linux-kernel - Re: [PATCH v2 1/4] cpufreq: pxa: use generic platdev driver for device-tree

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Message-ID: <87insl3f4y.fsf@belgarion.home>
Date:   Fri, 21 Oct 2016 17:17:49 +0200
From:   Robert Jarzmik <robert.jarzmik@...e.fr>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Daniel Mack <daniel@...que.org>,
        Haojian Zhuang <haojian.zhuang@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Rafael Wysocki <rjw@...ysocki.net>,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v2 1/4] cpufreq: pxa: use generic platdev driver for device-tree

Viresh Kumar <viresh.kumar@...aro.org> writes:

> On 19-10-16, 22:06, Robert Jarzmik wrote:
>> Viresh Kumar <viresh.kumar@...aro.org> writes:
>> 
>> >> >> +	{ .compatible = "marvell,pxa250", },
>> >> >> +	{ .compatible = "marvell,pxa270", },
>> >> >>  
>> >> >>  	{ .compatible = "samsung,exynos3250", },
>> >> >>  	{ .compatible = "samsung,exynos4210", },
>> >> >
>> >> > Isn't there a race between cpufreq-dt and the platform driver to
>> >> > register first ?
>> >> Ah, could you be more specific about the race you're talking of ?
>> >> 
>> >> My understanding was that cpufreq-dt-platdev does create the device, and
>> >> cpufreq-dt is a driver for it, so there is no race but a direct relationship
>> >> AFAIU.
>> >
>> > I mean that both the driver may try to register to the cpufreq core if
>> > they are both compiled in a single image.
>> Euh I still don't follow you. The only driver that can register to the cpufreq
>> core is cpufreq-dt.
>
> I was wondering on what will happen if both cpufreq-dt and your pxa2xx-cpufreq
> driver are present in the same kernel image. In that case the init routines of
> both of them will try to call cpufreq_register_driver().
Right.

In my case, cpufreq-dt comes first, and wins.
pxa_cpu_init() calls cpufreq_register_driver() and returns -EEXIST.

Cheers.

-- 
Robert