[U-Boot] [PATCH 1/2] efikamx: Configure the pins as GPIOs prior to using gpio_get_value.

[Mike Frysinger]

On Tuesday 22 November 2011 03:15:47 Stefano Babic wrote:
> On 21/11/2011 22:22, Mike Frysinger wrote:
> >> Of course ... considering there's always one correct setting for
> >> the pin to be in GPIO mode, which I suspect might not be
> >> completely true today anymore.
> > 
> > i find it hard to envision a pinmux system where individual pins
> > would have different pinmux configurations to get it into GPIO
> > mode.  probably be saner to have gpio_request() do the right thing
> > and wait for someone to come forward with the unusual setup --
> > worry about it then.
> 
> In fact it would be nicer if gpio_request() takes care of the pinmux,
> in the way I can see on the davinci SOCs. However, on the IMXs a
> single GPIO can be connected (not at the same time, of course) to
> different PADs, depending on a general setup (GPR register) or if the
> daisy chain in the multiplexer is activated.

if it's different physical pins, then perhaps it should be different GPIO 
numbers ?

> The second point I will arise is that, mainly due to the different
> internal layout but also for historical reasons, the setup and the
> provided function for the multiplexer is very different among the SOCs.
> 
> Only mx35 and mx5 expone the same interface (mxc_request_iomux), while
> mx31/mx25/mx27/mx28 have its own. Because we use and we want to use
> the GPIO framework, the gpio driver, common to all IMX SOCs, should be
> able to set up the multiplexer independently from the SOC type, that
> means we should have the same interface for the multiplexer, and we
> have not (yet ?).

this is shaking out in Linux with the pinmux framework, so probably best to 
grit our teeth until that's done and then adopt what they implement.
-mike
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