thermal: cpu_cooling: introduce of_cpufreq_cooling_register

This patch introduces an API to register cpufreq cooling device
based on device tree node.

The registration via device tree node differs from normal
registration due to the fact that it is needed to fill
the device_node structure in order to be able to match
the cooling devices with trip points.

Cc: Zhang Rui <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Eduardo Valentin <[e-mail]>

drivers/thermal/Kconfig

···
 config CPU_THERMAL
 	bool "generic cpu cooling support"
 	depends on CPU_FREQ
+	depends on THERMAL_OF
 	help
 	  This implements the generic cpu cooling mechanism through frequency
 	  reduction. An ACPI version of this already exists

drivers/thermal/cpu_cooling.c

···
 };
 
 /**
- * cpufreq_cooling_register - function to create cpufreq cooling device.
+ * __cpufreq_cooling_register - helper function to create cpufreq cooling device
+ * @np: a valid struct device_node to the cooling device device tree node
  * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
  *
  * This interface function registers the cpufreq cooling device with the name
  * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
- * cooling devices.
+ * cooling devices. It also gives the opportunity to link the cooling device
+ * with a device tree node, in order to bind it via the thermal DT code.
  *
  * Return: a valid struct thermal_cooling_device pointer on success,
  * on failure, it returns a corresponding ERR_PTR().
  */
-struct thermal_cooling_device *
-cpufreq_cooling_register(const struct cpumask *clip_cpus)
+static struct thermal_cooling_device *
+__cpufreq_cooling_register(struct device_node *np,
+			   const struct cpumask *clip_cpus)
 {
 	struct thermal_cooling_device *cool_dev;
 	struct cpufreq_cooling_device *cpufreq_dev = NULL;
···
 	snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
 		 cpufreq_dev->id);
 
-	cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
-						   &cpufreq_cooling_ops);
+	cool_dev = thermal_of_cooling_device_register(np, dev_name, cpufreq_dev,
+						      &cpufreq_cooling_ops);
 	if (IS_ERR(cool_dev)) {
 		release_idr(&cpufreq_idr, cpufreq_dev->id);
 		kfree(cpufreq_dev);
···
 
 	return cool_dev;
 }
+
+/**
+ * cpufreq_cooling_register - function to create cpufreq cooling device.
+ * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
+ *
+ * This interface function registers the cpufreq cooling device with the name
+ * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
+ * cooling devices.
+ *
+ * Return: a valid struct thermal_cooling_device pointer on success,
+ * on failure, it returns a corresponding ERR_PTR().
+ */
+struct thermal_cooling_device *
+cpufreq_cooling_register(const struct cpumask *clip_cpus)
+{
+	return __cpufreq_cooling_register(NULL, clip_cpus);
+}
 EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
+
+/**
+ * of_cpufreq_cooling_register - function to create cpufreq cooling device.
+ * @np: a valid struct device_node to the cooling device device tree node
+ * @clip_cpus: cpumask of cpus where the frequency constraints will happen.
+ *
+ * This interface function registers the cpufreq cooling device with the name
+ * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
+ * cooling devices. Using this API, the cpufreq cooling device will be
+ * linked to the device tree node provided.
+ *
+ * Return: a valid struct thermal_cooling_device pointer on success,
+ * on failure, it returns a corresponding ERR_PTR().
+ */
+struct thermal_cooling_device *
+of_cpufreq_cooling_register(struct device_node *np,
+			    const struct cpumask *clip_cpus)
+{
+	if (!np)
+		return ERR_PTR(-EINVAL);
+
+	return __cpufreq_cooling_register(np, clip_cpus);
+}
+EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
 
 /**
  * cpufreq_cooling_unregister - function to remove cpufreq cooling device.

include/linux/cpu_cooling.h

···
 #ifndef __CPU_COOLING_H__
 #define __CPU_COOLING_H__
 
+#include <linux/of.h>
 #include <linux/thermal.h>
 #include <linux/cpumask.h>
 
···
 cpufreq_cooling_register(const struct cpumask *clip_cpus);
 
 /**
+ * of_cpufreq_cooling_register - create cpufreq cooling device based on DT.
+ * @np: a valid struct device_node to the cooling device device tree node.
+ * @clip_cpus: cpumask of cpus where the frequency constraints will happen
+ */
+#ifdef CONFIG_THERMAL_OF
+struct thermal_cooling_device *
+of_cpufreq_cooling_register(struct device_node *np,
+			    const struct cpumask *clip_cpus);
+#else
+static inline struct thermal_cooling_device *
+of_cpufreq_cooling_register(struct device_node *np,
+			    const struct cpumask *clip_cpus)
+{
+	return NULL;
+}
+#endif
+
+/**
  * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
  * @cdev: thermal cooling device pointer.
  */
···
 #else /* !CONFIG_CPU_THERMAL */
 static inline struct thermal_cooling_device *
 cpufreq_cooling_register(const struct cpumask *clip_cpus)
+{
+	return NULL;
+}
+static inline struct thermal_cooling_device *
+of_cpufreq_cooling_register(struct device_node *np,
+			    const struct cpumask *clip_cpus)
 {
 	return NULL;
 }