cpufreq: scmi: Prepare to move OF parsing of domain-id to cpufreq

The OF parsing of the clock domain specifier seems to better belong in the
scmi cpufreq driver, rather than being implemented behind the generic
->device_domain_id() perf protocol ops.

To prepare to remove the ->device_domain_id() ops, let's implement the OF
parsing in the scmi cpufreq driver instead.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20230825112633.236607-4-ulf.hansson@linaro.orgSigned-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/cpufreq/scmi-cpufreq.c

@@ -70,13 +70,24 @@ static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
 	return 0;
 }
 
+static int scmi_cpu_domain_id(struct device *cpu_dev)
+{
+	struct of_phandle_args clkspec;
+
+	if (of_parse_phandle_with_args(cpu_dev->of_node, "clocks",
+				       "#clock-cells", 0, &clkspec))
+		return -EINVAL;
+
+	return clkspec.args[0];
+}
+
 static int
 scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
 {
 	int cpu, domain, tdomain;
 	struct device *tcpu_dev;
 
-	domain = perf_ops->device_domain_id(cpu_dev);
+	domain = scmi_cpu_domain_id(cpu_dev);
 	if (domain < 0)
 		return domain;
 
@@ -88,7 +99,7 @@ scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
 		if (!tcpu_dev)
 			continue;
 
-		tdomain = perf_ops->device_domain_id(tcpu_dev);
+		tdomain = scmi_cpu_domain_id(tcpu_dev);
 		if (tdomain == domain)
 			cpumask_set_cpu(cpu, cpumask);
 	}
@@ -104,7 +115,7 @@ scmi_get_cpu_power(struct device *cpu_dev, unsigned long *power,
 	unsigned long Hz;
 	int ret, domain;
 
-	domain = perf_ops->device_domain_id(cpu_dev);
+	domain = scmi_cpu_domain_id(cpu_dev);
 	if (domain < 0)
 		return domain;
 
@@ -209,7 +220,7 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy)
 	}
 
 	priv->cpu_dev = cpu_dev;
-	priv->domain_id = perf_ops->device_domain_id(cpu_dev);
+	priv->domain_id = scmi_cpu_domain_id(cpu_dev);
 
 	policy->driver_data = priv;
 	policy->freq_table = freq_table;