linux-kernel - Re: [PATCH v7 12/12] led: bd71828: Support LED outputs on ROHM BD71828 PMIC

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Date:   Sat, 21 Dec 2019 20:48:02 +0100
From:   Pavel Machek <pavel@....cz>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     mazziesaccount@...il.com,
        Jacek Anaszewski <jacek.anaszewski@...il.com>,
        Dan Murphy <dmurphy@...com>, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Lee Jones <lee.jones@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-gpio@...r.kernel.org, linux-rtc@...r.kernel.org
Subject: Re: [PATCH v7 12/12] led: bd71828: Support LED outputs on ROHM
 BD71828 PMIC

Hi!

> ROHM BD71828 power management IC has two LED outputs for charge status
> and button pressing indications. The LED outputs can also be forced
> by SW so add driver allowing to use these LEDs for other indications
> as well.
> 
> Leds are controlled by SW using 'Force ON' bits. Please note the
> constrains mentioned in data-sheet:
>     1. If one LED is forced ON - then also the other LED is forced.
>             => You can't use SW control to force ON one LED and allow HW
>                to control the other.
>     2. You can't force both LEDs OFF. If the FORCE bit for both LED's is
>        zero, then LEDs are controlled by HW and indicate button/charger
>        states as explained in data-sheet.

That's really quite sad, is it?

All the effort and all we got is ... one working LED. Because hardware
does not allow you to control both LEDs...

...and we don't even have support selecting if the LED should be sw or
hw controlled in the mainline, yet...

Best regards,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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