Dear Pals,
I am working on IMX53_smd (sabre tablet). since I was trying to toggle the LEDs in Linux ( charge and user debug D27, D32 from schematic ) which are connected to these pins :
MX53_PAD_EIM_D30__GPIO_30
MX53_PAD_PATA_DA_1__GPIO7_7
But these definitions are already registered in "iomux-mx53.h" and "mx53_smd.c"
so I tried to access the pins directly from sysfs like this....
for MX53_PAD_EIM_D30__GPIO_30 : "echo 94 > /sys/class/gpio/export
But when I do ls i count see any new directory..
for MX53_PAD_PATA_DA_1__GPIO7_7 I did "echo 199 > sys/class/gpio/export
Here also No directories created... I dont understand why .. Is it because these pins are already being used for Charge_done and USER_DEBUG ??
Another case :
I thought I will access the free GPIO pin on the expansion connector,
that is 40th pin on J78 i.e. MX53_PAD_GPIO_17__GPIO7_12
So i Added this pin in "../mach-mx5/mx53_smd.c" in static iomux_v3_cfg_t mx53_smd_pads[] array..
then i recompiled the kernel and deployed it, booted from SD card.
But when I try to access it : echo 204 > export
echo out > gpio204/direction
echo 1 > gpio204/value
But when i see the value it is still '0' and the Pin doesnt change. but direction has changed to "out"
What am I doing wrong here ... ??
Regards,
Winston.
Hi Yixing Kong,
I have same problem if you know please kindly help me .
i want to toggle gpio pins in sysfs entries.
eg: pin7
echo 7 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio7/direction
cat /sys/class/gpio/gpio7/direction
out
cat /sys/class/gpio/gpio7/value
0
echo 1 > /sys/class/gpio/gpio7/value
cat /sys/class/gpio/gpio7/value
0
Here i am not able to change value for this gpio.
i tried with some other gpio's also all are giving like this only
can anyone please help me i am new to the device tree files.
for this am i need to give any thing in dts file.
Thanks & Regards,
Lavanya
Please set SION Software Input On Field.
You can refer to
Simple GPIO Example - quandry
But in older version kernels which have BSP support (3.0.35) without SION bit as 0 also we can able to control the value of output gpio.
So what is the difference between dts file and BSP for this SION bit related.
Thanks & Regards,
Lavanya
Please read the following link carefully.
Simple GPIO Example - quandry
https://community.freescale.com/message/598834#598834
Then confirm your IOMUXC changes in your dts file.
And check the GPIO status in debug fs.
Hi Biyong Sun,
Thank you, with this above link i can able to change the status of gpio in debug fs, now i can able see the change in gpio status from out lo to out hi.
But my doubt is why in older version we are not using SION bit settings to access sysfs, even though if we are not using SION bit as 1 in older versions sysfs entries we can able to change the values. can you please tell me the difference between these old and new versions kernel for this SION bit.I am new to the device tree.
Thanks & Regards,
Lavanya
Could you please dump the IOMUX settings in the old Linux version that we can have a check?
Ya sure here i attached the old IOMUX links can you check once.
Thanks & Regards,
lavanya
I mean runtime dump register.
I don't believe if the SION is not set the GPIO can do capture.
Also you provide the i.MX6 header.
But in older version kernels which have BSP support (3.0.35) without SION bit as 1 also we can able to control the value of output gpio.
So what is the difference between dts file and BSP for this SION bit related.
Thanks & Regards,
Lavanya
Winston
This discussion is closed since no activity. If you still need help, please feel free to reply with an update to this discussion, or create another discussion.
Thanks,
Yixing
Winston
We have not got your response yet and will close the diacussion in 3 days. If you still need help, please feel free to
reply with an update to this discussion.
Thanks,
Yixing
Winston
We are sorry for getting back to you so late. Are you still stuck with the issue? If you have somehow to resolved the
issue, can we close the discussion? If you still need Freescale help, please feel free to contact us.
Thanks,
Yixing