Configured as digital input pin do not change value ?

nirmalpanchal — Thu, 13 Apr 2017 14:39:20 GMT

Hi,

I am using DART 6UL CPU for one of my custom board

ref: DART-6UL CPU: NXP/Freescale i.MX 6UltraLite / i.MX 6ULL - Variscite

I want to configure 8 Digital Input pins out of which I have successfully configured 7.

But I am not able to drive GPIO1_0 as an input pin.

I removed GPIO1_0 from my dtsi file, in order to make it usable from user space.

I can configure pin as input using

echo 0 > /sys/class/gpio/export

echo in > /sys/class/gpio/gpio0/direction

and it also appears in the /sys/kernel/debug/gpio list.

But it do not change its value when driven high or low.

Can anybody help me out here ??

Questions :

1. What could be possible cause ?

2. If uboot source could the reason , where i can find source file and where to look for it ?

3. Is there anyother way I can free the pin, to make sure it is not configured by kernel !

Thank you in advance.

Re: Configured as digital input pin do not change value ?

igorpadykov — Fri, 14 Apr 2017 00:03:55 GMT

Hi Nirmal

one can attach jtag and check gpio registers described in

i.MX6UL Reference Manual Chapter 4 External Signals and Pin Multiplexing,

Chapter 26 General Purpose Input/Output (GPIO)

http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6ULRM.pdf

for uboot one can look at variscite resources

Variscite · GitHub

Best regards
igor
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Configured as digital input pin do not change value ?

Re: Configured as digital input pin do not change value ?