Hi Rui,
> -----Original Message-----
> From: Zhang, Rui
> Sent: Thursday, August 16, 2012 9:00 AM
> To: R, Durgadoss
> Cc: lenb@xxxxxxxxxx; rjw@xxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; linux-
> pm@xxxxxxxxxxxxxxx; eduardo.valentin@xxxxxx; amit.kachhap@xxxxxxxxxx;
> wni@xxxxxxxxxx
> Subject: RE: [PATCH 07/13] Thermal: Update binding logic based on platform
> data
>
> On 三, 2012-08-15 at 03:17 -0600, R, Durgadoss wrote:
> > Hi Rui,
> >
> > > > > > +static void update_bind_info(struct thermal_cooling_device
> *cdev)
> > > > > > +{
> > > > > > + int i, ret;
> > > > > > + struct thermal_zone_params *tzp;
> > > > > > + struct thermal_zone_device *pos = NULL;
> > > > > > +
> > > > > > + mutex_lock(&thermal_list_lock);
> > > > > > +
> > > > > > + list_for_each_entry(pos, &thermal_tz_list, node) {
> > > > > > + if (!pos->tzp && !pos->ops->bind)
> > > > > > + continue;
> > > > > > +
> > > > > > + if (!pos->tzp && pos->ops->bind) {
> > > > > > + ret = pos->ops->bind(pos, cdev);
> > > > > > + if (ret)
> > > > > > + print_bind_err_msg(pos, cdev, ret);
> > > > > > + }
> > > > > > +
> > > > > > + tzp = pos->tzp;
> > > > > > + for (i = 0; i < tzp->num_cdevs; i++) {
> > > > > > + if (!strcmp(tzp->cdevs_name[i], cdev->type))
> {
> > > > > > + __bind(pos, tzp->trip_mask[i], cdev);
> > > > > > + break;
> > > > > > + }
> > > > > > + }
> > > > > > + }
> > > > > > + mutex_unlock(&thermal_list_lock);
> > > > > > +}
> > > > >
> > > > > I still do not understand why we need this kind of bind.
> > > > > Say, the platform thermal driver knows the platform data, i.e. it
> knows
> > > > > which cooling devices should be bound to which trip points.
> > > > > why we can not move this kind of logic to the .bind() callback, offered
> > > > > by the platform thermal driver?
> > > > > say, in .bind() callback,
> > > > > the platform thermal driver has the pointer of the platform data,
> right?
> > > > > the .cdev parameter can be used to find the cooling device name,
> > > > > and we can make the comparison there. instead of introducing new
> binding
> > > > > functions in the generic thermal layer.
> > > >
> > > > For once, I got little confused between the generic platform thermal
> sensor
> > > > drivers (the chip drivers) and the platform level driver (not specific for
> chip,
> > > > but for a platform). So, yes we can put this in the platform level driver.
> > > >
> > > Hmm,
> > > I'm not clear about the difference between these two drivers.
> > > what is supposed to be done in the platform thermal sensor drivers and
> > > what is supposed to be done in the platform level driver?
> >
> > A sensor driver can be a generic chip driver like emc1403 (this is the one
> > that I have worked on..) or coretemp (the CPU DTS driver for x86). They sit
> > in different sub systems (these two in hwmon). We might not be allowed
> to
> > add any thermal framework specific code in these drivers. The same driver
> > works on all platforms.
>
> does the sensor know anything about the "policy"?
> Say, does it have any trip points? does it know which device can be
> throttled to cool itself?
> I think the answer is "no", right?
Yes. You are right :-)
The answer is 'No'.
> >
> > A platform level thermal driver knows information about the thermal
> sensors,
> > and their zones on the platform; and is specific to the platform.
> > For x86, this will be in drivers/x86/platform/ whereas might be in some
> other
> > place for other architectures. An example is intel_mid_thermal.c which sits
> > in drivers/x86/platform. We can add our thermal framework specific code
> > to this driver.
> >
> but I think intel_mide_thermal driver is also a platform thermal sensor
> driver at the same time.
Yes today it is both..
> > >
> > > At least for now, all the thermal drivers are both thermal sensor driver
> > > and platform level driver, right?
> >
> > Not all the times, although there are some instances where both are same.
> > We use coretemp.c and intel_mid_thermal.c (which are different), for the
> > x86 mid platforms.
> >
> so you want to use coretemp.c as a temperature sensor, and then bind
> your own cooling devices to it in your platform level thermal driver?
Yes, coretemp is one fine example.
At least I would like to get the same thing done for emc1403.c
(and few hwmon drivers)..
Thanks,
Durga
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