Commit Graph

38 Commits

Author SHA1 Message Date
Viresh Kumar 979d86fac5 cpufreq: Remove cpufreq_generic_exit()
cpufreq_generic_exit() is empty now and can be deleted.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-12 01:06:00 +01:00
Linus Torvalds 91466574be Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux
Pull thermal management updates from Zhang Rui:
 "This time, the biggest change is the work of representing hardware
  thermal properties in device tree infrastructure.

  This work includes the introduction of a device tree bindings for
  describing the hardware thermal behavior and limits, and also a parser
  to read and interpret the data, and build thermal zones and thermal
  binding parameters.  It also contains three examples on how to use the
  new representation on sensor devices, using three different drivers to
  accomplish it.  One driver is in thermal subsystem, the TI SoC
  thermal, and the other two drivers are in hwmon subsystem.

  Actually, this would be the first step of the complete work because we
  still need to check other potential drivers to be converted and then
  validate the proposed API.  But the reason why I include it in this
  pull request is that, first, this change does not hurt any others
  without using this approach, second, the principle and concept of this
  change would not break after converting the remaining drivers.  BTW,
  as you can see, there are several points in this change that do not
  belong to thermal subsystem.  Because it has been suggested by Guenter
  R that in such cases, it is recommended to send the complete series
  via one single subsystem.

  Specifics:

   - representing hardware thermal properties in device tree
     infrastructure

   - fix a regression that the imx thermal driver breaks system suspend.

   - introduce ACPI INT3403 thermal driver to retrieve temperature data
     from the INT3403 ACPI device object present on some systems.

   - introduce debug statement for thermal core and step_wise governor.

   - assorted fixes and cleanups for thermal core, cpu cooling, exynos
     thrmal, intel powerclamp and imx thermal driver"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux: (34 commits)
  thermal: remove const flag from .ops of imx thermal
  Thermal: update thermal zone device after setting emul_temp
  intel_powerclamp: Fix cstate counter detection.
  thermal: imx: add necessary clk operation
  Thermal cpu cooling: return error if no valid cpu frequency entry
  thermal: fix cpu_cooling max_level behavior
  thermal: rcar-thermal: Enable driver compilation with COMPILE_TEST
  thermal: debug: add debug statement for core and step_wise
  thermal: imx_thermal: add module device table
  drivers: thermal: Mark function as static in x86_pkg_temp_thermal.c
  thermal:samsung: fix compilation warning
  thermal: imx: correct suspend/resume flow
  thermal: exynos: fix error return code
  Thermal: ACPI INT3403 thermal driver
  MAINTAINERS: add thermal bindings entry in thermal domain
  arm: dts: make OMAP4460 bandgap node to belong to OCP
  arm: dts: make OMAP443x bandgap node to belong to OCP
  arm: dts: add cooling properties on omap5 cpu node
  arm: dts: add omap5 thermal data
  arm: dts: add omap5 CORE thermal data
  ...
2014-01-24 17:13:49 -08:00
Viresh Kumar 652ed95d5f cpufreq: introduce cpufreq_generic_get() routine
CPUFreq drivers that use clock frameworks interface,i.e. clk_get_rate(),
to get CPUs clk rate, have similar sort of code used in most of them.

This patch adds a generic ->get() which will do the same thing for them.
All those drivers are required to now is to set .get to cpufreq_generic_get()
and set their clk pointer in policy->clk during ->init().

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-17 02:00:44 +01:00
Paul Walmsley 2209b0c964 cpufreq: cpufreq-cpu0: clk_round_rate() can return a zero upon error
Treat both negative and zero return values from clk_round_rate()
as errors.  This is needed since subsequent patches will convert
clk_round_rate()'s return value to be an unsigned type, rather
than a signed type, since some clock sources can generate rates
higher than (2^31)-1 Hz.

Eventually, when calling clk_round_rate(), only a return value of
zero will be considered a error.  All other values will be
considered valid rates.  The comparison against values less than
0 is kept to preserve the correct behavior in the meantime.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-06 23:19:19 +01:00
Eduardo Valentin 77cff5926a cpufreq: cpufreq-cpu0: add dt node parsing for cooling device properties
This patch changes the cpufreq-cpu0 driver to consider if
a cpu needs cooling (with cpufreq). In case the cooling is needed,
the cpu0 device tree node needs to be properly configured
with cooling device properties.

