Re: [PATCH 5/8] thermal:cpu cooling:tegra: Provide deferred probing for tegra driver

Lukasz Majewski
2014-11-14T11:24:50Z

Hi Mikko,

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

Thanks for testing.

>
> 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.

Yes, this is a potential issue. However, this option in tegra_defconfig
is by default disabled when thermal is enabled.

> But I don't really have a solution for this either.

Ok. I see.

>
> 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;
> >
>

--
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group