Re: [PATCH v2 1/5] thermal: Add support for hardware-tracked trip points

Caesar Wang
2016-05-25T03:27:24Z

Hi Javi,

Thanks your reviewing.

On 2016年05月24日 20:57, Javi Merino wrote:
> On Tue, May 03, 2016 at 05:33:29PM +0800, Caesar Wang wrote:
>> From: Sascha Hauer <s.hauer@pengutronix.de>
>>
>> This adds support for hardware-tracked trip points to the device tree
>> thermal sensor framework.
>>
>> The framework supports an arbitrary number of trip points. Whenever
>> the current temperature is updated, the trip points immediately
>> below and above the current temperature are found. A .set_trips
>> callback is then called with the temperatures. If there is no trip
>> point above or below the current temperature, the passed trip
>> temperature will be -INT_MAX or INT_MAX respectively. In this callback,
>> the driver should program the hardware such that it is notified
>> when either of these trip points are triggered. When a trip point
>> is triggered, the driver should call `thermal_zone_device_update'
>> for the respective thermal zone. This will cause the trip points
>> to be updated again.
>>
>> If .set_trips is not implemented, the framework behaves as before.
>>
>> This patch is based on an earlier version from Mikko Perttunen
>> <mikko.perttunen@kapsi.fi>
>>
>> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
>> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
>> Cc: Zhang Rui <rui.zhang@intel.com>
>> Cc: Eduardo Valentin <edubezval@gmail.com>
>> Cc: linux-pm@vger.kernel.org
>>
>> ---
>>
>> Changes in v2:
>> - update the sysfs-api.txt for set_trips
>>
>> Documentation/thermal/sysfs-api.txt | 7 +++++
>> drivers/thermal/thermal_core.c | 52 +++++++++++++++++++++++++++++++++++++
>> include/linux/thermal.h | 3 +++
>> 3 files changed, 62 insertions(+)
<cut..>
>> + /*
>> + * Set a temperature window. When this window is left the driver
>> + * must inform the thermal core via thermal_zone_device_update.
>> + */
>> + ret = tz->ops->set_trips(tz, low, high);
>> + if (ret)
>> + dev_err(&tz->device, "Failed to set trips: %d\n", ret);
> This function can be called at the same time from multiple places so
> it should be reentrant. I think you should call mutex_lock(tz->lock)
> before "if (tz->prev_low_trip == low && ..." and unlock it here.

Sound reasonable, fixes it in next version.

>> +}
>> +
>> static void update_temperature(struct thermal_zone_device *tz)
>> {
>> int temp, ret;
>> @@ -569,6 +614,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
>>
>> update_temperature(tz);
>>
>> + thermal_zone_set_trips(tz);
>> +
>> for (count = 0; count < tz->trips; count++)
>> handle_thermal_trip(tz, count);
>> }
>> @@ -754,6 +801,9 @@ trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
>> */
>> ret = tz->ops->set_trip_hyst(tz, trip, temperature);
>>
>> + if (!ret)
>> + thermal_zone_set_trips(tz);
>> +
> You should add a similar call to thermal_zone_set_trips() in trip_point_temp_store()

No, this patch has been done.

if you see the linux next kernel.
72f3ada UPSTREAM: thermal: trip_point_temp_store() calls
thermal_zone_device_update()

--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -733,8 +733,12 @@ trip_point_temp_store(struct device *dev, struct
device_attribute *attr,
return -EINVAL;

ret = tz->ops->set_trip_temp(tz, trip, temperature);
+ if (ret)
+ return ret;

- return ret ? ret : count;
+ thermal_zone_device_update(tz);
+
+ return count;
}

So the "thermal_zone_set_trips(tz)" have been set in
thermal_zone_device_update.

>> return ret ? ret : count;
>> }
>>
>> @@ -1843,6 +1893,8 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
>> tz->trips = trips;
>> tz->passive_delay = passive_delay;
>> tz->polling_delay = polling_delay;
>> + tz->prev_low_trip = INT_MAX;
>> + tz->prev_high_trip = -INT_MAX;
>> /* A new thermal zone needs to be updated anyway. */
>> atomic_set(&tz->need_update, 1);
>>
>> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
>> index e45abe7..e258359 100644
>> --- a/include/linux/thermal.h
>> +++ b/include/linux/thermal.h
>> @@ -98,6 +98,7 @@ struct thermal_zone_device_ops {
>> int (*unbind) (struct thermal_zone_device *,
>> struct thermal_cooling_device *);
>> int (*get_temp) (struct thermal_zone_device *, int *);
>> + int (*set_trips) (struct thermal_zone_device *, int, int);
>> int (*get_mode) (struct thermal_zone_device *,
>> enum thermal_device_mode *);
>> int (*set_mode) (struct thermal_zone_device *,
>> @@ -199,6 +200,8 @@ struct thermal_zone_device {
>> int last_temperature;
>> int emul_temperature;
>> int passive;
>> + int prev_low_trip;
>> + int prev_high_trip;
> Please document these fields in the kerneldoc comment before struct
> thermal_zone_device.

Okay, done.

Thanks!

-
Caesar
>> unsigned int forced_passive;
>> atomic_t need_update;
>> struct thermal_zone_device_ops *ops;
> Cheers,
> Javi
>
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