Re: [PATCH 1/3] thermal: hisilicon: add new hisilicon thermal sensor driver

From: kongxinwei
Date: Mon Mar 23 2015 - 04:31:13 EST

On 03/23/2015 12:46 PM, Leo Yan wrote:
On Fri, Mar 20, 2015 at 03:55:27PM +0000, Mark Rutland wrote:
That may be the case in the code as it stands today, but per the binding
the trip points are the temperatures at which an action is to be taken.

The thermal-zone has poilling-delay and polling-delay-passive, but
there's no reason you couldn't also use the interrupt to handle the
"hot" trip-point, adn the reset at the "critical" trip-point. All that's
missing is the plumbing in order to do so.

So please co-ordinate with the thermal framework to do that.
Let's dig further more for this point, so that we can get more specific
gudiance and have a good preparation for next version's patch set.

After i reviewed the thermal framework code, currently have one smooth
way to co-ordinate the trip points w/t thermal framework: use the function
*thermal_zone_device_register()* to register sensor, and can use the
callback function .get_trip_temp to tell thermal framework for the
trip points' temperature.

For hisi thermal case, now the driver is using the function
*thermal_zone_of_sensor_register* to register sensor, but use this way
i have not found there have standard APIs which can be used by sensor
driver to get the trip points info from thermal framework.

I may miss something for thermal framework, so if have existed APIs to
get the trip points, could pls point out?
I am only familiar with the binding, not the Linux implementation -- The
latter can change to accomodate your hardware without requiring binding
changes. Please co-ordinate with the thermal maintainers.
Found the functions of_thermal_get_trip_points(tz) and of_thermal_get_ntrips(tz)
will help for this.

+ if (of_property_read_bool(np, "hisilicon,tsensor-bind-irq")) {
+ if (data->irq_bind_sensor != -1)
+ dev_warn(&pdev->dev, "irq has bound to index %d\n",
+ data->irq_bind_sensor);
+ /* bind irq to this sensor */
+ data->irq_bind_sensor = index;
+ }
I don't see why this should be specified in the DT. Why do you believe
it should?
The thermal sensor module has four sensors, but have only one
interrupt signal; This interrupt can only be used by one sensor;
So want to use dts to bind the interrupt with one selected sensor.
That's not all that great, though I'm not exactly sure how the kernel
would select the best sensor to measure with. It would be good if you
could talk to the thermal maintainers w.r.t. this.
This will be decided by the silicon, right? Every soc has different
combination with cpu/gpu/vpu, so which part is hottest, this maybe
highly dependent on individual SoC.

S/W just need provide the flexibility so that later can choose
the interrupt to bind with the sensor within the hottest part.
Then the property you care about is which sensor is closest to what is
likely to be the hottest component. Given that, the kernel can decide
how to use the interrupt.
Will modify the driver to dynamically bind the interrupt to hottest
sensor; Appreciate for good suggestion.

Leo Yan

Hi mark:
Thank you for your comments,please wait the next version to slove your
presenting problem.


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