Regmap cache mechanism is enabled in default. Thus, IO expander wouldn't
handle GPIO set really before resuming back.
But there are cases need to toggle gpio in NO_IRQ stage.
e.g. To align with PCIe specification, PERST# signal connected on the IO
expander must be toggled during PCIe RC's NO_IRQ_RESUME.
Do not enable the regmap cache when IO expander doesn't have the regulator
during system PM. That means the power of IO expander would be kept on,
and the GPIOs of the IO expander can be toggled really during system PM.
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
Tested-by: Sherry Sun <sherry.sun@nxp.com>
Acked-by: Jason Liu <jason.hui.liu@nxp.com>