cpufreq: imx6q: Use auto-registration of thermal cooling device

Use the CPUFREQ_IS_COOLING_DEV flag to allow cpufreq core to
automatically register as a thermal cooling device.

This allows removal of boiler plate code from the driver.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/imx6q-cpufreq.c

@@ -9,7 +9,6 @@
 #include <linux/clk.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
-#include <linux/cpu_cooling.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/nvmem-consumer.h>
@@ -52,7 +51,6 @@ static struct clk_bulk_data clks[] = {
 };
 
 static struct device *cpu_dev;
-static struct thermal_cooling_device *cdev;
 static bool free_opp;
 static struct cpufreq_frequency_table *freq_table;
 static unsigned int max_freq;
@@ -193,16 +191,6 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
 	return 0;
 }
 
-static void imx6q_cpufreq_ready(struct cpufreq_policy *policy)
-{
-	cdev = of_cpufreq_cooling_register(policy);
-
-	if (!cdev)
-		dev_err(cpu_dev,
-			"running cpufreq without cooling device: %ld\n",
-			PTR_ERR(cdev));
-}
-
 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 {
 	int ret;
@@ -214,22 +202,14 @@ static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 	return ret;
 }
 
-static int imx6q_cpufreq_exit(struct cpufreq_policy *policy)
-{
-	cpufreq_cooling_unregister(cdev);
-
-	return 0;
-}
-
 static struct cpufreq_driver imx6q_cpufreq_driver = {
-	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
+		 CPUFREQ_IS_COOLING_DEV,
 	.verify = cpufreq_generic_frequency_table_verify,
 	.target_index = imx6q_set_target,
 	.get = cpufreq_generic_get,
 	.init = imx6q_cpufreq_init,
-	.exit = imx6q_cpufreq_exit,
 	.name = "imx6q-cpufreq",
-	.ready = imx6q_cpufreq_ready,
 	.attr = cpufreq_generic_attr,
 	.suspend = cpufreq_generic_suspend,
 };