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Date: Thu, 20 Oct 2011 10:45:56 +0800
From: Shawn Guo <shawn.guo@freescale.com>
To: Stephen Warren <swarren@nvidia.com>
CC: Linus Walleij <linus.walleij@stericsson.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Barry Song <21cnbao@gmail.com>,
        Linaro Dev <linaro-dev@lists.linaro.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        David Brown <davidb@codeaurora.org>,
        Grant Likely <grant.likely@secretlab.ca>,
        Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH 2/2] pinctrl: add a generic control interface
Message-ID: <20111020024556.GD32007@S2100-06.ap.freescale.net>
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On Wed, Oct 19, 2011 at 04:04:29PM -0700, Stephen Warren wrote:
> > @@ -113,6 +204,10 @@ extern struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
> ...
> > +extern int pin_config(struct pinctrl_dev *pctldev, int pin,
> > +		      enum pin_config_param param, unsigned long data);
> > +extern int pin_config_group(struct pinctrl_dev *pctldev, const char *pin_group,
> > +			    enum pin_config_param param, unsigned long data);
> 
> Hmmm. Do we really want to expose these as public APIs? I suppose it
> will allow us to start configuring all these parameters ASAP, but all
> previous discussion has been aimed at having the pinctrl core set up an
> initial set of values at boot-time using a board-supplied table (so no
> external API), and then we were still talking about how to manipulate
> the values at run-time. Do we really want to encode all this information
> into drivers calling these APIs?
> 
+1

We should not require device driver to call these APIs directly.  There
are so many pinctrl subsystem internal details left to its users.

The Stephen's proposal [1] about adding a new param into pinmux_enable()
to specify pin configuration is much preferred to me.

Regards,
Shawn

[1] http://article.gmane.org/gmane.linux.ports.arm.kernel/137341