On 2014/02/16 14:43, Sven-Volker Nowarra wrote: > Hi, > > I am currently extending my asmc driver (in kernel) to listen to a userland > utility (asmcctl). > I want to be able to e.g. tell the kernel asmc driver to increase/decrease > backlight. > Now I need to get this "brightness integer" from userland (everybody should > be able to do this without privilegdes) to the kernel module. > I went through the recommended docs: > > An Introductory 4.4BSD Interprocess Communication Tutorial > An Advanced 4.4BSD Interprocess Communication Tutorial > > Does IPC apply for calls between kernel and userland? Or is the syscall > framework the right path ? (man 9 syscall). > > Trying to proceed, I could only find two additional docs explaining some > principles: > > 1. NetBSD Documentation: Writing a pseudo device > 2. OpenBSD Loadable Kernel Modules (well, I don't really wand a lkm...). > > I was thinking to use s.th. like wsconsctl or the usr.bin/radioctl/radioctl.c > and sys/dev/radio.c, but got stuck on that machine independent stuff (struct > device * > radio_attach_mi ...). > > Can someone point me to the right direction ? > > thx > Volker > >
Hooking into the wsconsctl framework would probably be most appropriate for this. You may like to look at scoop_set_backlight / lcd_param in the source files in /sys/arch/zaurus/zaurus/ as a possible starting point.
