linux-kernel - Re: [PATCH v6 2/4] leds: Add driver for Qualcomm LPG

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Date:   Wed, 5 May 2021 07:21:53 +0200
From:   Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Pavel Machek <pavel@....cz>,
        Thierry Reding <thierry.reding@...il.com>,
        Lee Jones <lee.jones@...aro.org>, Dan Murphy <dmurphy@...com>,
        Rob Herring <robh+dt@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Martin Botka <martin.botka1@...il.com>,
        linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-pwm@...r.kernel.org
Subject: Re: [PATCH v6 2/4] leds: Add driver for Qualcomm LPG

Hello,

On Tue, May 04, 2021 at 11:13:27AM -0500, Bjorn Andersson wrote:
> On Tue 04 May 10:43 CDT 2021, Pavel Machek wrote:
> > > So downstream they have (last time I looked at the code) an addition in
> > > the PWM API where the LED driver can inform the PWM driver part about
> > > the indices to use. Naturally I don't think that's a good idea.
> > 
> > Dunno. Is it bad idea?
> > 
> > pattern support for other PWMs (vibration?) seems useful, too. Yes, it
> > means more discussion and extending PWMs properly..
> > 
> 
> @Thierry, @Lee, @Uwe, are you interested in extending the PWM api with
> some sort of support for specifying an array of "duty_cycle" and some
> property for how fast the hardware should cycle through those duty
> cycles? (And I need a bit/bool to indicate if the pattern should run
> once of be repeated)
> 
> The (current) use case relates to being able to alter the duty cycle
> over time to create "effects" such as pulsing an LED.

My personal opinion here is that this is too special to be worth the
generalisation.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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