usb: typec: tcpm: fix debug accessory mode detection for sink ports

The port in debug accessory mode can be either a source or sink. The
previous tcpm_port_is_debug() function only checked for source port.

Commit 8db73e6a42b6 ("usb: typec: tcpm: allow sink (ufp) to toggle into
accessory mode debug") changed the detection logic to support both roles,
but left some logic in _tcpm_cc_change() unchanged, This causes the state
machine to transition to an incorrect state when operating as a sink in
debug accessory mode. Log as below:

[  978.637541] CC1: 0 -> 5, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected]
[  978.637567] state change TOGGLING -> SRC_ATTACH_WAIT [rev1 NONE_AMS]
[  978.637596] pending state change SRC_ATTACH_WAIT -> DEBUG_ACC_ATTACHED @ 180 ms [rev1 NONE_AMS]
[  978.647098] CC1: 5 -> 0, CC2: 5 -> 5 [state SRC_ATTACH_WAIT, polarity 0, connected]
[  978.647115] state change SRC_ATTACH_WAIT -> SRC_ATTACH_WAIT [rev1 NONE_AMS]

It should go to SNK_ATTACH_WAIT instead of SRC_ATTACH_WAIT state.

To fix this, add tcpm_port_is_debug_source() and tcpm_port_is_debug_sink()
helper to explicitly identify the power mode in debug accessory mode.
Update the state transition logic in _tcpm_cc_change() to ensure the state
machine transitions comply with Type-C specification. Also update the logic
in run_state_machine() to keep consistency.

Fixes: 8db73e6a42b6 ("usb: typec: tcpm: allow sink (ufp) to toggle into accessory mode debug")
Cc: stable <stable@kernel.org>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Amit Sunil Dhamne <amitsd@google.com>
Link: https://patch.msgid.link/20260424074009.2979266-1-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions