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Message-ID: <547CED4C.1050407@nvidia.com>
Date: Mon, 1 Dec 2014 14:35:56 -0800
From: navneet kumar <navneetk@...dia.com>
To: Eduardo Valentin <edubezval@...il.com>
CC: <rui.zhang@...el.com>, <linux-pm@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] thermal: of: notify sensor driver on trip updates
On 12/01/2014 01:23 PM, Eduardo Valentin wrote:
> * PGP Signed by an unknown key
>
> On Mon, Dec 01, 2014 at 12:45:52PM -0800, navneet kumar wrote:
>> Hi Eduardo,
>>
>> On 11/27/2014 06:32 AM, Eduardo Valentin wrote:
>>>> Old Signed by an unknown key
>>>
>>> Hello Navneet,
>>>
>>> On Wed, Nov 26, 2014 at 05:16:29PM -0800, Navneet Kumar wrote:
>>>> From: navneet kumar <navneetk@...dia.com>
>>>>
>>>> some thermal sensor hardwares include logic which
>>>> can raise interrupts at certain programmed temperature
>>>> thresholds.
>>>>
>>>> Drivers for such sensors should be able to learn the
>>>> appropriate threshold temperatures for interrupts by querying
>>>> the thermal framework.
>>>>
>>>> This change provides a mechanism to allow a sensor driver to
>>>> update it's thresholds when userspace changes a trip point
>>>> temperature.
>>>>
>>>> While this behavior may not make sense in thermal zones
>>>> with more than one sensor, no such examples exist in
>>>> the kernel.
>>>>
>>>> Signed-off-by: navneet kumar <navneetk@...dia.com>
>>>> ---
>>>> drivers/thermal/of-thermal.c | 7 +++++++
>>>> include/linux/thermal.h | 1 +
>>>> 2 files changed, 8 insertions(+)
>>>>
>>>> diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
>>>> index 3d47a0cf3825..3568e4a586dc 100644
>>>> --- a/drivers/thermal/of-thermal.c
>>>> +++ b/drivers/thermal/of-thermal.c
>>>> @@ -258,6 +258,9 @@ static int of_thermal_set_trip_temp(struct thermal_zone_device *tz, int trip,
>>>> /* thermal framework should take care of data->mask & (1 << trip) */
>>>> data->trips[trip].temperature = temp;
>>>>
>>>> + if (data->sops.trip_update)
>>>> + data->sops.trip_update(data->sensor_data, trip);
>>>> +
>>>> return 0;
>>>> }
>>>>
>>>> @@ -285,6 +288,9 @@ static int of_thermal_set_trip_hyst(struct thermal_zone_device *tz, int trip,
>>>> /* thermal framework should take care of data->mask & (1 << trip) */
>>>> data->trips[trip].hysteresis = hyst;
>>>>
>>>> + if (data->sops.trip_update)
>>>> + data->sops.trip_update(data->sensor_data, trip);
>>>> +
>>>> return 0;
>>>> }
>>>>
>>>> @@ -500,6 +506,7 @@ void thermal_zone_of_sensor_unregister(struct device *dev,
>>>>
>>>> tz->sops.get_temp = NULL;
>>>> tz->sops.get_trend = NULL;
>>>> + tz->sops.trip_update = NULL;
>>>> tz->sensor_data = NULL;
>>>> mutex_unlock(&tzd->lock);
>>>> }
>>>> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
>>>> index 58341c56a01f..b93e65815175 100644
>>>> --- a/include/linux/thermal.h
>>>> +++ b/include/linux/thermal.h
>>>> @@ -292,6 +292,7 @@ struct thermal_genl_event {
>>>> struct thermal_of_sensor_ops {
>>>> int (*get_temp)(void *, long *);
>>>> int (*get_trend)(void *, long *);
>>>> + int (*trip_update)(void *, int);
>>>
>>> First thing I ask you is to update your work on top of my -linus branch,
>>> as I already mentioned. Reasoning is that part of the changes you are
>>> sending is already there.
>> will do.
>>>
>>> As for this new callback, I am fine with it as long as it is also
>>> available for drivers that do not use of-thermal. Once again, of-thermal
>>> is not a competitor of thermal core. It will never be. It is not a new
>>> thermal API.
>> I agree that this callback is not a part of the thermal_core functionality.
>> However, when a driver registers directly with the thermal_core (doesn't use
>> of-thermal), it 'owns' the set_trip_XX callbacks in the first place; which is
>> the sole purpose of using the 'trip_update' callback in of-thermal.
>>
>> Adding an additional 'update' to the thermal_core ops would be a no-op. right?
>
> Yes, you are right. Now I understand your point.
>
> Can we then re-use the .set_trips nomenclature?
Sorry, I fail to understand. Are you suggesting to re-use the interface for set_trip 'temp' as well as 'hyst'?
If so, is it just to maintain the commonality across thermal_core and of-thermal interfaces?
The way i see it, the driver just needs to get some kind of 'update' that 'something' changed with
a trip point; and can later query the trips from of-thermal. (Lukasz's patch helps with that).
Functionality-wise, using two callbacks seems excessive. But i may be wrong :-)
>
> Cheers,
>
>>>
>>> That said, it does not make sense to have functionality in of-thermal that
>>> do not belong to thermal core. Exceptions are, of course, for helping
>>> doing the same operations we already have in thermal core.
>>>
>>> All the best,
>>>
>>> Eduardo Valentin
>>>
>>>> };
>>>>
>>>> /* Function declarations */
>>>> --
>>>> 1.8.1.5
>>>>
>>>
>>> * Unknown Key
>>> * 0x7DA4E256
>>>
>
> * Unknown Key
> * 0x7DA4E256
>
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