Document bindings for this Type-C USB 3.1 Gen 1 and DisplayPort v1.2
combo redriver.

The PTN36502 can also run in GPIO mode where it is configured
differently, without any I2C connection, but this is not supported yet.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Link: https://lore.kernel.org/r/20231020-ptn36502-v2-1-b37a337d463e@fairphone.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>