GPIO Linux

Technical Support
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1

Hello.

I have a question. How can I disable the alternative function of some interface port (UART, SPI, Parallel LCD, Parallel Camera, PWM) and use it as a simple GPIO with three states on linux?

2

Have a look at the following article on our developer website.

3

I had such a problem. I’m trying to use the KB_ROW7 and KB_ROW6 pins of the parallel camera interface as GPIO. I execute the following commands:

echo 143 > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio143/direction
echo 1 > /sys/class/gpio/gpio143/value

But the output stay in a low state. Why is this happening? What should I do with this?

4

GPIO 143 is SODIMM 173 which is hardware multiplexed KB_ROW7 and VI_D9. Did you change the multiplexing of both pins? KB_ROW7 would have to multiplexed as GPIO and VI_D9 would have to be tristated. See here and here.

5

Yes. I want to change multiplexing of both pins and use its oly as GPIO. To do this I must comment this lines?

	DEFAULT_PINMUX(KB_ROW6, KBC, PULL_DOWN, TRISTATE, INPUT),
	DEFAULT_PINMUX(KB_ROW7, KBC, PULL_DOWN, TRISTATE, INPUT),