From: Greg KH <gregkh@linuxfoundation.org>
To: Pavel Machek <pavel@denx.de>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>,
Dan Murphy <dmurphy@ti.com>,
linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RESEND PATCH v17 00/17] Multi Color LED Framework
Date: Thu, 27 Feb 2020 13:43:29 +0100 [thread overview]
Message-ID: <20200227124329.GA994747@kroah.com> (raw)
In-Reply-To: <20200227105808.GA27003@duo.ucw.cz>
On Thu, Feb 27, 2020 at 11:58:08AM +0100, Pavel Machek wrote:
> Hi, Jacek!
>
> (and thanks for doing this).
>
> > We have here long lasting discussion related to LED multicolor class
> > sysfs interface design. We went through several iterations and worked
> > out the solution with individual file per each color sub-LED in the
> > color directory as shown below:
> >
> > /sys/class/leds/<led>/colors/<color>_intensity
> >
> > This is in line with one-value-per-file sysfs rule, that is being
> > frequently highlighted, and we even had not so long ago a patch
> > for led cpu trigger solving the problem caused by this rule not
> > being adhered to.
>
> Yep. One of the problems is that it is nice to change all the hardware
> channels at once to produce color (it is often on i2c -- and slow), so
> current proposals use "interesting" kind of latching.
>
> > Now we have the voice below bringing to attention another caveat
> > from sysfs documentation:
> >
> > "it is socially acceptable to express an array of values of the same
> > type"
> >
> > and proposing the interface in the form of two files:
> >
> > channel_intensity (file containing array of u32's)
> > channel_names (usually containing "red green blue")
>
> And thus I want to have it in one file, so it is naturaly atomic. RGB
> leds with 3 channels are common; I have not user yet, but there are
> RGBW with 4 channels (and some more exotic stuff). I don't expect to
> have more than 5 channels.
Writing 3 or 4 or 5 numbers all at once in a single sysfs file to
represent a single output should be fine.
thanks,
greg k-h
next prev parent reply other threads:[~2020-02-27 12:43 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-27 15:00 [RESEND PATCH v17 00/17] Multi Color LED Framework Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 01/17] dt-bindings: leds: Add multicolor ID to the color ID list Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 02/17] " Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 03/17] leds: multicolor: Introduce a multicolor class definition Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 04/17] dt: bindings: lp50xx: Introduce the lp50xx family of RGB drivers Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 05/17] leds: lp50xx: Add the LP50XX family of the RGB LED driver Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 06/17] dt: bindings: lp55xx: Be consistent in the document with LED acronym Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 07/17] dt: bindings: lp55xx: Update binding for Multicolor Framework Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 08/17] ARM: dts: n900: Add reg property to the LP5523 channel node Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 09/17] ARM: dts: imx6dl-yapp4: Add reg property to the lp5562 " Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 10/17] ARM: dts: ste-href: Add reg property to the LP5521 channel nodes Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 11/17] leds: lp55xx: Convert LED class registration to devm_* Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 12/17] leds: lp55xx: Add multicolor framework support to lp55xx Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 13/17] leds: lp5523: Update the lp5523 code to add multicolor brightness function Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 14/17] leds: lp5521: Add multicolor framework multicolor brightness support Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 15/17] leds: lp55xx: Fix checkpatch file permissions issues Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 16/17] leds: lp5523: Fix checkpatch issues in the code Dan Murphy
2020-01-27 15:00 ` [RESEND PATCH v17 17/17] dt: bindings: Update lp55xx binding to recommended LED naming Dan Murphy
2020-02-12 13:09 ` [RESEND PATCH v17 00/17] Multi Color LED Framework Dan Murphy
2020-02-25 10:19 ` Pavel Machek
2020-02-25 22:17 ` Jacek Anaszewski
2020-02-25 22:44 ` Dan Murphy
2020-02-26 12:59 ` Pavel Machek
2020-02-26 20:45 ` Jacek Anaszewski
2020-02-26 22:10 ` Dan Murphy
2020-02-27 10:58 ` Pavel Machek
2020-02-27 12:43 ` Greg KH [this message]
2020-02-27 13:07 ` Dan Murphy
2020-02-27 13:29 ` Dan Murphy
2020-02-27 21:22 ` Jacek Anaszewski
2020-02-28 7:42 ` Greg KH
2020-02-28 9:34 ` Pavel Machek
2020-02-28 12:30 ` Dan Murphy
2020-02-28 9:39 ` Pavel Machek
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