imx27: pinctrl: GPIO set output value failed

[Uwe Kleine-König]

Hello Chriss,

[expanded Cc: a bit]

On Wed, Jan 22, 2014 at 05:07:44PM +0800, Chris Ruehl wrote:
> On Wednesday, January 22, 2014 04:50 PM, Uwe Kleine-König wrote:
> >>after fix the imx_read_2bit() the registers show the expected values.
> >>Ergo the problem must be in the gpiolib, my guess
> >>
> >>pin 9 (MX27_PAD_LD3) GPIO 1, function 0, direction 1, oconf 3, iconfa 0, iconfb 0
> >>pin 10 (MX27_PAD_LD4) GPIO 1, function 0, direction 1, oconf 3, iconfa 0, iconfb 0
> >>pin 11 (MX27_PAD_LD5) GPIO 1, function 0, direction 0, oconf 3, iconfa 0, iconfb 0
> >>pin 12 (MX27_PAD_LD6) GPIO 1, function 0, direction 1, oconf 3, iconfa 0, iconfb 0
> >Can dump the gpio register space (e.g. using jtag or memedit)? Then try
> >something like:
> memedit can download from your Web right, sadly I didn't have a jtag
> on my CPU card.
yeah, http://www.pengutronix.de/software/memedit/downloads/. I think
there are alternatives, too.

Can you confirm that:
 # echo 0 > /sys/class/gpio/gpio9/value
 # echo 0 > /sys/class/gpio/gpio10/value
 # cat /sys/kernel/debug/gpio
 ...
   gpio-9   (sysfs               ) out lo
   gpio-10  (sysfs               ) out lo
 ...
 # echo 1 > /sys/class/gpio/gpio9/value
 # echo 1 > /sys/class/gpio/gpio10/value
 # cat /sys/kernel/debug/gpio
 ...
   gpio-9   (sysfs               ) out hi
   gpio-10  (sysfs               ) out lo

But still the pins work as expected, i.e. both are 0 after the first two
commands and both 1 at the end? Also, are the voltage levels OK?

In a different thread here on lakml
(http://thread.gmane.org/gmane.linux.ports.arm.kernel/295260/focus=295299)
it was suggested to implement a per-gpiochip flag to signal if the given
gpiochip can read from an output. If the above is right, we'd need a
per-gpio flag instead on i.MX27 (or not set it at all and so loose the
ability to read from the working pins).

Best regards
Uwe
    
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Pengutronix e.K.                           | Uwe Kleine-König            |
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