Currently there is no callback for cpufreq drivers which is called once the policy is ready to be used. There are some requirements where such a callback is required.
One of them is registering a cooling device with the help of of_cpufreq_cooling_register(). This routine tries to get 'struct cpufreq_policy' for CPUs which isn't yet initialed at the time ->init() is called and so we face issues while registering the cooling device.
Because we can't register cooling device from ->init(), we need a callback that is called after the policy is ready to be used and hence we introduce ->usable() callback.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/cpufreq/cpufreq.c | 5 +++++ include/linux/cpufreq.h | 4 ++++ 2 files changed, 9 insertions(+)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index de2c3e1..4fb95b9 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1285,8 +1285,13 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) up_write(&policy->rwsem);
kobject_uevent(&policy->kobj, KOBJ_ADD); + up_read(&cpufreq_rwsem);
+ /* Callback for handling stuff after policy is ready */ + if (cpufreq_driver->usable) + cpufreq_driver->usable(policy); + pr_debug("initialization complete\n");
return 0; diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index db3c130..4795c0b 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -267,6 +267,10 @@ struct cpufreq_driver { void (*stop_cpu)(struct cpufreq_policy *policy); int (*suspend)(struct cpufreq_policy *policy); int (*resume)(struct cpufreq_policy *policy); + + /* Will be called after the driver is fully initialized */ + void (*usable)(struct cpufreq_policy *policy); + struct freq_attr **attr;
/* platform specific boost support code */