On Mon, May 23, 2016 at 04:05:23PM +0200, Johannes Thoma wrote:
Dear list,
I am writing a driver which uses the "new" descriptor interface of the GPIO library. As far as I have understood it, gpiod_get(8) is the way to allocate (and also lock?) GPIOs pins for use. My question is how do I find what to pass as the con_id parameter (this should identify the pin but please correct me if I am wrong, in that case how to I tell gpiod_get which pin I want?). Is there a file somewhere where I can find the pin names of my hardware (which is a raspberry 1 for now), something like /sys/class/gpio/xxx/gpio_pin_names or so, or do I have to look them up in the device tree or somewhere else? Or do I have to configure the pin somewhere in the device tree? What I would like to do is offer an interface (via configfs) where the pins the sensor is attached can be configured dynamically at run-time.
The driver itself is OpenSource (GPL) and can be obtained at
http://github.com/johannesthoma/linux-hc-sro4
(iio branch is currently the dev branch where this problem occurs).
Thanks a lot,
A while ago i was trying to understand how to use descriptor based interface playing with my RPi, you can find ressults here: https://github.com/krinkinmu/rpi-gpio-example (*.tex files are in russian, sorry), IFAIU, you have to specify name in device tree before you can use it.
- Johannes
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