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

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Message-ID: <55abafbd-c010-32b5-6d76-26040830d5b0@linaro.org>
Date:   Tue, 25 Jun 2019 23:12:35 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Anson.Huang@....com, tglx@...utronix.de, robh+dt@...nel.org,
        mark.rutland@....com, shawnguo@...nel.org, s.hauer@...gutronix.de,
        kernel@...gutronix.de, festevam@...il.com, l.stach@...gutronix.de,
        abel.vesa@....com, ccaione@...libre.com, angus@...ea.ca,
        andrew.smirnov@...il.com, agx@...xcpu.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Cc:     Linux-imx@....com
Subject: Re: [PATCH RESEND V2 1/3] clocksource/drivers/sysctr: Add optional
 clock-frequency property

On 23/06/2019 14:38, Anson.Huang@....com wrote:
> From: Anson Huang <Anson.Huang@....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.

Isn't it possible to create a fixed-clock and refer to it? So no need to
create a specific action before calling timer_of_init() ?

> Signed-off-by: Anson Huang <Anson.Huang@....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.
> +
>  Example:
>  
>  	system_counter: timer@...a0000 {
> @@ -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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