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    SubjectRe: [PATCH V2 0/6] thermal: exynos: Add kernel thermal support for exynos platform
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    On 三, 2012-04-11 at 18:17 +0530, Amit Kachhap wrote:
    > Hi Rui,
    >
    > Thanks for looking into the patches.
    >
    > On 10 April 2012 06:28, Zhang Rui <rui.zhang@intel.com> wrote:
    > > Hi, Amit,
    > >
    > > On 三, 2012-04-04 at 10:02 +0530, Amit Kachhap wrote:
    > >> Hi Len/Rui,
    > >>
    > >> Any comment or feedback from your side about the status of this patch?
    > >> Is it merge-able or major re-work is needed? I have fixed most of the
    > >> comments in this patchset and currently working on some of the minor
    > >> comments received and will submit them shortly.
    > >>
    > > Sorry for the late response.
    > >
    > > First of all, it makes sense to me to introduce the generic cpufrq
    > > cooling implementation.
    > ok thanks
    > > But I still have some questions.
    > > I think the key reason why THERMAL_TRIP_STATE_INSTANCE is introduced is
    > > that the MONIROR_ZONE and WARN_ZONE on exynos4 can not fit into the
    > > current passive handling in the generic thermal layer well, right?
    > > e.g. there is no tc1/tc2 on exynos4.
    > >
    > > If yes, is it possible that we can enhance the passive cooling to
    > > support the generic processor cooling?
    > > say, introduce another way to throttle the processor in
    > > thermal_zone_device_passive when tc1 and tc2 are not available?
    >
    > I agree that this new trip type code can be moved into passive trip
    > type when tc1 and tc2 are 0. but this is special type of cooling
    > devices behaviour where only instances of the same cooling device is
    > binded to a trip point. The order of mapping is the only
    > differentiating criteria and there are some checks used to implement
    > this like
    > 1) The trip points should be in ascending order.(This is missing in my
    > original patch, so I added below)
    > 2) The set_cur_state has to be called for the exact temp range so
    > get_cur_state(&state) and set_cur_state(state ++/state--) logic is not
    > possible.
    > 3) set_cur_state is called as set_cur_state(cdev_instance).

    Do you really need two THERMAL_TRIP_STATE_INSTANCE trip points?

    I'm not sure if my understanding is right, but IMO, we can have one
    THERMAL_TRIP_STATE_INSTANCE only, for both MONIROR_ZONE and WARN_ZONE,
    and the trip temperature equals MONIROR_ZONE.
    The cpufreq cooling device will work in the same way, no?

