On Fri, Oct 11, 2024 at 7:04 AM Heikki Krogerus
<heikki.krogerus@xxxxxxxxxxxxxxx> wrote:
>
> On Fri, Oct 11, 2024 at 03:09:57PM +0200, Greg Kroah-Hartman wrote:
> > 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 :)
>
> Indeed. I'm sorry.
>
> >
> > > +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?
>
> I'll drop it, unless Abhishek, you guys would have use for it. Let me
> know. I'll send v4 next week.
I think you are ok to remove this. We would care about this value when
registering the partner and when activating a specific USB mode. With
the latter, we can just depend on the synchronous nature of
usb_mode_store (i.e. we can check the result after writing to the
sysfs file).
>
> > > +}
> > > +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()?
>
> Yes. These are going back to the internal review. Too many mistakes.
> Sorry.
>
> thanks,
>
> --
> heikki
