usb: typec: tcpm/tcpci_maxim: fix non-contaminant CC handling

usb: typec: tcpm/tcpci_maxim: fix non-contaminant CC handling

tcpci_maxim currently never triggers the TCPM state machine when CC
status has not changed due to a contaminant but due to a real
connection event, i.e. a genuine plug event, meaning the system will
stay idle and not notify any subscribers.

The reason is that the initial state of the port is 'toggling', which
causes _max_tcpci_irq() to only drive the contamination part of the
TCPM state machine (via tcpm_port_clean()).

What should happen instead is that if no contamination was detected,
the TCPM should be notified of the CC change in this case.

To fix this, we update ...is_contaminant() to also allow its caller to
determine if more CC processing is required and then call into the TCPM
as required.

While at it, add a kernel-doc for max_contaminant_is_contaminant().

Note: the code has an issue where I2C errors during contaminant
detection also cause the TCPM state machine to not be updated. This
commit doesn't change this behaviour and should be addressed by
follow-up commit(s).

Signed-off-by: André Draszik <andre.draszik@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240806-max33359-toggling-v2-1-a66ab37baafb@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>