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cpufreq: Add doc style comment about cpufreq_cpu_{get|put}()

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This clearly states what the code inside these routines is doing and how these
must be used.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar 2015-02-19 17:02:03 +05:30 committed by Rafael J. Wysocki
parent f133d08a39
commit 50e9c85213
1 changed files with 27 additions and 0 deletions
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27
drivers/cpufreq/cpufreq.c
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@ -207,6 +207,23 @@ struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
return per_cpu(cpufreq_cpu_data, cpu);
}
/**
* cpufreq_cpu_get: returns policy for a cpu and marks it busy.
*
* @cpu: cpu to find policy for.
*
* This returns policy for 'cpu', returns NULL if it doesn't exist.
* It also increments the kobject reference count to mark it busy and so would
* require a corresponding call to cpufreq_cpu_put() to decrement it back.
* If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
* freed as that depends on the kobj count.
*
* It also takes a read-lock of 'cpufreq_rwsem' and doesn't put it back if a
* valid policy is found. This is done to make sure the driver doesn't get
* unregistered while the policy is being used.
*
* Return: A valid policy on success, otherwise NULL on failure.
*/
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
{
struct cpufreq_policy *policy = NULL;
@ -237,6 +254,16 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
/**
* cpufreq_cpu_put: Decrements the usage count of a policy
*
* @policy: policy earlier returned by cpufreq_cpu_get().
*
* This decrements the kobject reference count incremented earlier by calling
* cpufreq_cpu_get().
*
* It also drops the read-lock of 'cpufreq_rwsem' taken at cpufreq_cpu_get().
*/
void cpufreq_cpu_put(struct cpufreq_policy *policy)
{
kobject_put(&policy->kobj);