cpufreq: Introduce ->ready() callback for cpufreq drivers

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 ->ready()
callback.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Eduardo Valentin <edubezval@gmail.com>
Tested-by: Eduardo Valentin <edubezval@gmail.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 9 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index de2c3e198b62..a09a29c312a9 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->ready)
+                cpufreq_driver->ready(policy);
+
         pr_debug("initialization complete\n");
 
         return 0;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index db3c13085671..4d078cebafd2 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            (*ready)(struct cpufreq_policy *policy);
+
         struct freq_attr **attr;
 
         /* platform specific boost support code */