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LibGPIO Chip/Line mapping to physical CN8 pins

pittengermdp
Associate

‎2024-04-16 02:01 PM

I have a stm32mp135F-DK and I am attempting to do some GPIO control.  My question is where can I find the mapping of libgpiod chip/line mapping to physical pin.  I am particularly interested in the mapping to the CN8 pins as I will be wanting to read/write signals coming from external sources. I have looked at the toggle_led.sh script and see that LD7 (green LED, PA14) is mapped to gpiochip0 line 14.  One note is when I attempt to run this I get a Device/Resource is busy and when I run gpioinfo

gpiochip0 - 16 lines:
line   0:      unnamed       unused   input  active-high
line   1:      unnamed       kernel   input  active-high [used]
line   2:      unnamed       kernel   input  active-high [used]
line   3:      unnamed       kernel   input  active-high [used]
line   4:      unnamed       unused   input  active-high
line   5:      unnamed       unused   input  active-high
line   6:      unnamed       kernel   input  active-high [used]
line   7:      unnamed       unused   input  active-high
line   8:      unnamed       unused   input  active-high
line   9:      unnamed       kernel   input  active-high [used]
line  10:      unnamed       unused   input  active-high
line  11:      unnamed       unused   input  active-high
line  12:      unnamed       kernel   input  active-high [used]
line  13:      unnamed  "User-PA13"   input   active-low [used pull-up]
line  14:      unnamed "blue:heartbeat" output active-low [used]
line  15:      unnamed       kernel   input  active-high [used]
gpiochip1 - 16 lines:
line   0:      unnamed       unused   input  active-high
line   1:      unnamed       unused   input  active-high
line   2:      unnamed       kernel   input  active-high [used]
line   3:      unnamed       kernel   input  active-high [used]
line   4:      unnamed       kernel   input  active-high [used]
line   5:      unnamed       unused   input  active-high
line   6:      unnamed       kernel   input  active-high [used]
line   7:      unnamed       kernel   input  active-high [used]
line   8:      unnamed       kernel   input  active-high [used]
line   9:      unnamed       kernel   input  active-high [used]
line  10:      unnamed       unused   input  active-high
line  11:      unnamed       kernel   input  active-high [used]
line  12:      unnamed       kernel   input  active-high [used]
line  13:      unnamed       unused   input  active-high
line  14:      unnamed       kernel   input  active-high [used]
line  15:      unnamed       kernel   input  active-high [used]
gpiochip2 - 16 lines:
line   0:      unnamed       unused   input  active-high
line   1:      unnamed       kernel   input  active-high [used]
line   2:      unnamed       unused   input  active-high
line   3:      unnamed       unused   input  active-high
line   4:      unnamed       kernel   input  active-high [used]
line   5:      unnamed       kernel   input  active-high [used]
line   6:      unnamed       kernel   input  active-high [used]
line   7:      unnamed       kernel   input  active-high [used]
line   8:      unnamed       kernel   input  active-high [used]
line   9:      unnamed       kernel   input  active-high [used]
line  10:      unnamed       kernel   input  active-high [used]
line  11:      unnamed       kernel   input  active-high [used]
line  12:      unnamed       kernel   input  active-high [used]
line  13:      unnamed       unused   input  active-high
line  14:      unnamed       unused   input  active-high
line  15:      unnamed       unused   input  active-high
gpiochip3 - 16 lines:
line   0:      unnamed       kernel   input  active-high [used]
line   1:      unnamed       kernel   input  active-high [used]
line   2:      unnamed       kernel   input  active-high [used]
line   3:      unnamed       kernel   input  active-high [used]
line   4:      unnamed       kernel   input  active-high [used]
line   5:      unnamed       kernel   input  active-high [used]
line   6:      unnamed       kernel   input  active-high [used]
line   7:      unnamed       kernel   input  active-high [used]
line   8:      unnamed       kernel   input  active-high [used]
line   9:      unnamed       kernel   input  active-high [used]
line  10:      unnamed       kernel   input  active-high [used]
line  11:      unnamed       kernel   input  active-high [used]
line  12:      unnamed       kernel   input  active-high [used]
line  13:      unnamed       unused   input  active-high
line  14:      unnamed       kernel   input  active-high [used]
line  15:      unnamed       kernel   input  active-high [used]
gpiochip4 - 16 lines:
line   0:      unnamed       kernel   input  active-high [used]
line   1:      unnamed       unused   input  active-high
line   2:      unnamed       kernel   input  active-high [used]
line   3:      unnamed       kernel   input  active-high [used]
line   4:      unnamed       kernel   input  active-high [used]
line   5:      unnamed       unused   input  active-high
line   6:      unnamed       unused   input  active-high
line   7:      unnamed       kernel   input  active-high [used]
line   8:      unnamed       kernel   input  active-high [used]
line   9:      unnamed       kernel   input  active-high [used]
line  10:      unnamed       unused   input  active-high
line  11:      unnamed       kernel   input  active-high [used]
line  12:      unnamed "panel-backlight" output active-high [used]
line  13:      unnamed       kernel   input  active-high [used]
line  14:      unnamed       kernel   input  active-high [used]
line  15:      unnamed       kernel   input  active-high [used]