In case these properties are present,, the driver will
load a cpufreq cooling device in the system. The cpufreq-cpu0
driver is not interested in determining how the system should
be using the cooling device. The driver is responsible
only of loading the cooling device.

Describing how the cooling device will be used can be
accomplished by setting up a thermal zone that references
and is composed by the cpufreq cooling device.

Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: cpufreq@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: devicetree-discuss@lists.ozlabs.org
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
2013-12-04 09:34:24 -04:00
Viresh Kumar d4019f0a92 cpufreq: move freq change notifications to cpufreq core
Most of the drivers do following in their ->target_index() routines:

	struct cpufreq_freqs freqs;
	freqs.old = old freq...
	freqs.new = new freq...

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

	/* Change rate here */

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

This is replicated over all cpufreq drivers today and there doesn't exists a
good enough reason why this shouldn't be moved to cpufreq core instead.

There are few special cases though, like exynos5440, which doesn't do everything
on the call to ->target_index() routine and call some kind of bottom halves for
doing this work, work/tasklet/etc..

They may continue doing notification from their own code as flag:
CPUFREQ_ASYNC_NOTIFICATION is already set for them.

All drivers are also modified in this patch to avoid breaking 'git bisect', as
double notification would happen otherwise.

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Russell King <linux@arm.linux.org.uk>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-31 00:11:08 +01:00
Viresh Kumar 9c0ebcf78f cpufreq: Implement light weight ->target_index() routine
Currently, the prototype of cpufreq_drivers target routines is:

int target(struct cpufreq_policy *policy, unsigned int target_freq,
		unsigned int relation);

And most of the drivers call cpufreq_frequency_table_target() to get a valid
index of their frequency table which is closest to the target_freq. And they
don't use target_freq and relation after that.

So, it makes sense to just do this work in cpufreq core before calling
cpufreq_frequency_table_target() and simply pass index instead. But this can be
done only with drivers which expose their frequency table with cpufreq core. For
others we need to stick with the old prototype of target() until those drivers
are converted to expose frequency tables.

This patch implements the new light weight prototype for target_index() routine.
It looks like this:

int target_index(struct cpufreq_policy *policy, unsigned int index);

CPUFreq core will call cpufreq_frequency_table_target() before calling this
routine and pass index to it. Because CPUFreq core now requires to call routines
present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time.

This also marks target() interface as deprecated. So, that new drivers avoid
using it. And Documentation is updated accordingly.

It also converts existing .target() to newly defined light weight
.target_index() routine for many driver.

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Russell King <linux@arm.linux.org.uk>
Acked-by: David S. Miller <davem@davemloft.net>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:42:24 +02:00
Rafael J. Wysocki 6ddee424fe Merge back earlier 'pm-cpufreq' material.
Conflicts:
	drivers/cpufreq/omap-cpufreq.c
2013-10-25 22:36:40 +02:00
Nishanth Menon e4db1c7439 PM / OPP: rename header to linux/pm_opp.h
Since Operating Performance Points (OPP) functions are specific
to device specific power management, be specific and rename opp.h
to pm_opp.h

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-25 22:33:23 +02:00
Nishanth Menon 47d43ba73e PM / OPP: rename data structures to dev_pm equivalents
Since Operating Performance Points (OPP) data structures are specific
to device specific power management, be specific and rename opp_* data
structures in OPP library with dev_pm_opp_* equivalent.

Affected structures are:
 struct opp
 enum opp_event

Minor checkpatch warning resulting of this change was fixed as well.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-25 22:33:23 +02:00
Nishanth Menon 5d4879cda6 PM / OPP: rename functions to dev_pm_opp*
Since Operating Performance Points (OPP) functions are specific to
device specific power management, be specific and rename opp_*
accessors in OPP library with dev_pm_opp_* equivalent.

