usb: typec: tipd: Handle mode transitions for CD321x

On Apple Silicon machines there is no control over which alt mode is
chosen. The CD321x' firmware negotiates the target mode on its own and
only lets the main CPU know after the mode has already been chosen.
Especially after plugging a new cable in this can result to quick mode
changes from e.g. power only -> USB3 only -> USB3+DisplayPort in a short
time. It is not possile to influence this in any way and we also do not
get direct access to the PDOs or VDOs exchanged via USB PD.

Additionally, mode changes must be tightly synchronized between DWC3 and
the Type C PHY and most mode changes require a full reset of DWC3 to
make the port work correctly.
This is all done synchronously from the role switch handler inside the
DWC3 glue driver on these machines to avoid tripping any failsafes or
watchdogs inside the Type-C PHY that may, in the worst case, reset the
entire SoC.

To be able to control all this we trigger the entire process in the
correct order directly from the TIPD driver and de-bounce any mode
changes to avoid tearing down and re-setting DWC3 back up multiple times
any time a new connection is made.

Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Co-developed-by: Sven Peter <sven@kernel.org>
Signed-off-by: Sven Peter <sven@kernel.org>
Reviewed-by: Janne Grunau <j@jannau.net>
Link: https://lore.kernel.org/r/20250914-apple-usb3-tipd-v1-11-4e99c8649024@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions