cpufreq: dt: Identify cpu-sharing for platforms without operating-points-v2

Existing platforms, which do not support operating-points-v2, can
explicitly tell the opp core that some of the CPUs share opp tables,
with help of dev_pm_opp_set_sharing_cpus().

For such platforms, explicitly ask the opp core to provide list of CPUs
sharing the opp table with current cpu device, before falling back to
platform data.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq-dt.c

@@ -147,7 +147,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 	struct clk *cpu_clk;
 	struct dev_pm_opp *suspend_opp;
 	unsigned int transition_latency;
-	bool opp_v1 = false;
+	bool fallback = false;
 	const char *name;
 	int ret;
 
@@ -167,14 +167,16 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 	/* Get OPP-sharing information from "operating-points-v2" bindings */
 	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 	if (ret) {
+		if (ret != -ENOENT)
+			goto out_put_clk;
+
 		/*
 		 * operating-points-v2 not supported, fallback to old method of
-		 * finding shared-OPPs for backward compatibility.
+		 * finding shared-OPPs for backward compatibility if the
+		 * platform hasn't set sharing CPUs.
 		 */
-		if (ret == -ENOENT)
-			opp_v1 = true;
-		else
-			goto out_put_clk;
+		if (dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus))
+			fallback = true;
 	}
 
 	/*
@@ -214,7 +216,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 		goto out_free_opp;
 	}
 
-	if (opp_v1) {
+	if (fallback) {
 		struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 
 		if (!pd || !pd->independent_clocks)