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>
diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index 0faf756..bb7b308 100644
--- a/drivers/cpufreq/cpufreq-cpu0.c
+++ b/drivers/cpufreq/cpufreq-cpu0.c
@@ -30,11 +30,6 @@
 static struct regulator *cpu_reg;
 static struct cpufreq_frequency_table *freq_table;
 
-static unsigned int cpu0_get_speed(unsigned int cpu)
-{
-	return clk_get_rate(cpu_clk) / 1000;
-}
-
 static int cpu0_set_target(struct cpufreq_policy *policy, unsigned int index)
 {
 	struct dev_pm_opp *opp;
@@ -100,6 +95,7 @@
 
 static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
 {
+	policy->clk = cpu_clk;
 	return cpufreq_generic_init(policy, freq_table, transition_latency);
 }
 
@@ -107,7 +103,7 @@
 	.flags = CPUFREQ_STICKY,
 	.verify = cpufreq_generic_frequency_table_verify,
 	.target_index = cpu0_set_target,
-	.get = cpu0_get_speed,
+	.get = cpufreq_generic_get,
 	.init = cpu0_cpufreq_init,
 	.exit = cpufreq_generic_exit,
 	.name = "generic_cpu0",