linux-kernel - Re: [PATCH 05/10] thermal: exynos: remove redundant pdata checks from exynos_tmu

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Message-id: <2098888.ybkVo6Z2Xi@amdc1032>
Date:	Thu, 15 May 2014 18:24:14 +0200
From:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:	Eduardo Valentin <edubezval@...il.com>
Cc:	Eduardo Valentin <eduardo.valentin@...com>,
	Zhang Rui <rui.zhang@...el.com>,
	Amit Daniel Kachhap <amit.daniel@...sung.com>,
	Tomasz Figa <t.figa@...sung.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	linux-samsung-soc@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 05/10] thermal: exynos: remove redundant pdata checks from
 exynos_tmu_initialize()

On Thursday, May 15, 2014 10:47:40 AM Eduardo Valentin wrote:
> Hello Bartlomiej,

Hi,

> On Mon, May 05, 2014 at 01:15:34PM +0200, Bartlomiej Zolnierkiewicz wrote:
> > Remove runtime checks for pdata sanity from exynos_tmu_initialize().
> > The current values hardcoded in pdata will never trigger the checks
> > and for the new code potential mistakes should be caught during
> > development/review phases.
> > 
> > There should be no functional changes caused by this patch.
> > 
> > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> > ---
> >  drivers/thermal/samsung/exynos_thermal_common.h |  1 -
> >  drivers/thermal/samsung/exynos_tmu.c            | 13 -------------
> >  2 files changed, 14 deletions(-)
> > 
> > diff --git a/drivers/thermal/samsung/exynos_thermal_common.h b/drivers/thermal/samsung/exynos_thermal_common.h
> > index 3eb2ed9..cd44719 100644
> > --- a/drivers/thermal/samsung/exynos_thermal_common.h
> > +++ b/drivers/thermal/samsung/exynos_thermal_common.h
> > @@ -27,7 +27,6 @@
> >  #define SENSOR_NAME_LEN	16
> >  #define MAX_TRIP_COUNT	8
> >  #define MAX_COOLING_DEVICE 4
> > -#define MAX_THRESHOLD_LEVS 5
> >  
> >  #define ACTIVE_INTERVAL 500
> >  #define IDLE_INTERVAL 10000
> > diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
> > index 903566f..789d745 100644
> > --- a/drivers/thermal/samsung/exynos_tmu.c
> > +++ b/drivers/thermal/samsung/exynos_tmu.c
> > @@ -158,23 +158,10 @@ static int exynos_tmu_initialize(struct platform_device *pdev)
> >  	    data->temp_error > pdata->max_efuse_value)
> >  		data->temp_error = pdata->efuse_value & EXYNOS_TMU_TEMP_MASK;
> >  
> > -	if (pdata->max_trigger_level > MAX_THRESHOLD_LEVS) {
> > -		dev_err(&pdev->dev, "Invalid max trigger level\n");
> > -		ret = -EINVAL;
> > -		goto out;
> > -	}
> > -
> >  	for (i = 0; i < pdata->max_trigger_level; i++) {
> >  		if (!pdata->trigger_levels[i])
> >  			continue;
> >  
> > -		if ((pdata->trigger_type[i] == HW_TRIP) &&
> > -		(!pdata->trigger_levels[pdata->max_trigger_level - 1])) {
> > -			dev_err(&pdev->dev, "Invalid hw trigger level\n");
> > -			ret = -EINVAL;
> > -			goto out;
> > -		}
> > -
> 
> Does it mean no new pdata are going to be written? i.e., no new soc is
> going to be supported by this driver that needs proper pdata checking?

This is not a proper checking.  The checks in question are done at runtime
in a production code for data that is hardcoded inside driver during
development time and later it doesn't change.  Such data should be verified
during development and review time (i.e. by a script parsing relevant data
from exynos_tmu_data.c, one can also argue that verification to be done is
so simple that the review by a maintainer should be enough).

> >  		/* Count trigger levels except the HW trip*/
> >  		if (!(pdata->trigger_type[i] == HW_TRIP))
> >  			trigger_levs++;

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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