powercap/drivers/dtpm: Add CPU DT initialization support

Based on the previous DT changes in the core code, use the 'setup'
callback to initialize the CPU DTPM backend.

Code is reorganized to stick to the DTPM table description. No
functional changes.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20220128163537.212248-4-daniel.lezcano@linaro.org

Author: dlezcano

drivers/powercap/dtpm_cpu.c

@@ -21,6 +21,7 @@
 #include <linux/cpuhotplug.h>
 #include <linux/dtpm.h>
 #include <linux/energy_model.h>
+#include <linux/of.h>
 #include <linux/pm_qos.h>
 #include <linux/slab.h>
 #include <linux/units.h>
@@ -176,13 +177,28 @@ static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
 }
 
 static int cpuhp_dtpm_cpu_online(unsigned int cpu)
+{
+	struct dtpm_cpu *dtpm_cpu;
+
+	dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
+	if (dtpm_cpu)
+		return dtpm_update_power(&dtpm_cpu->dtpm);
+
+	return 0;
+}
+
+static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
 {
 	struct dtpm_cpu *dtpm_cpu;
 	struct cpufreq_policy *policy;
 	struct em_perf_domain *pd;
 	char name[CPUFREQ_NAME_LEN];
 	int ret = -ENOMEM;
 
+	dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
+	if (dtpm_cpu)
+		return 0;
+
 	policy = cpufreq_cpu_get(cpu);
 	if (!policy)
 		return 0;
@@ -191,10 +207,6 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
 	if (!pd)
 		return -EINVAL;
 
-	dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
-	if (dtpm_cpu)
-		return dtpm_update_power(&dtpm_cpu->dtpm);
-
 	dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
 	if (!dtpm_cpu)
 		return -ENOMEM;
@@ -207,7 +219,7 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
 
 	snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu);
 
-	ret = dtpm_register(name, &dtpm_cpu->dtpm, NULL);
+	ret = dtpm_register(name, &dtpm_cpu->dtpm, parent);
 	if (ret)
 		goto out_kfree_dtpm_cpu;
 
@@ -231,7 +243,18 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
 	return ret;
 }
 
-static int __init dtpm_cpu_init(void)
+static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np)
+{
+	int cpu;
+
+	cpu = of_cpu_node_to_id(np);
+	if (cpu < 0)
+		return 0;
+
+	return __dtpm_cpu_setup(cpu, dtpm);
+}
+
+static int dtpm_cpu_init(void)
 {
 	int ret;
 
@@ -272,4 +295,5 @@ static int __init dtpm_cpu_init(void)
 struct dtpm_subsys_ops dtpm_cpu_ops = {
 	.name = KBUILD_MODNAME,
 	.init = dtpm_cpu_init,
+	.setup = dtpm_cpu_setup,
 };