    thanks,
    rui

    > There is a chance that people might confuse that these checks are
    > applicable for passive trip types also which is not the case here.
    >
    > @@ -1187,6 +1228,21 @@ struct thermal_zone_device
    > *thermal_zone_device_register(char *type,
    > tz->ops->get_trip_type(tz, count, &trip_type);
    > if (trip_type == THERMAL_TRIP_PASSIVE)
    > passive = 1;
    > + /*
    > + * For THERMAL_TRIP_STATE_INSTANCE trips, thermal zone should
    > + * be in ascending order.
    > + */
    > + if (trip_type == THERMAL_TRIP_STATE_INSTANCE) {
    > + tz->ops->get_trip_temp(tz, count, &trip_temp);
    > + if (first_trip_temp == 0)
    > + first_trip_temp = trip_temp;
    > + else if (first_trip_temp < trip_temp)
    > + first_trip_temp = trip_temp;
    > + else if (first_trip_temp > trip_temp) {
    > + pr_warn("Zone trip points should be in
    > ascending order\n");
    > + goto unregister;
    > + }
    > + }
    > }
    >
    > if (!passive)
    >
    > Anyway there is other alternative where this new trip type is not
    > needed and I can just use the existing trip type THERMAL_TRIP_ACTIVE
    > and create 2 separate cooling devices for MONITOR_ZONE and WARN_ZONE.
    > I had thought to make this generic and just to manage with 1 cooling
    > device.
    > What is your view?
    >
    > Thanks,
    > Amit Daniel
    >
    >
    > >
    > > thanks,
    > > rui
    > >
    > >> Regards,
    > >> Amit Daniel
    > >>
    > >> On 19 March 2012 11:47, Amit Daniel Kachhap <amit.kachhap@linaro.org> wrote:
    > >> > Changes since V1:
    > >> > *Moved the sensor driver to driver/thermal folder from driver/hwmon folder
    > >> > as suggested by Mark Brown and Guenter Roeck
    > >> > *Added notifier support to notify the registered drivers of any cpu cooling
    > >> > action. The driver can modify the default cooling behaviour(eg set different
    > >> > max clip frequency).
    > >> > *The percentage based frequency replaced with absolute clipped frequency.
    > >> > *Some more conditional checks when setting max frequency.
    > >> > *Renamed the new trip type THERMAL_TRIP_STATE_ACTIVE to
    > >> > THERMAL_TRIP_STATE_INSTANCE
    > >> > *Many review comments from R, Durgadoss <durgadoss.r@intel.com> and
    > >> > eduardo.valentin@ti.com implemented.
    > >> > *Removed cooling stats through debugfs patch
    > >> > *The V1 based can be found here,
    > >> > https://lkml.org/lkml/2012/2/22/123
    > >> > http://lkml.org/lkml/2012/3/3/32
    > >> >
    > >> > Changes since RFC:
    > >> > *Changed the cpu cooling registration/unregistration API's to instance based
    > >> > *Changed the STATE_ACTIVE trip type to pass correct instance id
    > >> > *Adding support to restore back the policy->max_freq after doing frequency
    > >> > clipping.
    > >> > *Moved the trip cooling stats from sysfs node to debugfs node as suggested
    > >> > by Greg KH greg@kroah.com
    > >> > *Incorporated several review comments from eduardo.valentin@ti.com
    > >> > *Moved the Temperature sensor driver from driver/hwmon/ to driver/mfd
    > >> > as discussed with Guenter Roeck <guenter.roeck@ericsson.com> and
    > >> > Donggeun Kim <dg77.kim@samsung.com> (https://lkml.org/lkml/2012/1/5/7)
    > >> > *Some changes according to the changes in common cpu cooling APIs
    > >> > *The RFC based patches can be found here,
    > >> > https://lkml.org/lkml/2011/12/13/186
    > >> > https://lkml.org/lkml/2011/12/21/169
    > >> >
    > >> >
    > >> > Brief Description:
    > >> >
    > >> > 1) The generic cooling devices code is placed inside driver/thermal/* as
    > >> > placing inside acpi folder will need un-necessary enabling of acpi code. This
    > >> > codes is architecture independent.
    > >> >
    > >> > 2) This patchset adds a new trip type THERMAL_TRIP_STATE_INSTANCE which passes
    > >> > cooling device instance number and may be helpful for cpufreq cooling devices
    > >> > to take the correct cooling action. This trip type avoids the temperature
    > >> > comparision check again inside the cooling handler.
    > >> >
    > >> > 3) This patchset adds generic cpu cooling low level implementation through
    > >> > frequency clipping and cpu hotplug. In future, other cpu related cooling
    > >> > devices may be added here. An ACPI version of this already exists
    > >> > (drivers/acpi/processor_thermal.c). But this will be useful for platforms
    > >> > like ARM using the generic thermal interface along with the generic cpu
    > >> > cooling devices. The cooling device registration API's return cooling device
    > >> > pointers which can be easily binded with the thermal zone trip points.
    > >> > The important APIs exposed are,
    > >> > a)struct thermal_cooling_device *cpufreq_cooling_register(
    > >> > struct freq_clip_table *tab_ptr, unsigned int tab_size,
    > >> > const struct cpumask *mask_val)
    > >> > b)void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
    > >> >
    > >> > 4) Samsung exynos platform thermal implementation is done using the generic
    > >> > cpu cooling APIs and the new trip type. The temperature sensor driver present
    > >> > in the hwmon folder(registered as hwmon driver) is moved to thermal folder
    > >> > and registered as a thermal driver.
    > >> >
    > >> > All this patchset is based on Kernel version 3.3-rc7
    > >> >
    > >> > A simple data/control flow diagrams is shown below,
    > >> >
    > >> > Core Linux thermal <-----> Exynos thermal interface <----- Temperature Sensor
    > >> > | |
    > >> > \|/ |
    > >> > Cpufreq cooling device <---------------
    > >> >
    > >> >
    > >> > Amit Daniel Kachhap (6):
    > >> > thermal: Add a new trip type to use cooling device instance number
    > >> > thermal: Add generic cpufreq cooling implementation
    > >> > thermal: Add generic cpuhotplug cooling implementation
    > >> > hwmon: exynos4: Move thermal sensor driver to driver/thermal
    > >> > directory
    > >> > thermal: exynos4: Register the tmu sensor with the kernel thermal
    > >> > layer
    > >> > ARM: exynos4: Add thermal sensor driver platform device support
    > >> >
    > >> > Documentation/hwmon/exynos4_tmu | 81 ---
    > >> > Documentation/thermal/cpu-cooling-api.txt | 76 +++
    > >> > Documentation/thermal/exynos4_tmu | 52 ++
    > >> > Documentation/thermal/sysfs-api.txt | 4 +-
    > >> > arch/arm/mach-exynos/Kconfig | 11 +
    > >> > arch/arm/mach-exynos/Makefile | 1 +
    > >> > arch/arm/mach-exynos/clock.c | 4 +
    > >> > arch/arm/mach-exynos/dev-tmu.c | 39 ++
    > >> > arch/arm/mach-exynos/include/mach/irqs.h | 2 +
    > >> > arch/arm/mach-exynos/include/mach/map.h | 1 +
    > >> > arch/arm/mach-exynos/mach-origen.c | 1 +
    > >> > arch/arm/plat-samsung/include/plat/devs.h | 1 +
    > >> > drivers/hwmon/Kconfig | 10 -
    > >> > drivers/hwmon/Makefile | 1 -
    > >> > drivers/hwmon/exynos4_tmu.c | 514 -------------------
    > >> > drivers/thermal/Kconfig | 21 +
    > >> > drivers/thermal/Makefile | 2 +
    > >> > drivers/thermal/cpu_cooling.c | 529 +++++++++++++++++++
    > >> > drivers/thermal/exynos4_thermal.c | 790 +++++++++++++++++++++++++++++
    > >> > drivers/thermal/thermal_sys.c | 45 ++-
    > >> > include/linux/cpu_cooling.h | 78 +++
    > >> > include/linux/platform_data/exynos4_tmu.h | 7 +
    > >> > include/linux/thermal.h | 1 +
    > >> > 23 files changed, 1660 insertions(+), 611 deletions(-)
    > >> > delete mode 100644 Documentation/hwmon/exynos4_tmu
    > >> > create mode 100644 Documentation/thermal/cpu-cooling-api.txt
    > >> > create mode 100644 Documentation/thermal/exynos4_tmu
    > >> > create mode 100644 arch/arm/mach-exynos/dev-tmu.c
    > >> > delete mode 100644 drivers/hwmon/exynos4_tmu.c
    > >> > create mode 100644 drivers/thermal/cpu_cooling.c
    > >> > create mode 100644 drivers/thermal/exynos4_thermal.c
    > >> > create mode 100644 include/linux/cpu_cooling.h
    > >> >
    > >
    > >


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