Affected functions are:
 opp_get_voltage
 opp_get_freq
 opp_get_opp_count
 opp_find_freq_exact
 opp_find_freq_floor
 opp_find_freq_ceil
 opp_add
 opp_enable
 opp_disable
 opp_get_notifier
 opp_init_cpufreq_table
 opp_free_cpufreq_table

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-25 22:33:23 +02:00
Viresh Kumar 78b3d10936 cpufreq: cpufreq-cpu0: use cpufreq_generic_init()
Use generic cpufreq_generic_init() routine instead of replicating the same code
here.

Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-16 00:50:33 +02:00
Viresh Kumar 179b889f7c cpufreq: cpu0: don't initialize part of policy set by core too
Many common initializations of struct policy are moved to core now and hence
this driver doesn't need to do it. This patch removes such code.

Most recent of those changes is to call ->get() in the core after calling
->init().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-16 00:50:29 +02:00
Viresh Kumar f793d79f08 cpufreq: cpufreq-cpu0: Use generic cpufreq routines
Most of the CPUFreq drivers do similar things in .exit() and .verify() routines
and .attr. So its better if we have generic routines for them which can be used
by cpufreq drivers then.

This patch uses these generic routines in the cpufreq-cpu0 driver.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-16 00:50:24 +02:00
Viresh Kumar 7a90684956 cpufreq: cpufreq-cpu0: use cpufreq_table_validate_and_show()
Lets use cpufreq_table_validate_and_show() instead of calling
cpufreq_frequency_table_cpuinfo() and cpufreq_frequency_table_get_attr().

Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-30 20:18:41 +02:00
Philipp Zabel 43c638e3dd cpufreq: cpufreq-cpu0: NULL is a valid regulator, part 2
Since the patch "cpufreq: cpufreq-cpu0: NULL is a valid regulator", cpu_reg
contains an error value if the regulator is not set, instead of NULL.
Accordingly, fix the remaining check for non-NULL cpu_reg.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-30 20:08:59 +02:00
Sudeep KarkadaNagesha e1825b2530 cpufreq: cpufreq-cpu0: assign cpu_dev correctly to cpu0 device
Commit f837a9b5ab "cpufreq: cpufreq-cpu0:
remove device tree parsing for cpu nodes" assumed the pdev->dev is set to
cpu0 device in the platform code. But it actually points to the virtual
cpufreq-cpu0 platform device which is not present in the device tree.
Most of the information needed by cpufreq is stored in cpu0 DT node.
So cpu_dev must point to cpu0 device.

This patch fixes the wrong assignment to cpu_dev.

Reported-and-tested-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-19 03:53:43 +02:00
Linus Torvalds 40031da445 Merge tag 'pm+acpi-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management updates from Rafael Wysocki:

 1) ACPI-based PCI hotplug (ACPIPHP) subsystem rework and introduction
    of Intel Thunderbolt support on systems that use ACPI for signalling
    Thunderbolt hotplug events.  This also should make ACPIPHP work in
    some cases in which it was known to have problems.  From
    Rafael J Wysocki, Mika Westerberg and Kirill A Shutemov.

 2) ACPI core code cleanups and dock station support cleanups from
    Jiang Liu and Rafael J Wysocki.

 3) Fixes for locking problems related to ACPI device hotplug from
    Rafael J Wysocki.

 4) ACPICA update to version 20130725 includig fixes, cleanups, support
    for more than 256 GPEs per GPE block and a change to make the ACPI
    PM Timer optional (we've seen systems without the PM Timer in the
    field already).  One of the fixes, related to the DeRefOf operator,
    is necessary to prevent some Windows 8 oriented AML from causing
    problems to happen.  From Bob Moore, Lv Zheng, and Jung-uk Kim.

 5) Removal of the old and long deprecated /proc/acpi/event interface
    and related driver changes from Thomas Renninger.

 6) ACPI and Xen changes to make the reduced hardware sleep work with
    the latter from Ben Guthro.

 7) ACPI video driver cleanups and a blacklist of systems that should
    not tell the BIOS that they are compatible with Windows 8 (or ACPI
    backlight and possibly other things will not work on them).  From
    Felipe Contreras.

