[PATCH] pinctrl/pinconfig: add debug interface

[Tony Lindgren]

* Stephen Warren <swarren at wwwdotorg.org> [130211 12:57]:
> On 02/10/2013 01:11 PM, Linus Walleij wrote:
> > From: Laurent Meunier <laurent.meunier at st.com>
> > 
> > This update adds a debugfs interface to modify a pin configuration
> > for a given state in the pinctrl map. This allows to modify the
> > configuration for a non-active state, typically sleep state.
> > This configuration is not applied right away, but only when the state
> > will be entered.
> > 
> > This solution is mandated for us by HW validation: in order
> > to test and verify several pin configurations during sleep without
> > recompiling the software.
> 
> I never understood why HW engineers can't just recompile the kernel.
> Besides, it's just a device tree change these days - no recompile even
> required, right?

Typically when bringing up a new board you do not have the driver
specific mux settings verified. For developers, it's easiest to tweak
the muxing during runtime do the drivers as a loadable module, then
export the verified mux configuration into a .dts file.

Regards,

Tony