RE: [PATCH RESEND V2 1/3] clocksource/drivers/sysctr: Add optional clock-frequency property

From: Anson Huang <anson.huang@nxp.com>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"shawnguo@kernel.org" <shawnguo@kernel.org>,
	"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	"festevam@gmail.com" <festevam@gmail.com>,
	"l.stach@pengutronix.de" <l.stach@pengutronix.de>,
	Abel Vesa <abel.vesa@nxp.com>,
	"ccaione@baylibre.com" <ccaione@baylibre.com>,
	"angus@akkea.ca" <angus@akkea.ca>,
	"andrew.smirnov@gmail.com" <andrew.smirnov@gmail.com>,
	"agx@sigxcpu.org" <agx@sigxcpu.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Cc: dl-linux-imx <linux-imx@nxp.com>
Subject: RE: [PATCH RESEND V2 1/3] clocksource/drivers/sysctr: Add optional clock-frequency property
Date: Thu, 27 Jun 2019 13:11:55 +0000	[thread overview]
Message-ID: <DB3PR0402MB3916D17328CF69C09C74A3D8F5FD0@DB3PR0402MB3916.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <bb362db6-9c50-5d2c-349a-4097dea0449f@linaro.org>

Hi, Daniel

> On 23/06/2019 14:38, Anson.Huang@nxp.com wrote:
> > From: Anson Huang <Anson.Huang@nxp.com>
> >
> > Systems which use platform driver model for clock driver require the
> > clock frequency to be supplied via device tree when system counter
> > driver is enabled.
> >
> > This is necessary as in the platform driver model the of_clk
> > operations do not work correctly because system counter driver is
> > initialized in early phase of system boot up, and clock driver using
> > platform driver model is NOT ready at that time, it will cause system
> > counter driver initialization failed.
> >
> > Add the optinal clock-frequency to the device tree bindings of the NXP
> > system counter, so the frequency can be handed in and the of_clk
> > operations can be skipped.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> > ---
> > Changes since V1:
> > 	- improve commit log, no content change.
> > ---
> >  Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt | 6
> > ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git
> > a/Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt
> > b/Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt
> > index d576599..c9907a0 100644
> > --- a/Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt
> > +++ b/Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt
> > @@ -14,6 +14,11 @@ Required properties:
> >  - clocks : 	    Specifies the counter clock.
> >  - clock-names: 	    Specifies the clock's name of this module
> >
> > +Optional properties:
> > +
> > +- clock-frequency : Specifies system counter clock frequency and indicates
> system
> > +		    counter driver to skip clock operations.
> > +
> 
> Shouldn't it be required and mutually exclusive with clocks/clock-names?
>
Yes, make sense, I ever thought about it when doing this patch, but eventually I picked
the optional...will fix it in next version.

Thanks,
Anson

> >  Example:
> >
> >  	system_counter: timer@306a0000 {
> > @@ -22,4 +27,5 @@ Example:
> >  		clocks = <&clk_8m>;
> >  		clock-names = "per";
> >  		interrupts = <GIC_SPI 47 IRQ_TYPE_LEVEL_HIGH>;
> > +		clock-frequency = <8333333>;
> >  	};
> >
> 
> 

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