linux-kernel - Re: [PATCH v2 2/4] pwm: Add Apple PWM controller

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Date:   Wed, 2 Nov 2022 18:57:59 +0300
From:   Sasha Finkelstein <fnkl.kernel@...il.com>
To:     Biju Das <biju.das.jz@...renesas.com>
Cc:     "thierry.reding@...il.com" <thierry.reding@...il.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        "marcan@...can.st" <marcan@...can.st>,
        "sven@...npeter.dev" <sven@...npeter.dev>,
        "alyssa@...enzweig.io" <alyssa@...enzweig.io>,
        "asahi@...ts.linux.dev" <asahi@...ts.linux.dev>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-pwm@...r.kernel.org" <linux-pwm@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/4] pwm: Add Apple PWM controller

On Wed, 2 Nov 2022 at 18:33, Biju Das <biju.das.jz@...renesas.com> wrote:
> > +     clk = devm_clk_get_enabled(&pdev->dev, NULL);
> > +     if (IS_ERR(clk))
> > +             return PTR_ERR(clk);
>
> What is your use case?
>
> PWM is configured by bootloader intially??
>
> Or
>
> PWM is configured by Linux not by the bootloader?
>
> Or
>
> Driver needs to support both ??

The PWM device itself is configured by linux, but the clock it uses is
the systemwide 24 MHz clock, and that is configured by platform
firmware.