Re: [PATCH] leds: Introduce userspace leds driver
From: Pavel Machek
Date: Thu Sep 15 2016 - 08:41:23 EST
Hi!
> Thanks for the patch. It is very nice. I have only one minor remark
> in the code.
>
> I think that it would be good to add a documentation for this
> driver to Documentation/leds, with exemplary C program instead
> of python one. The program could poll the dev node in a loop,
> which allows to conveniently check the impact of setting particular
> triggers and all other brightness change events.
Actually, I'd say that python is fine -- it is used heavily in tools/.
But perhaps the example program should go to tools/?
> >def change_brightness(b):
> > with open('/sys/class/leds/{}/brightness'.format(name) , 'w') as f:
> > f.write(str(b))
> >
> >
> >with open('/dev/uleds', 'rb+', 0) as uleds:
> > bname = name.encode("ascii")
> > # create the leds class device
> > uleds.write(bname + b'\0' * (ULEDS_MAX_NAME_SIZE - len(bname)))
Umm. I don't see it in the kernel code. You let userspace provide a
LED name?
Where is the LED name tested for sanity? I guess there could be a lot
of fun naming a led ".." for example...
Best regards,
Pavel
--
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