On 16/06/2025 16:31, Andrei Kuchynski wrote:
> This patch series introduces a flexible mechanism for USB Type-C mode
> selection, enabling into USB4 mode, Thunderbolt alternate mode, or
> DisplayPort alternate mode.
> Two new sysfs attributes are exposed to provide user control over mode
> selection:
> `altmode_priorities`: Allows users to define their preferred order for
> attempting mode entry.
> `mode_selection`: Initiates an automatic mode entry process based on the
> configured priorities and reports the outcome.
> The mode selection logic attempts to enter prioritized modes sequentially.
> A mode is considered successfully negotiated only when its alternate mode
> driver explicitly reports a positive status. Alternate mode drivers are
> required to report their mode entry status (either successful or failed).
> If an alt-mode driver does not report its status within a defined timeout
> period, the system automatically proceeds to attempt entry into the next
> preferred mode.
>
> This series was tested on a ChromeOS Brya device running kernel 6.6, and on
> an Android OS device with kernel 6.12.
Both kernels are terribly old. Please run the tests on top of linux-next
or usb-next.
>
> Andrei Kuchynski (10):
> usb: typec: Add alt_mode_override field to port property
> platform/chrome: cros_ec_typec: Set alt_mode_override flag
> usb: typec: ucsi: Set alt_mode_override flag
> usb: typec: Expose alternate mode priorities via sysfs
> usb: typec: Implement automated alternate mode selection
> Revert "usb: typec: displayport: Receive DP Status Update NAK request
> exit dp altmode"
> usb: typec: Report altmode entry status via callback
> usb: typec: ucsi: displayport: Propagate DP altmode entry result
> platform/chrome: cros_ec_typec: Propagate altmode entry result
> platform/chrome: cros_ec_typec: Report USB4 mode entry status via
> callback
>
> Documentation/ABI/testing/sysfs-class-typec | 34 ++
> drivers/platform/chrome/cros_ec_typec.c | 11 +
> drivers/platform/chrome/cros_typec_altmode.c | 32 +-
> drivers/platform/chrome/cros_typec_altmode.h | 6 +
> drivers/usb/typec/Makefile | 2 +-
> drivers/usb/typec/altmodes/displayport.c | 17 +-
> drivers/usb/typec/altmodes/thunderbolt.c | 6 +
> drivers/usb/typec/class.c | 95 +++-
> drivers/usb/typec/class.h | 16 +
> drivers/usb/typec/mode_selection.c | 505 +++++++++++++++++++
> drivers/usb/typec/mode_selection.h | 42 ++
> drivers/usb/typec/ucsi/displayport.c | 4 +-
> drivers/usb/typec/ucsi/ucsi.c | 2 +
> include/linux/usb/pd_vdo.h | 2 +
> include/linux/usb/typec.h | 1 +
> include/linux/usb/typec_altmode.h | 12 +
> include/linux/usb/typec_dp.h | 2 +
> include/linux/usb/typec_tbt.h | 3 +
> 18 files changed, 775 insertions(+), 17 deletions(-)
> create mode 100644 drivers/usb/typec/mode_selection.c
> create mode 100644 drivers/usb/typec/mode_selection.h
>
--
With best wishes
Dmitry