From: Pavel Machek <pavel@ucw.cz>
To: "hamza.farooq@siemens.com" <hamza.farooq@siemens.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux LED Subsystem <linux-leds@vger.kernel.org>,
Platform Driver <platform-driver-x86@vger.kernel.org>,
"henning.schild@siemens.com" <henning.schild@siemens.com>,
"jan.kiszka@siemens.com" <jan.kiszka@siemens.com>,
"Haeussler, Gerd" <gerd.haeussler.ext@siemens.com>
Subject: Re: Define LEDs with mixed colors
Date: Mon, 1 Nov 2021 13:18:40 +0100 [thread overview]
Message-ID: <20211101121840.GB2571@duo.ucw.cz> (raw)
In-Reply-To: <DBAPR10MB42198EA968C14B13B510834D8ACD9@DBAPR10MB4219.EURPRD10.PROD.OUTLOOK.COM>
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Hi!
> > > I am toying with the idea of writing a multicolor LED GPIO driver. What
> > would be the right way to define mixed color LEDs (for leds-gpio), in device
> > tree or ACPI?
> > > Consider the following:
> > >
> > > leds {
> > > compatible = "gpio-leds";
> > > led0 {
> > > gpios = <&mcu_pio 0 GPIO_ACTIVE_LOW>;
> > > color = <LED_COLOR_ID_RED>;
> > > };
> > >
> > > led1 {
> > > gpios = <&mcu_pio 1 GPIO_ACTIVE_HIGH>;
> > > color = <LED_COLOR_ID_GREEN>;
> > > };
> > > led2 {
> > > gpios = <&mcu_pio 0 GPIO_ACTIVE_LOW
> > > &mcu_pio 1 GPIO_ACTIVE_LOW>;
> > > color = <LED_COLOR_ID_AMBER>;
> > > };
> > > };
> > >
> > > This probably won't work as "gpios" seem to be single object in gpio-leds
> > driver code, but what can I do to achieve something similar?
> > > It is important to define this LED in DT/ACPI in order for the user app to see
> > it in the /sys/class/led folder, without having to write platform-specific
> > driver.
> > >
> >
> > So you have one package with red and green LED, each connected to one
> > GPIO?
> Right. It is possible to create orange color, and I want to use DT/ACPI to present this info to the userland.
>
> >
> > Can you take a look at Documentation/leds/leds-class-multicolor.rst?
> Couldn't find a hint there therefore this email thread. I might eventually write a multicolor led-gpio driver so want to know how to handle mixed LED.
>
There's no similar driver in the tree, and we don't have estabilished
API. You are mostly on your own.
Best regards,
Pavel
--
http://www.livejournal.com/~pavelmachek
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prev parent reply other threads:[~2021-11-01 12:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-01 8:39 Define LEDs with mixed colors hamza.farooq
2021-09-01 11:09 ` Pavel Machek
2021-09-01 11:24 ` hamza.farooq
2021-11-01 12:18 ` Pavel Machek [this message]
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