On Mon, 28 May 2018, Jason Thorpe wrote:
I’m going to be writing a driver for the NXP PCA9685, and want to glue it into
the PWM kernel API jmcneill@ added… but I have a bunch of uses for this device
that won’t really be covered by FDT, so I think there needs to be some sort of
user space API as well.
I have to say that I’m growing frustrated with the proliferation of ioctl-based
APIs and *ctl programs. I’m tempted to start doing more of this stuff with
sysctl(), and then perhaps hiding the details from applications inside a shared
library API that exposes only opaque types and accessors / mutators. (Gawd,
historically, BSD has done such a terrible job at API design…)
My concern about sysctl(), though, is that because of the way it’s structured,
you’ve got a latency problem, which is not a concern in my application, but
might be an issue if you have an application that needs to control a servo
using PWM.
Curious to hear your thoughts on this.
I do this from time to time, mostly out of laziness (sys/dev/led.c for
example). Biggest issue I have is that with sysctl we lose the ability to
use chmod/chown/chgrp.
