Message-ID: <5465DDC5.6090301@kapsi.fi>
Date: Fri, 14 Nov 2014 12:47:33 +0200
From: Mikko Perttunen <mikko.perttunen@kapsi.fi>
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To: Lukasz Majewski <l.majewski@samsung.com>,
        Eduardo Valentin <edubezval@gmail.com>,
        Zhang Rui <rui.zhang@intel.com>
CC: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>,
        Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
        Linux PM list <linux-pm@vger.kernel.org>,
        Vincenzo Frascino <vincenzo.frascino@st.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Lukasz Majewski <l.majewski@majess.pl>,
        Nobuhiro Iwamatsu <iwamatsu@nigauri.org>,
        Mikko Perttunen <mperttunen@nvidia.com>,
        Stephen Warren <swarren@wwwdotorg.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Alexandre Courbot <gnurou@gmail.com>, linux-tegra@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/8] thermal:cpu cooling:tegra: Provide deferred probing
 for tegra driver
References: <1411547232-21493-1-git-send-email-l.majewski@samsung.com> <1415898165-27406-1-git-send-email-l.majewski@samsung.com> <1415898165-27406-6-git-send-email-l.majewski@samsung.com>
In-Reply-To: <1415898165-27406-6-git-send-email-l.majewski@samsung.com>
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Sender: linux-kernel-owner@vger.kernel.org

Tested-by: Mikko Perttunen <mikko.perttunen@kapsi.fi>

One potential issue I can see is that if the cpufreq driver fails to 
probe then you'll never get the thermal driver either. For example, 
Tegra124 currently has no cpufreq driver, so if CONFIG_CPU_THERMAL was 
enabled, then the soctherm driver would never be able to probe. But I 
don't really have a solution for this either.

Cheers,
Mikko

On 11/13/2014 07:02 PM, Lukasz Majewski wrote:
> When CPU freq is used as a thermal zone cooling device, one needs to wait
> until cpufreq subsystem is properly initialized.
>
> This code is similar to the one already available in imx_thermal.c file.
>
> Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
> ---
>   drivers/thermal/tegra_soctherm.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/drivers/thermal/tegra_soctherm.c b/drivers/thermal/tegra_soctherm.c
> index 70f7e9e..9c5aaa4 100644
> --- a/drivers/thermal/tegra_soctherm.c
> +++ b/drivers/thermal/tegra_soctherm.c
> @@ -26,6 +26,7 @@
>   #include <linux/platform_device.h>
>   #include <linux/reset.h>
>   #include <linux/thermal.h>
> +#include <linux/cpufreq.h>
>
>   #include <soc/tegra/fuse.h>
>
> @@ -346,6 +347,12 @@ static int tegra_soctherm_probe(struct platform_device *pdev)
>
>   	const struct tegra_tsensor *tsensors = t124_tsensors;
>
> +#ifdef CONFIG_CPU_THERMAL
> +	if (!cpufreq_get_current_driver()) {
> +		dev_dbg(&pdev->dev, "no cpufreq driver!");
> +		return -EPROBE_DEFER;
> +	}
> +#endif
>   	tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
>   	if (!tegra)
>   		return -ENOMEM;
>

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