gpio: qpnp-gpio: Add debugfs support

Add the capability to read and write PMIC gpio parameters through
debugfs on a per chip and gpio basis.

Ex.

pm8941_gpios ->
              1 ->
                 direction
                 invert
                 src_select
                 out_strength
                 output_type
                 vin_sel
                 pull
                 master_en
              2 ->
                 ...

This support is useful for bringup and debugging. It is not
intended to be a replacement for the gpiolib debug support
preexisting in the framework. Use this support for PMIC specific
configurations that cannot be manipulated through the standard
gpiolib interface. Use of this interface is dangerous and can
result in misconfiguration or hardware damage.

Change-Id: I58b2b28532f0b15187f91b34c469c3a71aaf3d73
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
2 files changed