From mboxrd@z Thu Jan  1 00:00:00 1970
From: tony@atomide.com (Tony Lindgren)
Date: Mon, 11 Feb 2013 13:00:42 -0800
Subject: [PATCH] pinctrl/pinconfig: add debug interface
In-Reply-To: <51195A63.7080706@wwwdotorg.org>
References: <1360527070-18430-1-git-send-email-linus.walleij@stericsson.com>
 <51195A63.7080706@wwwdotorg.org>
Message-ID: <20130211210041.GW4801@atomide.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

* Stephen Warren <swarren@wwwdotorg.org> [130211 12:57]:
> On 02/10/2013 01:11 PM, Linus Walleij wrote:
> > From: Laurent Meunier <laurent.meunier@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