cpufreq: mediatek: Unregister platform device on exit

stable inclusion
from stable-v5.10.121
commit ec5ded7acb38c0084ce1e060517a725e3c12c6b8
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6CQ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ec5ded7acb38c0084ce1e060517a725e3c12c6b8

--------------------------------

[ Upstream commit f126fbad ]

We register the platform device when driver inits. However, we do not
unregister it when driver exits.

To resolve this, we declare the platform data to be a global static
variable and rename it to be "cpufreq_pdev". With this global variable,
we can do platform_device_unregister() when driver exits.

Fixes: 501c574f ("cpufreq: mediatek: Add support of cpufreq to MT2701/MT7623 SoC")
Signed-off-by: NRex-BC Chen <rex-bc.chen@mediatek.com>
[ Viresh: Commit log and Subject ]
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/cpufreq/mediatek-cpufreq.c

@@ -44,6 +44,8 @@ struct mtk_cpu_dvfs_info {
 	bool need_voltage_tracking;
 };
 
+static struct platform_device *cpufreq_pdev;
+
 static LIST_HEAD(dvfs_info_list);
 
 static struct mtk_cpu_dvfs_info *mtk_cpu_dvfs_info_lookup(int cpu)
@@ -546,7 +548,6 @@ static int __init mtk_cpufreq_driver_init(void)
 {
 	struct device_node *np;
 	const struct of_device_id *match;
-	struct platform_device *pdev;
 	int err;
 
 	np = of_find_node_by_path("/");
@@ -570,11 +571,11 @@ static int __init mtk_cpufreq_driver_init(void)
 	 * and the device registration codes are put here to handle defer
 	 * probing.
 	 */
-	pdev = platform_device_register_simple("mtk-cpufreq", -1, NULL, 0);
-	if (IS_ERR(pdev)) {
+	cpufreq_pdev = platform_device_register_simple("mtk-cpufreq", -1, NULL, 0);
+	if (IS_ERR(cpufreq_pdev)) {
 		pr_err("failed to register mtk-cpufreq platform device\n");
 		platform_driver_unregister(&mtk_cpufreq_platdrv);
-		return PTR_ERR(pdev);
+		return PTR_ERR(cpufreq_pdev);
 	}
 
 	return 0;
@@ -583,6 +584,7 @@ module_init(mtk_cpufreq_driver_init)
 
 static void __exit mtk_cpufreq_driver_exit(void)
 {
+	platform_device_unregister(cpufreq_pdev);
 	platform_driver_unregister(&mtk_cpufreq_platdrv);
 }
 module_exit(mtk_cpufreq_driver_exit)