 8) Assorted ACPI fixes and cleanups from Aaron Lu, Hanjun Guo,
    Kuppuswamy Sathyanarayanan, Lan Tianyu, Sachin Kamat, Tang Chen,
    Toshi Kani, and Wei Yongjun.

 9) cpufreq ondemand governor target frequency selection change to
    reduce oscillations between min and max frequencies (essentially,
    it causes the governor to choose target frequencies proportional
    to load) from Stratos Karafotis.

10) cpufreq fixes allowing sysfs attributes file permissions to be
    preserved over suspend/resume cycles Srivatsa S Bhat.

11) Removal of Device Tree parsing for CPU device nodes from multiple
    cpufreq drivers that required some changes related to
    of_get_cpu_node() to be made in a few architectures and in the
    driver core.  From Sudeep KarkadaNagesha.

12) cpufreq core fixes and cleanups related to mutual exclusion and
    driver module references from Viresh Kumar, Lukasz Majewski and
    Rafael J Wysocki.

13) Assorted cpufreq fixes and cleanups from Amit Daniel Kachhap,
    Bartlomiej Zolnierkiewicz, Hanjun Guo, Jingoo Han, Joseph Lo,
    Julia Lawall, Li Zhong, Mark Brown, Sascha Hauer, Stephen Boyd,
    Stratos Karafotis, and Viresh Kumar.

14) Fixes to prevent race conditions in coupled cpuidle from happening
    from Colin Cross.

15) cpuidle core fixes and cleanups from Daniel Lezcano and
    Tuukka Tikkanen.

16) Assorted cpuidle fixes and cleanups from Daniel Lezcano,
    Geert Uytterhoeven, Jingoo Han, Julia Lawall, Linus Walleij,
    and Sahara.

17) System sleep tracing changes from Todd E Brandt and Shuah Khan.

18) PNP subsystem conversion to using struct dev_pm_ops for power
    management from Shuah Khan.

* tag 'pm+acpi-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (217 commits)
  cpufreq: Don't use smp_processor_id() in preemptible context
  cpuidle: coupled: fix race condition between pokes and safe state
  cpuidle: coupled: abort idle if pokes are pending
  cpuidle: coupled: disable interrupts after entering safe state
  ACPI / hotplug: Remove containers synchronously
  driver core / ACPI: Avoid device hot remove locking issues
  cpufreq: governor: Fix typos in comments
  cpufreq: governors: Remove duplicate check of target freq in supported range
  cpufreq: Fix timer/workqueue corruption due to double queueing
  ACPI / EC: Add ASUSTEK L4R to quirk list in order to validate ECDT
  ACPI / thermal: Add check of "_TZD" availability and evaluating result
  cpufreq: imx6q: Fix clock enable balance
  ACPI: blacklist win8 OSI for buggy laptops
  cpufreq: tegra: fix the wrong clock name
  cpuidle: Change struct menu_device field types
  cpuidle: Add a comment warning about possible overflow
  cpuidle: Fix variable domains in get_typical_interval()
  cpuidle: Fix menu_device->intervals type
  cpuidle: CodingStyle: Break up multiple assignments on single line
  cpuidle: Check called function parameter in get_typical_interval()
  ...
2013-09-03 15:59:39 -07:00
Rafael J. Wysocki 09198f8fef Merge branch 'cpu_of_node' of git://linux-arm.org/linux-skn into pm-cpufreq-next
Pull DT/core/cpufreq cpu_ofnode updates for v3.12 from Sudeep KarkadaNagesha.

