linux-kernel - Re: [PATCH 1/4] arm64: dts: exynos: Add PWM interrupts on Exynos7

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Date:   Thu, 2 Jul 2020 08:00:02 +0200
From:   'Krzysztof Kozlowski' <krzk@...nel.org>
To:     Alim Akhtar <alim.akhtar@...sung.com>
Cc:     'Rob Herring' <robh+dt@...nel.org>,
        'Kukjin Kim' <kgene@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        'Marek Szyprowski' <m.szyprowski@...sung.com>,
        'Bartlomiej Zolnierkiewicz' <b.zolnierkie@...sung.com>,
        'Sylwester Nawrocki' <snawrocki@...nel.org>,
        'Chanwoo Choi' <cw00.choi@...sung.com>,
        'Pankaj Dubey' <pankaj.dubey@...sung.com>
Subject: Re: [PATCH 1/4] arm64: dts: exynos: Add PWM interrupts on Exynos7

On Tue, Jun 30, 2020 at 08:54:28PM +0530, Alim Akhtar wrote:
> Hi Krzysztof,
> 
> > -----Original Message-----
> > From: Krzysztof Kozlowski <krzk@...nel.org>
> > Sent: 30 June 2020 02:15
> > To: Rob Herring <robh+dt@...nel.org>; Kukjin Kim <kgene@...nel.org>;
> > Krzysztof Kozlowski <krzk@...nel.org>; devicetree@...r.kernel.org;
> linux-arm-
> > kernel@...ts.infradead.org; linux-samsung-soc@...r.kernel.org; linux-
> > kernel@...r.kernel.org
> > Cc: Marek Szyprowski <m.szyprowski@...sung.com>; Bartlomiej Zolnierkiewicz
> > <b.zolnierkie@...sung.com>; Sylwester Nawrocki <snawrocki@...nel.org>;
> > Alim Akhtar <alim.akhtar@...sung.com>; Chanwoo Choi
> > <cw00.choi@...sung.com>; Pankaj Dubey <pankaj.dubey@...sung.com>
> > Subject: [PATCH 1/4] arm64: dts: exynos: Add PWM interrupts on Exynos7
> > 
> > Add required interrupts to PWM node on Exynos7.  This fixes DT schema
> > warning:
> > 
> >     pwm@...c0000: 'interrupts' is a required property
> > 
> > Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> > 
> > ---
> > 
> > Not tested
> > ---
> >  arch/arm64/boot/dts/exynos/exynos7.dtsi | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/exynos/exynos7.dtsi
> > b/arch/arm64/boot/dts/exynos/exynos7.dtsi
> > index f590891efe25..523547b3d539 100644
> > --- a/arch/arm64/boot/dts/exynos/exynos7.dtsi
> > +++ b/arch/arm64/boot/dts/exynos/exynos7.dtsi
> > @@ -581,6 +581,11 @@
> >  		pwm: pwm@...c0000 {
> >  			compatible = "samsung,exynos4210-pwm";
> >  			reg = <0x136c0000 0x100>;
> > +			interrupts = <GIC_SPI 444 IRQ_TYPE_LEVEL_HIGH>,
> > +				     <GIC_SPI 445 IRQ_TYPE_LEVEL_HIGH>,
> > +				     <GIC_SPI 446 IRQ_TYPE_LEVEL_HIGH>,
> > +				     <GIC_SPI 447 IRQ_TYPE_LEVEL_HIGH>,
> > +				     <GIC_SPI 448 IRQ_TYPE_LEVEL_HIGH>;
> PWM IRQs are from 449 ~ 453 for PWM[0] ~ PWM[4] on this SoC.
> 444 ~ 447 are for HSI2C and 448 is for ADC.

Ah, indeed.

> Please see the exynos7.dtsi
> Also drivers/pwm/pwm-samsung.c does not uses interrupt at all, still we need
> interrupts property to be added here?

That's a good point. For S3C SoCs the PWM timer was used also as a
clocksource so it required interrupts. But since Exynos this is not
used.  I don't know why the bindings introduced required interrupts...
It seems it would be better just to remove them from bindings and DTS.

Best regards,
Krzysztof