On Fri, Feb 27, 2015 at 10:19 PM, folkert <[email protected]> wrote: >> > Mmm, I was thinking it would be nice to have a (new, redesigned) sysfs >> > interface for this. :P >> > >> > Aren't we going to make things less accessible if we use a char device? >> >> Since sysfs has a "one value per file" paradigm, it also has a >> "one context switch per operation" paradigm, meaning any >> efficiency-oriented use cases where a lot of stuff needs to be >> changed in one context switch are by the very construction >> not suitable for sysfs IMO. That is the use case for ioctl() >> operations that can pass an entire struct of stuff over. >> >> And things like bit-banging a clock+data line which would in >> a sysfs case involve two context switches (one per value, since >> that is one file per GPIO line) in an ioctl() case it would be >> just one, already 50% less context switches for a very basic >> use case. >> >> But I may be just so wrong ... input welcome. > > Another bad thing of the current sysfs versions: it is ascii. > So I need to convert a=1 to a='1' first before write()ing it to the > file. Very inconvenient because it adds boilerplate code. > On the other hand, the sysfs is very much extensible.
write(fd, a == 0 ? '0' : '1', 1); That doesn't look like too much boilerplate to me. And it can easily be hidden under a dedicated macro/function. -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
