb_pd_identity *id;
> +
> + id = get_pd_identity(dev);
> + if (!id)
> return -EINVAL;
>
> - typec_report_identity(&partner->dev);
> + if (to_typec_port(dev->parent)->data_role == TYPEC_HOST) {
> + u32 devcap = PD_VDO_UFP_DEVCAP(id->vdo[0]);
> +
> + if (devcap & (DEV_USB2_CAPABLE | DEV_USB2_BILLBOARD))
> + usb_capability |= USB_CAPABILITY_USB2;
> + if (devcap & DEV_USB3_CAPABLE)
> + usb_capability |= USB_CAPABILITY_USB3;
> + if (devcap & DEV_USB4_CAPABLE)
> + usb_capability |= USB_CAPABILITY_USB4;
> + } else {
> + usb_capability = PD_VDO_DFP_HOSTCAP(id->vdo[0]);
> + }
> +
> + if (partner->usb_capability != usb_capability) {
> + partner->usb_capability = usb_capability;
> + sysfs_notify(&dev->kobj, NULL, "usb_mode");
> + }
> +
> + typec_report_identity(dev);
> return 0;
> }
> EXPORT_SYMBOL_GPL(typec_partner_set_identity);
> @@ -917,6 +1017,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
> partner->usb_pd = desc->usb_pd;
> partner->accessory = desc->accessory;
> partner->num_altmodes = -1;
> + partner->usb_capability = desc->usb_capability;
> partner->pd_revision = desc->pd_revision;
> partner->svdm_version = port->cap->svdm_version;
> partner->attach = desc->attach;
> @@ -936,6 +1037,15 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
> partner->dev.type = &typec_partner_dev_type;
> dev_set_name(&partner->dev, "%s-partner", dev_name(&port->dev));
>
> + if (port->usb2_dev) {
> + partner->usb_capability |= USB_CAPABILITY_USB2;
> + partner->usb_mode = USB_MODE_USB2;
> + }
> + if (port->usb3_dev) {
> + partner->usb_capability |= USB_CAPABILITY_USB2 | USB_CAPABILITY_USB3;
> + partner->usb_mode = USB_MODE_USB3;
> + }
> +
> ret = device_register(&partner->dev);
> if (ret) {
> dev_err(&port->dev, "failed to register partner (%d)\n", ret);
> @@ -1935,13 +2045,18 @@ static void typec_partner_attach(struct typec_connector *con, struct device *dev
> struct typec_port *port = container_of(con, struct typec_port, con);
> struct typec_partner *partner = typec_get_partner(port);
> struct usb_device *udev = to_usb_device(dev);
> + enum usb_mode usb_mode;
>
> - if (udev->speed < USB_SPEED_SUPER)
> + if (udev->speed < USB_SPEED_SUPER) {
> + usb_mode = USB_MODE_USB2;
> port->usb2_dev = dev;
> - else
> + } else {
> + usb_mode = USB_MODE_USB3;
> port->usb3_dev = dev;
> + }
>
> if (partner) {
> + typec_partner_set_usb_mode(partner, usb_mode);
> typec_partner_link_device(partner, dev);
> put_device(&partner->dev);
> }
> diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
> index 85bc50aa54f7..b3076a24ad2e 100644
> --- a/drivers/usb/typec/class.h
> +++ b/drivers/usb/typec/class.h
> @@ -35,6 +35,8 @@ struct typec_partner {
> int num_altmodes;
> u16 pd_revision; /* 0300H = "3.0" */
> enum usb_pd_svdm_ver svdm_version;
> + enum usb_mode usb_mode;
> + u8 usb_capability;
>
> struct usb_power_delivery *pd;
>
> diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
> index d8999472212d..c35221b0e164 100644
> --- a/include/linux/usb/typec.h
> +++ b/include/linux/usb/typec.h
> @@ -220,6 +220,7 @@ struct typec_cable_desc {
> * @accessory: Audio, Debug or none.
> * @identity: Discover Identity command data
> * @pd_revision: USB Power Delivery Specification Revision if supported
> + * @usb_capability: Supported USB Modes
> * @attach: Notification about attached USB device
> * @deattach: Notification about removed USB device
> *
> @@ -237,6 +238,7 @@ struct typec_partner_desc {
> enum typec_accessory accessory;
> struct usb_pd_identity *identity;
> u16 pd_revision; /* 0300H = "3.0" */
> + u8 usb_capability;
>
> void (*attach)(struct typec_partner *partner, struct device *dev);
> void (*deattach)(struct typec_partner *partner, struct device *dev);
> @@ -252,6 +254,7 @@ struct typec_partner_desc {
> * @pd_get: Get available USB Power Delivery Capabilities.
> * @pd_set: Set USB Power Delivery Capabilities.
> * @usb_mode_set: Set the USB Mode to be used with Enter_USB message
> + * @data_reset: Set new USB mode by using the Data Reset message
> */
> struct typec_operations {
> int (*try_role)(struct typec_port *port, int role);
> @@ -263,6 +266,7 @@ struct typec_operations {
> struct usb_power_delivery **(*pd_get)(struct typec_port *port);
> int (*pd_set)(struct typec_port *port, struct usb_power_delivery *pd);
> int (*usb_mode_set)(struct typec_port *port, enum usb_mode mode);
> + int (*data_reset)(struct typec_port *port, enum usb_mode mode);
I have a problem with the naming of these two functions,
"usb_mode_set" and "data_reset".
The former, usb_mode_set, seems to exist to set the default USB mode
on data reset. The latter, data_reset, seems to really be Data Reset +
Enter_USB.
The former, "usb_mode_set", seems mostly useful to in-kernel TCPM to
be able to set the default USB response after a data reset. UCSI (and
cros_ec_typec on ChromeOS) doesn't expose this level of control.
A better declaration may be:
* int (*default_usb_mode_set)(struct typec_port *port, enum usb_mode mode);
* int (*enter_usb_mode)(struct typec_port *port, enum usb_mode mode);
> };
>
> enum usb_pd_svdm_ver {
> @@ -365,6 +369,7 @@ int typec_port_set_usb_power_delivery(struct typec_port *port, struct usb_power_
> int typec_partner_set_usb_power_delivery(struct typec_partner *partner,
> struct usb_power_delivery *pd);
>
> +void typec_partner_set_usb_mode(struct typec_partner *partner, enum usb_mode usb_mode);
> void typec_port_set_usb_mode(struct typec_port *port, enum usb_mode mode);
>
> /**
> --
> 2.45.2
>
Thanks,
Abhishek
