linux-kernel - Re: [PATCH v10 2/2] leds: sc27xx: Add pattern

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Date:   Fri, 7 Sep 2018 10:51:04 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     Pavel Machek <pavel@....cz>
Cc:     Jacek Anaszewski <jacek.anaszewski@...il.com>,
        rteysseyre@...il.com, Bjorn Andersson <bjorn.andersson@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Linux LED Subsystem <linux-leds@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v10 2/2] leds: sc27xx: Add pattern_set/clear interfaces
 for LED controller

Hi Pavel,

On 7 September 2018 at 05:16, Pavel Machek <pavel@....cz> wrote:
> Hi!
>
>> diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
>> new file mode 100644
>> index 0000000..d8056d5
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
>> @@ -0,0 +1,22 @@
>> +What:                /sys/class/leds/<led>/hw_pattern
>> +Date:                September 2018
>> +KernelVersion:       4.20
>> +Description:
>> +             Specify a hardware pattern for the SC27XX LED. For the SC27XX
>> +             LED controller, it only supports 4 stages to make a single
>> +             hardware pattern, which is used to configure the rise time,
>> +             high time, fall time and low time for the breathing mode.
>> +
>> +             For the breathing mode, the SC27XX LED only expects one brightness
>> +             for the high stage. To be compatible with the hardware pattern
>> +             format, we should set brightness as 0 for rise stage, fall
>> +             stage and low stage.
>> +
>> +             Min stage duration: 125 ms
>> +             Max stage duration: 31875 ms
>> +
>> +             Since the stage duration step is 125 ms, the duration must be
>> +             a multiplier of 125, like 125ms, 250ms, 375ms, 500ms ... 31875ms.
>> +
>> +             Thus the format of the hardware pattern values should be:
>> +             "0 rise_duration brightness high_duration 0 fall_duration 0 low_duration".
>
> If I'm not mistaken, this is:
>
>                 "0 rise_duration brightness high_duration brightness
>                 fall_duration 0 low_duration".
>
> Right?

Hmmm, for SC27XX led, there is no need to set brightness for rise and
fall stage.

>
> With that fixed:
>
> Acked-by: Pavel Machek <pavel@....c>

Thanks.

-- 
Baolin Wang
Best Regards