standard kernels won't know about. And for some tasks, simple userspace
GPIO drivers could be all that the system really needs.
-DO NOT ABUSE SYFS TO CONTROL HARDWARE THAT HAS PROPER KERNEL DRIVERS.
+DO NOT ABUSE SYSFS TO CONTROL HARDWARE THAT HAS PROPER KERNEL DRIVERS.
PLEASE READ THE DOCUMENT NAMED "drivers-on-gpio.txt" IN THIS DOCUMENTATION
DIRECTORY TO AVOID REINVENTING KERNEL WHEELS IN USERSPACE. I MEAN IT.
REALLY.
Paths in Sysfs
--------------
-There are three kinds of entry in /sys/class/gpio:
+There are three kinds of entries in /sys/class/gpio:
- Control interfaces used to get userspace control over GPIOs;
"label" ... provided for diagnostics (not always unique)
- "ngpio" ... how many GPIOs this manges (N to N + ngpio - 1)
+ "ngpio" ... how many GPIOs this manages (N to N + ngpio - 1)
Board documentation should in most cases cover what GPIOs are used for
what purposes. However, those numbers are not always stable; GPIOs on