* 'cpu_of_node' of git://linux-arm.org/linux-skn:
  cpufreq: pmac32-cpufreq: remove device tree parsing for cpu nodes
  cpufreq: pmac64-cpufreq: remove device tree parsing for cpu nodes
  cpufreq: maple-cpufreq: remove device tree parsing for cpu nodes
  cpufreq: arm_big_little: remove device tree parsing for cpu nodes
  cpufreq: kirkwood-cpufreq: remove device tree parsing for cpu nodes
  cpufreq: spear-cpufreq: remove device tree parsing for cpu nodes
  cpufreq: highbank-cpufreq: remove device tree parsing for cpu nodes
  cpufreq: cpufreq-cpu0: remove device tree parsing for cpu nodes
  cpufreq: imx6q-cpufreq: remove device tree parsing for cpu nodes
  drivers/bus: arm-cci: avoid parsing DT for cpu device nodes
  ARM: mvebu: remove device tree parsing for cpu nodes
  ARM: topology: remove hwid/MPIDR dependency from cpu_capacity
  of/device: add helper to get cpu device node from logical cpu index
  driver/core: cpu: initialize of_node in cpu's device struture
  ARM: DT/kernel: define ARM specific arch_match_cpu_phys_id
  of: move of_get_cpu_node implementation to DT core library
  powerpc: refactor of_get_cpu_node to support other architectures
  openrisc: remove undefined of_get_cpu_node declaration
  microblaze: remove undefined of_get_cpu_node declaration
2013-08-23 00:57:19 +02:00
Sudeep KarkadaNagesha f837a9b5ab cpufreq: cpufreq-cpu0: remove device tree parsing for cpu nodes
Now that the cpu device registration initialises the of_node(if available)
appropriately for all the cpus, parsing here is redundant.

This patch removes all DT parsing and uses cpu->of_node instead.

Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
2013-08-21 10:29:53 +01:00
Mark Brown 4a511de96d cpufreq: cpufreq-cpu0: NULL is a valid regulator
Since NULL could in theory be a valid regulator we ought to check for
IS_ERR() rather than for NULL. In practice this is unlikely to be an
issue but it's better for neatness.

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-08-14 22:24:22 +02:00
Mark Brown 7d748971c0 cpufreq: cpufreq-cpu0: Use devm_regulator_get_optional()
Since the cpufreq-cpu0 driver is capable of coping without a software
controllable regulator and would be confused by a dummy one it should
use devm_regulator_get_optional() to ensure no dummy is provided.

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-08-13 17:07:44 +01:00
Guennadi Liakhovetski 0ca6843655 cpufreq: cpufreq-cpu0: use the exact frequency for clk_set_rate()
clk_set_rate() isn't supposed to accept approximate frequencies, instead
a supported frequency should be obtained from clk_round_rate() and then
used to set the clock.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-05 13:51:29 +02:00
Viresh Kumar 5aaa9cc7ab cpufreq: cpufreq-cpu0: Free parent node for error cases
We are freeing parent node in success cases but not in failure cases.
Let's do it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-12 14:04:16 +02:00
Nishanth Menon fc31d6f559 cpufreq: cpufreq-cpu0: defer probe when regulator is not ready
With commit 1e4b545, regulator_get will now return -EPROBE_DEFER
when the cpu0-supply node is present, but the regulator is not yet
registered.

It is possible for this to occur when the regulator registration
by itself might be defered due to some dependent interface not yet
instantiated. For example: an regulator which uses I2C and GPIO might
need both systems available before proceeding, in this case, the
regulator might defer it's registration.

However, the cpufreq-cpu0 driver assumes that any un-successful
return result is equivalent of failure.

When the regulator_get returns failure other than -EPROBE_DEFER, it
makes sense to assume that supply node is not present and proceed
with the assumption that only clock control is necessary in the
platform.

With this change, we can now handle the following conditions:
 a) cpu0-supply binding is not present, regulator_get will return
    appropriate error result, resulting in cpufreq-cpu0 driver
    controlling just the clock.
 b) cpu0-supply binding is present, regulator_get returns
    -EPROBE_DEFER, we retry resulting in cpufreq-cpu0 driver
    registering later once the regulator is available.
 c) cpu0-supply binding is present, regulator_get returns
    -EPROBE_DEFER, however, regulator never registers, we retry until
    cpufreq-cpu0 driver fails to register pointing at device tree
    information bug. However, in this case, the fact that
    cpufreq-cpu0 operates with clock only when the DT binding clearly
    indicates need of a supply is a bug of it's own.
 d) cpu0-supply gets an regulator at probe - cpufreq-cpu0 driver
    controls both the clock and regulator

Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-12 14:04:16 +02:00