On Fri, Oct 11, 2024 at 03:44:00PM +0300, Heikki Krogerus 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..a3afe04b2688 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
It's later than this :)
> +Contact: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> +Description: The USB Modes that the partner device supports. The active mode
> + is displayed in brackets. The active USB mode can be changed by
> + 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)
We should probably add all of this info to 'lsusb' one of these days.
I'll add it to my todo list...
> +
> 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 ea9ee47bb246..a6fedafc9c86 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");
Who is listening for this and what are they going to do with the
information?
> +}
> +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';
Again, sysfs_emit_at()?
thanks,
greg k-h
