linux-kernel - Re: [PATCH 1/2] leds: Add driver for Qualcomm LPG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170329021734.afhqmfpmbcjyv7bu@rob-hp-laptop>
Date:   Tue, 28 Mar 2017 21:17:34 -0500
From:   Rob Herring <robh@...nel.org>
To:     Pavel Machek <pavel@....cz>
Cc:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Richard Purdie <rpurdie@...ys.net>,
        Jacek Anaszewski <jacek.anaszewski@...il.com>,
        linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, Mark Rutland <mark.rutland@....com>,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 1/2] leds: Add driver for Qualcomm LPG

On Thu, Mar 23, 2017 at 09:37:49PM +0100, Pavel Machek wrote:
> Hi!
> 
> > The Light Pulse Generator (LPG) is a PWM-block found in a wide range of
> > PMICs from Qualcomm. It can operate on fixed parameters or based on a
> > lookup-table, altering the duty cycle over time - which provides the
> > means for e.g. hardware assisted transitions of LED brightness.
> 
> Ok, this is not first hardware that supports something like this. We
> have similar hardware that can do blinking on Nokia N900 -- please
> take a look at leds-lp55*.c

And perhaps some alignment on the bindings too if the N900 has bindings.

> And it would be really good to provide hardware abstraction. We really
> don't want to have different userspace for LPG and for N900 and for

I'm interested in what this looks like as several AOSP platforms do 
tri-color LEDs with custom sysfs extensions.

Do any of the Dragonboards have tri-color LEDs?

Rob