linux-kernel - Re: [PATCH v5 1/9] leds: multicolor: Add sysfs interface definition

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Date:   Sun, 15 Sep 2019 15:57:55 +0200
From:   Jacek Anaszewski <jacek.anaszewski@...il.com>
To:     Dan Murphy <dmurphy@...com>, pavel@....cz
Cc:     robh+dt@...nel.org, linux-leds@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 1/9] leds: multicolor: Add sysfs interface definition

Hi Dan,

On 9/11/19 8:01 PM, Dan Murphy wrote:
> Add a documentation of LED Multicolor LED class specific
> sysfs attributes.
> 
> Signed-off-by: Dan Murphy <dmurphy@...com>
> ---
>  .../ABI/testing/sysfs-class-led-multicolor    | 73 +++++++++++++++++++
>  1 file changed, 73 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-led-multicolor
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-led-multicolor b/Documentation/ABI/testing/sysfs-class-led-multicolor
> new file mode 100644
> index 000000000000..4ea54c2ad4c8
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-led-multicolor
> @@ -0,0 +1,73 @@
> +What:		/sys/class/leds/<led>/brightness
> +Date:		Sept 2019
> +KernelVersion:	5.5
> +Contact:	Dan Murphy <dmurphy@...com>
> +Description:	read/write
> +		The multicolor class will redirect the device drivers call back
> +		function for brightness control to the multicolor class
> +		brightness control function.
> +
> +		Writing to this file will update all LEDs within the group to a
> +		calculated percentage of what each color LED in the group is set
> +		to.  The percentage is calculated via the equation below:
> +
> +		led_brightness = requested_value * led_color_intensity/led_color_max_intensity
> +
> +		For additional details please refer to
> +		Documentation/leds/leds-class-multicolor.rst.
> +
> +		The value of the color is from 0 to
> +		/sys/class/leds/<led>/max_brightness.
> +
> +What:		/sys/class/leds/<led>/colors/color_mix
> +Date:		Sept 2019
> +KernelVersion:	5.5
> +Contact:	Dan Murphy <dmurphy@...com>
> +Description:	read/write
> +		The values written to this file should contain the intensity
> +		values of each multicolor LED within the colors directory. The
> +		index of given color is reported by the color_id file present in
> +		colors/<color> directory. The index determines the position in
> +		the sequence of	intensities on which the related intensity
> +		should be passed to this file.
> +
> +		For additional details please refer to
> +		Documentation/leds/leds-class-multicolor.rst.

As already mentioned in the reply to Pavel - let's avoid the
introduction of another sysfs file with multiple values.

Color intensity files will only cache the value and actual
write will be performed upon writing brightness file.

> +
> +What:		/sys/class/leds/<led>/colors/<led_color>/color_id
> +Date:		Sept 2019
> +KernelVersion:	5.5
> +Contact:	Dan Murphy <dmurphy@...com>
> +Description:	read only
> +		This file when read will return the index of the color in the
> +		color_mix.
> +
> +		For additional details please refer to
> +		Documentation/leds/leds-class-multicolor.rst.
> +
> +What:		/sys/class/leds/<led>/colors/<led_color>/intensity
> +Date:		Sept 2019
> +KernelVersion:	5.5
> +Contact:	Dan Murphy <dmurphy@...com>
> +Description:	read/write
> +		The led_color directory is dynamically created based on the
> +		colors defined by the registrar of the class.
> +		The led_color can be but not limited to red, green, blue,
> +		white, amber, yellow and violet.  There is one directory per color
> +		presented.  The brightness file is created under each
> +		led_color directory and controls the individual LED color
> +		setting.
> +
> +		The value of the color is from 0 to
> +		/sys/class/leds/<led>/colors/<led_color>/max_intensity.
> +
> +What:		/sys/class/leds/<led>/colors/<led_color>/max_intensity
> +Date:		Sept 2019
> +KernelVersion:	5.5
> +Contact:	Dan Murphy <dmurphy@...com>
> +Description:	read only
> +		Maximum intensity level for the LED color, default is
> +		255 (LED_FULL).
> +
> +		If the LED does not support different intensity levels, this
> +		should be 1.
> 

-- 
Best regards,
Jacek Anaszewski