gpiochip5 - 16 lines:
line   0:      unnamed       unused   input  active-high
line   1:      unnamed       kernel   input  active-high [used]
line   2:      unnamed       kernel   input  active-high [used]
line   3:      unnamed       kernel   input  active-high [used]
line   4:      unnamed       kernel   input  active-high [used]
line   5:      unnamed  "interrupt"   input  active-high [used]
line   6:      unnamed       kernel   input  active-high [used]
line   7:      unnamed       kernel   input  active-high [used]
line   8:      unnamed       kernel   input  active-high [used]
line   9:      unnamed       unused   input  active-high
line  10:      unnamed       unused   input  active-high
line  11:      unnamed       unused   input  active-high
line  12:      unnamed       kernel   input  active-high [used]
line  13:      unnamed       unused   input  active-high
line  14:      unnamed       unused   input  active-high
line  15:      unnamed       unused   input  active-high
gpiochip6 - 16 lines:
line   0:      unnamed       kernel   input  active-high [used]
line   1:      unnamed       unused   input  active-high
line   2:      unnamed       kernel   input  active-high [used]
line   3:      unnamed       unused   input  active-high
line   4:      unnamed       kernel   input  active-high [used]
line   5:      unnamed       kernel   input  active-high [used]
line   6:      unnamed       kernel   input  active-high [used]
line   7:      unnamed       kernel   input  active-high [used]
line   8:      unnamed       kernel   input  active-high [used]
line   9:      unnamed       kernel   input  active-high [used]
line  10:      unnamed       kernel   input  active-high [used]
line  11:      unnamed       kernel   input  active-high [used]
line  12:      unnamed  "interrupt"   input  active-high [used]
line  13:      unnamed       kernel   input  active-high [used]
line  14:      unnamed       kernel   input  active-high [used]
line  15:      unnamed       unused   input  active-high
gpiochip7 - 15 lines:
line   0:      unnamed       unused   input  active-high
line   1:      unnamed       unused   input  active-high
line   2:      unnamed      "reset"  output   active-low [used]
line   3:      unnamed       unused   input  active-high
line   4:      unnamed         "cd"   input   active-low [used pull-up]
line   5:      unnamed       unused   input  active-high
line   6:      unnamed       kernel   input  active-high [used]
line   7:      unnamed       unused   input  active-high
line   8:      unnamed       kernel   input  active-high [used]
line   9:      unnamed       kernel   input  active-high [used]
line  10:      unnamed       unused   input  active-high
line  11:      unnamed       unused   input  active-high
line  12:      unnamed       kernel   input  active-high [used]
line  13:      unnamed       kernel   input  active-high [used]
line  14:      unnamed       kernel   input  active-high [used]
gpiochip8 - 8 lines:
line   0:      unnamed       unused   input  active-high
line   1:      unnamed       kernel   input  active-high [used]
line   2:      unnamed  "interrupt"   input  active-high [used]
line   3:      unnamed       kernel   input  active-high [used]
line   4:      unnamed       unused   input  active-high
line   5:      unnamed       unused   input  active-high
line   6:      unnamed       unused   input  active-high
line   7:      unnamed     "enable"  output  active-high [used]
gpiochip9 - 16 lines:
line   0:      unnamed       unused   input  active-high
line   1:      unnamed       unused   input  active-high
line   2:      unnamed      "reset"  output   active-low [used]
line   3:      unnamed  "powerdown"  output   active-low [used]
line   4:      unnamed      "reset"  output   active-low [used]
line   5:      unnamed       unused   input  active-high
line   6:      unnamed       unused   input  active-high
line   7:      unnamed       unused   input  active-high
line   8:      unnamed       unused   input  active-high
line   9:      unnamed  "PHY reset"  output   active-low [used]
line  10:      unnamed  "PHY reset"  output   active-low [used]
line  11:      unnamed      "reset"  output   active-low [used]
line  12:      unnamed       unused   input  active-high
line  13:      unnamed   "shutdown"  output  active-high [used]
line  14:      unnamed       unused   input  active-high
line  15:      unnamed       unused   input  active-high

I don't know if this is due to the sample application running or not, see the attached picture.

Ultimately what I am looking for is when I read in the User manual that GPIO2 is pin 3, PH6, what gpiochip and line is this for example?  
I imagine this will also clear up the other question of how do I know if I can access that pin or if for some reason another application or the kernel has the pin under control or if I can peek/poke it through gpioget and gpioset.  Thanks in advance for your time.

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pittengermdp
Associate

‎2024-04-17 07:02 AM

So I've been doing some more reading and I see that H bank is GPIOCHIP 7 and so 6 would be line 6. But it is used by the kernel, how can I set the pin to be usable to the userspace?  As I see that PH6 is GPIO2 and is pin3 on the cn8 connector.

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Olivier GALLIEN
ST Employee
In response to pittengermdp

‎2024-05-31 05:27 AM

Hi @pittengermdp ,

 

Did you have a look to STM32MP135x-DK - hardware description - stm32mpu

 

It might help 

 

Olivier 

Olivier GALLIEN
In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.
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