From: Pavel Machek <pavel@ucw.cz>
To: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Dan Murphy <dmurphy@ti.com>,
linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, dachaac@gmail.com,
robh+dt@kernel.org
Subject: Re: RGB LED class Re: [PATCH v2 2/2] leds: lp50xx: Add the LP50XX family of the RGB LED driver
Date: Tue, 29 Jan 2019 00:04:08 +0100 [thread overview]
Message-ID: <20190128230408.GB5728@amd> (raw)
In-Reply-To: <9d2e0220-69f0-faaa-adb9-13d905f9c51d@gmail.com>
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Hi!
> >>What algorithm would be used for mapping brightness levels to RGB values
> >>in case of devices without hardware support for that?
> >
> >Output power = brightness / max_brightness * pwm_channel[x].
>
> IIUC you mean it as a formula for calculating r,g,b, values?
> I.e., on brightness setting we would have to do this calculation for
> each of three channels?
>
> Then, it will result in changing hue as well. That's why we're
> discussing HSV.
It should not change the hue, AFAICT, modulo the rounding errors.
> >>s/pwm/color/
> >
> >s/pwm/power/ would work for me.
>
> Power implies physical units. I'd prefer "intensity".
Intensity would work for me, too.
> >>Besides white also other color presets could be defined in DT.
> >
> >They should not be neccessary. When userspace knows what is white and
> >that power is linear with values in power_channels, it should be able
> >to do colorspace conversion itself.
>
> Have you verified it in practice? Would it allow to convert RGB values
> of the color displayed on the monitor to LED RGB class intensities,
> allowing to achieve similar color on the LED?
Yes, I think so.
My code is in unicsy_demo repository, in monitor/notint.py .
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2019-01-28 23:04 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-14 21:17 [PATCH v2 1/2] dt: bindings: lp50xx: Introduce the lp50xx family of RGB drivers Dan Murphy
2019-01-14 21:17 ` [PATCH v2 2/2] leds: lp50xx: Add the LP50XX family of the RGB LED driver Dan Murphy
2019-01-15 21:47 ` Jacek Anaszewski
2019-01-15 22:22 ` Pavel Machek
2019-01-16 0:20 ` Dan Murphy
2019-01-16 10:55 ` Pavel Machek
2019-01-16 18:41 ` Dan Murphy
2019-01-16 22:04 ` Pavel Machek
2019-01-16 23:33 ` Dan Murphy
2019-01-17 10:06 ` Pavel Machek
2019-01-17 13:27 ` Dan Murphy
2019-01-17 21:10 ` Jacek Anaszewski
2019-01-18 0:02 ` RGB LED class " Pavel Machek
2019-01-18 15:57 ` Dan Murphy
2019-01-28 23:03 ` Pavel Machek
2019-01-18 22:13 ` Jacek Anaszewski
2019-01-19 21:36 ` Pavel Machek
2019-01-20 15:30 ` Jacek Anaszewski
2019-01-21 19:38 ` Jacek Anaszewski
2019-01-28 23:04 ` Pavel Machek [this message]
2019-01-18 13:45 ` Dan Murphy
2019-01-18 13:58 ` Dan Murphy
2019-01-20 6:42 ` Vesa Jääskeläinen
2019-01-22 21:39 ` Jacek Anaszewski
2019-01-22 22:44 ` Dan Murphy
2019-01-23 21:52 ` Jacek Anaszewski
2019-01-24 21:00 ` Dan Murphy
2019-01-24 21:55 ` Jacek Anaszewski
2019-01-29 13:56 ` Dan Murphy
2019-01-29 20:19 ` Jacek Anaszewski
2019-01-29 20:26 ` Dan Murphy
2019-01-29 21:45 ` Pavel Machek
2019-01-29 21:46 ` Dan Murphy
2019-01-29 21:53 ` Jacek Anaszewski
2019-01-20 15:32 ` Jacek Anaszewski
2019-01-17 21:08 ` Jacek Anaszewski
2019-01-19 19:11 ` Vesa Jääskeläinen
2019-01-19 21:46 ` Pavel Machek
2019-01-19 22:44 ` Vesa Jääskeläinen
2019-01-20 6:51 ` Vesa Jääskeläinen
2019-01-21 13:27 ` Dan Murphy
2019-01-21 15:12 ` Vesa Jääskeläinen
2019-01-24 20:32 ` Dan Murphy
2019-01-24 21:14 ` Jacek Anaszewski
2019-01-15 21:42 ` [PATCH v2 1/2] dt: bindings: lp50xx: Introduce the lp50xx family of RGB drivers Jacek Anaszewski
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