From: Pavel Machek <pavel@ucw.cz>
To: Jacek Anaszewski <j.anaszewski@samsung.com>
Cc: David Lechner <david@lechnology.com>,
Richard Purdie <rpurdie@rpsys.net>,
linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org,
Marcel Holtmann <marcel@holtmann.org>
Subject: Re: [PATCH] leds: Introduce userspace leds driver
Date: Thu, 15 Sep 2016 14:41:03 +0200 [thread overview]
Message-ID: <20160915124103.GF13132@amd> (raw)
In-Reply-To: <04c5ee0d-9bfb-6e0a-2616-6cf720fc8763@samsung.com>
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
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2016-09-15 12:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-06 2:15 [PATCH] leds: Introduce userspace leds driver David Lechner
2016-09-06 5:09 ` Peter Meerwald-Stadler
2016-09-06 15:21 ` David Lechner
2016-09-08 9:58 ` Jacek Anaszewski
2016-09-15 12:41 ` Pavel Machek [this message]
2016-09-15 14:53 ` Jacek Anaszewski
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