cpufreq: tegra124: Allow building as a module

This requires four changes:
* Using the cpufreq-dt register helper to establish a hard dependency
  for depmod to track
* Adding a remove routine to remove the cpufreq-dt device
* Adding a exit routine to handle cleaning up the driver
* Populating module license

Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Author: webgeek1234

drivers/cpufreq/Kconfig.arm

@@ -237,7 +237,7 @@ config ARM_TEGRA20_CPUFREQ
 	  This adds the CPUFreq driver support for Tegra20/30 SOCs.
 
 config ARM_TEGRA124_CPUFREQ
-	bool "Tegra124 CPUFreq support"
+	tristate "Tegra124 CPUFreq support"
 	depends on ARCH_TEGRA || COMPILE_TEST
 	depends on CPUFREQ_DT
 	default ARCH_TEGRA

drivers/cpufreq/tegra124-cpufreq.c

@@ -16,6 +16,10 @@
 #include <linux/pm_opp.h>
 #include <linux/types.h>
 
+#include "cpufreq-dt.h"
+
+static struct platform_device *tegra124_cpufreq_pdev;
+
 struct tegra124_cpufreq_priv {
 	struct clk *cpu_clk;
 	struct clk *pllp_clk;
@@ -55,7 +59,6 @@ static int tegra124_cpufreq_probe(struct platform_device *pdev)
 	struct device_node *np __free(device_node) = of_cpu_device_node_get(0);
 	struct tegra124_cpufreq_priv *priv;
 	struct device *cpu_dev;
-	struct platform_device_info cpufreq_dt_devinfo = {};
 	int ret;
 
 	if (!np)
@@ -95,11 +98,7 @@ static int tegra124_cpufreq_probe(struct platform_device *pdev)
 	if (ret)
 		goto out_put_pllp_clk;
 
-	cpufreq_dt_devinfo.name = "cpufreq-dt";
-	cpufreq_dt_devinfo.parent = &pdev->dev;
-
-	priv->cpufreq_dt_pdev =
-		platform_device_register_full(&cpufreq_dt_devinfo);
+	priv->cpufreq_dt_pdev = cpufreq_dt_pdev_register(&pdev->dev);
 	if (IS_ERR(priv->cpufreq_dt_pdev)) {
 		ret = PTR_ERR(priv->cpufreq_dt_pdev);
 		goto out_put_pllp_clk;
@@ -173,6 +172,21 @@ static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
 	return err;
 }
 
+static void tegra124_cpufreq_remove(struct platform_device *pdev)
+{
+	struct tegra124_cpufreq_priv *priv = dev_get_drvdata(&pdev->dev);
+
+	if (!IS_ERR(priv->cpufreq_dt_pdev)) {
+		platform_device_unregister(priv->cpufreq_dt_pdev);
+		priv->cpufreq_dt_pdev = ERR_PTR(-ENODEV);
+	}
+
+	clk_put(priv->pllp_clk);
+	clk_put(priv->pllx_clk);
+	clk_put(priv->dfll_clk);
+	clk_put(priv->cpu_clk);
+}
+
 static const struct dev_pm_ops tegra124_cpufreq_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(tegra124_cpufreq_suspend,
 				tegra124_cpufreq_resume)
@@ -182,12 +196,12 @@ static struct platform_driver tegra124_cpufreq_platdrv = {
 	.driver.name	= "cpufreq-tegra124",
 	.driver.pm	= &tegra124_cpufreq_pm_ops,
 	.probe		= tegra124_cpufreq_probe,
+	.remove		= tegra124_cpufreq_remove,
 };
 
 static int __init tegra_cpufreq_init(void)
 {
 	int ret;
-	struct platform_device *pdev;
 
 	if (!(of_machine_is_compatible("nvidia,tegra124") ||
 		of_machine_is_compatible("nvidia,tegra210")))
@@ -201,15 +215,25 @@ static int __init tegra_cpufreq_init(void)
 	if (ret)
 		return ret;
 
-	pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
-	if (IS_ERR(pdev)) {
+	tegra124_cpufreq_pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
+	if (IS_ERR(tegra124_cpufreq_pdev)) {
 		platform_driver_unregister(&tegra124_cpufreq_platdrv);
-		return PTR_ERR(pdev);
+		return PTR_ERR(tegra124_cpufreq_pdev);
 	}
 
 	return 0;
 }
 module_init(tegra_cpufreq_init);
 
+static void __exit tegra_cpufreq_module_exit(void)
+{
+	if (!IS_ERR_OR_NULL(tegra124_cpufreq_pdev))
+		platform_device_unregister(tegra124_cpufreq_pdev);
+
+	platform_driver_unregister(&tegra124_cpufreq_platdrv);
+}
+module_exit(tegra_cpufreq_module_exit);
+
 MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
 MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
+MODULE_LICENSE("GPL");