thermal/drivers/cpufreq_cooling: Use device name instead of auto-numbering

Currently the naming of a cooling device is just a cooling technique
followed by a number. When there are multiple cooling devices using
the same technique, it is impossible to clearly identify the related
device as this one is just a number.

For instance:

 thermal-cpufreq-0
 thermal-cpufreq-1
 etc ...

The 'thermal' prefix is redundant with the subsystem namespace. This
patch removes the 'thermal' prefix and changes the number by the device
name. So the naming above becomes:

 cpufreq-cpu0
 cpufreq-cpu4
 etc ...
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lore.kernel.org/r/20210314111333.16551-2-daniel.lezcano@linaro.org

drivers/thermal/cpufreq_cooling.c

@@ -13,10 +13,10 @@
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/cpu_cooling.h>
+#include <linux/device.h>
 #include <linux/energy_model.h>
 #include <linux/err.h>
 #include <linux/export.h>
-#include <linux/idr.h>
 #include <linux/pm_opp.h>
 #include <linux/pm_qos.h>
 #include <linux/slab.h>
@@ -50,8 +50,6 @@ struct time_in_idle {
 
 /**
  * struct cpufreq_cooling_device - data for cooling device with cpufreq
- * @id: unique integer value corresponding to each cpufreq_cooling_device
- *	registered.
  * @last_load: load measured by the latest call to cpufreq_get_requested_power()
  * @cpufreq_state: integer value representing the current state of cpufreq
  *	cooling	devices.
@@ -69,7 +67,6 @@ struct time_in_idle {
  * cpufreq_cooling_device.
  */
 struct cpufreq_cooling_device {
-	int id;
 	u32 last_load;
 	unsigned int cpufreq_state;
 	unsigned int max_level;
@@ -82,7 +79,6 @@ struct cpufreq_cooling_device {
 	struct freq_qos_request qos_req;
 };
 
-static DEFINE_IDA(cpufreq_ida);
 static DEFINE_MUTEX(cooling_list_lock);
 static LIST_HEAD(cpufreq_cdev_list);
 
@@ -528,11 +524,11 @@ __cpufreq_cooling_register(struct device_node *np,
 {
 	struct thermal_cooling_device *cdev;
 	struct cpufreq_cooling_device *cpufreq_cdev;
-	char dev_name[THERMAL_NAME_LENGTH];
 	unsigned int i;
 	struct device *dev;
 	int ret;
 	struct thermal_cooling_device_ops *cooling_ops;
+	char *name;
 
 	dev = get_cpu_device(policy->cpu);
 	if (unlikely(!dev)) {
@@ -567,16 +563,6 @@ __cpufreq_cooling_register(struct device_node *np,
 	/* max_level is an index, not a counter */
 	cpufreq_cdev->max_level = i - 1;
 
-	ret = ida_simple_get(&cpufreq_ida, 0, 0, GFP_KERNEL);
-	if (ret < 0) {
-		cdev = ERR_PTR(ret);
-		goto free_idle_time;
-	}
-	cpufreq_cdev->id = ret;
-
-	snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
-		 cpufreq_cdev->id);
-
 	cooling_ops = &cpufreq_cooling_ops;
 
 #ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
@@ -591,7 +577,7 @@ __cpufreq_cooling_register(struct device_node *np,
 		pr_err("%s: unsorted frequency tables are not supported\n",
 		       __func__);
 		cdev = ERR_PTR(-EINVAL);
-		goto remove_ida;
+		goto free_idle_time;
 	}
 
 	ret = freq_qos_add_request(&policy->constraints,
@@ -601,11 +587,18 @@ __cpufreq_cooling_register(struct device_node *np,
 		pr_err("%s: Failed to add freq constraint (%d)\n", __func__,
 		       ret);
 		cdev = ERR_PTR(ret);
-		goto remove_ida;
+		goto free_idle_time;
 	}
 
-	cdev = thermal_of_cooling_device_register(np, dev_name, cpufreq_cdev,
+	cdev = ERR_PTR(-ENOMEM);
+	name = kasprintf(GFP_KERNEL, "cpufreq-%s", dev_name(dev));
+	if (!name)
+		goto remove_qos_req;
+
+	cdev = thermal_of_cooling_device_register(np, name, cpufreq_cdev,
 						  cooling_ops);
+	kfree(name);
+
 	if (IS_ERR(cdev))
 		goto remove_qos_req;
 
@@ -617,8 +610,6 @@ __cpufreq_cooling_register(struct device_node *np,
 
 remove_qos_req:
 	freq_qos_remove_request(&cpufreq_cdev->qos_req);
-remove_ida:
-	ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id);
 free_idle_time:
 	free_idle_time(cpufreq_cdev);
 free_cdev:
@@ -712,7 +703,6 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
 
 	thermal_cooling_device_unregister(cdev);
 	freq_qos_remove_request(&cpufreq_cdev->qos_req);
-	ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id);
 	free_idle_time(cpufreq_cdev);
 	kfree(cpufreq_cdev);
 }