Hi all, I've been porting the mainline Linux kernel to the Technologic Systems TS-7670 industrial computers which are based on the Freescale i.MX286 SoC.
I've had to make a couple of hacks to get things working, my code is at https://github.com/vrtsystems/linux/tree/ts7670-4.4.1 Right now, there's a couple of GPIO lines for controlling power to things like RS-232 and CANBus transceivers. The RS-485 port on these devices also has a couple of pins that are connected to a CPU-controlled MOSFET to allow turning an external device on/off. Previously I used the generic GPIO sysfs interface. This worked well, but the names suddenly changed on me and so now my scripts don't work. It's also not that user friendly. Implementing a kernel driver is doable, but all I'm doing is just repeating work that the sysfs GPIO interface does already. Currently I'm doing it with the "LEDs" framework, since they'll have a consistent name -- users can for example, turn the RS-232 transceivers off by setting /sys/class/leds/rs232_en/brightness to 0. It's controlled by device tree. (Better in the case of RS-232, would be to have the port automatically turn the transceivers on. I managed to get the CANBus side to do that.) Is there some sort of mechanism by which GPIO lines could be clearly labelled to present a consistent interface in sysfs between kernel revisions? Regards, -- _ ___ Stuart Longland - Systems Engineer \ /|_) | T: +61 7 3535 9619 \/ | \ | 38b Douglas Street F: +61 7 3535 9699 SYSTEMS Milton QLD 4064 http://www.vrt.com.au
