Add spicc loopback mode for debugging convenience.
Signed-off-by: Sunny Luo <sunny.luo@amlogic.com>
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240612-spi_lbc-v1-1-d52e8c8011bd@amlogic.comSigned-off-by: Mark Brown <broonie@kernel.org>