Hi, I am trying to blink an led connected to EXP_IO9 pin on j1003 connector on imx8mnano evk.
I have followed kernal device tree configuration in the following linkhttps://variwiki.com/index.php?title=MX8M_GPIO .
I have found gpio definition #define MX8MN_IOMUXC_GPIO1_IO09_GPIO1_IO9 in imx8mn-pinfunc.h and added the definition MX8MN_IOMUXC_GPIO1_IO09_GPIO1_IO9 in the iomuxc node edited arch/arm64/boot/dts/freescale/fsl-imx8mn-evk.dtsi, for verifying whether the correct .dtsi file I have edited "yellow:status" default led on imx8mn evk to "yellow1:status" and done bitbake imx-image-multimedia then flashed the image in imx8mnano evk. Then checked the gpioinfo command but there "yellow:status" is not changed to "yellow1:status", tried gpioset gpiochip1 9=0/1 and gpioget gpiochip1 9, but there is no change in status its always '1'.
I would like to know whether the above approach is correct ?..if no suggest the approach to access the gpio's on j1003 pin header
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Hello,
You can use the GPIO on our demo image without modify the device tree.
The GPIO pins of RPI connector are connected to a I2C port expander on I2C3.
Using gpioinfo you can see it on gpiochip5:
EXP_IO9 is on line 11 and you need to use the next command:
gpioset -c gpiochip5 11=1
or
gpioset -c gpiochip5 11=0
Also, this link could be helpful.
Best regards.
Hello @JorgeCas ,
may ask you where you find this information "EXP_IO9 is on line 11" please?
I don't find the relation between EXP_IO9 and (gpiochip5, line 11)
Regards
Hello Jorge,
Thanks for the post, I followed it and able to control the led on j1003 with gpioset commands. I would like to know the procedure by writing a recipe c code to control led for the same gpio(EXP_IO 09). I have added the c code mentioned in the link mentioned by you and done bitbake, but getting errors. can you suggest the procedure to control led in c or python(tried to install python libgpiod package but failed with errors).