Commit Graph

6 Commits

Author SHA1 Message Date
Viresh Kumar 9076eaca60 cpufreq: arm_big_little_dt: Instantiate as platform_driver
As multiplatform build is being adopted by more and more ARM platforms, initcall
function should be used very carefully. For example, when both arm_big_little_dt
and cpufreq-cpu0 drivers are compiled in, arm_big_little_dt driver may try to
register even if we had platform device for cpufreq-cpu0 registered.

To eliminate this undesired the effect, the patch changes arm_big_little_dt
driver to have it instantiated as a platform_driver. Then it will only run on
platforms that create the platform_device "arm-bL-cpufreq-dt".

Reported-and-tested-by: Rob Herring <robherring2@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-22 12:43:33 +02:00
Viresh Kumar 92a9b5c291 cpufreq: arm_big_little_dt: Register driver only if DT has valid data
If arm_big_little_dt driver is enabled, then it will always try to register with
big LITTLE cpufreq core driver. In case DT doesn't have relevant data for cpu
nodes, i.e. operating points aren't present, then we should exit early and
shouldn't register with big LITTLE cpufreq core driver. Otherwise we will fail
continuously from the driver->init() routine.

This patch fixes this issue.

Reported-and-tested-by: Jon Medhurst <tixy@linaro.org>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-22 12:42:34 +02:00
Viresh Kumar 3c792e0fe1 cpufreq: ARM big LITTLE DT: Return CPUFREQ_ETERNAL if clock-latency isn't found
If "/cpus" node isn't present or "clock-latency" isn't defined we are
returning error currently. Let's return CPUFREQ_ETERNAL instead, so
that we don't fail.

Flag appropriate messages to user in such cases.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-12 14:04:15 +02:00
Viresh Kumar 996905f333 cpufreq: ARM big LITTLE DT: Return correct transition latency
By mistake we are returning zero for successful call to
dt_get_transition_latency(), whereas we should return
transition_latency.  Fix that.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-12 14:04:15 +02:00
Viresh Kumar 763f8c3fe4 cpufreq: ARM big LITTLE: put DT nodes after using them
DT nodes should be put using of_node_put() to balance their usage counts. This
is not done properly in ARM's big LITTLE driver. Fix it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-22 00:53:40 +02:00
Viresh Kumar 8a67f0ef2b cpufreq: ARM big LITTLE: Add generic cpufreq driver and its DT glue
big LITTLE is ARM's new Architecture focussing power/performance needs of modern
world. More information about big LITTLE can be found here:

http://www.arm.com/products/processors/technologies/biglittleprocessing.php
http://lwn.net/Articles/481055/

In order to keep cpufreq support for all big LITTLE platforms simple/generic,
this patch tries to add a generic cpufreq driver layer for all big LITTLE
platforms.

The driver is divided into two parts:
- Core driver: Generic and shared across all big LITTLE SoC's
- Glue drivers: Per platform drivers providing ops to the core driver

This patch adds in a generic glue driver which would extract information from
Device Tree.

Future SoC's can either reuse the DT glue or write their own depending on the
need.

Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-02 15:26:32 +02:00