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From: Pavel Machek <pavel@denx.de>
To: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>, 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 11:58:08 +0100	[thread overview]
Message-ID: <20200227105808.GA27003@duo.ucw.cz> (raw)
In-Reply-To: <20f6bdd5-e899-aead-8c35-1c3a3d09145f@gmail.com>

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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.

Best regards,
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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  parent reply	other threads:[~2020-02-27 10:58 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 [this message]
2020-02-27 12:43             ` Greg KH
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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