Re: [PATCH v7 1/5] dt-bindings: leds: Add pattern initialization from Device Tree

[Jacek Anaszewski <jacek.anaszewski@gmail.com>]

Hi Krzysztof,

Thank you for the update.

Patch set looks good to me.

Now we're missing only ack from Rob for this patch.

Best regards,
Jacek Anaszewski

On 1/9/19 3:44 PM, Krzysztof Kozlowski wrote:
> Document new led-pattern property for initialization of LED triggers.
> The property format is trigger-specific (except being array of
> integers).  For pattern trigger, the explanation of pattern format was
> moved to a common file shared with sysfs ABI.
> 
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> Acked-by: Pavel Machek <pavel@ucw.cz>
> ---
>   .../ABI/testing/sysfs-class-led-trigger-pattern    | 51 ++--------------------
>   Documentation/devicetree/bindings/leds/common.txt  | 12 +++++
>   .../bindings/leds/leds-trigger-pattern.txt         | 49 +++++++++++++++++++++
>   3 files changed, 64 insertions(+), 48 deletions(-)
>   create mode 100644 Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
> index 1e5d172e0646..bd92ef9d6faa 100644
> --- a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
> +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
> @@ -7,55 +7,10 @@ Description:
>   		timer. It can do gradual dimming and step change of brightness.
>   
>   		The pattern is given by a series of tuples, of brightness and
> -		duration (ms). The LED is expected to traverse the series and
> -		each brightness value for the specified duration. Duration of
> -		0 means brightness should immediately change to new value, and
> -		writing malformed pattern deactivates any active one.
> +		duration (ms).
>   
> -		1. For gradual dimming, the dimming interval now is set as 50
> -		milliseconds. So the tuple with duration less than dimming
> -		interval (50ms) is treated as a step change of brightness,
> -		i.e. the subsequent brightness will be applied without adding
> -		intervening dimming intervals.
> -
> -		The gradual dimming format of the software pattern values should be:
> -		"brightness_1 duration_1 brightness_2 duration_2 brightness_3
> -		duration_3 ...". For example:
> -
> -		echo 0 1000 255 2000 > pattern
> -
> -		It will make the LED go gradually from zero-intensity to max (255)
> -		intensity in 1000 milliseconds, then back to zero intensity in 2000
> -		milliseconds:
> -
> -		LED brightness
> -		    ^
> -		255-|       / \            / \            /
> -		    |      /    \         /    \         /
> -		    |     /       \      /       \      /
> -		    |    /          \   /          \   /
> -		  0-|   /             \/             \/
> -		    +---0----1----2----3----4----5----6------------> time (s)
> -
> -		2. To make the LED go instantly from one brightness value to another,
> -		we should use zero-time lengths (the brightness must be same as
> -		the previous tuple's). So the format should be:
> -		"brightness_1 duration_1 brightness_1 0 brightness_2 duration_2
> -		brightness_2 0 ...". For example:
> -
> -		echo 0 1000 0 0 255 2000 255 0 > pattern
> -
> -		It will make the LED stay off for one second, then stay at max brightness
> -		for two seconds:
> -
> -		LED brightness
> -		    ^
> -		255-|        +---------+    +---------+
> -		    |        |         |    |         |
> -		    |        |         |    |         |
> -		    |        |         |    |         |
> -		  0-|   -----+         +----+         +----
> -		    +---0----1----2----3----4----5----6------------> time (s)
> +		The exact format is described in:
> +		Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
>   
>   What:		/sys/class/leds/<led>/hw_pattern
>   Date:		September 2018
> diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
> index aa1399814a2a..70876ac11367 100644
> --- a/Documentation/devicetree/bindings/leds/common.txt
> +++ b/Documentation/devicetree/bindings/leds/common.txt
> @@ -37,6 +37,18 @@ Optional properties for child nodes:
>        "ide-disk" - LED indicates IDE disk activity (deprecated),
>                     in new implementations use "disk-activity"
>        "timer" - LED flashes at a fixed, configurable rate
> +     "pattern" - LED alters the brightness for the specified duration with one
> +                 software timer (requires "led-pattern" property)
> +
> +- led-pattern : Array of integers with default pattern for certain triggers.
> +                Each trigger may parse this property differently:
> +                - one-shot : two numbers specifying delay on and delay off (in ms),
> +                - timer : two numbers specifying delay on and delay off (in ms),
> +                - pattern : the pattern is given by a series of tuples, of
> +                  brightness and duration (in ms).  The exact format is
> +                  described in:
> +                  Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
> +
>   
>   - led-max-microamp : Maximum LED supply current in microamperes. This property
>                        can be made mandatory for the board configurations
> diff --git a/Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt b/Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
> new file mode 100644
> index 000000000000..d3696680bfc8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
> @@ -0,0 +1,49 @@
> +* Pattern format for LED pattern trigger
> +
> +The pattern is given by a series of tuples, of brightness and duration (ms).
> +The LED is expected to traverse the series and each brightness value for the
> +specified duration. Duration of 0 means brightness should immediately change to
> +new value, and writing malformed pattern deactivates any active one.
> +
> +1. For gradual dimming, the dimming interval now is set as 50 milliseconds. So
> +the tuple with duration less than dimming interval (50ms) is treated as a step
> +change of brightness, i.e. the subsequent brightness will be applied without
> +adding intervening dimming intervals.
> +
> +The gradual dimming format of the software pattern values should be:
> +"brightness_1 duration_1 brightness_2 duration_2 brightness_3 duration_3 ...".
> +For example (using sysfs interface):
> +
> +echo 0 1000 255 2000 > pattern
> +
> +It will make the LED go gradually from zero-intensity to max (255) intensity in
> +1000 milliseconds, then back to zero intensity in 2000 milliseconds:
> +
> +LED brightness
> +    ^
> +255-|       / \            / \            /
> +    |      /    \         /    \         /
> +    |     /       \      /       \      /
> +    |    /          \   /          \   /
> +  0-|   /             \/             \/
> +    +---0----1----2----3----4----5----6------------> time (s)
> +
> +2. To make the LED go instantly from one brightness value to another, we should
> +use zero-time lengths (the brightness must be same as the previous tuple's). So
> +the format should be: "brightness_1 duration_1 brightness_1 0 brightness_2
> +duration_2 brightness_2 0 ...".
> +For example (using sysfs interface):
> +
> +echo 0 1000 0 0 255 2000 255 0 > pattern
> +
> +It will make the LED stay off for one second, then stay at max brightness for
> +two seconds:
> +
> +LED brightness
> +    ^
> +255-|        +---------+    +---------+
> +    |        |         |    |         |
> +    |        |         |    |         |
> +    |        |         |    |         |
> +  0-|   -----+         +----+         +----
> +    +---0----1----2----3----4----5----6------------> time (s)
>