[PATCH v3] ARM: dts: add gpio-ranges property to iMX GPIO controllers

[u.kleine-koenig@pengutronix.de (Uwe Kleine-König)]

On Fri, Sep 09, 2016 at 11:44:10AM +0300, Vladimir Zapolskiy wrote:
> Hi Uwe,
> 
> On 09/09/2016 10:20 AM, Uwe Kleine-K?nig wrote:
> > On Fri, Sep 09, 2016 at 05:02:36AM +0300, Vladimir Zapolskiy wrote:
> > > To establish a connection between GPIO controllers and pin multiplexor
> > > controller add gpio-ranges properties to all GPIO controllers found
> > > on iMX50, iMX6Q/D, iMX6DL/S, iMX6SL, iMX6SX, iMX6UL and iMX7D/S
> > > SoCs. The change was done after human parsing of output from
> > 
> > When looking at doing the same for i.MX35 there are a few pin pairs that
> > are driven by the same GPIO, e.g.:
> > 
> > 	$ grep GPIO3_9 imx35-pinfunc.h
> > 	#define MX35_PAD_CTS1__GPIO3_9					0x194 0x5d8 0x918 0x5 0x0
> > 	#define MX35_PAD_FEC_COL__GPIO3_9				0x2ec 0x750 0x918 0x5 0x1
> > 
> > With this it's not possible to correctly add a gpio-ranges, right?
> 
> this is an interesting exceptional case, I don't think that pinctrl
> and gpio subsystems are ready to handle it.
> 
> If both pads are muxed to the same GPIO, then I presume on output it
> behaves like a tee, but do you know what would be the input value,
> if one line is driven high and another one is low?

That depends on the setting of register
IOMUXC_GPIO3_IPP_IND_G_IN_9_SELECT_INPUT at offset 0x918 (third value in
the constants). If it's 0 (fifth value) the value at MX35_PAD_CTS1 is
read, if it's 1 MX35_PAD_FEC_COL is used.

Best regards
Uwe

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