> -----Original Message-----
> From: Eduardo Valentin [mailto:eduardo.valen...@ti.com]
> Sent: Friday, April 05, 2013 1:52 AM
> To: R, Durgadoss
> Cc: Eduardo Valentin; Zhang, Rui; linux...@vger.kernel.org; linux-
> ker...@vger.kernel.org
> Subject: Re: [PATCHv2 1/3] thermal: introduce
> thermal_zone_get_zone_by_name helper function
>
> On 04-04-2013 13:12, R, Durgadoss wrote:
> >> -----Original Message-----
> >> From: Eduardo Valentin [mailto:eduardo.valen...@ti.com]
> >> Sent: Thursday, April 04, 2013 3:43 AM
> >> To: Zhang, Rui
> >> Cc: linux...@vger.kernel.org; linux-kernel@vger.kernel.org; R,
> Durgadoss;
> >> Eduardo Valentin
> >> Subject: [PATCHv2 1/3] thermal: introduce
> >> thermal_zone_get_zone_by_name helper function
> >>
> >> This patch adds a helper function to get a reference of
> >> a thermal zone, based on the zone type name.
> >>
> >> It will perform a zone name lookup and return a reference
> >> to a thermal zone device that matches the name requested.
> >> In case the zone is not found or when several zones match
> >> same name or if the required parameters are invalid, it will return
> >> the corresponding error code (ERR_PTR).
> >>
> >> Signed-off-by: Eduardo Valentin <eduardo.valen...@ti.com>
> >> ---
> >> drivers/thermal/thermal_sys.c | 34
> >> ++++++++++++++++++++++++++++++++++
> >> include/linux/thermal.h | 1 +
> >> 2 files changed, 35 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/drivers/thermal/thermal_sys.c
> b/drivers/thermal/thermal_sys.c
> >> index 5bd95d4..6e1da0a 100644
> >> --- a/drivers/thermal/thermal_sys.c
> >> +++ b/drivers/thermal/thermal_sys.c
> >> @@ -1790,6 +1790,40 @@ void thermal_zone_device_unregister(struct
> >> thermal_zone_device *tz)
> >> }
> >> EXPORT_SYMBOL_GPL(thermal_zone_device_unregister);
> >>
> >> +/**
> >> + * thermal_zone_get_zone_by_name() - search for a zone and returns
> its
> >> ref
> >> + * @name: thermal zone name to fetch the temperature
> >> + *
> >> + * When only one zone is found with the passed name, returns a
> reference
> >> to it.
> >> + *
> >> + * Return: On success returns a reference to an unique thermal zone
> with
> >> + * matching name equals to @name, a ERR_PTR otherwise.
> >> + */
> >> +struct thermal_zone_device *thermal_zone_get_zone_by_name(const
> >> char *name)
> >> +{
> >> + struct thermal_zone_device *pos = NULL, *ref = ERR_PTR(-EINVAL);
> >> + int found = 0;
> >> +
> >> + if (!name)
> >> + goto exit;
> >> +
> >> + mutex_lock(&thermal_list_lock);
> >> + list_for_each_entry(pos, &thermal_tz_list, node)
> >> + if (!strnicmp(name, pos->type, THERMAL_NAME_LENGTH)) {
> >> + found++;
> >> + ref = pos;
> >> + }
> >> + mutex_unlock(&thermal_list_lock);
> >> +
> >> + /* Success only when an unique zone is found */
> >> + if (found != 1)
> >> + ref = ERR_PTR(-ENODEV);
> >
> > I think we should differentiate between the two cases:
> > 1. The zone does not exist at all
> > return NULL in this case
> > 2. There are multiple zones
> > return ERR_PTR(-EEXIST) in this case
> >
> > This way the calling function can figure out the exact reason
> > for failure.
>
> I think the code documentation is already clear enough to say that this
> is for unique matches. But in case you want to differentiate these
> cases, I can resend it. Do you have a usage for this?
Yes, the calling function may want to re-try (or even unregister a zone,
to proceed further..)
>
> Besides, I would prefer to return ERR_PTR(-ENODEV) in the first case.
> The way it is in the original patch.
Okay, I am fine with that too :-)
>
> >
> > Thanks,
> > Durga
> >
> >> +
> >> +exit:
> >> + return ref;
> >> +}
> >> +EXPORT_SYMBOL_GPL(thermal_zone_get_zone_by_name);
> >> +
> >> #ifdef CONFIG_NET
> >> static struct genl_family thermal_event_genl_family = {
> >> .id = GENL_ID_GENERATE,
> >> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> >> index 542a39c..0cf9eb5 100644
> >> --- a/include/linux/thermal.h
> >> +++ b/include/linux/thermal.h
> >> @@ -237,6 +237,7 @@ void thermal_zone_device_update(struct
> >> thermal_zone_device *);
> >> struct thermal_cooling_device *thermal_cooling_device_register(char *,
> >> void *,
> >> const struct thermal_cooling_device_ops *);
> >> void thermal_cooling_device_unregister(struct thermal_cooling_device
> *);
> >> +struct thermal_zone_device *thermal_zone_get_zone_by_name(const
> >> char *name);
> >>
> >> int thermal_zone_trend_get(struct thermal_zone_device *, int);
> >> struct thermal_instance *thermal_instance_get(struct
> >> thermal_zone_device *,
> >> --
> >> 1.7.7.1.488.ge8e1c
> >
> >
> >
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